,transcrib]'s ,note3 ,italic text delimit$ by und]scores1 bold text delimit$ by equal signs4 ,s+le und]score foll[$ by text enclos$ by braces indicates subscript4 ,c>et foll[$ by s+le "* or text enclos$ by braces text is sup]script text4 ,,riv] ,,& ,,canal ,,eng9e]+ ,by ! ,same ,au?or ,,hydraulics ,,) ,,work+ ,,tables4 ,second ,edition4 #afj illu/rations1 xii #caa pp41 #hvo 7#aiaa74 #ab_/- net4 ,,punjab ,,riv]s ,,& ,,works4 ,second ,edition4 #dg illu/rations1 viii #fd pp41 folio 7#aiab74 #h_/- net4 ,,irrigation ,,works 79 ! press74 #bg illu/rations1 vi #acj pp41 #hvo 7#aiac74 #f_/- net4 ,,! ,,suction ,,caus$ ,,by ,,%ips4 ,expla9$ 9 ,popul> ,language4 #b plates1 #bf pp41 #hvo1 sew$ 7#aiab74 #a_/- net4 ,e4 ,f4 ,n4 ,,spon1 ,,ltd41 ,,london ,,riv] ,,& ,,canal ,,eng9e]+ ,,! ,,*>act]i/ics ,,( ,,op5 ,,fl[+ ,,/reams1 ,,& ,,! ,,pr9ciples ,,& ,,me?ods ,,to ,,be ,,foll[$ ,,9 ,,deal+ ,,) ,,!m ,,by ,e4 ,s4 ,,bellasis1 ,m4,,in/4,c4,e4 ,,rec5tly ,,sup]9t5d+ ,,eng9e] ,,9 ,,! ,,irrigation ,,bran* ,,( ,,! ,,public ,,works ,,dep>tm5t ,,( ,,india #gb ,,illu/rations ,illu/ration ,london ,e4 ,f4 ,n4 ,,spon1 ,,ltd41 #eg ,,haym>ket1 ,s4,w4 ,new ,york ,,spon ,,*amb]la91 #abc ,,lib]ty ,,/reet #aiac ,,table ,,( ,,cont5ts ,,*apt] ,i ,,introduction ,,article ,,page #a4 ,prelim9>y ,rem>ks #a #b4 ,rsum ( ! ,subject #a #c4 ,design & ,execution ( ,works #c #d4 ,! ,hydraulics ( ,op5 ,/reams #d ,,*apt] ,,ii ,,ra9fall #a4 ,ra9fall ,/ati/ics #f #b4 ,available ,ra9fall #i #c4 ,measurem5t ( ,ra9fall #ac #d4 ,influ5ce ( ,=e/s & ,vegetation #ad #e4 ,heavy ,falls 9 ,%ort ,p]iods #ae ,,*apt] ,,iii ,,collection ,,( ,,in=mation ,,conc]n+ ,,/reams #a4 ,prelim9>y ,rem>ks #ah #b4 ,/ream ,gauges #ai #c4 ,plan & ,sections #ba #d4 ,dis*>ge ,obs]vations #ba #e4 ,dis*>ge ,curves & ,tables #bc #f4 ,small ,/reams #bd #g4 ,int]mitt5t ,/reams #be #h4 ,rem>ks #bf ,,*apt] ,,iv ,,! ,,silt+ ,,& ,,sc\r+ ,,action ,,( ,,/reams #a4 ,prelim9>y ,rem>ks #bg #b4 ,roll$ ,mat]ial #bi #c4 ,mat]ials c>ri$ 9 ,susp5sion #ca #d4 ,me?ods ( ,inve/igation #cc #e4 ,quantity & ,di/ribution ( ,silt #ce #f4 ,practical ,=mul & ,figures #cg #g4 ,action on ! ,sides ( a ,*annel #dj #h4 ,action at ,b5ds #db #i4 ,g5]al ,t5d5cies ( ,/reams #de ,,*apt] ,v ,,me?ods ,,( ,,increas+ ,,or ,,r$uc+ ,,silt+ ,,or ,,sc\r #a4 ,prelim9>y ,rem>ks #dh #b4 ,increase ( ,sc\r or ,r$uction ( ,silt+ #dh #c4 ,production ( ,silt ,deposit #ea #d4 ,arrangem5ts at ,bifurcations #ec #e4 ,a ,canal ) ,headworks 9 a ,riv] #ed #f4 ,protection ( ! ,b$ #eh ,,*apt] ,,vi ,,works ,,= ,,! ,,protection ,,( ,,banks #a4 ,prelim9>y ,rem>ks #fj #b4 ,spurs #fa #c4 ,cont9u\s ,l9+ ( ! ,bank #fd #d4 ,heavy ,/one ,pit*+ ) ,apron #ga ,,*apt] ,,vii ,,div]sions ,,& ,,closures ,,( ,,/reams #a4 ,div]sions #gc #b4 ,closure ( a ,fl[+ ,/ream #ge #c4 ,in/ances ( ,closures ( ,/reams #hj ,,*apt] ,,viii ,,! ,,tra9+ ,,& ,,canalisation ,,( ,,riv]s #a4 ,prelim9>y ,rem>ks #hd #b4 ,dr$g+ & ,excavat+ #hd #c4 ,r$uction ( ,wid? #he #d4 ,alt]ation ( ,dep? or ,wat]-,level #hh #e4 ,tra9+ & ,canalis+ #hi ,,*apt] ,,ix ,,canals ,,& ,,conduits #a4 ,banks #ib #b4 ,navigation ,canals #ic #c4 ,locks #if #d4 ,o!r ,artificial ,*annels #ajj ,,*apt] ,x ,,weirs ,,& ,,sluices #a4 ,prelim9>y ,rem>ks #ajb #b4 ,g5]al ,design ( a ,weir #aje #c4 ,weirs on ,s&y or ,por\s ,soil #ajf #d4 ,v>i\s ,types ( ,weirs #aaa #e4 ,weirs ) ,sluices #aae #f4 ,fall+ ,%utt]s #aba #g4 ,adju/able ,weirs #abf #h4 ,rem>ks on ,sluices #abh ,,*apt] ,,xi ,,bridges ,,& ,,syphons #a4 ,bridges #acb #b4 ,syphons & ,culv]ts #ace #c4 ,tra9+ ,works #acf ,,*apt] ,,xii ,,dra9age ,,& ,,floods #a4 ,prelim9>y ,rem>ks #ada #b4 ,small ,/reams #ada #c4 ,riv]s #adf #d4 ,pr$iction ( ,floods #aej #e4 ,prev5tion ( ,floods #aec #f4 ,l[]+ ! ,wat]-,level #aed #g4 ,flood ,embankm5ts #aef ,,*apt] ,,xiii ,,res]voirs ,,& ,,dams #a4 ,res]voirs #afb #b4 ,capacity ( ,res]voirs #afg #c4 ,e>!n ,dams #agd #d4 ,masonry ,dams #aha ,,*apt] ,,xiv ,,tidal ,,wat]s ,,& ,,works #a4 ,tides #aij #b4 ,tidal ,riv]s #aib #c4 ,works 9 ,tidal ,riv]s #aif #d4 ,tidal ,e/u>ies #aig #e4 ,works 9 ,tidal ,e/u>ies #aih ,,*apt] ,,xv ,,riv] ,,b>s #a4 ,deltaic ,riv]s #bjc #b4 ,o!r ,riv]s #bje ,,app5dix ,a4 ,fallacies 9 ! ,hydraulics ( ,/reams #bji 0 ,b4 ,pit*+ & ,b$ ,protection #bab ,,index #bac ,,preface ,! object ( ?is book is to describe ! pr9ciples & practice adopt$ 9 ! ,eng9e]+ ( ,op5 ,/reams4 ,if ! book seems to be some:at small = its object1 x w1 x is hop$1 be f\nd t ?is is due to c>e 9 ! arrangem5t & word+4 ,s\rces ( in=mation h be5 ackn[l$g$ 9 ! text1 b special m5tion may be made ( lectures giv5 by ,pr(essor ,unw9 at ,coop]s ,hill ,college1 ( ,h>c\rt's l>ge "w on ,riv]s & ,canals1 ( ! pap]s#a by ,b9nie on ra9fall1 by ,%aw on ! clos+ ( ! riv] ,ti/a1 by ,h>c\rt on movable weirs & on e/u>ies1 by ,/range on res]voirs1 & by ,ottley & ,brightmore1 ,gore & ,wilson1 & ,hill on ! /resses 9 masonry dams2 ( ! articles by ,bligh#b on weirs ) por\s f\ndations & by ,deacon#c on res]voir capacity1 ( ! ,indian ,gov]nm5t pap] by ,spr+ on 8,riv] ,control on ! ,guide ,bank ,sy/em10 & ( ! ,punjab ,gov]nm5t pap] conta9+ ,k5n$y's rem>ks on silt+ & sc\r 9 ! ,sirh9d ,canal4 ,! two pap]s la/ m5tion$ are n easily accessible1 & !y conta9 matt] ( great int]e/4 ,! important po9ts1 (t5 obscur$ by masses ( detail or figures1 h be5 extract$4#d ,silt+ & sc\r 7,,*ap4 ,,iv47 _h already be5 dealt ) 9 ,hydraulics1#e b "s fur!r in=mation has s9ce come to light & ! subject has be5 treat$ afre% & ! matt] re-writt54 ,e4 ,s4 ,b4 ,,*elt5ham1 #a/ ,may #aiac4 ,,riv] ,,& ,,canal ,,eng9e]+ ,,*apt] ,i ,,introduction #a4 ,prelim9>y ,rem>ks4--,riv] & ,canal ,eng9e]+ is t bran* ( eng9e]+ sci5ce :i* deals ) ! *>act]i/ics ( /reams fl[+ 9 op5 *annels1 & ) ! pr9ciples & me?ods :i* %\ld be foll[$ 9 deal+ )1 alt]+1 & controll+ !m4 ,x is n necess>y to make a g5]al di/9ction betwe5 natural & artificial /reams2 "s irrigation canals or o!r artificial *annels are z l>ge z riv]s & h _m ( ! same *>act]i/ics4 ,any special rem>ks applicable to ei!r class w be giv5 z occasion requires4 #b4 ,rsum ( ! ,subject4--,,*ap4 ,,ii4 ( ?is book deals ) ! collection ( in=mation conc]n+ /reams1 a proc$ure :i* is necess>y be=e any consid]able "w 9 connection ) a /ream c be und]tak51 & (t5 be=e x c ev5 be decid$ :e!r or n x is to be und]tak54 ,,*ap4 ,,iii4 deals ) ra9fall1 & describes h[ ra9fall figures & /ati/ics c be utilis$ by ! eng9e] 9 deal+ ) /reams4 ,,*ap4 ,,iv4 expla9s ! laws ( silt+ & sc\r+ action1 a subject ( great importance & "o to :i* ! att5tion ord9>ily giv5 is insuffici5t4 ,! g5]al *>act]i/ics ( /reams1 be+ due entirely to silt+ or sc\r+ t5d5cies1 are includ$ 9 ?is *apt]4 ,,*ap4 ,v4 describes h[ silt+ or sc\r+ may be1 "u "s circum/ances1 artificially induc$ or ret>d$4 ,,*ap4 ,,vi4 deals ) v>i\s me?ods ( protect+ banks aga9/ erosion or damage4 ,,*ap4 ,,vii4 treats ( div]sions or ! op5+ out ( new *annels1 & ) ! opposite ( ?is1 viz4 ! clos+ ( *annels1 a feat :i*1 :5 ! /ream is fl[+1 is sometimes v difficult to a*ieve4 ,?is *apt] also deals ) dr$g+ & excavation4 ,,*ap4 ,,viii4 discusses ! subject ( ! tra9+ ( /reams1 a class ( "w :i* is g5]ally und]tak5 9 ord] to make !m navigable or to improve _! exi/+ capacities = navigation1 b may be und]tak5 = o!r reasons4 ,! ma9 features ( ?is k9d ( "w are ! n>r[+ & deep5+ ( ! /ream1 (t5 ! r$uction ( ! velocity & slope1 & g5]ally ! rais+ ( ! wat]-level4 ,9 ?is k9d ( "w a *annel may be completely remodell$ & ev5 new rea*es con/ruct$4 ,,*ap4 ,,ix4 deals ) artificial *annels ( e>? or masonry1 & includes navigation canals4#f ,9 ,,*aps4 ,x4 & ,,xi4 ! *ief masonry works or isolat$ /ructures--z di/+ui%$ f g5]al works :i* ext5d ov] consid]able l5g?s ( *annel--are dealt )1 & ^? pr9ciples ( design discuss$ :i* affect ! works 9 _! hydraulic capacities4 ,g5]al pr9ciples ( design applicable to all k9ds ( works1 su* z ! ?icknesses ( ar*es or reta9+ walls1 are n consid]$2 !y c be f\nd 9 books on g5]al eng9e]+ design4 ,,*ap4 ,,xii4 treats ( /orm wat]s & riv] floods1 & %[s h[ works c be design$ = gett+ rid ( flood wat] & h[ floods c be mitigat$ or prev5t$1 "o ( ! *ief measures1 ! wid5+ ( ! *annel & ! l[]+ ( ! wat]-level1 be+ ! opposite ( t adopt$ = tra9+ works4 ,embankm5ts = /opp+ flood+ are also dealt )4 ,,*ap4 ,,xiii4 deals ) res]voirs1 includ+ ! design ( e>!n & masonry dams4 ,,*aps4 ,,xiv4 & ,,xv4 deal ) tidal wat]s1 riv] m\?s & e/u>ies1 & works 9 connection ) !m1 viz4 ! tra9+ ( e/u>ies & ! me?ods ( deal+ ) b>s1 ! object be+ 9 all cases ! improvem5t ( ! navigable capacities ( ! *annels4 #c4 ,design & ,execution ( ,works4--,aft] obta9+ full in=mation conc]n+ ! /ream to be dealt )1 c>eful calculations are1 9 ! case ( any l>ge & important "w1 made z to ! effects :i* w be produc$ by x4 ,^! effects _c always be exactly =ese54 ,sometimes matt]s c be arrang$ s t ! "w c be /opp$ %ort at "s /age )\t de/roy+ ! utility ( ! portion done1 or s t ! complet$ "w c be alt]$ to "s ext5t4 ,9 works = controll+ /reams !re is1 z w appe> 9 due c\rse1 a consid]able *oice ( types ( "w & me?ods ( con/ruction4 ,9 practice x w g5]ally be f\nd t !re are1 9 any p>ticul> locality1 reasons = giv+ pref]5ce to "o p>ticul> type or k9d ( "w or1 at all ev5ts1 t ! *oice is limit$ to a few ( !m1 ei!r because c]ta9 k9ds ( mat]ials & appliances c be obta9$ m *eaply & readily ?an o!rs1 or because works ( a p>ticul> type h already be5 successfully adopt$ !re1 or because ! p ( ! di/rict are accu/om$ to c]ta9 classes ( "w or me?ods ( con/ruction4 ,9 out-(-!-way places x is (t5 undesirable to avoid any type ( "w :i* _c be quickly repair$ or readily kept 9 ord] by su* means z exi/ ne> ! spot4 ,x is sometimes said t p]i%able mat]ials1 su* z trees1 /akes1 & bru%wood1 _c produce p]man5t results4 ,!y c produce results :i* w la/ = a long "t & :i* may ev5 be p]man5t4 ,by ! "t ! mat]ials h decay$1 ! *anges wr\ght may h be5 v great1 deposits ( %+le or silt may h occurr$ & become cov]$ ) vegetation1 & !re may be little t5d5cy = matt]s to rev]t to _! =m] condition4 ,if ! exp5se ( us+ m la/+ mat]ials _h _h to be incurr$1 ! works might nev] h be5 c>ri$ out at all4 ,on ! ,mississippi enorm\s quantities ( "w h be5 done ) fasc9es4 #d4 ,! ,hydraulics ( ,op5 ,/reams4--,:5 any rea* ( a /ream is alt]$1 say by wid5+1 n>r[+1 or deep5+1 s t ! wat]-level is *ang$1 !re w also be a *ange 9 ! wat]-level1 a gradually dim9i%+ *ange1 = "s di/ance up/ream ( ! rea*4 ,also 9 ! l[e/ portion ( ! rea* ! *ange w gradually dim9i% & x w vani% at ! extreme d[n/ream end ( ! rea*4 ,9 ! next l[e/ rea* !re is no *ange4 ,?us if x is desir$ t ! *ange 9 ! wat]-level %all take full effect ?r\gh\t ! :ole ( a rea*1 ! *ange 9 ! *annel mu/ be c>ri$ fur!r d[n4 ,if a weir is built !re is no *ange 9 ! wat]-level d[n/ream ( x except su* z may be due to loss ( wat] 9 ! rea* up/ream ( x4 ,! above po9ts are m5tion$ "h because1 al?\gh !y are really que/ions ( hydraulics1 !y are ( mu* importance & ( v g5]al application4 ,matt]s connect$ ) ! hydraulics ( op5 /reams seem to l5d !mselves 9 a peculi> way to loosely express$ rem>ks & fallaci\s op9ions4 ,! set ( a /ream t[>ds a bank is sometimes suppos$ to pr(\ndly affect ! dis*>ge ( a div]sion or bran*4 ,its effect is simply t ( 8velocity ( approa*10 :i*1 z is well kn[n1 is q small ) ord9>y velocities1 & is m]ely equival5t to a v small increase ( head4 ,n>r[ bridges or o!r works are sometimes said to s]i\sly 8ob/ruct0 a /ream )\t any obs]vations be+ made ( ! fall 9 ! wat] surface ?r\gh ! bridge4 ,?is fall is ! only measure ( ! real ob/ruction4#g ,,*apt] ,,ii ,,ra9fall #a4 ,ra9fall ,/ati/ics4--,! mean annual ra9fall v>ies v greatly accord+ to ! locality4 ,9 ,engl& x v>ies f ab\t #bj in*es at ,hun/anton 9 ,cambridge%ire1 to ab\t #bjj in*es at ,sea?waite 9 ,cumb]l&2 9 ,india1 f #b or #c in*es 9 p>ts ( ,sc9de1 to #dej in*es or m at ,*]rapunji 9 ! ,ea/]n ,himalayas4 ,ra9 is br\ght by w9ds :i* bl[ across ! sea4 ,h5ce ! ra9fall 9 any c\ntry is g5]ally greate/ 9 ^? localities :]e ! prevail+ w9ds bl[ f seaw>d1 provid$ !y h travell$ a great di/ance ov] ! sea4 ,ra9fall is great] among hills ?an else:]e1 because ! temp]ature at great elevations is l[]4 ,curr5ts ( moi/ air /rik+ ! hills are deflect$ upw>ds1 become cool$1 & ! wat] vap\r becomes ra94 ,?is process1 if ! hills are n l(ty1 may n produce its full effect till ! air curr5ts h pass$ ov] ! hills1 & ?us ! ra9fall on ! leew>d slopes may be great] ?an else:]e1 b on ! inn] & m l(ty ranges ! ra9fall is g5]ally greate/ on ! w9dw>d side4 ,?us ! ra9fall may v>y greatly at places n f> ap>t4 ,an extreme in/ance ( ?is occurs 9 ! ,bombay hills1 :]e ! mean annual falls at two /ations only t5 miles ap>t are respectively #cjj in*es & #ej in*es4 ,9 temp]ate climates ! ra9fall is g5]ally di/ribut$ ov] all ! mon?s ( ! ye>2 9 ! tropics ! great bulk ( ! ra9 (t5 falls 9 a few mon?s4 ,! fall at any "o place v>ies greatly f ye> to ye>4 ,to obta9 really reliable figures conc]n+ any place1 obs]vations at t place %\ld ext5d ov] a p]iod ( ?irty to ?irty-five ye>s4 ,! figures ( ! mean annual fall w !n probably be correct to )9 #b p] c5t4 ,! degree ( accuracy to be expect$ 9 results d$uc$ f obs]vations ext5d+ ov] %ort] p]iods is z foll[s3-- ,no4 ( ye>s #be #bj #ae #aj #e ,error p] c5t4 #c #c #e #h #ae ,^! figures 7 d$uc$ by ,b9nie 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cix47 f an exam9ation ( ra9fall figures obta9$ ov] long p]iods ( "t at _m places scatt]$ ov] ! _w4 ,! errors may1 ( c\rse1 be plus or m9us4 ,!y are ! av]ages ( ! errors actually f\nd1 & are !mselves subject to fluctuations4 ,?us ! #ae p] c5t4 error = a five-ye> p]iod may be #af or #ac1 ! #h p] c5t4 error = a t5-ye> p]iod may be #h or #g1 ) simil> b m9ute fluctations = ! o!r p]iods4 ,b9nie's figures also %[ t ! ratio ( ! fall at any place 9 ! drie/ ye> to ! mean annual fall1 av]ages #ea to #fh1 ) a g5]al av]age ( #fj1 & t ! ratio 9 ! wette/ ye> to ! mean annual fall av]ages #ada to #age1 ) a g5]al av]age ( #aea4 ,= ,india ! g5]al av]ages are #ej & #age4 ,^! figures are useful z a means ( e/imat+ ! probable greate/ & lea/ annual fall1 b !y are av]ages = gr\ps ( places4 ,! greate/ fall at any p>ticul> place may occasionally be twice ! mean annual fall4 ,at "s places 9 ,india1 9 ,mauritius1 & at ,m>seilles x has be5 two & a half times ! mean annual fall4 ,! lea/ annual fall may1 9 ,india1 be z l[ z #bg ( ! mean4 ,9 ,engl& ! fall 9 a dry ye> has1 once at lea/1 be5 f\nd to be only #cj ( ! mean annual fall4 ,! mean fall 7av]age = all places7 9 ! ?ree drie/ ye>s is1 f ,b9nie's figures1 ab\t #gf ( ! mean annual fall4 ,! figures giv5 above1 except :5 a p>ticul> c\ntry is m5tion$1 apply to all c\ntries & to places :]e ! ra9fall is heavy1 z well z to ^? :]e x is light4 ,b 9 extremely dry places ! fluctuations are likely to be mu* great]4 ,at ,kurra*ee1 ) a mean annual fall ( only #ge in*es1 ! fall 9 a v wet ye> has be5 f\nd to be #cgc times1 & 9 a v dry ye> only #jg times ! mean annual fall4 ,9 ! ,unit$ ,k+dom ! probable ra9fall at any place 9 ! drie/ ye> may be tak5 z #fc ( ! mean annual fall4 ,= p]iods ( two1 ?ree1 f\r1 five & six consecutive dry ye>s1 ! figures are #gb1 #gg1 #hj1 #hb1 & #hce4 ,^! figures are ( importance 9 calculations = ! capacity ( res]voirs 7,,*ap4 ,,xiii41 ,art4 #b74 ,:5 accurate /ati/ics ( ra9fall are requir$ = any "w1 ! ra9fall ( ! tract conc]n$ mu/ be specially /udi$ & local figures obta9$ = z _m ye>s z possible4 ,v frequ5tly x is necess>y to set up a ra9-gauge1 or sev]al if ! tract is ext5sive or consi/s ( sev]al areas at diff]5t elevations4 ,sometimes !re is only a ye> or s 9 :i* to collect figures4 ,9 ?is case ! ratio ( ! obs]v$ fall to t1 = ! same p]iod1 at ! ne>e/ /ation :]e regul> records are kept1 is calculat$4 ,?is ratio is assum$ to hold good ?r\gh\t1 & ?us ! probable ra9fall figures = ! new /ation c be obta9$ = ! :ole p]iod ov] :i* ! records h be5 kept at ! regul> /ation4 ,! volumes ( ! ,briti% ,ra9fall ,organisation conta9 a va/ am\nt ( in=mation reg>d+ ra9fall4 ,= a l>ge area !re %\ld be "o ra9-gauge = e #ejj acres1 = a small area m4 ,9 ! case ( a valley !re %\ld be at lea/ ?ree gauges along ! l9e ( ! deepe/ "p--"o at ! highe/ po9t1 "o at ! l[e/1 & "o midway z reg>ds height--& two gauges half way up ! sides & opposite ! middle gauge 7,ency4 ,brit41 ,t5? ,edition1 vol4 xxxiii474 ,"s extra gauges may be set up = %ort p]iods 9 ord] to see :e!r ! regul> gauges give fair indications ( ! ra9fall ( ! tract4 ,if !y d n d s "s all[ances c be made = ?is4 #b4 ,available ,ra9fall4--,! area dra9$ by a /ream is call$ its 8cat*m5t area0 or 8bas940 ,! available ra9fall 9 a cat*m5t area is ! total fall less ! quantity :i* is evaporat$ or absorb$ by vegetation4 ,! evaporation does n *iefly take place directly f ! surface4 ,ra9 s9ks a %ort di/ance into ! gr\nd1 & is subsequ5tly evaporat$4 ,! available ra9fall does n all fl[ directly into ! /reams4 ,"s s9ks deep into ! gr\nd & =ms spr+s1 & ^! _m mon?s lat] augm5t ! fl[ ( ! /ream & ma9ta9 x 9 dry seasons4 ,! available ra9fall ( a giv5 cat*m5t area is kn[n z ! 8yield0 ( t area4 ,e/imation ( ! available ra9fall is necess>y *iefly 9 cases :]e wat] is to be /or$ 9 res]voirs = t[n supply or irrigation4 ,! ratio ( ! available to ! total ra9fall dep5ds *iefly on ! nature & /eepness ( ! surface ( ! cat*m5t area1 on ! temp]ature & dryness ( ! air1 & on ! am\nt & di/ribution ( ! ra9fall4 ,! ratio is f> great] :5 ! falls are heavy ?an :5 !y are light4 ,aga91 :5 ! gr\nd is fairly dry & ! temp]ature high--z 9 summ] 9 ,engl&--ne>ly ! :ole ( ! ra9fall may evaporate2 b :5 ! gr\nd is soak$ & ! temp]ature l[--z 9 late autumn & w9t] 9 ,engl&--! bulk ( ! ra9fall runs (f4 ,9 ! eighte5 ye>s f #ahic to #aijj ! av]age dis*>ge ( ! ,?ames at ,t$d+ton1 aft] all[+ = ab/ractions by wat] companies1 0 9 ,july1 ,augu/1 & ,septemb] #ab p] c5t4 ( ! ra9fall--#fi in*es--9 its bas91 & 9 ,janu>y1 ,febru>y1 & ,m>* #fj p] c5t4 ( ! fall :i* 0 #ei in*es4 ,! total fall 9 ! ye> 0 #bfd in*es4 ,"s riv]s 9 ,spa9 dis*>ge1 9 ye>s ( heavy ra9fall1 #ci p] c5t41 & 9 ye>s ( light ra9fall #i p] c5t4 ( ! ra9fall 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxvii474 ,! dis*>ge ( a riv] is n always greate/ 9 ! mon?1 or ev5 ! ye>1 ( greate/ ra9fall4 ,! table opposite gives "s figures obta9$ by comp>ison ( ra9fall figures & /ream dis*>ges4 ,! case ( ! area ( #bbjh acres ne> ,cape ,t[n is describ$ 9 a pap] by ,b>tlett 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxxviii471 & x is %[n by figures t "p ( ! ra9fall 9 ! ra9y season w5t to increase ! und]gr\nd supply :i* aft]w>ds ma9ta9$ ! fl[ 9 ! dry season4 ---------------------------------------- ---------------------------------------- --------------------- ,place4 ,cat*m5t ,p]iod ov] :i* ,total ,available ,rem>ks ,area4 ,obs]vations ,ra9fall ,ra9fall4 ,ext5d$4 ,obs]v$4 ---------------------------------------- ---------------------------------------- --------------------- ,acres4 ,in*es4 ,ratio to ,total4 ,nagpur1 ,c5tral ,india #d1bbd ,june to ,septemb] #dd #dj 7,monsoon p]iod74 0 0 0 0 #cj #bg ,m]c>a1 ,s\? ,india #dh ,:ole ye>4 #aai #cg ,gravelly soil ov]ly+ ,k+ ,william's ,t[n1 granite4 ,cape ,colony #fg1bjj 0 #bg #ba ,hills ) =e/ & ,ne> ,cape ,t[n1 ,cape bu%4 ,colony #aaj ,may to ,octob] #cae #ea ,b>e hills4 ,ne> ,cape ,t[n1 ,cape 7ra9y season74 ,colony #b1bjh 0 #dc #dj 0 ,melbury ,moor1 ,devon%ire 444 ,:ole ye>4 #ejg #ed ,newport1 ,monm\?%ire 444 0 #dj #dj ,newport1 ,isle ( ,wight 444 0 #cb #dj ,bas9 ( ,nepean ,riv]1 #bhd sq4 ,n4,s4,w4 miles 0 #ddc #dd ,b>e1 brok5 gr\nd4 ,bas9 ( ,cat>act ,riv]1 ,n4,s4,w4 #gj sq4 miles 0 #ed #de 0 0 ---------------------------------------- ---------------------------------------- --------------------- ,! foll[+ /atem5t %[s h[ ! available ra9fall may v>y f ye> to ye>4 ,! figures are ^? ( a cat*m5t area ( #ej squ>e miles on ! ,cat>act ,riv]1 ,new ,s\? ,wales 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxxi473-- ---------------------------------------- -------------------------- ,ye>4,ra9fall4 ,available ,rem>ks4 ,ra9fall4 ---------------------------------------- -------------------------- ,in*es4 ,ratio to ,total4 #ahie #cda #hd ,heavy ra9 fall+ on saturat$ area4 #ahif #ccg #bh ,ev5ly di/ribut$ fall4 #ahig #ddg #di ,heavy ra9s 9 ,may4 #ahih #efd #de 0 0 ,febru>y 7#ae ins474 #ahii #edi #dc 0 0 ,augu/ 7#aae ins474 #aijj #bfa #ej 0 0 ,may & ,july4 #aija #cgd #aa ,ev5ly di/ribut$ fall4 #aijb #bii #jf #aijc #dag #bc ,no heavy fall4 ---------------------------------------- -------------------------- ,! mann] 9 :i* ! available ra9fall may v>y f mon? to mon? is %[n 9 ! foll[+ /atem5t1 :i* gives ! figures = #aije = ! ,sudbury ,riv] 9 ,massa*usetts3-- ---------------------------------------- - ,mon?4 ,ra9fall4 ,available ,ra9fall4 ---------------------------------------- - ,in*es4 ,p]c5tage ( fall4 ,janu>y #ec #dh ,febru>y #bb #bd ,m>* #cb #adb ,april #bg #ajd ,may #ac #dj ,june #ej #af ,july #ee #f ,augu/ #bg #h ,septemb] #fi #ca ,octob] #ae #ah ,novemb] #ba #bc ,decemb] #dj #dj ---------------------------------------- - ,total #dbc ,av]age #cie ---------------------------------------- - ,rank9e gives ! ratio ( ! available ra9fall to ! :ole fall z #aj on /eep rocks1 #h to #f on moorl& & hilly pa/ure1 #e to #d on flat1 cultivat$ c\ntry1 & nil on *alk4 ,^! figures are only r\gh4 ,! figures = rocks & pa/ures are too high4 ,! loss f evaporation & absorption is n proportional to ! ra9fall4 ,x is f> m correct to consid] ! loss z a fairly con/ant quantity 9 any giv5 locality b increas+ some:at :5 ! ra9fall is great4 ,! available ra9fall 9 ,great ,brita9 has g5]ally be5 ov]e/imat$4 ,sometimes x has be5 tak5 z be+ #fj ( ! :ole fall4 ,m commonly ! loss is tak5 to be #ac to #ae in*es4 ,?is is correct = ! we/]n m\nta9 di/ricts1 :]e ! ra9fall is ab\t #hj in*es & ! soil consi/s *iefly ( rocks p>tly cov]$ ) moorl& or pa/ure4 ,9 o!r p>ts ( ! c\ntry1 especially :]e flat1 ! loss is (t5 #ag to #bj in*es4 ,all ! above figures are1 h[ev]1 g5]al av]ages4 ,! prop] e/imation ( ! available ra9fall at any place 9 any c\ntry dep5ds a great deal on exp]i5ce & judgm5t1 & on ! ext5t to :i* figures = actual cases ( simil> "* are available4 ,reg>d+ ! 8run-(f0 f saturat$ l& dur+ %ort p]iods1 see ,,*ap4 ,,xii41 ,arts4 #a & #b4 #c4 ,measurem5t ( ,ra9fall4--,a ra9-gauge %\ld be 9 op5 gr\nd & n %elt]$ by objects ( any k9d4 ,! ord9>y ra9-gauge is a %ort cyl9d]4 ,?is is (t5 connect$ by a tap]+ piece to a long] cyl9d] ( small] diamet]4 ,9 ?is ! ra9 is /or$ safely & is measur$ by a graduat$ rod4 ,! measurem5t c be made m accurately ?an if ! diamet] 0 ?r\gh\t ! same z at ! top4 ,9 o!r cases ! wat] is p\r$ out ( ! cyl9d] into a measur+ vessel4 ,if ! ra9-gauge 0 sunk s t ! top 0 level ) ! gr\nd1 ra9 fall+ outside ! gauge w\ld spla% into x & vitiate ! read+s unless ! gauge 0 surr\nd$ by a tr5*4 ,ord9>ily ! top ( ! gauge is f #a to #c feet above ! gr\nd4 ,:5 x is #a metre above ! gr\nd ! ra9 regi/]$ is said to be on ! av]age ab\t #f p] c5t4 less ?an x %\ld be1 ow+ to ! fact t w9d causes eddies & curr5ts & c>ries away drops :i* %\ld h fall5 into ! gauge4 ,! velocity ( ! w9d increases ) ! height above ! gr\nd1 & s does ! error ( ! ra9-gauge4 ,devices = gett+ rid ( ! eddies h be5 inv5t$ by ,bo]n/e9 & ,niph] 7,ency4 ,brit41 ,t5? ,edition1 vol4 xviii471 b !y h n yet come into g5]al use4 ,! ,bo]n/e9 device is be+ us$ exp]im5tally at ,eskdalemuir4 ,x w\ld appe> t mu* spla%+ _c take place :5 ! gr\nd is cov]$ ) grass1 & t 9 su* a case ! top ( ! gauge c\ld be #a foot above ! gr\nd1 ?us mak+ ! error v small4 ,if ! gr\nd is at fir/ level1 !n rises & !n aga9 becomes level1 a ra9-gauge at ! foot ( ! slope w1 ) ! prevail+ w9d bl[+ up ! slope1 regi/] too mu*1 & a ra9-gauge j beyond ! top ( ! slope w regi/] too little 7,ency4 ,brit41 ,t5? ,edition1 vol4 xxxiii474 #d4 ,influ5ce ( ,=e/s & ,vegetation4--,:5 ! gr\nd is cov]$ ) vegetation1 & especially =e/s1 ! humus or m\ld =m$ f leaves1 etc41 absorbs & reta9s moi/ure4 ,x acts l a res]voir1 s t ! run-(f takes place sl[ly & ! d5udation & erosion ( ! soil is *eck$4 ,! roots ( ! trees or o!r vegetation also b9d ! soil toge!r4 ,vegetation & =e/s ?us mitigate ! sev]ity ( floods & r$uce ! quantity ( silt br\ght into ! /reams4 ,!y also %ield ! gr\nd f ! direct rays ( ! sun & s r$uce evaporation1 & ?us1 on ! :ole1 augm5t ! available ra9fall4 ,=e/s r5d] ! climate m equable & t5d to r$uce ! temp]ature1 & !y ?us1 at lea/ on hills1 increase ! actual ra9fall to "s ext5t4 ,if a =e/ is fell$ & replac$ by cultivation1 ! pl\gh+ ( ! soil acts 9 ! same way z ! humus ( ! =e/1 & ! crops replace ! trees2 & x has be5 /at$ t 9 ! ,u4,s4,a4 ! cultivation is z b5eficial z ! =e/s 9 mitigat+ floods & *eck+ d5udation ( ! soil 7,proc4 ,am4 ,soc4 ,c4,e41 vol4 xxxiv474 ,b :5 =e/s are fell$ !y are n1 at lea/ 9 hilly c\ntry1 always replac$ by cultivation4 ,measures to put a /op to ! de/ruction ( =e/s or to af=e/ or re=e/ b>e l& may ent] into que/ions ( ! rgime ( /reams or ! supply ( wat]4 ,on ! ,rh9e1 increase 9 ! sev]ity ( floods 0 di/9ctly trac$ to de=e/ation ( ! dra9age area4 ,x is usually said t =e/s act z res]voirs by prev5t+ sn[s f melt+4 ,?is is disput$ 9 ! pap] above quot$1 & x is /at$ t 9 ! abs5ce ( =e/s ! sn[ =ms drifts ( enorm\s dep?1 & ^! melt v gradually & act z res]voirs aft] ! sn[ 9 ! =e/s has disappe>$4 #e4 ,heavy ,falls 9 ,%ort ,p]iods4--,:5 ra9 wat]1 in/ead ( be+ /or$ or utilis$1 has to be got rid (1 x is ( prim>y importance to e/imate r\ghly--exact e/imates are impossible--! greate/ probable fall 9 a %ort "t4 ,?is be>s a r\gh ratio to ! mean annual fall4 ,! maximum obs]v$ falls 9 tw5ty-f\r h\rs range1 9 ! ,unit$ ,k+dom1 g5]ally f #je to #aj ( ! mean annual fall--b on "o occasion ! figure has be5 #bj1--;& 9 ! tropics f #aj to #be4 ,actual figures = p>ticul> places c be extract$ f ! ra9 regi/]s1 b ! probability ( _! be+ exce$$ mu/ be tak5 into acc\nt4 ,! greate/ fall obs]v$ 9 tw5ty-f\r h\rs 9 ! ,unit$ ,k+dom is #g in*es1 & 9 ,india #cj in*es 9 ! ,ea/]n ,himalayas4 ,b mu* %ort] p]iods ?an tw5ty-f\r h\rs h to be dealt )4 ,! foll[+ figures are giv5 by ,*ami] 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cxxxiv47 z applicable to ,new ,s\? ,wales1 & he consid]s t !y are fair guides1 err+ on ! side ( safety1 = o!r c\ntries3-- ,duration ( fall 9 h\rs #a #d #ab #bd ,ratio ( fall to maximum daily fall #a ,! above figures are probably safe = ,engl&4 ,= ,india ! case is f> o!rwise4 ,! foll[+ falls h be5 obs]v$ !re3-- --------------------------------------- ,p]iod4 ,fall4 ,rate p] ,h\r4,rem>ks4 --------------------------------------- ,in*es4 ,in*es4 #g h\rs #aj #adc #de h\rs #gg #ag #b h\rs #h #d #a h\r #e #e #bj m9utes #af #dh #aj m9utes #a #f --------------------------------------- ,! falls ( #a in* 9 t5 m9utes 7 frequ5tly obs]v$ ne> ! head ( ! ,upp] ,jhelum ,canal1 a place :]e ! annual ra9fall is n m ?an #cj in*es 7see also ,,*ap4 ,,xii41 ,art4 #a74 ,9 "s p>ts ( ! ,ea/]n ,himalayas1 :]e #cj in*es ( ra9 has fall5 9 a day1 x is possible t #h in*es may h fall5 9 an h\r4 ,9 ,engl& #d in*es has fall5 9 an h\r4 ,! heavie/ falls 9 %ort p]iods d n usually occur 9 ! wette/ ye>s1 & !y may occur 9 v dry ye>s4 ,nor d !y always occur on a v wet day4 ,,*apt] ,,iii ,,collection ,,( ,,in=mation ,,conc]n+ ,,/reams #a4 ,prelim9>y ,rem>ks4--,! in=mation :i* is requir$ conc]n+ /reams dep5ds on ! "* ( ! /ream & on ! nature ( ! "w :i* is to be done4 ,= ! pres5t let x be suppos$ t ! /ream is l>ge & p]5nial4 ,o!r k9ds ( /reams w be dealt ) 9 ,arts4 #f & #g4 ,9 deal+ ) a l>ge p]5nial /ream x is ne>ly always necess>y to "k ! approximate highe/ & l[e/ wat]-levels1 & ^! c g5]ally be asc]ta9$ by local inquiry1 comb9$ ) obs]vations ( wat] m>ks2 b a high] level ?an ! highe/ kn[n & a l[] level ?an ! l[e/ kn[n are always liable to occur1 & mu/ to "s ext5t be all[$ =4 ,if navigation exi/s or is to be arrang$ =1 ! highe/ & l[e/ levels consi/5t ) navigation mu/ be asc]ta9$4 ,! highe/ su* level dep5ds *iefly on ! heights ( bridges4 ,a plan to a fairly l>ge scale is also necess>y 9 mo/ cases4 ,if an embankm5t to keep out floods is to be made along a riv] :i* is s l>ge t its flood-level _c be appreciably affect$ by ! con/ruction ( ! "w1 x may be necess>y to obta9 in=mation only z to ! actual flood-levels1 & z to ! ext5t to :i* ! /ream is liable to erode its bank4 ,if a l5g? ( ! bank ( a /ream has to be protect$ aga9/ sc\r1 x is necess>y to "k ( :at mat]ials ! b$ & bank are compos$1 & :e!r ! *annel is liable to *anges & to :at ext5t4 ,x is also desirable to "k to :at ext5t ! wat] transports solids1 if any4 ,9 "s k9ds ( protective "w ^! solids are utilis$4 ,b 9 cases :]e ! /ream is to be mu* int]f]$ )1 x is necess>y to h full in=mation conc]n+ x1 n only z reg>ds wat]-levels1 *anges 9 ! *annel1 & transport ( solids1 b z reg>ds ! longitud9al pr(ile & cross-sections1 & ! dis*>ges correspond+ to diff]5t wat]-levels4 ,! collection ( "s ( ?is in=mation1 p>ticul>ly z to ! wat]-levels & dis*>ges at diff]5t times ( ! ye> & 9 floods1 may occupy a consid]able "t4 ,me?ods ( asc]ta9+ ! quantity ( silt c>ri$ 9 ! wat] ( a /ream are describ$ 9 ,,*ap4 ,,iv41 ,art4 #d4 ,rem>ks reg>d+ ! o!r k9ds ( in=mation requir$--! /ream be+ /ill suppos$ to be l>ge & p]5nial--are giv5 9 ,arts4 #b to #e ( ?is *apt]4 ,! degree ( accuracy requir$ 9 ! in=mation dep5ds1 h[ev]1 on ! importance ( ! "w1 & sometimes ! proc$ure c be simplifi$4 ,detail$ rem>ks on gauges & on ! in/rum5ts us$ & me?ods adopt$ = obs]v+ dis*>ges & surface slopes1 are giv5 9 ,hydraulics1 ,,*ap4 ,,viii4 & ,app5dix ,h4 #b4 ,/ream ,gauges4--,unless ! /ream be+ dealt ) is an artificial "o1 x is unlikely t ! fl[ 9 ! rea* ) :i* ! "w is conc]n$ w be uni=m4 ,! rise & fall ( ! wat] at "o place _c !re=e be correctly inf]r$ f ^? at ano!r4 ,x w be desirable to h two gauges1 ei!r read daily or else automatically1 record+ ! wat]-level1 "o ne> ea* end ( ! rea* conc]n$1 ) int]m$iate gauges if ! rea* is v long4 ,if1 9 or ne> ! rea*1 !re is already a gauge :i* has be5 regul>ly read1 x may be suffici5t to set up only "o new gauge1 & to read x only = su* a p]iod ( "t z w give a good range ( wat]-level1 & to comp>e ! read+s ) ^? ( ! old gauge4 ,! read+s ( ! new gauge = wat]-levels outside ! range ( ^? obs]v$ c !n be inf]r$1 b if ! /ream is v irregul> ?is may involve "s tr\ble 7,art4 #d74 ,9 ! case ( a l>ge /ream :i* %ifts its c\rse1 ! read+ ( a gauge does n give a prop] indication ( ! wat]-level4 ,9 o!r words1 ! di/ance ( ! gauge f ! two ends ( ! rea* is subject to alt]ation4 ,! case is ! same z if ! /ream 0 /able & ! gauge 0 %ift$ ab\t4 ,9 su* a /ream !re ought1 if accuracy is requir$1 to be a gr\p ( two or m gauges = ea* po9t :]e !re w\ld be only "o if ! /ream 0 n a %ift+ "o4 ,also1 ow+ to erosion ( ! bank or ! =mation ( a s&bank1 x may (t5 be necess>y to %ift ! gauge4 ,:5 possible x %\ld be kept 9 a fix$ l9e laid d[n at "r angles to ! g5]al direction ( ! /ream4 ,:5 %ift$1 its z]o level %\ld be alt]$ 9 su* a way t ! read+ at ! new site at ! "t ( %ift+ is ! same z x 0 be=e %ift+4 ,:5 ! gauge is mov$ back to ! orig9al site its z]o %\ld be plac$ at its orig9al level1 ?\gh ?is may give rise to a sudd5 jump 9 ! read+ = ! reason giv5 9 ! fir/ s5t5ce ( ?is p>agraph4 #c4 ,plan & ,sections4--,mak+ a survey & plan1 & lay+ d[n on x ! l9es = longitud9al & cross-sections1 & tak+ levels = ! sections1 are ord9>y op]ations ( survey+4 ,if any l& is liable to be flood$1 its b\nd>ies %\ld be %[n on ! plan & on "s ( ! cross-sections4 ,unless ! wat] is %all[1 x is necess>y to obta9 ! b$ levels f ! wat]-level by s\nd+s1 ! level ( a peg at ! wat]-level hav+ be5 obta9$ by levell+4 ,all ! sections %\ld %[ ! wat]-level z x 0 at "s p>ticul> "t1 b ! wat]-level w probably h alt]$ :ile ! survey 0 9 progress1 & all[ance mu/ be made = ?is4 ,! pegs at all ! cross-sections & on bo? banks ( ! /ream--= ! wat]-levels at opposite banks may n be exactly ! same--may1 = in/ance1 be driv5 d[n to ! wat]-level :5 x is /eady1 & !reaft] any *anges 9 x not$ & ! s\nd+s correct$ accord+ly4 ,9 ord] to asc]ta9 :at *anges are occurr+ 9 ! *annel x may be necess>y to repeat ! s\nd+s at int]vals &1 if !re is mu* erosion ( ! bank1 to make fre% plans4 #d4 ,dis*>ge ,obs]vations4--,= a l>ge /ream x is necess>y to obs]ve ! dis*>ges by tak+ cross-sections & measur+ ! velocity4 ,if !re is a suffici5t range ( wat]-levels1 x w be possible to make actual obs]vations ( a suffici5t numb] ( dis*>ges4 ,if s\nd+s _c1 ow+ to ! dep? or velocity1 be tak5 at high wat]1 !y mu/ be inf]r$ f ^? previ\sly tak51 b ?is does n all[ = *anges 9 ! *annel1 :i* are sometimes consid]able & rapid4 ,if !re is n a suffici5t range ( wat]-level1 ! dis*>ges = "s wat]-levels mu/ be calculat$ f ^? at o!r wat]-levels4 ,9 ?is case obs]vations ( ! surface slope w be requir$1 & ! dis*>ge site %\ld be s select$ t no abrupt *anges 9 ! *annel w come )9 ! l5g? ov] :i* ! obs]vations are to ext5d4 ,?is l5g? %\ld be su* t ! fall 9 ! wat] surface w be great en\gh to admit ( accurate obs]vation4 ,if ! cross-section ( ! /ream is ne>ly uni=m ?r\gh\t ! :ole ( ?is l5g?1 or if x v>ies 9 a regul> mann]1 be+ greate/ at "o end ( ! l5g? & lea/ at ! o!r end4 ! diff]5ces 9 ! areas ( ! two end sections be+ n m ?an #aj or #ab p] c5t41 !n ! velocity & cross-section ( ! /ream c be obs]v$ 9 ! usual mann] at ! c5tre ( ! l5g?2 b o!rwise !y %\ld be obs]v$ at int]vals ov] ! :ole l5g?1 or at lea/ 9 two places1 "o :]e ! section is small & "o :]e x is great1 & ! mean tak54 ,or ! velocity c be obs]v$ at only "o cross-section & calculat$ = ! o!rs by simple proportion & ! mean tak54 ,! coeffici5t ,c c !n be f\nd f ! =mula ,c ,v_/7,,rs74 ,to f9d ! dis*>ge = a high] or l[] wat]-level1 ! *ange 9 ! value ( ,c correspond+ to ! *ange 9 ,r c be e/imat$ by look+ out ! values ( ,c 9 tables1 & ! dis*>ge calculat$ by us+ ! new values ( ,c & ,r & ! new sectional area1 ,s rema9+ unalt]$4 ,b if ! *annel is su* t1 ) ! new wat]-level1 a *ange 9 ,s is likely to h occurr$1 ?is *ange mu/ be all[$ =4 ,any su* *ange w be due to ! *ang$ relative effects ( irregul>ities1 ei!r 9 ! l5g? ov] :i* ! obs]vations ext5d$ or d[n/ream ( t l5g?4 ,! effect ( irregul>ities 9 ! b$ is greate/ at l[ wat]4 ,! effect ( lat]al n>r[+s is greate/ at high wat]4 ,s9ce a *ange ( #aj p] c5t4 9 ,s causes a *ange ( only #e p] c5t4 9 ,v1 x w usually suffice to draw on ! longitud9al section ! actual wat] surface obs]v$ & to sket* ! probable surface = ! new wat]-level4 ,if ! :ole *annel is fairly regul> = a long di/ance d[n/ream ( ! dis*>ge site1 no slope obs]vations ne$ be made nor ne$ sev]al sections be tak5 9 ord] to f9d ,v4 ,! *ang$ value ( ,c %\ld1 h[ev]1 be e/imat$ 9 ! mann] above indicat$4 ,= ?is purpose any probable value ( ,s w suffice4 #e4 ,dis*>ge ,curves & ,tables4--,ord9>ily x w be possible1 by plott+ ! obs]v$ dis*>ges z ord9ates1 ! gauge read+s be+ ! absciss1 to draw a dis*>ge curve & f x con/ruct a dis*>ge table4 ,unless ! *annel is ( firm mat]ial & n liable to *ange1 !re are likely to be discrepancies among ! obs]v$ dis*>ges1 s t a regul> dis*>ge curve w n pass ?r\gh all ! plott$ po9ts4 ,if ! discrepancies are n s]i\s1 !y c be disreg>d$ & ! curve drawn s z to pass z ne> z possible to all ! po9ts1 b o!rwise tr\ble & unc]ta9ty may arise4 ,! s\nd+s %\ld be comp>$ 9 ord] to see :e!r *anges h occurr$ 9 ! *annel4 ,if su* *anges d n acc\nt = ! discrepancies1 ! cause mu/ be s\ght = 9 "s ( ! record$ velocities4 ,if no s\rces ( error 9 ^! c be f\nd1 su* z w9d1 x is possible t ! velocity has be5 affect$ by a *ange 9 ! surface slope ow+ to "s *ange 9 ! *annel d[n/ream ( ! l5g?4 ,fail+ ?is explanation1 ! discrepancies mu/ be set d[n to unkn[n causes4 ,) an un/able *annel & :]e accuracy is requir$1 ! sectional areas & velocities %\ld be regul>ly tabulat$ or plott$ s t *anges may be wat*$ & inve/igat$4 ,to d ?is x may be necess>y to take surface slope obs]vations1 or to set up extra gauges :i* w %[ any *anges 9 ! slope4 ,if1 d[n/ream ( ! dis*>ge site1 !re is any place :]e afflu5ts come 9 & br+ v>y+ volumes ( wat]1 or :]e gates or sluices are manipulat$1 & if ! influ5ce ( ?is ext5ds up to ! dis*>ge site1 ! wat]-level !re no long] dep5ds only on ! dis*>ge1 & a dis*>ge table mu/ be "o ) sev]al columns ^: head+s indicate v>i\s conditions at ! place :]e ! di/urbances occur4 ,9 ord] to %[ h[ ! gauge read+s & dis*>ges v>y f day to day ?r\gh\t ! ye>1 a diagram %\ld be prep>$ %[+ ! gauge read+s & dis*>ges z ord9ates1 ! absciss be+ ! times 9 days />t+ f any conv5i5t date z z]o4 ,su* a diagram1 %[+ only gauge read+s1 is giv5 9 fig4 #ef1 ,,*ap4 ,,xii4 #f4 ,small ,/reams4--,small /reams w n[ be consid]$1 ^?1 = in/ance1 :i* are too small to be navigable & :i* occasionally run dry or ne>ly dry4 ,if ! wat] ( ! /ream is to be /or$ = wat] supply1 p[] or irrigation purposes1 full in=mation z to dis*>ges & silt c>ri$ w be requir$4 ,if ! /ream is small en\gh ! dis*>ges c be asc]ta9$ by means ( a weir ( planks4 ,! dis*>ge is !n kn[n f ! gauge read+s4 ,cross-sections & l>ge scale plans w n be requir$ unless ! /ream is to be alt]$ or embank$4 ,if ! wat]1 in/ead ( be+ /or$1 is to be got rid (1 z 9 dra9age "w1 ! only in=mation requir$ z to dis*>ges is ! maximum dis*>ge4 ,l>ge scale plans1 sections1 or in=mation z to silt or wat]-levels 7except z a means ( e/imat+ ! dis*>ge7 w n be requir$ unless ! /ream is to be alt]$ or embank$4 ,9 all ^! cases ( small /reams ! in=mation requir$ is g5]ally1 z has be5 se51 less ?an 9 ! case ( l>ge p]5nial /reams1 b x is g5]ally m difficult to obta94 ,if ! /ream is ill-def9$ or its fl[ int]mitt5t1 especially if x is also v small & ! place sp>sely inhabit$1 x may be difficult to obta9 any dis*>ge figures except ^? bas$ on figures ( ra9fall4 ,! me?od ( obta9+ su* figures has be5 /at$ 9 ,,*ap4 ,,ii4 ,! figures requir$ are ^? ( ! annual & mon?ly fall :5 ! wat] is to be /or$1 & ^? ( ! greate/ fall 9 a %ort p]iod :5 ! wat] is to be got rid (4 ,( c\rse a plan ( ! cat*m5t area is requir$4 #g4 ,int]mitt5t ,/reams4--,9 ! case ( l>ge /reams ^: fl[ is int]mitt5t1 ! in=mation requir$ w1 z be=e1 dep5d ^u ! circum/ances4 ,su* /reams occur 9 _m c\ntries4 ,! difficulty 9 obta9+ in=mation is (t5 v great4 ,to obta9 figures ( daily dis*>ge a gauge mu/ be set up 9 ! /ream & a regi/] kept4 ,! *ief difficulty 9 an out-(-!-way place is likely to be ! obta9+ correct in=mation z to ! maximum dis*>ge4 ,in=mation1 d]iv$ f reports or f suppos$ flood m>ks1 z to ! highe/ wat]-level1 may be inaccurate1 & in=mation bas$ on ra9fall figures may be extremely d\btful ow+ to ! l>ge size ( ! cat*m5t area1 ! abs5ce ( ra9 gauges1 & ! difficulty1 especially if ! ra9 is n heavy1 9 e/imat+ ! available fall4 ,all s\rces ( in=mation mu/ be utilis$ &1 :5ev] possible1 obs]vations %\ld be made ov] a long p]iod ( "t4 #h4 ,rem>ks4--,v mu* rema9s to be done 9 collect+ & publi%+ in=mation conc]n+ ! ratio ( ! dis*>ges to ! ra9fall4 ,by obs]v+ a fall ( ra9 & ! dis*>ge ( a /ream be=e & aft] ! fall1 x is possible to asc]ta9 ! figures = t occasion1 b !y w n hold good = all occasions4 ,cont9u\s obs]vations are requir$4 ,! *ief ob/acle is ! exp5se4 ,n only h measur+ weirs & app>atus = automatically record+ ! wat]-level to be provid$1 b ! weirs w\ld (t5 cause flood+ ( l& involv+ paym5t ( comp5sation4 ,! mo/ suitable places = mak+ obs]vations are ^? :]e res]voirs = wat]-works exi/ or are ab\t to be made4 ,,*apt] ,,iv ,,! ,,silt+ ,,& ,,sc\r+ ,,action ,,( ,,/reams #a4 ,prelim9>y ,rem>ks4--,:5 fl[+ wat] c>ries solid sub/ances 9 susp5sion1 !y are kn[n z 8silt40 ,mat]ial is also mov$ by be+ roll$ along ! b$ ( ! /ream4 ,! diff]5ce betwe5 silt & roll$ mat]ial is "o ( degree & n ( k9d4 ,mat]ial ( "o k9d may be roll$ & c>ri$ alt]nately4 ,! quantity ( silt pres5t 9 ea* cubic foot ( wat] is call$ ! 8*>ge0 ( silt4 ,silt consi/s *iefly ( mud & f9e s&2 roll$ mat]ial ( s&1 gravel1 %+le1 & b\ld]s4 ,:5 a /ream erodes its *annel1 x is said to 8sc\r40 ,:5 x deposits mat]ial 9 its *annel1 x is said to 8silt40 ,bo? t]ms are us$ irrespective ( :e!r ! mat]ial is silt or roll$ mat]ial4 ,a /ream ( giv5 velocity & dep? c c>ry only a c]ta9 *>ge ( silt4 ,:5 x is c>ry+ ?is x is said to be 8fully *>g$40 ,if a /ream has p[] to sc\r any p>ticul> mat]ial f its *annel1 x has p[] to transport x2 b ! conv]se is n true4 ,if ! mat]ial is h>d or coh]5t1 ! /ream may h f> m difficulty 9 erod+ x ?an 9 m]ely keep+ x mov+4 ,& !re is g5]ally a little m difficulty ev5 :5 ! mat]ial is s(t4 ,silt+ or sc\r may affect ! b$ ( a *annel or ! sides or bo?4 ,! *annel may ?us decrease or increase 9 wid? or--if "o bank is affect$ m ?an1 or 9 a diff]5t mann] to1 ! o!r--alt] its position lat]ally :e!r or n x is alt]+ its b$ level1 & vice v]sa4 ,! cross-section ( a /ream is g5]ally 8%all[10 i4e4 ! wid? ( ! b$ is great] ?an ! comb9$ subm]g$ l5g?s ( ! sides1 & ! action on ! b$ is g5]ally great] ?an on ! sides4 ,silt+ & sc\r+ are g5]ally regul> or irregul> 9 _! action accord+ z ! fl[ is regul> or irregul>1 t is1 accord+ z ! *annel is free or n f abrupt *anges & eddies4 ,9 a uni=m canal f$ f a riv]1 ! deposit 9 ! head rea* ( ! canal =ms a w$ge-%ap$ mass1 ! dep? ( ! deposit decreas+ ) a fair approa* to uni=mity4 ,sali5t angles or places alongside ( ob/ructions are mo/ liable to sc\r1 & deep holl[s or recesses to silt4 ,eddies h exceptionally /rong sc\r+ p[]4 ,imm$iately d[n/ream ( an abrupt *ange sc\r is (t5 sev]e4 ,an abrupt *ange is "o1 :e!r ( sectional area or direction ( fl[1 & :e!r or n accompani$ by a junction or bifurcation1 :i* is s sudd5 z to cause eddies4 ,! hole sc\r$ alongside ( an ob/ruction may ext5d to its up/ream side1 ?\gh !re is g5]ally little initial t5d5cy to sc\r !re4 ,an ob/ruction is any?+ caus+ an abrupt decrease 9 any "p ( ! cross-section ( a /ream1 :e!r or n !re is a decrease 9 ! :ole cross-section1 e4g4 a bridge pi] or spur4 ,mo/ /reams v>y greatly at diff]5t times bo? 9 volume & velocity & 9 ! quantity ( mat]ial br\ght into !m4 ,h5ce ! action is n con/ant4 ,a /ream may silt at "o season & sc\r at ano!r1 ma9ta9+ a /eady av]age4 ,:5 ?is happ5s to a mod]ate ext5t1 or :5 ! /ream nev] silts or sc\rs appreciably1 x is said to be 9 8p]man5t rgime10 or 8/able40 ,mo/ /reams 9 e>!n *annels are ei!r j /able & no m1 or are un/able4 ,waves1 :e!r due to w9d or o!r ag5cy1 may cause sc\r1 especially ( ! banks4 ,_! effect on ! b$ becomes less z ! dep? ( wat] increases1 b does n cease altoge!r at a dep? ( #ba feet1 z has be5 suppos$4 ,salt wat] possesses a p[] ( caus+ mud1 b n s&1 to deposit4 ,arts4 #b1 #c1 & #f ( ?is *apt] ref] to action on ! b$ ( a /ream4 ,action on ! sides w be consid]$ 9 ,art4 #g4 ,we$s usually gr[ only 9 wat] :i* has s l[ a velocity t x c>ries no silt to speak (1 b if any silt is introduc$ ! we$s cause a deposit4 ,! we$s also ?rive on su* a deposit4 #b4 ,roll$ ,mat]ial4--,if a numb] ( bodies h simil> %apes1 & if ,d is ! diamet] ( "o ( !m & ,v ! velocity ( ! wat] relatively to x1 ! roll+ =ce is !oretically z ,v#b ,d#b1 & ! resi/+ =ce or weight z ,d#c4 ,if ^! are j balanc$1 ,d v>ies z ,v#b1 or ! diamet]s ( simil>ly %ap$ bodies :i* c j be roll$ are z ,v#b & _! weights z ,v#f4 ,f practical obs]vations1 x seems t ! diamet]s d n v>y q s rapidly z !y w\ld by ! above law1 ! weights be+ m ne>ly z ,v#e4 ,let a /ream ( pure wat] hav+ a dep? ,d1 & ) b\ld]s on its b$1 h a velocity ,v j suffici5t to move !m v sl[ly4 ,any l>g] b\ld]s w\ld n be mov$4 ,any small] b\ld]s w\ld move m quickly4 ,simil>ly1 f9e s& w\ld be roll$ m quickly ?an co>se s&4 ,if ! velocity ( ! /ream increases1 l>g] b\ld]s w\ld be mov$4 ,/reams are ?us con/antly sort+ out ! mat]ials :i* !y roll4 ,if ! b$ is exam9$ x w be f\nd t l>ge b\ld]s exi/ only d[n to a c]ta9 po9t1 small] b\ld]s1 %+le1 gravel1 co>se s& & f9e s& foll[+ 9 succession4 ,if ! wat]1 in/ead ( be+ pure1 is suppos$ to conta9 silt1 ?is may affect its velocity--x is n1 h[ev]1 kn[n to d s--b1 giv5 a c]ta9 velocity1 x is n likely t ! roll+ p[] ( ! /ream is mu* affect$ by its conta9+ silt4 ,x is sometimes suppos$ t increas$ dep? gives increas$ roll+ p[]1 because ( ! increas$ pressure1 b ?is is n s4 ,! increas$ pressure due to dep? acts on bo? ! up/ream & d[n/ream sides ( a body4 ,x is mov$ only by ! pressure due to ! velocity4 ,:5 s& is roll$ along ! b$ ( a /ream !re is usually a succession ( abrupt falls 9 ! b$4 ,aft] ea* fall !re is a long g5tle upw>d slope till ! next fall is rea*$4 ,! s& is roll$ up ! long slope & falls ov] ! /eep "o4 ,x soon becomes buri$4 ,! positions ( ! falls ( c\rse keep mov+ d[n/ream4 ,! height ( a fall 9 a l>ge *annel is p]haps #f in*es or #a foot1 & ! di/ance betwe5 ! falls #bj or #cj feet4 ,a fall does n usually ext5d /raight across ! b$ b zigzags4 ,x has sometimes be5 said t ! incl9ation ( ! b$ ( a /ream1 :5 high1 facilitates sc\r1 ! mat]ial roll+ m easily d[n a /eep incl9$ plane4 ,! incl9ation is ne>ly always too small to h any appreciable direct effect4 ,! incl9ation ( ! surface ( ! /ream ( c\rse affects its velocity1 & ?is is ! *ief factor 9 ! case4 ,a sudd5 rise 9 ! b$ ( a /ream does n necess>ily cause roll$ mat]ials to accumulate !re1 except p]haps to ! ext5t necess>y to =m a g5tle slope4 ,frequ5tly ev5 ?is slope is n =m$1 especially if ! roll$ mat]ial is only s&4 ,! eddies /ir x up & x is c>ri$ on4 ,! above rem>ks apply also to weirs or o!r local rises 9 ! b$4 #c4 ,mat]ials c>ri$ 9 ,susp5sion4--,x has long be5 kn[n t ! sc\r+ & transport+ p[] ( a /ream increases ) its velocity4 ,obs]vations made by ,k5n$y h %[n t its p[] to c>ry silt decreases z ! dep? ( wat] increases 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cxix474 ,! p[] is probably d]iv$ f ! eddies :i* are produc$ at ! b$4 ,e susp5d$ p>ticle t5ds to s9k1 if its specific gravity is great] ?an unity4 ,x is prev5t$ f s9k+ by ! upw>d compon5ts ( ! eddies4 ,if ,v is ! velocity ( ! /ream & ,d its dep?1 ! =ce ex]t$ by ! eddies g5]at$ on #a squ>e foot ( ! b$ is great] z ! velocity is great]1 & is probably z ,v#b or !reab\ts4 ,b1 giv5 ! *>ge ( silt1 ! weight ( silt 9 a v]tical column ( wat] ^: base is #a squ>e foot is z ,d4 ,!re=e ! p[] ( a /ream to support silt is z ,v#b & inv]sely z ,d4 ,! silt *>ge :i* a /ream ( dep? ,d c c>ry is z ,v4 ,v is call$ ! 8critical velocity0 = t dep?1 & is designat$ z ,v#j4 ,! full *>ge mu/ be affect$ by ! nature ( ! silt4 ,! specific gravity ( f9e mud is n mu* great] ?an t ( wat]1 :ile t ( s& is ab\t #ae times z great4 ,moreov]1 ! p>ticles ( s& are f> l>g] ?an ! p>ticles ( mud4 ,if two /reams ( equal dep?s & velocities are fully *>g$1 "o ) p>ticles ( mud & ! o!r ) p>ticles ( s&1 ! latt] w s9k m rapidly & w h to be m frequ5tly ?r[n up4 ,!y w be few] 9 numb]4 ,f "s obs]vations ref]r$ to by ,k5n$y 7,punjab ,irrigation ,pap]1 ,no4 #i1 8,silt & ,sc\r 9 ! ,sirh9d ,canal10 #aijd71 x appe>s t 9 a fully *>g$ /ream :i* c>ri$ #a_/ccjj ( its volume ( a mixture ( mud & s& ( v>i\s grades1 s& ( a p>ticul> degree ( co>s5ess =m$ only #a_/ce1jjj ( ! volume ( ! wat]1 b t :5 ! same /ream 0 cle> & 0 turn$ on to a b$ ( ! co>se s& x took up #a_/ae1jjj ( its volume4 ,x w\ld ?us appe> t ! full *>ge ( silt is less z its co>s5ess & heav9ess are great]4 ,?is is 9 accordance ) ! laws m5tion$ above 7,art4 #b1 p>4 #a74 ,see also ,,*ap4 ,v41 ,art4 #b1 la/ p>agraph4 ,x is probable t f9e mud is c>ri$ almo/ equally into all p>ts ( ! /ream1 :]eas s& is ne>ly always f\nd 9 great] proportion ne> ! b$ &1 z be=e rem>k$1 "s mat]ials may be roll$ & susp5d$ alt]nately4 ,! *>ge ( mix$ silt :i* a /ream c c>ry is1 no d\bt1 some?+ betwe5 ! *>ge :i* x c c>ry ( ea* k9d sep>ately1 b ! laws ( ?is "p ( ! subject are n yet fully kn[n4 ,f ! obs]vations above ref]r$ to1 ,k5n$y concludes t a canal ) velocity ,v#j w c>ry 9 susp5sion #a_/ccjj to #a_/ejjj ( its volume ( silt1 accord+ z x is *>g$ ) s& ( all classes or only ) ! heavi] classes4 ,let a /ream be c>ry+ a full *>ge ( any k9d ( silt4 ,!n if !re is any r$uction 9 velocity1 a deposit w occur--unless !re is also a r$uction ( dep?--until ! *>ge ( silt is r$uc$ aga9 to ! full *>ge = ! /ream4 ,! deposit g5]ally occurs sl[ly1 & ext5ds ov] a consid]able l5g? ( *annel4 ,! heavi] mat]ials are1 ( c\rse1 deposit$ fir/4 ,if a /ream is n fully *>g$1 x t5ds to become s by sc\r+ its *annel4 ,x is g5]ally believ$ t a /ream fully *>g$ ) silt _c sc\r silt f its *annel1 or be> any introduction ( fur!r silt4 ,?is seems to be correct 9 ! ma91 b ! rem>ks made 9 ! latt] "p ( ! prec$+ p>agraph mu/ be tak5 into consid]ation4 ,x has be5 /at$ 7,art4 #b7 t a weir or a sudd5 rise 9 ! b$ does n necess>ily cause an accumulation ( roll$ mat]ial4 ,x nev] causes a deposit ( susp5d$ mat]ial unless x causes a head+ up & r$uction ( velocity to bel[ ! critical velocity4 #d4 ,me?ods ( ,inve/igation4--,! quantity ( silt 9 wat] is f\nd by tak+ specim5s ( ! wat] & evaporat+ x or1 if ! silt is pres5t 9 great quantity1 leav+ x to settle = twelve h\rs--an ounce ( alum c be add$ = e #aj cubic feet ( wat] to accel]ate settlem5t--draw+ (f ! wat] by a syphon1 & heat+ ! deposit to dry x4 ,! deposit is !n measur$ or weigh$4 ,x is be/ to weigh x4 ,if clay is fill$ into a measure1 ! volume dep5ds greatly on ! mann] 9 :i* x is fill$ 94 ,:5 silt deposits 9 l>ge quantities 9 a *annel1 or :5 heavy sc\r occurs1 ! volume deposit$ or sc\r$ is asc]ta9$ by tak+ c>eful sections ( ! *annel4 ,illu/ration3 ,,fig4 #a4 ,silt is be/ classifi$ by obs]v+ its rate ( fall ?r\gh /ill wat]4 ,a s& :i* falls at #aj feet p] second is1 9 ,india1 call$ class 7#a71 & mix$ s& :i* falls at rates v>y+ f #a to #b feet p] second is call$ class #a_/b4 ,fig4 #a %[s a s& sep>ator design$ by ,k5n$y4 ,! scale is 4 ,x has a syphon action1 & ! rate ( fl[ c be alt]$ by alt]+ ! l5g? ( ! exit pipe4 ,suppose x is desir$ to measure ! s& ( class 7#aj7 & all heavi] k9ds4 ,! pipe is adju/$ s z to give a velocity ( #a foot p] second to ! upw>d fl[+ wat]1 :i* !n c>ries (f all silt ( class 7#aj7 or f9]4 ,all heavi] silt falls into ! glass tube4 ,x c be sep>at$ aga9 by be+ mix$ ) wat] & pass$ ?r\gh ! in/rum5t aga91 ! velocity ( fl[ ?r\gh ! in/rum5t be+ increas$4 ,! quantity ( silt pres5t at v>i\s dep?s c be f\nd by pump+ specim5s ( wat] ?r\gh pipes4 ,at ea* *ange ( dep? ! pipe1 deliv]y hose1 etc41 %\ld be clean$4 ,all[ance mu/ be made = ! velocity ( asc5t ( ! wat] up ! pipe4 ,suppose ?is to be #ad feet p] second4 ,!n ! velocity ( s& ( class 7#b7 w\ld be #ab feet p] second1 & ! quantity ( s& actually f\nd 9 ! wat] w\ld h to be increas$ by "o-six?4 #e4 ,quantity & ,di/ribution ( ,silt4--,! quantity ( silt pres5t 9 wat] v>ies enorm\sly4 ,f9e mud1 ev5 ?\gh suffici5t to discol\r ! wat]1 may be s small 9 volume t x only deposits :5 ! wat] is /ill1 & ev5 !n deposits sl[ly4 ,9 ! riv] ,tay1 ne> ,p]?1 ! silt 0 f\nd to be ord9>ily #a_/aj1jjj ( ! volume ( wat]1 & at l[ wat] only #a_/bh1jjj4 ,9 ! riv] ,sutlej at ,rup>1 ne> :]e x issues f ! ,himalayas1 ! silt 9 ! flood season is extremely heavy4 ,out ( #cfj obs]vations1 made at v>i\s dep?s1 dur+ ! flood seasons ( f\r successive ye>s1 9 wat] ^: dep? rang$ up to #ab feet1 ! silt 0 once f\nd to be #ba p] c5t4 by weight ( t ( ! wat]4 ,x 0 m ?an #ab p] c5t4 on f\r occasions1 & m ?an #jc p] c5t4 7or #c 9 #ajjj7 on sixty-f\r occasions4 ,g5]ally ab\t "o-half ( ! silt 0 clay & s& ( classes f9] ?an 7#aj71 ab\t "o-?ird 0 s& ( class #a_/b1 & ! residue 0 s& ( class #b_/c4 ,! s& ( ! riv] ,*5ab is g5]ally co>s] ?an t ( ! ,sutlej4 ,!re are v great diff]5ces 9 ! degree ( co>s5ess ( riv] s&4 ,! s& 9 any riv] becomes f9] & f9] z ! gradi5t flatt5s 9 approa*+ ! sea4 ,sea s& has be5 f\nd to be ( class 7#bj74 ,9 ! ,sirh9d ,canal1 :i* takes out f ! ,sutlej at ,rup>1 ! maximum quantity ( susp5d$ silt obs]v$ 9 ! f\r flood seasons 0 #jg p] c5t41 on "o occasion out ( #bgj1 & x exce$$ #jc p] c5t4 on tw5ty-five occasions4 ,ab\t #hj p] c5t4 ( ! silt 0 clay4 ,9 ano!r "p ( ! pap] quot$1 x is /at$ t ! silt susp5d$ 9 ! canal wat] av]ag$1 dur+ ! :ole ( "o flood season1 ab\t #a_/agjj ( ! volume ( ! wat]4 ,?is w\ld be ab\t #a_/abjj by weight4 ,! silt deposit$ 9 ! b$ ( ! canal1 9 a p]iod ( a few days1 0 sometimes z mu* z #a_/ajjj ( ! wat] :i* _h pass$ along1 & occasionally z mu* z #a_/ejj4 ,x 0 ne>ly all s&1 only ab\t #c p] c5t4 be+ clay4 ,silt ( classes f9] ?an 7#a7 gave no tr\ble1 & 7 to be elim9at$ 9 future inve/igations4 ,9 a canal1 z 9 a riv]1 ! s& on ! b$ becomes f9] ! fur!r f ! head4 ,reg>d+ ! di/ribution ( ! silt at v>i\s dep?s1 9 wat] #e to #ag feet deep1 ! quantity ( silt ne> ! b$ may1 :5 ! *>ge is heavy & consi/s ( mix$ silt1 be #a to #c times t at ! surface4 ,if ! *>ge is f9e mud1 !re is likely to be z mu* silt at ! surface z ne> ! b$1 if s&1 !re may be none at ! surface & little 9 ! upp] "p ( ! /ream4 ,9 all cases s+le obs]vations are likely to %[ extraord9>ily discordant results2 a numb] ( obs]vations mu/ be made at ea* po9t & av]ag$4 #f4 ,practical ,=mul & ,figures4--,a /ream :i* c>ries silt g5]ally rolls mat]ials along its b$4 ,! proportion betwe5 ! quantities ( mat]ial roll$ & c>ri$ is nev] kn[n1 & ?is makes x impossible to frame an exact =mula applicable to su* cases1 b ,k5n$y1 f 8 obs]vations on canals fully *>g$ ) ! heavy silt & f9e s& usually f\nd 9 ,indian riv]s ne> ! hills1 arriv$ at ! empirical =mula = critical velocities ,v #hd ,d#fd ,! obs]vations 7 made on ! ,b>i ,doab ,canal & its bran*es1 ! wid?s ( ! *annels v>y+ f #h feet to #ia feet1 & ! dep?s ( wat] f #bc feet to #gc feet4 ,! b$s ( ^! *annels h1 9 ! c\rse ( ye>s1 adju/$ !mselves by silt+ or sc\r+1 s t !re is a /ate ( p]man5t rgime1 ea* /ream c>ry+ its full *>ge ( silt1 & ! *>ges 9 all be+ ab\t equal4 ,f fur!r obs]vations ref]r$ to above 7,art4 #c1 p>4 #b7 x appe>s t ?is k9d ( silt =ms ab\t #a_/ccjj ( ! volume ( ! wat]1 & t on ! ,sirh9d ,canal1 s& co>s] ?an ! 7#aj7 class1 =m$ #a_/ce1jjj ( ! volume ( wat]4 ,! =mula gives ! foll[+ critical velocities = v>i\s dep?s3-- ,d #a #b #c #d #e #f #g ,v#j #hd #acj #agj #bjd #bce #bfd #bib ,d #h #i #aj ,v#j #cah #cdc #cfg4 ,9 ,indian riv]s n ne> ! hills ! silt c>ri$ is n s heavy1 & ! critical velocities are suppos$ to be ab\t ?ree-f\r?s ( ! above4 ,?rupp 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxi47 gives ! foll[+ ranges ( velocities z ^? :i* w enable /reams to c>ry diff]5t k9ds ( silt4 ,x does n appe> t ! /reams w\ld be fully *>g$ except at ! high] figure giv5 = ea* case4 ,d #aj #ajj ,v #ae to #bc #ce to #de 7,co>se s&74 ,v #ie to #ae #bc to #ce 7,heavy silt & f9e s&74 ,v #de to #ie #ab to #bc 7,f9e silt74 ,x _c be said t ! exact relations betwe5 ,d & ,v are yet kn[n1 b x is ( great practical importance to "k t ,v mu/ v>y ) ,d4 ,! precise mann] 9 :i* x mu/ v>y does n1 = mod]ate *anges1 make v mu* diff]5ce4 ,9 design+ a *annel a suitable relation ( dep? to velocity c be arrang$ =1 & "o quantity or ! o!r kept 9 ! asc5dant1 accord+ z sc\r+ or silt+ is ! evil to be gu>d$ aga9/4 ,! old idea 0 t an increase 9 ,v1 ev5 if accompani$ by an increase 9 ,d1 e4g4 simply runn+ a high] supply 9 a giv5 *annel1 gave increas$ silt-transport+ p[]4 ,9 a /ream ( v %all[ section ?is is probably correct1 = ,v increases fa/] ?an ,d#fd 7,hydraulics1 ,,*ap4 ,,vi41 ,art4 #b74 ,9 a /ream ( deep section a decrease 9 ,d gives increas$ silt-transport+ p[]4 ,if ! dis*>ge is fix$1 a *ange 9 ! dep? or wid? mu/ be met by a *ange ( ! opposite k9d 9 ! o!r quantity4 ,9 ?is case wid5+ or n>r[+ ! *annel may be prop] accord+ to circum/ances4 ,9 a deep section wid5+ w decrease ! dep? ( wat]1 & may also increase ! velocity1 & x w ?us give increas$ sc\r+ p[]4 ,9 a %all[ section1 n>r[+ w increase ! velocity m ?an x increases ,d#fd4 ,9 a m$ium section x is a matt] ( exact calculation to f9d out :e!r wid5+ or n>r[+ w improve matt]s4 ,if ! wat] ent]+ a *annel has a high] silt-*>ge ?an c be c>ri$ 9 ! *annel1 "s ( x mu/ deposit4 ,suppose an increas$ dis*>ge to be run1 & t ?is gives a high] silt-c>ry+ p[] & a small] rate ( deposit p] cubic foot ( dis*>ge1 x does n foll[ t ! deposit w be less4 ,! quantity ( silt ent]+ ! *annel is n[ great] ?an be=e4 ,ow+ to want ( k reg>d+ ! proportions ( silt & roll$ mat]ial1 & to want ( exactness 9 ! =mul1 reliable calculations reg>d+ proportions deposit$ _c be made4 ,! *annels 9 :i* ! obs]vations above ref]r$ to 7 made h all assum$ ne>ly rectangul> cross-sections1 ! sides hav+ become v]tical by ! deposit on !m ( f9] silt2 b ! =mula probably applies approximately to any *annel if ,d is ! mean dep? f side to side1 & ,v ! mean velocity 9 ! :ole section4 ,if ! ratio ( ,v to ,d diff]s 9 diff]5t p>ts ( a cross-section1 !re is a t5d5cy t[>ds deposit 9 ! p>ts :]e ! ratio is lea/1 or to sc\r :]e x is greate/4 ,!re is a t5d5cy = ! silt-*>ge to adju/ itself1 t is1 to become less :]e ! above ratio is less1 b ! irregul> movem5ts ( ! /ream cause a transf]5ce ( wat] among all p>ts1 & ?is t5ds to equalise ! silt-*>ge4 ,dubuat gives ! foll[+ z ! velocities close to ! b$ :i* w enable a /ream to sc\r or roll v>i\s mat]ials4 ,! b$ velocity is probably less ?an ! mean velocity 9 ! ratio ( ab\t #f to #a 9 r\gh *annels1 & ab\t #g to #a 9 smoo? *annels3-- ,gravel z l>ge z peas #gj feet p] second 0 0 ,fr5* beans #aj 0 0 0 0 #a in* 9 diamet] #bbe 0 0 0 ,pebbles #a in* 9 diamet] #ccc 0 0 0 ,heavy %+le #dj 0 0 0 ,s(t rock1 brick1 e>!nw>e #de 0 0 0 ,rock ( v>i\s k9ds #fj 0 0 0 & upw>d4 ,! figures = brick1 e>!nw>e1 & rock c apply only to mat]ials ( exce$+ly poor quality4 ,masonry ( good h>d /one w /& #bj feet p] second1 & in/ances h occurr$ 9 :i* brickwork has )/ood a velocity ( #ij feet p] second )\t injury s long z ! wat] did n c>ry s& & m]ely fl[$ along ! brickwork4 ,if !re are abrupt *anges 9 ! /ream1 caus+ eddies1 or if !re is impact & %ock1 or if s&1 gravel1 %+le1 or b\ld]s are liable to be c>ri$ along1 velocities mu/ be limit$4 #g4 ,action on ! ,sides ( a ,*annel4--,x has be5 se5 t ! laws ( silt+ & sc\r on ! b$ ( a *annel dep5d on ! ratio ( ! dep? to ! velocity4 ,! same laws probably hold good 9 ! case ( a g5tly %elv+ bank1 s t "h aga9 ,v ought to v>y z ,d#fd4 ,! velocity ne> ! angle :]e ! slope meets ! wat] surface seems to decrease fa/] ?an ,d#fd4 ,at all ev5ts1 silt t5ds to deposit 9 ! angle & ! slope to become /eep4 ,:5 ! slope is /eep ! law seems to be diff]5t1 ! t5d5cy = deposit or sc\r to occur on ! bank dep5d+ on ! actual velocity )\t mu* relation to ! dep?4 ,! velocity v ne> to a /eep bank is always l[ relatively to t 9 ! re/ ( ! /ream4 ,?us !re is (t5 a t5d5cy = silt to deposit on ! bank1 especially 9 ! upp] "p1 & = ! side to become v]tical except = a slight r\nd+ at ! l[] corn]4 ,a bank may receive deposits :5 ! b$ may be receiv+ none1 & x may h a p]si/5t t5d5cy to gr[ out t[>ds ! /ream4 ,! gr[? ( ! bank is g5]ally regul>1 ! l9e ( ! bank be+ pres]v$1 b x may be irregul>1 especially if vegetation1 o!r ?an small grass1 becomes e/abli%$ on ! new deposits4 ,:5 sc\r ( ! sides ( a *annel occurs x may occur by direct action ( ! /ream on ! sides ne> ! wat]-level1 or by action at or ne> ! toe ( ! slope1 :i* causes ! upp] "p ( ! bank to fall 94 ,su* fall+ 9 is g5]ally m or less irregul>1 & ! bank pres5ts an unev5 appe>ance4 ,! fall5 pieces ( bank may rema91 m or less intact1 especially if !y are held toge!r by ! roots ( grasses1 etc41 :]e !y fell1 & prev5t fur!r sc\r occurr+ along ! toe ( ! slope4 ,fall+ 9 ( banks is mo/ liable to occur 9 l>ge /reams & ) light soils4 ,x may be caus$ by ! waves :i* are produc$ by /eam]s & boats or1 especially 9 broad /reams1 by w9d4 ,! action on ! banks at b5ds is discuss$ 9 ,art4 #h4 ,?us 9 design+ a *annel accord+ to ! pr9ciples laid d[n 9 ,art4 #f1 ! "q ( action on ! sides ( ! *annel has to be dealt ) z foll[s4 ,:e!r or n ! velocity is to be l[1 relatively to ! dep?1 i4e4 :e!r or n deposit on ! b$ is m likely to occur ?an sc\r1 c>e c be tak5 n to make x actually too l[1 & n to make x actually too high1 p>ticul>ly if ! soil is light & friable4 ,) ord9>y soils a mean velocity ( #cc feet p] second 9 ! *annel is g5]ally safe z reg>ds sc\r ( ! sides4 ,any velocity ( m ?an #ce feet p] second may give tr\ble4 ,a velocity ( less ?an #a foot p] second is likely to give rise to deposit on ! sides4 ,9 *annels 9 alluvial soils ! fall+ 9 ( banks is sometimes said to occur m :5 ! /ream is fall+ ?an at o!r times4 ,?is has be5 notic$ on bo? ! ,mississippi & ! ,indus4 ,! cause has be5 said to be ! dra9+ out ( wat] :i* _h p]colat$ into ! bank1 ! wat] 9 fl[+ out c>ry+ "s s& ) x4 ,! effect ( ?is _c h[ev] be great4 #h4 ,action at ,b5ds4--,at a b5d1 ow+ to ! action ( c5trifugal =ce & to cross-curr5ts caus$ !reby1 !re is a deposit ne> ! convex bank & a correspond+ deep5+--unless ! b$ is too h>d to be sc\r$--ne> ! concave bank4 ,! wat]-level at ! concave bank is slightly high] ?an at ! convex bank4 ,! greate/ velocity in/ead ( be+ 9 mid-/ream is ne>] ! concave bank4 ,z ! transv]se curr5t & transv]se surface slope _c comm5ce or end abruptly1 !re is a c]ta9 l5g? 9 :i* !y v>y4 ,9 ?is l5g? ! radius ( curvature ( ! b5d & ! =m ( ! cross-section also t5d to v>y4 ,?is c (t5 be se5 9 plans ( riv] b5ds1 ! curvature be+ less %>p t[>ds ! ends4 ,:5 once a /ream has assum$ a curv$ =m1 be x ev] s slight1 ! t5d5cy is = ! b5d to increase4 ,! great] velocity & great] dep? ne> ! concave bank react on ea* o!r1 ea* induc+ ! o!r4 ,! concave bank is worn away1 or becom+ v]tical by erosion ne> ! b$1 cracks1 falls 91 & is wa%$ away1 a deposit ( silt occurr+ at ! convex bank1 s t ! wid? ( ! /ream rema9s tol]ably con/ant4 ,! b5d may g on increas+1 & x (t5 t5ds to move d[n/ream4 ,illu/ration3 ,,fig4 #b4 ,9 fig4 #b ! deep places are %[n by dott$ l9es4 ,along ! /raight dott$ l9e !re is no deep place4 ,su* a l9e w\ld be us$ = a =d4 ,at l[ wat] x becomes a %oal4 ,?is is ! *ief reason :y a tortu\s /ream at l[ wat] consi/s ( alt]nate pools & rapids4 ,x is sometimes said t deep wat] occurs ne> to a /eep h>d bank4 ,su* deep5+ is due to b5ds or ob/ructions :i* give ! curr5t a set t[>ds ! bank1 or x is due to irregul>ities 9 ! bank :i* cause eddies4 ,9 a /raight *annel ) ev5 & regul> banks !re is no su* deep5+4 ,:5 a b5d has =m$ 9 a *annel previ\sly /raight1 ! /ream at ! l[] end ( ! b5d1 by sett+ aga9/ ! opposite bank1 t5ds to cause ano!r b5d ( ! opposite k9d to ! fir/4 ,?us ! t5d5cy is = ! /ream to become tortu\s &1 :ile ! tortuosity is slight1 ! l5g?1 & !re=e ! slope & velocity1 are little affect$2 b ! action may cont9ue until ! increase 9 ! l5g? ( ! /ream mat]ially flatt5s ! slope1 & ! consequ5t r$uction 9 velocity causes erosion to cease4 ,or ! /ream dur+ a flood may f9d1 along ! *ord ( a b5d1 a direct r\te )1 ( c\rse1 a /eep] slope4 ,sc\r+ a *annel along ?is r\te x /raight5s itself1 & its action !n comm5ces afre%4 ,%ort cuts ( ?is k9d d n1 h[ev]1 occur s frequ5tly z is sometimes believ$4 ,9 "s /reams ! b5ds acquire a horse-%oe %ape & ! neck becomes v n>r[ & %ort cuts may !n occur4 ,o!rwise !y are n common4 ,v increases only z 7,s71 & if ! c\ntry is cov]$ ) vegetation x is n easy = a /ream to sc\r out a new *annel4 ,! effect ( b5ds on ! velocity ( a /ream is n well und]/ood4 ,9 case ( a b5d ( #ij ! increas$ resi/ance to fl[ :5 ! b5d is absolutely sudd5 7a sudd5 b5d is kn[n z an 8elb[07 am\nts p]haps to ,v#b_/7b;g74 ,:e!r x is great] or less 9 ! case ( a g5tle b5d ( #ij is n kn[n4 ,9 ! case ( a pipe !re is a c]ta9 radius :i* gives a m9imum resi/ance 7,hydraulics1 ,,*ap4 ,v474 ,! increas$ resi/ance at a b5d is due p>tly to ! fact t ! maximum velocity is no long] 9 ! c5tre ( ! /ream1 & p>tly to ! fact t ! velocities at ! diff]5t p>ts ( ! cross-section h to be re>rang$ at ! comm5cem5t ( ! b5d & aga9 at its t]m9ation4 ,?us ! effect ( a b5d ( #de is a good deal m ?an half ( t ( a b5d ( #ij4 ,two b5ds ( #de1 bo? 9 ! same direction1 ) a /raight rea* betwe5 !m1 w cause m resi/ance ?an a s+le b5d ( #ij ) ! /raight rea* above or bel[ ! b5d4 ,if ! two b5ds ( #de are 9 diff]5t directions ! resi/ance w be /ill great]4 ,a succession ( %>p b5ds may produce a s]i\s effect1 am\nt+ to an increase 9 r\ghness ( ! *annel4 ,a succession ( g5tle b5ds1 ( any consid]able angle1 _c ( c\rse occur )9 a mod]ate l5g? ( *annel4 ,:5 !re is head to sp>e !re is cle>ly no objection to b5ds1 except t ! bank may ne$ protection4 ,at a place :]e ! bank has 9 any case to be protect$1 e4g4 at a weir1 !re is no objection to an elb[4 #i4 ,g5]al ,t5d5cies ( ,/reams4--,s9ce ! velocity is great] z ! area ( ! cross-section is less1 a /ream always t5ds to sc\r :]e n>r[ or %all[1 & to silt :]e wide or deep4 ,! cross-section ?us t5ds to become uni=m 9 size4 ,suppose two cross-sections to be equal 9 size b diff]5t 9 %ape4 ,! velocities ( ! two sections w be equal4 ,! t5d5cy ( ! b$ to silt w 7,art4 #f7 be great] at ! deep] section &1 :5 silt+ has occurr$ on ! b$1 ! section w be r$uc$ & !re w be a t5d5cy to sc\r at ! sides4 ,?us ! cross-sections t5d to become also uni=m 9 %ape4 ,if a bank ( silt has =m$ 9 a /ream1 ! t5d5cy is = sc\r to occur4 ,!re is also a t5d5cy = silt to deposit j bel[ ! po9t :]e ! bank ends4 ,h5ce a silt bank (t5 moves d[n/ream4 ,ow+ to ! t5d5cy to sc\r alongside (1 or d[n/ream (1 ob/ructions 7,art4 #a71 x is cle> t a /ream con/antly t5ds to de/roy ob/ructions4 ,!re is an obvi\s t5d5cy = silt to deposit :]e ! b$ slope ( a /ream flatt5s1 & = sc\r to take place :]e x /eep5s 7,hydraulics1 figs4 #af & #ag1 pp4 #bd & #be71 & ?us ! t5d5cy is = ! slope to become uni=m4 ,9 a natural /ream fl[+ f hilly c\ntry to a lake or sea1 ! slope is /eepe/ at ! comm5cem5t & gradually flatt5s4 ,!re is ?us a t5d5cy = ! b$ to rise except at ! m\? ( ! /ream4 ,?is ris+ t5ds to increase ! slope & velocity 9 ! l[] rea*es1 & ?is aga9 enhances ! t5d5cy1 describ$ 9 ! prec$+ article1 ( ! /ream to increase 9 tortuosity4 ,:5 a silt-be>+ /ream ov]fl[s its banks ! dep? ( wat] on ! flood$ bank is probably small & its velocity v l[1 & a deposit ( silt takes place on ! bank4 ,:5 ! deposit has rea*$ a c]ta9 height x acts l a weir on ! wat] ( ! next flood1 :i* fl[s quickly ov] x &1 in/ead ( rais+ x high]1 deposits its silt fur!r away f ! /ream4 ,9 ?is way a /rip ( c\ntry along ! /ream gradually becomes rais$1 ! rais+ be+ greate/ close to ! /ream4 ,! c\ntry slopes d[nw>ds 9 go+ away f ! /ream4 ,9 o!r words1 ! /ream runs on a ridge4 ,if ! bank becomes rais$ s high t flood+ no long] occurs1 ! rais+ action ceases1 b if1 z is likely 9 alluvial c\ntry1 ! b$ ( ! /ream also rises1 ! action may cont9ue & ! ridge become v pron\nc$4 ,"s riv]s h v wide & s(t *annels :i* are only fill$ f bank to bank 9 floods1 if !n4 ,! deep /ream w9ds ab\t 9 ! *annel1 & ! re/ ( x is occupi$ by s&banks & m9or arms4 ,! w9d+ is ! result ( ! velocity be+ too great = ! *annel4 ,! /reams1 especially ! ma9 /ream1 con/antly %ift _! c\rses by sc\r+ "o bank or ! o!r4 ,n[ & !n ! ma9 /ream takes a %ort cut1 ei!r d[n a m9or arm or across an easily erod$ s&bank4 ,?is is a v diff]5t matt] f a %ort cut across high gr\nd4 ,! s&banks receive deposits ( silt 9 floods1 b are con/antly be+ cut away at ! sides4 ,su* riv]s frequ5tly erode _! banks to an extraord9>y ext5t4 ,! ,indus sometimes cuts into its bank #ajj feet or m 9 a day1 & x may cut = half a mile or m )\t cessation4 ,! tortuosity ( su* a /ream increases z x gets ne>] ! sea4 ,! actual l5g? ( ! ,indus 9 ! #djj miles ne>e/ ! sea is #ci p] c5t4 great] ?an its c\rse measur$ along ! bank4 ,9 ! rea* f ! #fjj? to ! #gjj? mile f ! sea1 ! diff]5ce is only #c p] c5t4 ,= a detail$ description ( "s su* riv]s1 see ,punjab ,riv]s & ,works4 ,sometimes g5]al /atem5ts are made reg>d+ silt+ or sc\r 9 connection1 = in/ance1 ) a /ream :i* is conf9$ betwe5 embankm5ts or tra9+ walls1 or has ov]fl[$ its banks or is held up by a weir4 ,x is impossible to say t any su* condition1 or any condition1 w cause silt+ or sc\r1 unless ! velocity dep? & silt *>ge are kn[n4 ,,*apt] ,v ,,me?ods ,,( ,,increas+ ,,or ,,r$uc+ ,,silt+ ,,or ,,sc\r #a4 ,prelim9>y ,rem>ks4--,mo/ important works :i* affect ! rgime ( a /ream h "s effect on its silt+ or sc\r+ action1 b ?is is n g5]ally _! *ief object4 ,su* works w be dealt ) 9 due c\rse1 & ! effects :i* !y are likely to produce on silt+ or sc\r+ w be m5tion$4 ,9 ! pres5t *apt] only ^? works & measures w be consid]$ ^: *ief object is to cause a /ream to alt] its silt+ or sc\r+ action4 ,x does n matt]1 s f> z ?is discussion is conc]n$1 :e!r ! object is direct1 i4e4 conc]n$ only ) ! p>ticul> place :]e ! effect is to be produc$1 or indirect1 z1 = in/ance1 :]e a /ream is made to sc\r 9 ord] t x may deposit mat]ial fur!r d[n ! /ream4 ,! protection ( banks f sc\r is consid]$ 9 ,,*ap4 ,,vi4 ,dr$g+ is dealt ) 9 ,,*ap4 ,,viii4 #b4 ,production ( ,sc\r or ,r$uction ( ,silt+4--,sometimes ! silt on ! b$ ( a /ream is artificially /irr$ up by simple measures1 z1 = in/ance1 by scrap]s or h>r[s atta*$ to boats :i* are all[$ to drift ) ! /ream1 or by means ( a cyl9d] :i* has claw-l tee? project+ f its circumf]5ce & is roll$ along ! b$1 or by fitt+ up boats ) %utt]s :i* are let d[n close to ! b$ & s cause a ru% ( wat] "u !m1 or by an*or+ a /eam] & work+ its screw propell]4 ,x is ?us possible to cause a great deal ( local sc\r1 b ! silt t5ds to deposit aga9 quickly1 & x is n easy to keep any consid]able l5g? ( *annel p]man5tly sc\r$4 ,! sy/em is suitable 9 a case 9 :i* a local %all[ or s&bank is to be got rid ( & deposit ( silt a little fur!r d[n is n objectionable4 ,x may be suitable 9 a case 9 :i* ! b$ is to be sc\r$ :ile a deposit ( silt at ! sides ( ! *annel is requir$1 especially if "s arrangem5t to enc\rage silt deposit at ! sides is us$ 7,art4 #c1 p>4 #d2 also ,,*ap4 ,,vi41 ,art4 #c74 ,hold+ back ! wat] by means1 = in/ance1 ( a regulator or movable weir1 & lett+ x 9 aga9 ) some:at ( a ru%1 w1 if frequ5tly repeat$1 h "s effect 9 mov+ silt on 9 ! d[n/ream rea*4 ,reg>d+ ! up/ream rea*1 x has be5 rem>k$ 7,,*ap4 ,,iv41 ,art4 #c7 t a weir does n necess>ily cause silt deposit4 ,if1 9 a /ream :i* does n ord9>ily silt1 a regulator or movable weir causes1 :5 ! wat] is head$ up1 "s silt deposit1 ! cessation ( ! head+ up n only removes ! t5d5cy to silt1 b ! section ( ! /ream1 at ! place :]e ! deposit occurr$1 is less ?an else:]e1 & !re is ?us a t5d5cy to sc\r !re4 ,if a regulator is alt]nately clos$ & op5$1 no p]man5t deposit ( mu* consequ5ce is likely to occur4 ,a /ream may be made to sc\r its *annel by op5+ an escape or bran*4 ,?is causes a draw 9 ! /ream1 & an increase 9 velocity = a long di/ance up/ream ( ! bifurcation 7,hydraulics1 ,,*ap4 ,,vii41 ,art4 #f74 ,?is proc$ure is sometimes adopt$ on irrigation canals4 ,! escape is g5]ally op5$ 9 ord] to r$uce ! quantity ( wat] pass+ d[n1 b x may be op5$ solely to induce sc\r or prev5t silt+4 ,! floor ( ! escape head is usually high] ?an ! b$ ( ! canal1 b ?is does n int]f]e ) op]ations except at l[ supplies4 ,x may 7,,*ap4 ,,iv41 ,art4 #b7 h "s effect on ! quantity ( roll$ mat]ial pass$ out ( ! escape4 ,if !re is a weir 9 ! riv] bel[ ! (f-take ( ! canal1 & if ! escape runs back to ! riv] & ?us has a good fall1 ! sc\r+ action 9 ! canal may be v p[]ful4 ,if ! ma9 *annel has a uni=m slope ?r\gh\t1 ! slope ( its wat] surface is great] up/ream ( ! escape ?an d[n/ream ( ! escape1 & !re is ?us an abrupt r$uction ( velocity & possibly a deposit ( silt 9 ! ma9 *annel bel[ ! escape4 ,?is may or may n be objectionable4 ,9 ! case ( an irrigation canal1 x is f> less objectionable ?an deposit 9 ! head ( ! canal4 ,! be/ po9t = ! (f-take ( any escape or sc\r+ *annel dep5ds on ! position ( ! deposits 9 ! ma9 *annel4 ,! (f-take %\ld be d[n/ream ( ! *ief deposits1 b z ne> to all ( !m z possible4 ,a brea* 9 a bank acts ( c\rse 9 ! same way z an escape4 ,a /ream ( cle> wat] :5 s5t d[n a *annel w sc\r x if ! mat]ial is suffici5tly s(t4 ,9 ! case ( ! ,sirh9d ,canal1 x has already be5 m5tion$ 7,,*ap4 ,,iv41 ,art4 #c71 t :5 ! riv] wat] became cle> aft] ! floods ! proportion ( co>se s&1 i4e4 s& above ! 7#aj7 class1 c>ri$ by ! canal wat] 0 ab\t #a_/ae1jjj by volume4 ,?is 0 9 ! p]iod f #bbnd ,septemb] to #g? ,octob]4 ,f #h? to #bcrd ,octob] ! proportion av]ag$ #a_/cb1jjj f #bd? ,octob] to #h? ,novemb] #a_/dd1jjj1 & f #i? to #bd? ,novemb] #a_/he1jjj4 ,! reason ( ?is r$uction 0 t ! comp>atively cle> wat] kept pick+ up ! s& f ! b$ & mov+ x on1 ! f9] k9ds be+ mov$ mo/ quickly4 ,z ! co>se s& left on ! b$ became less 9 quantity1 ! wat] took up less4 ,x appe>s1 h[ev]1 t ! wat] also pick$ up "s clay :i* 0 left1 & t ! total susp5d$ silt 9 ,novemb] 0 #a_/ijjj ( ! wat]4 ,all ! obs]vations m5tion$ 9 ?is p>agraph appe> to h be5 made at ,g>hi1 #bf miles f ! head ( ! canal4 #c4 ,production ( ,silt ,deposit4--,works or measures = caus+ silt deposit may be und]tak5 9 ord] to cause silt deposit 9 specific places :]e x w be useful1 or 9 ord] to free ! wat] f silt4 ,sometimes bo? objects are comb9$4 ,if a /ream c be turn$ into a l>ge pond or l[ gr\nd--a bank be+ built r\nd x if necess>y--x c be made to "p ) "s or all ( its silt :e!r roll$ or susp5d$4 ,ev5 if ! pond is s l>ge t ! velocity becomes imp]ceptible1 ! :ole ( ! susp5d$ matt] w n deposit unless x has suffici5t "t1 b ! matt] :i* rema9s 9 ! wat] is likely to be extremely small 9 am\nt4 ,! silt+ up ( m>%es1 pools1 borr[-pits1 etc41 is n[ be+ effect$1 or %\ld be effect$1 9 places :]e mosquitoes & mal>ia are preval5t4 ,9 ! upp] or torr5tial "p ( a /ream1 a high dam1 provid$ ) a sluice & a high-level wa/e weir1 may be built across x4 ,! space above ! dam becomes m or less fill$ ) gravel1 etc4 ,?is has be5 done 9 ,switz]l& 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxi474 ,9 ! ,u4,s4,a4 long weirs h be5 built 9 ord] to /op ! progress ( detritus f gold m9es4 ,su* detritus 0 liable to *oke up riv]s & damage ! adjo9+ l&s4 ,! detritus f hill torr5ts c also be r$uc$ by af=e/ation ( ! hill sides4 ,illu/ration3 ,,fig4 #c4 ,illu/ration3 ,,fig4 #d4 ,:5 a /ream is 9 embankm5t--irrigation *annels are frequ5tly s--! bank c be set back 7fig4 #c71 & susp5d$ silt w !n deposit on ! b]ms4 ,! object ( ?is arrangem5t is g5]ally to create v /rong banks 9 l[ gr\nd4 ,a simil> plan c be adopt$ :5 ! b]m is only slightly bel[ ! wat]-level & ev5 :5 x is only occasionally subm]g$4 ,9 ?is case ! deposit ( a small bank ( silt along ! edge ( ! b]m next ! /ream w prev5t ! access ( fre% supplies ( silt-be>+ wat] to ! p>ts fur!r away4 ,gaps %\ld be cut 9 ! bank ( silt at int]vals1 & cross banks made to =m 8silt+ tanks10 z %[n 9 fig4 #d4 ,! inlets to ! tank %\ld be l>ge1 & ! outlets small1 s t ! wat] 9 ! tank may h little velocity4 ,x is n1 h[ev]1 correct to h ! outlet s small--unless ! wat] conta9 v little silt--t !re is v little fl[ ?r\gh ! tank4 ,! tanks w g5]ally be silt$ up mo/ quickly by all[+ a good fl[ ?r\gh !m1 ev5 ?\gh only a small proportion ( ! silt 9 ! wat] is deposit$4 ,regul> banks arrang$ to =m tanks on ! above pr9ciple c be made beh9d ! orig9al banks ( a canal 9 cases :]e ! orig9al banks 7 n1 = any reason1 set back4 ,:5 a *annel is made 9 l[ gr\nd & ! excavation is n suffici5t to make ! banks1 borr[-pits c be dug 9 ! b$ ( ! *annel4 ,su* pits %\ld n be long & cont9u\s1 b wide b>s %\ld be left s t a numb] ( %ort pits w result4 ,^! pits w trap roll$ mat]ial z well z susp5d$ silt4 ,! object 9 ?is case is to free ! wat] f silt & to r$uce ! size ( ! *annel & ?us r$uce ! loss ( wat] f p]colation4 ,on ! ,indus1 :]e x has a /rong t5d5cy to %ift we/w>ds1 long e>!n dams or groynes are run out f ! we/ bank across ! s&banks4 ,"o object is to cause silt deposit1 & s increase ! quantity ( mat]ial :i* ! riv] w h to cut away1 b :e!r ?is result is a*iev$ is d\btful4 ,! s&banks receive deposits 9 any case4 ,a groyne may increase ! deposit on its up/ream side1 b x cuts (f ! flood wat] f its d[n/ream side & s r$uces ! deposit !re4 #d4 ,arrangem5ts at ,bifurcations4--,at a bifurcation1 z :]e a bran* takes (f f a canal1 x is possible to r$uce ! quantity ( roll$ mat]ial ent]+ ! canal by rais+ its b$ or con/ruct+ a weir or 8sill0 9 its head4 ,?is arrangem5t may h great effect 9 exclud+ b\ld]s1 %+le1 or gravel4 ,z reg>ds roll$ s&1 x has mu* less effect ?an might be expect$ 7,,*ap4 ,,iv41 ,art4 #b74 ,if ! canal is r$uc$ 9 wid? 7fig4 #e7 !re w be eddies bel[ ! b$ level ( ! bran*4 ,!y w /ir up ! s& & "s ( x w ent] ! bran*4 ,if ! canal is n r$uc$ 9 wid?1 eddies w be produc$ 9 ! surface wat]1 & !y w affect ! b$4 ,! above rem>ks apply also to ! case ( a canal tak5 (f f a riv] :5 !re are no works 9 ! riv]4 ,illu/ration3 ,,fig4 #e4 ,illu/ration3 ,,fig4 #f4 #e4 ,a ,canal ) ,headworks 9 a ,riv]4--,9 ! case ( a canal tak+ (f f a riv] & provid$ ) complete headworks1 x is possible to d a great deal m4 ,! case ( ! ,sirh9d ,canal1 already ref]r$ to 7,,*ap4 ,,iv41 ,arts4 #e & #f71 is a notable example4 ,! canal 7fig4 #f7 is m ?an #bjj feet wide1 ! full dep? ( wat] #aj feet1 & ! full dis*>ge ab\t #gjjj cubic feet p] second4 ,9 #ahic :5 ! irrigation _h develop$1 & x became necess>y to run high supplies 9 ! summ]--,july1 ,augu/1 & "p ( ,septemb]--! increase 9 ! silt deposit ?reat5$ to /op ! work+ ( ! canal4 ,9 ! autumn & w9t]1 say f #be? ,septemb] to #ae? ,m>*1 ! wat] ent]+ ! canal is cle> & mu* ( ! deposit 0 pick$ up by x1 b n all4 ,9 ! five ye>s #ahic to #ahig inclusive1 ! foll[+ rem$ial measures 7 adopt$4 ,increas$ use 0 made ( ! escape at ! twelf? mile4 ,?is did "s good1 b !re 0 seldom wat] to sp>e4 ,9 #ahic to #ahid ! sill ( ! regulator 0 rais$ to #g feet above ! canal b$1 & x 0 possible to raise x #c feet m by means ( %utt]s4 ,?is _h little effect4 ,! co>se/ class ( s& 0 #d1 & ! velocity ( ! wat]1 ev5 ( t "p ( x :i* came up f ! riv] b$ & pass$ ov] ! sill1 0 ov] #b feet p] second1 s t all s& 0 c>ri$ ov]4 ,9 #ahid to #ahie ! divide wall1 :i* _h be5 only #ei feet long1 0 l5g!n$ to #gaj feet1 s z to make a pond betwe5 ! divide wall & ! regulator1#h b probably ! leakage ?r\gh ! "u-sluices 0 (t5 z mu* z ! canal supply1 & ! wat] 9 ! pond 0 ?us kept 9 rapid movem5t & full ( silt4 ,! canal 0 clos$ 9 heavy floods4 ,?is did "s good1 b probably ! canal 0 (t5 clos$ ne$lessly :5 ! wat] look$ muddy b conta9$ no excessive quantity ( s&4 ,! above comm5ts on ! measures tak5 7 made by ,mr ,k5n$y :5 *ief eng9e]4 ,! above measures did n r$uce ! silt deposits1 b ! sc\r 9 ! cle> wat] season improv$1 probably because high] supplies 7 run ow+ to increas$ irrigation4 ,! deposit 9 ! upp] rea*es ( ! canal1 :5 at its maximum ab\t ! end ( ,augu/ ( ea* ye>1 0 g5]ally m ?an tw5ty million cubic feet4 ,f ! ye> #aijj a bett] sy/em ( regulation 0 en=c$1 ! "u-sluices be+ kept clos$ z mu* z possible1 s t !re 0 mu* less movem5t 9 ! pond & mu* less silt 9 its wat]4 ,by #aijd ! deposit 9 ! canal _h be5 r$uc$ to ?ree million cubic feet1 & no fur!r tr\ble occurr$4 ,dur+ ! p]iod f #bj? ,septemb] #aijh to #aj? ,octob] #aijh ! quantity ( silt 9 ! canal above ,*amk\r 7twelf? mile7 decreas$ f #ai1cbe1hjj cubic feet to #ab1dgg1fjj cubic feet4 ,! quantity sc\r$ away 0 #f1hdh1bjj cubic feet4 ,dur+ ?is p]iod no silt ent]$ ! canal4 ,! quantity :i* pass$ out ( ! rea* 9 "q 9 susp5sion 0 #d1ahc1ffj cubic feet1 s t #b1ffd1edj cubic feet ( mat]ial mu/ h be5 roll$ along ! b$4 ,! roll$ mat]ial 0 #fd p] c5t4 ( ! susp5d$ mat]ial4 ,dur+ ?is p]iod ! ,dah] escape1 9 ! twelf? mile1 0 op51 & ! mean velocity 9 ! canal j above ! escape 0 ab\t #d feet p] second1 ! dep? ( wat] be+ ab\t #aj feet4 ,! velocity ne> ! escape 0 ?us great] ?an ! critical velocity = mix$ silt 7,,*ap4 ,,iv41 ,art4 #f71 & ev5 a long way up ! canal x w\ld be 9 excess ( ! critical velocity4 ,! wat] seems to h c>ri$ ab\t #a_/ahjj ( its volume ( silt4 ,:e!r ! above proportions ( roll$ to susp5d$ matt] w\ld hold good 9 a fully *>g$ /ream fl[+ ) ! critical velocity x is n easy to say4 ,z silt deposits 9 ! pond1 ! velocity ( ! wat] 9 x1 along ! c\rse ( ! ma9 curr5t t[>ds ! canal1 increases & ev5tually ! wat] beg9s to c>ry co>se s& dang]\s = ! canal4 ,9 ord] to asc]ta9 :5 ?is /ate ( affairs has be5 rea*$1 two me?ods ( proc$ure are possible4 ,"o is to frequ5tly te/ specim5s ( ! wat] 9 ! pond along ! c\rse ( ! ma9 curr5t & see :5 x conta9s m ?an #a_/ae1jjj ( its volume ( co>se s&4 ,?is plan w\ld be tr\blesome & liable to error1 & is reject$ by ,k5n$y1 :o sugge/s t ! dep? & velocity ( ! wat] 9 ! pond be frequ5tly obs]v$ along ! c\rse ( ! ma9 curr5t4 ,z soon z ! velocity exce$s ! critical velocity = mix$ silt1 x is "t to close ! canal & op5 ! "u-sluices & sc\r out ! deposit f ! pond4 ,! p]iod 9 :i* mo/ silt is believ$ to h be5 deposit$ 9 ! canal is ! spr+ & e>ly summ]1 say f #ae? ,m>* to #a/ ,july4 ,?is is ! "t :5 ! sn[s are melt+ & ! riv] wat] is cle>4 ,x c !n c>ry m s& ?an 9 ! ra9s--#a/ ,july to #ae? ,septemb]1--:5 x is muddy4 ,k5n$y also sugge/s t "s "u-sluices %\ld be provid$ at ! f> side ( ! riv]1 i4e4 at ! "r-h& side ( ! weir4 ,x w\ld !n be possible1 by op5+ !m1 to let floods pass )\t int]f]+ ) ! pond4 ,! two spurs or groynes1 %[n 9 ! plan1 7 con/ruct$ 9 #ahig s z to cause ! /ream to fl[ along ! face ( ! canal regulator & n all[ deposits to accumulate !re4 ,! dep? ( silt deposit$ 9 a great "p ( ! pond am\nt$ at times to #h or #aj feet4 #f4 ,protection ( ! ,b$4--,x is possible to af=d direct protection f sc\r to ! b$ ( a /ream by con/ruct+ walls across x1 b unless ! walls are ne> toge!r ! protection w n be effective4 ,an arrangem5t us$ 9 "s /reams 9 ,switz]l& consi/s ( tree trunks secur$ by %ort piles & re/+ on bru%wood4 ,b z long z ! walls are n rais$ above ! b$ !y _c entirely /op sc\r1 unless extremely close toge!r4 ,if rais$ above ! b$ !y =m a s]ies ( weirs4 ,! weirs mu/ be s design$ t ! dep? ( wat] 9 a rea* betwe5 two weirs is great en\gh to r$uce ! velocity d[n to ! critical velocity1 or less4 ,! fall 9 ! wat] surface at ea* weir be+ v small1 ! dis*>ge ov] ! weir c be f\nd by consid]+ x z an orifice ext5d+ up to ! d[n/ream wat] surface1 & ! head be+ ! fall 9 ! surface at ! weir4 ,to /op sc\r ( ! b$ by direct protection )\t rais+ ! wat]-level1 ! b$ c be pav$1 a plan adopt$ 9 artificial *annels ) v high velocities4 ,! pav+ c be ( /ones1 bricks1 or concrete blocks4 ,! ,villa sy/em ( protection1 :i* has be5 us$ 9 ,italy1 ,france1 & ,spa91 consi/s ( a flexible cov]+ laid on ! b$4 ,prisms ( burnt clay or cem5t are /rung on sev]al p>allel galvaniz$ iron wires1 :i* are atta*$ to cross-b>s s z to =m a grid a few feet squ>e4 ,! grids are loosely connect$ to "o ano!r at ! corn]s1 & ! :ole cov]+ adju/s itself to ! irregul>ities ( ! b$ 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cxlvii474 ,! special protection or pav+ requir$ 9 connection ) weirs & su*-l works is consid]$ 9 ,,*ap4 ,x41 ,arts4 #b & #c4 ,,*apt] ,,vi ,,works ,,= ,,! ,,protection ,,( ,,banks #a4 ,prelim9>y ,rem>ks4--,! protection ( a l5g? ( bank f sc\r may be effect$ by spurs1 :i* are works project+ into ! /ream at int]vals1 or by a cont9u\s l9+ ( ! bank4 ,a spur =ms an ob/ruction to ! /ream 7,,*ap4 ,,iv41 ,art4 #a71 & :5 con/ruct$1 or ev5 p>tly con/ruct$1 ! sc\r ne> its end may be v sev]e1 ev5 ?\gh !re may be little contraction ( ! /ream z a :ole4 ,if ! b$ is s(t a hole is sc\r$ out4 ,into ?is hole ! spur keeps subsid+1 & its con/ruction1 or ev5 its ma9t5ance1 may be a matt] ( ! greate/ difficulty4 ,a high flood may de/roy x4 ,if x does n d s1 x may be because ! /ream has1 = "s reason1 ceas$ to attack ! bank at t place4 ,a cont9u\s l9+ ( ! bank is n op5 to any objection1 & is g5]ally ! be/ me?od ( protection4 ,spurs made ( l>ge numb]s ( r small trees1 weight$ ) nets fill$ ) /ones1 h be5 us$ on ! great %ift+ riv]s ( ! ,punjab :i* swall[$ up enorm\s quantities ( mat]ials4 ,! use ( spurs on su* riv]s has n[1 9 mo/ cases1 be5 giv5 up4 ,if ,l is ! l5g? ( a spur measur$ at "r angles to ! bank1 ! l5g? ( bank :i* x protects is ab\t #g ,l--#c ,l up/ream & #d ,l d[n/ream1--b ! spur has to be /rongly built1 & its co/ is1 9 _m cases1 n mu* less ?an ! exp5se ( protect+ ! :ole bank ) a cont9u\s l9+4 ,:atev] me?od is adopt$1 a plan1 l>ge en\gh to %[ all irregul>ities1 %\ld always be prep>$1 & ! l9e to :i* x is int5d$ t ! bank %all be br\ght m>k$ on x4 ,illu/ration3 ,,fig4 #g4 ,sometimes natural spurs exi/ z1 = in/ance1 :]e a tree projects into a /ream or has fall5 into x1 & ! holes betwe5 ! spurs may be deep1 s t a cont9u\s protection w\ld be exp5sive4 ,or !re may be trees /&+ 9 su* positions t1 if fell$1 !y w be 9 good places = spurs4 ,9 cases su* z ! above1 spurs may be suitable ev5 9 a /ream ) a s(t *annel4 ,reg>d+ ! use ( spurs or groynes = div]sion works or = r$uc+ ! wid? ( a /ream1 see ,,*ap4 ,,vii41 ,art4 #a1 & ,,*ap4 ,,viii41 ,art4 #c4 #b4 ,spurs4--,a spur may be made (-- 7a7 ,loose /one1 :i* may be fac$ ) rubble above l[-wat] level 7fig4 #g74 7b7 ,lay]s ( fasc9es weight$ ) gravel or /ones4 7c7 ,e>? or s& closely cov]$ ) fasc9es4 7d7 ,a d\ble l9e ( /akes ) fasc9es or bru%wood laid betwe5 !m 7fig4 #h74 7e7 ,a s+le l9e ( /akes ) plank+ or basket "w on its up/ream side1 or ) twigs or wattle laid horizontally & pass$ 9 & out ( ! /akes1 z 9 fig4 #bj4 7f7 ,a s+le tree ) ! ?ick end ( ! trunk on ! bank & ) /akes1 if necess>y1 to prev5t ! curr5t f mov+ x4 7g7 ,a numb] ( small trees heap$ toge!r & weight$ ) nets full ( /ones4 7h7 ,a lay] ( poles & ov] !m a lay] ( fasc9es on :i* are built walls ( fasc9e "w s arrang$ z to =m cells or holl[ rectangul> spaces :i* become fill$ ) silt4 7i7 ,l>ge fasc9es runn+ out into ! /ream & hav+ _! inn] ends /ak$ to ! bank :ile ! out] ends float1 o!r fasc9es be+ add$ ov] !m & project+ fur!r into ! /ream1 & ! :ole ev5tually s9k+4 ,illu/ration3 ,,fig4 #h4 ,comb9ations ( ! above are also us$1 = in/ance1 7d7 or 7e7 may be us$ = ! upp] portion1 ! f\ndation be+ 7a7 or 7c74 ,illu/ration3 ,,fig4 #i4 ,illu/ration3 ,,fig4 #aj4 ,illu/ration3 ,,fig4 #aa4 ,in/ead ( runn+ out at "r angles to ! bank a spur may be incl9$ some:at d[n/ream4 ,?is some:at r$uces ! eddy+ & sc\r r\nd ! end4 ,! ends ( a sy/em ( spurs %\ld be 9 ! l9e :i* x is int5d$ t ! edge ( ! /ream %all h 7fig4 #i74 ,! tops ( %ort spurs are usually above high flood level4 ,sometimes spurs are made to slope d[nw>ds 7fig4 #aj71 & !y !n cause less di/urbance ( ! wat] & less sc\r ?an if built to ! =m %[n by ! dott$ l9e4 ,su* spurs are sometimes comb9$ ) a l[ wall runn+ across ! b$ ( ! /ream1 ! :ole =m+ a 8pr(ile0 ( ! cross-section to :i* x is int5d$ to br+ ! *annel4 ,reg>d+ su* walls1 see ,,*ap4 ,v41 ,art4 #f4 ,:5 a spur is long x may h small subsidi>y spurs 7fig4 #aa7 to r$uce ! ru% ( wat] along x2 or its end may h to be protect$ 9 ! same mann] z ! advanc+ end ( a closure dam 7,,*ap4 ,,vii41 ,art4 #b74 ,! foll[+ is a curi\s case ( misconception ( ! action ( spurs4 ,9 #aiji ! riv] ,indus 0 erod+ its "r bank & ?reat5+ to de/roy ! t[n ( ,d]a ,ghazi ,khan4 ,a clump ( date palms =m$ a promontory & resi/$ erosion to "s ext5t4 ,a sugge/ion 0 made--by an eng9e] ( em95ce :o _h =m]ly be5 consult$ 9 ! case--to ! effect t ! date palms be remov$1 ! reason giv5 be+ t !y caus$ di/urbance & sc\r4 ,on ?is pr9ciple spurs w\ld h to be made n to protect a bank b to cause x to be erod$4 #c4 ,cont9u\s ,l9+ ( ! ,bank4--,! l9+ or protection ( a bank may be ( /one or brick pit*+ 7figs4 #ab & #ac71 loose /one 7fig4 #ad71 fasc9es 7fig4 #ae71 turf+1 plantations1 bru%wood1 or ( o!r mat]ials laid on ! slopes4 ,be=e protect+ a bank x is be/ to remove irregul>ities & br+ x to a regul> l9e4 ,?is c g5]ally be done mo/ easily by fill+ 9 holl[s1 b sometimes x is done by cutt+ (f projections4 ,x is also necess>y to make ! side slope uni=m4 ,:]e ! slope is z %[n by ! dott$ l9es 9 figs4 #ab to #ad1 fill+ 9 c be effect$1 b cutt+ away ! upp] "p ( ! slope is also feasible4 ,su* cutt+ away has be5 propos$ z a rem$y 9 itself 9 cases :]e ! /eep upp] "p ( ! slope 0 fall+ 91 b x is n mu* ( a rem$y4 ,/one pit*+ may re/1 if boats are requir$ to come close to ! bank1 on a toe wall ( concrete1 z 9 fig4 #ac1i or o!rwise on a f\ndation ( loose /one1 z 9 fig4 #ab4 ,:5 concrete is us$ ! b$ is dr$g$ to su* a dep? z w provide aga9/ und]m9+ by sc\r4 ,slop+ bo>ds atta*$ to piles are plac$ along ! front face & ! concrete is ?r[n 9 "u wat]4 ,! slope ( /one or brick pit*+ is usually f #b to #a to #a to #a1 b x may be z /eep z to #a4 ,! e>? beh9d ! pit*+ mu/ be well ramm$ 9 lay]s4 ,9 ord] to prev5t ! e>? f be+ eat5 away by ! wat] :i* p5etrates ?r\gh ! int]/ices ( ! /one or brick1 a lay]1 #c to #f in*es ?ick1 ( gravel or balla/ is plac$ ov] ! e>? & ramm$4 ,:5 loose /one is us$1 dr$g+ is n necess>y1 b ! /one is all[$ to gradually s9k d[n & m is add$ at ! top4 ,a c]ta9 proportion ( ! /ones %\ld be ( l>ge size4 ,illu/ration3 ,,fig4 #ab4 ,illu/ration3 ,,fig4 #ac4 ,:5 fasc9+ is us$1 long twigs are made into bundles & ti$ up at e #b feet s z to =m fasc9es ab\t #d to #f in*es ?ick1 & ^! are laid on ! slopes & secur$ by pegs driv5 9 at %ort int]vals1 betwe5 ! fasc9es4 ,illu/ration3 ,,fig4 #ad4 ,illu/ration3 ,,fig4 #ae4 ,sometimes ! pit*+ or loose /one is n c>ri$ up to ! top ( ! bank1 or ev5 up to high flood-level1 & ! bank above ! pit*+ is protect$ by turf+--! pieces ( turf be+ plac$ on edge normally to ! slope if v /eep 7fig4 #ad7 or laid p>allel to ! slope if x is n v /eep--or1 above ord9>y wat]-level1 by plantations ( osi]s or will[s :i* ob/ruct ! wat] & t5d to cause silt+1 & ^: roots b9d ! banks toge!r4 ,illu/ration3 ,,fig4 #af4 ,ano!r me?od ( us+ fasc9es is to lay !m on ! slopes ) _! l5g?s normal to ! direction ( ! /ream4 ,! upp] end ( a fasc9e is above l[ wat]1 & ! l[] end ext5ds d[n to ! b$ ( ! /ream4 ,sometimes l>ge ropes made ( /raw1 or r\gh mats made ( grass1 are laid on ! slopes & pegg$ d[n1 or mattresses ( fasc9es are laid on ! slopes & weight$ ) /ones4 ,illu/ration3 ,,fig4 #ag4 ,a deep recess 9 ! bank 7fig4 #af7 c be fill$ 91 be=e ! protection is add$1 ) e>? well ramm$4 ,on ! ,adige ! fill+ mat]ial consi/$ 7fig4 #ag7 ( faggots fill$ ) /ones1 small cross dams be+ made at int]vals1 z %[n by ! dott$ l9es1 to arre/ flood wat] & cause x to deposit silt4 ,at ! back ( ! b]m1 popl> or will[ slips 7 plant$1 & ^! grew up & _! roots held ! bank toge!r4 ,?is sy/em succe$$ well4 ,a me?od ( protection :i* is suitable :5 ! wat] conta9s mu* silt is :at is kn[n 9 ,india z bu%+4 ,l>ge leafy bran*es ( trees are cut & hung1 z %[n 9 fig4 #ah1 by ropes to pegs4 ,!y mu/ be closely pack$ s z n to %ake4 ,at fir/ !y require look+ aft]1 b silt rapidly deposits & ! bran*es become fix$ & no long] dep5d5t on ! ropes4 ,if ! "w is c>efully done1 ! result is a smoo?1 regul>1 & t5aci\s b]m1 z p] dott$ l9e 9 ! figure4 ,illu/ration3 ,,fig4 #ah4 ,illu/ration3 ,,fig4 #ai4 ,ano!r me?od1 us$ on canals1 is to make up ! bank ) e>? & to revet x ) twigs or re$s1 z %[n 9 fig4 #ai4 ,! f\ndation mu/ be tak5 d[n well bel[ b$-level1 o!rwise ! "w may slip4 ,?is k9d ( "w _c be done except :5 ! canal is dry4 ,if ! bank consi/s ( s& or ( v s&y soil1 x mu/ 9 any case h a flat side slope su* z #c to #a4 ,if ! s& is 9 lay]s alt]nat+ ) firm soil1 x is a good plan to dig out "s ( ! s& & to replace x ) clods ( h>d e>?4 ,/ak+ 7fig4 #bj7 may be us$1 ! /akes be+ "o or two feet ap>t f c5tre to c5tre1 & long twigs laid horizontally be+ pass$ 9 & out ( ! /akes1 or bu%+ fill$ 9 beh9d ! /akes4 ,b bu%+ alone is *eap] & ne>ly z good4 ,illu/ration3 ,,fig4 #bj4 ,= protect+ ! banks ( ! ,indus x has be5 propos$ 7,punjab ,riv]s & ,works1 ,,*ap4 ,,iv47 to use trees 9 exactly ! same mann] z bu%+1 ! trees be+ gr[n 9 sev]al r[s p>allel to ! riv] s t :5ev] ! riv]1 by erod+ its bank1 comes up to ! l9es ( trees ! fir/ r[ w fall 94 ,! fir/ r[ w\ld be *a9$ to ! second1 :i* w\ld take ! place ( ! pegs us$ 9 bu%+4 ,! o!r r[s w\ld rema9 z a res]ve4 ,! ,villa sy/em ( b$ protection 7,,*ap4 ,v41 ,art4 #f7 has also be5 successfully us$ = bank protection on ! ,s*eldt1 & on ! ,brussels-,gh5t ,canal1 ! prisms be+ ab\t #aj #aj #d in*es1 & hav+ ov]lapp+ jo9ts4 ,! b&s ( prisms are plac$ 9 position by a boat1 ! b&s unroll+ ov] a drum4 ,! boat is provid$ ) an oscillat+ plat=m c>ry+ roll]s at its end4 ,a ?9 lay] ( gravel is laid ov] ! bank & is press$ d[n by ! roll]s be=e ! prisms are laid on x 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cxxxiv41 & vol4 clxxv474 ,9 ! case ( ! riv] m5tion$ 9 ,,*ap4 ,,xi41 ,art4 #c1 :]e extremely high velocities 7 met )1 cyl9drical rolls ( wire-nett+ 7 made1 ea* #ej feet long & #e feet 9 diamet]1 & fill$ ) b\ld]s4 ,^! rolls c be us$ = bank protection4 ,! nett+ 0 made by wires #f in*es ap>t1 cross+ ea* o!r at "r angles & ti$ toge!r at ! cross+s by %ort pieces ( wire4 ,illu/ration3 ,,fig4 #ba4 ,on %ip canals a b]m 7fig4 #ba7 is frequ5tly made a few feet bel[ ! wat]-level4 ,x s]ves z a f\ndation = ! pit*+1 :i* ne$ n usually ext5d d[n to m ?an #e feet bel[ ! wat]-level4 ,bel[ t ! wa% has little or no effect on ! banks4 ,on ord9>y navigation canals a simil> b]m is sometimes made--"o or two feet 9 wid? & a foot or less bel[ ! wat]-level--& ru%es are plant$ on x4 ,sometimes a bank has be5 protect$ by a k9d ( artificial we$1 consi/+ ( bu%es or bran*es ( trees atta*$ to ropes4 ,! end ( ! rope is fa/5$ to ! bank & ! we$s float 9 ! /ream alongside ! bank4 ,to protect a bank f ice1 :i* ex]cises an uplift+ =ce on pit*+1 use has be5 made ( a cov]+ ( a k9d ( re9=c$ concrete consi/+ ( slabs ( concrete ) wires emb$d$ 9 x1 & fa/5$ to ! bank by wires1 #bj in*es long1 runn+ into ! bank1 ^! wires be+ emb$d$ 9 mort> s z to act l /akes4 ,illu/ration3 ,,fig4 #bb4 #d4 ,heavy ,/one ,pit*+ ) ,apron4--,on ! great %ift+ riv]s ( ,india a sy/em ( bank protection is adopt$1 consi/+ ( a pit*$ slope ) an apron 7fig4 #bb74 ,! sy/em is us$ *iefly 9 connection ) railway bridges or weirs1 b x has be5 us$ 9 "o in/ance1 t ( ,d]a ,ghazi ,khan1 = ! protection ( ! bank ne> a t[n4 ,:51 z is usual1 ! flood-level is high] ?an ! riv] bank1 an artificial bank is made4 ,9 any case ! bank is prop]ly align$4 ,! pit*+ has a slope ( #b to #a1 & consi/s ( qu>ri$ blocks ( /one loosely laid1 ! l>ge/ blocks weigh+ p]haps #abj lbs4 ,! apron is laid at ! "t ( l[ wat] on ! s&bank or b$ ( ! /ream4 ,if necess>y1 ! gr\nd is specially levell$ = x4 ,x is int5d$ to slip :5 sc\r occurs4 ,! foll[+ dim5sions ( ! apron are giv5 by ,spr+ 7,gov]nm5t ( ,india ,te*nical ,pap]1 ,no4 #aec1 8,riv] ,tra9+ & ,control on ! ,guide ,bank ,sy/em10 #aijd74 ,! probable maximum dep? ( sc\r c be calculat$ z expla9$ 9 ,,*ap4 ,,xi41 ,art4 #c4 ,if ?is dep?1 measur$ f ! toe ( ! slope pit*+ is ,d1 & if ,t is ! ?ickness consid]$ necess>y = ! slope pit*+1 !n ! wid? ( ! apron %\ld be #ae ,d1 & its ?ickness #abe ,t next ! slope & #bh ,t next ! riv]4 ,x w !n be able to cov] ! sc\r$ slope to a ?ickness ( #abe ,t4 ,?is ?ickness is made great] ?an ,t because ! /one is n likely to slip q regul>ly4 ,! ?ickness ,t %\ld1 accord+ to ,spr+1 be #af in*es to #eb in*es1 be+ lea/ ) a sl[ curr5t & a *annel ( co>se s&1 & greate/ ) a m rapid curr5t & f9e s&2 b s9ce ! s& is g5]ally f9] z ! curr5t is sl[]1 x w\ld appe> t a ?ickness ( ab\t #c feet w\ld g5]ally be suitable4 ,"u ! r\gh /one !re %\ld be small] pieces or bricks4 ,along ! top ( ! bank !re is g5]ally a l9e ( rails s t /one f res]ve /acks1 :i* are plac$ at int]vals along ! bank1 c be quickly br\ght to ! spot 9 case ! riv] any:]e damages ! pit*$ slope4 ,= ! special protection to banks requir$ ne> weirs & simil> works1 see ,,*ap4 ,x41 ,arts4 #b & #c4 ,,*apt] ,,vii ,,div]sions ,,& ,,closures ,,( ,,/reams #a4 ,div]sions4--,:5 a /ream is p]man5tly div]t$ ! new c\rse is g5]ally %ort] ?an ! old "o1 & ! div]sion is !n (t5 call$ a cut-(f4 ,! fir/ result ( a cut-(f is a l[]+ ( ! wat]-level up/ream & a t5d5cy to sc\r !re1 & to silt d[n/ream ( ! cut-(f4 ,fig4 #bc %[s ! longitud9al section ( a /ream aft] a cut-(f ,a ,b has be5 made4 ,! b$ t5ds to assume ! position %[n by ! dott$ l9e4 ,if bo? ! div]sion & ! old *annel are to rema9 op51 ! wat]-level at ! bifurcation w be l[]$ /ill m1 & ! t5d5cy to sc\r 9 ! div]sion w be r$uc$4 ,illu/ration3 ,,fig4 #bc4 ,if ! mat]ial is s(t en\gh to be sc\r$ by ! /ream1 x is (t5 practicable to excavate a div]sion to a small section & to let x enl>ge itself by sc\r4 ,?is op]ation is imm5sely facilitat$ if ! old *annel c be clos$ at ! bifurcation4 ,! "q :e!r ! sc\r$ mat]ial w deposit 9 ! *annel d[n/ream ( ! div]sion mu/ be tak5 into consid]ation2 also ! "q :e!r ! div]sion w cont9ue to enl>ge itself m ?an is desirable4 ,! velocity 9 ! div]sion w be a maximum if its section is ( ! 8be/ =m10 i4e4 if its b$ & sides are tang5ts to a semicircle ^: diamet] co9cides ) ! wat] surface1 b ?is may n 7,,*ap4 ,,iv41 ,art4 #f7 be ! section :i* w give mo/ sc\r4 ,9 ord] to prev5t ! enl>gem5t ( ! div]sion tak+ place irregul>ly1 ! excavation c be made z %[n 9 fig4 #bd1 wat] be+ admitt$ only to ! c5tral gullet4 ,! side gullets %\ld n be q cont9u\s1 b unexcavat$ portions %\ld be left at int]vals1 s t if ! wat] 9 sc\r+ out ! *annel breaks into ! gullet1 x w n be able to fl[ along x until x has brok5 9 all along4 ,illu/ration3 ,,fig4 #bd4 ,if a div]sion is made1 n ) ! object ( l[]+ ! wat]-level b m]ely 9 ord] to %ort5 ! *annel1 ! increas$ velocity caus$ by ! /eep5$ slope may be inconv5i5t4 ,9 ?is case a weir or weirs c be add$ 7,,*ap4 ,,viii41 ,art4 #d74 ,if ! wat] conta9s suffici5t silt to enable ! ab&on$ loop to be silt$ up )9 a reasonable "t1 x may be desirable to d ?is4 ,! silt+ up may1 = in/ance1 increase ! value ( ! l&4 ,! loop %\ld be clos$ at its upp] end4 ,wat] ent]+ ! l[] end w cause a deposit !re4 ,:5 ! l[] end is well ob/ruct$ by silt1 ! upp] end %\ld be op5$4 ,! set ( ! /ream1 due1 = in/ance1 to a b5d at ! po9t :]e a div]sion takes (f has v little to d ) ! quantity ( wat] :i* goes d[n ! div]sion4 ,! only effect ( ! set ( ! /ream is a slight rise ( ! wat]-level z comp>$ ) ! opposite bank4 ,simil>ly1 ! angle at :i* ! div]sion takes (f is only ( importance 9 giv+1 9 "s cases1 a velocity ( approa* ^: effect is g5]ally small4 ,! di/ribution ( ! wat] betwe5 ! div]sion & ! old *annel really dep5ds on _! relative dis*>g+ capacities4 ,if ! requir$ quantity ( wat] does n fl[ d[n a div]sion x c be dr$g$4 ,sometimes a long spur is run out to s5d ! wat] t[>ds ! (f-take ( a div]sion4 ,! effect ( ?is is v small--x m]ely causes a set ( ! /ream1--unless its l5g? is s great t x am\nts to some?+ l a closure dam4 ,x is sometimes said t x is easi] to lead a riv] ?an to drive x4 ,?is rem>k is probably bas$ on ! fact t spurs1 su* z ^? "u consid]ation1 g5]ally produce little effect1 :]eas ! excavation ( a div]sion or ! deep5+ ( a bran* by dr$g+ x1 is m likely to produce "s result4 ,!re is1 h[ev]1 no c]ta9ty ab\t ?is4 ,sometimes too mu* is expect$ ( su* *annels4 ,calculations are n always made z to ! sc\r+ p[] ( ! /ream1 nor is acc\nt always tak5 ( ! fact t z ! cut sc\rs its gradi5t flatt5s4 #b4 ,closure ( a ,fl[+ ,/ream4--,! closure ( a fl[+ /ream by means ( a dam is usually att5d$ ) "s difficulty & sometimes ) enorm\s difficulty4 ,!re may be little tr\ble 9 runn+ out dams f bo? banks = a c]ta9 di/ance1 b z soon z ! gap betwe5 ! dams becomes mu* less ?an ! orig9al wid? ( ! /ream1 ! wat] on ! up/ream side is head$ up & !re is a ru% ( wat] ?r\gh ! gap1 :i* t5ds to deeply sc\r ! b$ & to und]m9e ! dams4 ,! small] ! gap becomes ! great] is ! ru% & sc\r4 ,! closure is mo/ easily effect$ at or ne> to ! place :]e ! /ream bifurcates f ano!r4 ,!n1 z ! gap decreases 9 wid?1 "s ( ! wat] is driv5 d[n ! o!r /ream & x does n rise s mu*4 ,ev5tually all ! wat] goes d[n ! o!r /ream1 & ! total rise is only s mu* z w enable ?is o!r /ream to c>ry ! increas$ dis*>ge4 ,if ! closure is n effect$ ne> a bifurcation1 ! rise ( ! wat] w g on ev5 aft] ! closure is complet$1 & x w n cease1 unless ! wat] escapes or breaks out some:]e1 until x has ris5 to ! same level z t to :i* x w\ld h ris5 if ! closure _h be5 at ! bifurcation1 or p]haps n q to ! same level1 s9ce !re may /ill be a slight slope 9 ! wat] surface & a small dis*>ge :i* p]colates ?r\gh ! dam4 ,sometimes 9 su* a case x is possible to arrange = tempor>y escapes or bifurcations1 :i* w be %all[ & !re=e easily clos$1 aft] ! ma9 closure has be5 complet$4 ,a closure is1 ( c\rse1 f> m easily effect$ :]e ! b$ is h>d ?an :]e x is s(t4 ,v (t5 x is be/ to close tempor>ily at su* a place or ne> a bifurcation1 ev5 if ! p]man5t dam has to be else:]e1 & !n to con/ruct ! p]man5t dam 9 ! dry *annel1 or 9 ! /ill wat]1 & remove ! tempor>y "o or cut a gap 9 x4 ,g5]ally ! be/ me?od to adopt 9 a closure is to cov] ! b$ ( ! *annel be=eh&--unless x is already h>d en\gh--) a mattress or floor1 su* t x _c be sc\r$ z ! gap closes4 ,a floor may consi/ ( a numb] ( /ones or s&bags dropp$ 9 f boats or by any suitable means1 & plac$ ) c>e s t !re %all n be gaps or m\nds4 ,s&bags %\ld be c>efully sewn up4 ,a mattress may be made ( fasc9es laid side by side & ti$ toge!r1 float$ into position1 weight$ & sunk4 ,ev5 a c>pet made ( matt+ or clo? & suitably weight$ has suffic$ 9 "s cases4 ,if ! sc\r is likely to be su* t /ones or s&bags w be c>ri$ away1 ! /ones may be plac$ 9 nets1 baskets1 or crates4 ,s&bags may also be plac$ 9 nets4 ,probably ! long rolls ( wire-nett+ fill$ ) /ones1 describ$ 9 ,,*ap4 ,,vi41 ,art4 #c1 w\ld be bett] ?an any?+1 & ! diamet] c\ld be r$uc$ some:at4 ,! floor or mattress ne$ n usually ext5d "r across ! /ream4 ,x mu/ cov] a wid? mu* great] ?an--p]haps twice z great z--! wid? ( ! gap is likely to be :5 sc\r beg9s4 ,its l5g?1 measur$ p>allel to ! direction ( ! /ream1 mu/ be su* t sev]e eddies 9 ! contract$ /ream w h ceas$ be=e ! /ream rea*es its d[n/ream edge4 ,x ne$ n ext5d to any consid]able di/ance up/ream ( ! l9e ( ! dam4 ,! dams :5 />t$ f ! banks c g5]ally be ( simple e>? or gravel1 or loose /ones1 b be=e !y h advanc$ f> !y w probably require protection at ! ends by /ones1 or by /ak+ & bru%wood1 or by fasc9es4 ,z soon z ! dams h advanc$ well onto ! mattress & _! ends h be5 well protect$1 x is be/ to cease contract+ ! /ream f ! sides & to contract x f ! bottom by lay+ a numb] ( s&bags across ! gap s z to =m a subm]g$ weir4 ,9 ?is way ! ru% ( wat] is spread ov] a consid]able wid? ( ! /ream4 ,! weir is !n rais$ until x comes up above wat]4 ,leakage c be /opp$ by ?r[+ 9 e>?1 or gravel1 or bundles ( grass on ! up/ream side4 ,sometimes x is be/ to con/ruct ! mattress ov] ! :ole wid? ( ! /ream1 & to effect ! closure entirely by a weir1 c>ry+ ea* lay] "r across be=e add+ ano!r4 ,! banks ( ! /ream1 if n h>d1 c be protect$ by s&bags1 /ones1 /ak+ or fasc9+4 ,! *ief cause ( failures ( attempts to close fl[+ /reams is neglect to provide a prop] floor or mattress4 ,! /ones or o!r mat]ials may be ( insuffici5t weight or n closely laid1 or ! ext5t ( ! floor may be insuffici5t4 ,9 a s(t *annel & deep wat] loose /ones 9 almo/ any quantity may fail unless a mattress ( fasc9es is laid "u !m4 ,ano!r cause ( failure is runn+ %ort ( mat]ials1 su* z s&bags4 ,all[ance %\ld be made = e cont+5cy1 includ+ mak+ good any failure ( p>ts ( ! "w4 ,enorm\s sums ( money h be5 wa/$1 & va/ inconv5i5ce1 loss & tr\ble incurr$1 9 futile attempts to close brea*es 9 banks1 or gaps 9 dams4 ,sometimes ! gap is clos$ by s9k+ a b>ge load$ ) /ones1 or by s9k+ a 8cradle0 or l>ge mattress made ( fasc9es1 tak5 out to ! site by f\r boats1 "o support+ ea* corn]1 & !n load$ ) /ones & sunk4 ,ano!r me?od is to run out a float+ mattress ( fasc9es f "o side ( ! gap to ! middle & s9k x1 !n to proce$ simil>ly on ! o!r side1 & s on4 ,an excell5t plan1 :5 x c be adopt$1 is to h m ?an "o l9e ( op]ations1 s t ! head+ up ( ! wat] is divid$ betwe5 !m4 ,9 ,india closures ( /reams hav+ dep?s ( #f or #h feet are effect$ by means ( r\gh tre/les made f trunks ( small trees & plac$ at int]vals 9 ! /ream l bridge pi]s1 "o leg ( ! tre/le incl9$ up/ream & "o d[n/ream4 ,ea* pair ( adjac5t tre/les is connect$ by a numb] ( r\gh1 horizontal poles4 ,aga9/ ^! are plac$ bundles ( bru%wood4 ,e>? is at ! same "t collect$ & is rapidly add$ at ! la/4 ,! *ief dang] is ! und]m9+ ( ! b$ by sc\r4 ,?is is prev5t$ by driv+ 9 /akes & plac+ bru%wood aga9/ !m4 ,closures ( small *annels or ( brea*es 9 ! banks ( canals are effect$ by means ( /ak+ & bru%wood4 ,:]e dang]\s brea*es are liable to occur1 x is a good plan to h a b>ge1 fitt$ up ) a small pile-driv] & c>ry+ a supply ( %eet piles1 ready at a conv5i5t spot4 ,hurdle dykes1 fir/ us$ on ! ,mississippi1 7 employ$ on ! ,indus 9 #aijb to close p>tially ! ma9 *annel ( ! riv]4 ,!re 7 to be ?ree dykes1 ea* dyke consi/+ ( ?ree l9es ( v long piles--"s 7 #fj feet long1--driv5 into ! b$ ( ! /ream1 :i* 0 to be protect$ ) mattresses made ( fasc9es & ext5d+ "r across x1 ) _! heads above flood-level4 ,! idea 0 n to :olly /op ! fl[ ( ! wat]1 b to ob/ruct x s mu* t silt w\ld deposit1 ! *annel become *ok$ up1 & ! wat] f9d a c\rse d[n ano!r *annel4 ,! "w 0 begun 9 ,m>* #aijb1 & 0 9 progress 9 ,may ( ! same ye> :5 an unusually e>ly flood put a /op to x4 ,! dykes _h at ?is "t advanc$ consid]able di/ances f ! "r bank ( ! /ream1 b none _h be5 complet$4 ,two dykes out ( ! ?ree 7 = ! mo/ "p c>ri$ away4 ,! riv]1 h[ev]1 took a new c\rse1 />t+ f a po9t f> up/ream1 ! we/]n *annel became a creek1 & ! rema9s ( ! dykes 7 soon emb$d$ 9 silt4 ,9 any case 9 :i* ! provision ( a prop] mattress has be5 omitt$1 or :5 ! mattress has be5 de/roy$1 or :5 a brea* has occurr$ 9 an embankm5t1 :5ev]1 9 %ort1 x is evid5t t ! gap _c be clos$ until "s o!r escape = ! wat] is provid$1 x may be possible to provide su* an escape by cutt+ p>tly ?r\gh ! dam or embankm5t on ! d[n/ream side at ano!r place1 & ?or\ghly protect+ ! place & ext5d+ ! protection d[n/ream & away f ! dam or embankm5t4 ,! wat] c !n be let 91 & ! closure ( ! old gap attempt$4 ,if a closure is effect$1 ! protect$ gap c !n be clos$4 ,sometimes x may be desirable to make su* a protect$ gap be=eh& & ) delib]ation4 ,dams = clos+ /reams :i* are dry c be made simil>ly to flood embankm5ts 7,,*ap4 ,,xii41 ,art4 #g74 ,s& does v well1 provid$ x is protect$ by a cov]+ ( clay or by fasc9+4 #c4 ,in/ances ( ,closures ( ,/reams4--,9 #aijd ! ,colorado ,riv] broke into ! ,salton ,s9k--a valley cov]+ #djjj squ>e miles4 ,unsuccessful attempts 7 made to close ! /ream by two r[s ( piles ) will[s & s&bags betwe5 !m1 by a gate #bjj feet long1 support$ on #ejj piles1 & by twelve gates ea* #ab feet wide4 ,a 8rock-fill0 dam 0 !n con/ruct$ on a mattress #ajj feet wide & #ae feet ?ick4 ,! riv]1 :i* 0 #fjj feet wide1 broke ?r\gh1 b 0 /opp$ by ! con/ruction ( ?ree p>allel rock-fill dams 9 ! gap 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxi474 ,illu/ration3 ,,fig4 #be4 ,at ! site ( ! railway bridge ov] ! riv] ,ti/a 9 ,b5gal1 x 0 necess>y to close ! ma9 /ream 7fig4 #be71 :i* fl[$ at ! left side ( ! *annel1 :ile ! bridge _h be5 built at ! "r4 ,! b$ 0 ( s&1 wid? #ejj feet1 dep? #f feet1 & dis*>ge #cgjj cubic feet p] second4 ,! fir/ attempt to close ! /ream 0 made at ,m ,n1 a floor ( /one #bjj feet long1 #bj feet wide1 & #b feet ?ick1 be+ laid 9 ! middle ( ! /ream1 & dams ( e>?1 s&bags1 & /ones be+ run out f ea* bank4 ,z ! gap decreas$ 9 wid? ! b$ 0 torn up & ! "w fail$4 ,! head+ up 0 #c feet #i in*es4 ,x 0 recognis$ lat] t ! site %\ld h be5 at ! bifurcation high] up1 & t ! /one floor %\ld h be5 laid on a mattress4 ,9 ! next work+ season ! dams ,c ,d & ,e ,f ,g 7 made4 ,! dam ,c ,d 0 ( e>?4 ,two walls1 ea* consi/+ ( a d\ble l9e ( bamboos ) ! spaces betwe5 ! l9es fill$ ) bundles ( grass weight$ ) e>?1 7 run out #ej feet 9 advance ( ! e>?work ne> ! l9es ( ! toes ( ! slopes4 ,along ! l9e ( ! upp] wall a mattress ( brok5 bricks #aj feet 9 wid?1 & #a foot ?ick1 0 laid1 & 0 kept #ej feet 9 advance ( ! wall4 ,a total l5g? ( #ajjj feet ( embankm5t 0 made 9 five mon?s & pit*$ on its up/ream side4 ,! end 0 /rongly protect$ by a mass ( /one4 ,! embankm5t ,f ,g 0 ( e>?4 ,! dam ,e ,f consi/$ ( ?ree l9es ( piles driv5 #aj feet into ! b$4 ,a mattress weight$ ) /ones ext5d$ = #bj feet up/ream ( ! dam & #dj feet d[n/ream4 ,a gap ( #aej feet 0 left at ,d ,e1 & 0 n protect$ by a floor ( any k9d4 ,a *annel1 p>allel to ,f ,g & ext5d+ to ,k1 _h be5 dug to a wid? ( #bjj feet4 ,dur+ ! floods ! head+ up at ,d ,e 0 ab\t #be feet1 & ! wat] 0 #cj feet deep4 ,! l9e ,e ,f 0 greatly damag$ & 0 repair$4 ,! cut ,f ,g ,k gradually enl>g$1 & by ! end ( ! floods m wat] 0 go+ d[n x ?an d[n ! ma9 /ream4 ,! gap ,d ,e 0 f9ally clos$ by means ( a l9e ( bamboos & grass1 ! b$ be+ protect$ by a c>pet1 #ajj #ej feet1 made ( common clo? weight$ ) s&bags4 ,! success ( ! op]ations turn$ on ! sc\r+ out ( ! cut ,f ,g ,k4 ,x is rem>kable t ! gap ,d ,e did n become :olly unmanageable 9 ! floods 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cl474 ,,*apt] ,,viii ,,! ,,tra9+ ,,& ,,canalisation ,,( ,,riv]s #a4 ,prelim9>y ,rem>ks4--,:5 a /ream is tra9$ or regul>is$ x is g5]ally made n>r[]1 b sometimes n>r[ places h to be wid5$4 ,deep5+ has also v frequ5tly to be effect$4 ,! object ( tra9+ is g5]ally ! improvem5t ( navigation1 b x may be ! prev5tion ( silt deposit4 ,"s natural arms ( riv]s :i* =m ! head rea*es ( canals 9 ! ,punjab are wide & tortu\s1 & !y are sometimes tra9$4 ,tra9+ (t5 includes /raight5+ or ! cutt+-(f ( b5ds1 z to :i* ref]5ce may be made to ,,*ap4 ,,vii4 #b4 ,dr$g+ & ,excavat+4--,:5 a fl[+ /ream is to be deep5$1 ! "w is usually done by dr$g]s4 ,dr$g]s c remove mud1 s&1 clay1 b\ld]s1 or brok5 pieces ( rock4 ,! 8bucket ladd]0 dr$g] is ! commone/ type4 ,! 8dipp]0 dr$g] is ano!r4 ,bo? ^! c "w 9 dep?s ( wat] rang+ up to #ce feet4 ,! 8grab bucket0 dr$g] c "w up to any dep? & 9 a conf9$ space4 ,! 8suction dr$g]0 drawls up mud or s& mix$ ) wat]4 ,a dr$g] may be fitt$ ) a hopp] or movable bottom1 by means ( :i* x c dis*>ge ! dr$g$ mat]ial--?is1 h[ev]1 involves cessation ( "w :ile ! dr$g] makes a j\rney to ! place :]e ! mat]ial is to be deposit$--or x c dis*>ge into hopp] b>ges or directly on to ! %ore by means ( long %oots4 ,= small works 9 comp>atively %all[ wat] ! 8bag & spoon0 dr$g]1 work$ by two m51 c be us$4 ,:5 rock has to be remov$ "u wat] x is bla/$ or brok5 up by ! bl[s ( heavy rams provid$ ) /eel-po9t$ cutt]s4 ,9 wid5+ a *annel ! excavation c be c>ri$ d[n 9 ! ord9>y way to bel[ ! wat]-level1 a n>r[ piece ( e>?1 l a wall1 be+ left to keep ! wat] out4 ,if ! *annel _c be laid dry1 ! "w c be f9i%$ by dr$g+4 ,reg>d+ me?ods by :i* ! /ream is itself made to deep5 or wid5 its *annel1 ref]5ce may be made to ,,*ap4 ,v4 #c4 ,r$uction ( ,wid?4--,if a *annel :i* is to be n>r[$ is n a wide "o1 ! r$uction 9 wid? c be effect$ by any ( ! processes describ$ "u bank protection 7,,*ap4 ,,vi474 ,b 9 a wide *annel1 r$uction ( ! wid? by any direct process is g5]ally impracticable4 ,! exp5se w\ld g5]ally be prohibitive4 ,e>?1 if fill$ 91 is liable to be wa%$ away unless protect$ all along4 ,r$uction 9 ! wid? ( a l>ge *annel is ne>ly always effect$ ei!r by groynes 7fig4 #bf7 or by tra9+ walls 7fig4 #bg74 ,spurs or %ort groynes = bank protection h be5 already describ$ 7,,*ap4 ,,vi41 ,art4 #b74 ,groynes = n>r[+ /reams are made 9 ! same way & ( ! same mat]ials1 b are long]4 ,!y are at "r angles to ! /ream or ne>ly s4 ,groynes 9 ! riv] ,sutlej h be5 m5tion$ 9 ,,*ap4 ,v41 ,art4 #e1 & are %[n 9 fig4 #f1 p4 #ee4 ,:e!r groynes or tra9+ walls are us$1 ! object is to conf9e ! /ream to a def9ite zone & to silt up ! spaces at ! sides4 ,^! spaces :5 p>tly silt$ c be plant$ ) osi]s or ) any?+ :i* w gr[ :5 p>tly subm]g$1 & ?is w assi/ 9 complet+ ! silt+4 ,illu/ration3 ,,fig4 #bf4 ,illu/ration3 ,,fig4 #bg4 ,a tra9+ wall c be made ( any ( ! mat]ials us$ = groynes4 ,9 ord] to silt up ! spaces betwe5 ea* wall & ! adjac5t bank ( ! /ream1 o!r walls are run at int]vals across !m4 ,usually ! tra9+ walls & cross walls are c>ri$ up only to ord9>y wat]-level1 sometimes only to l[-wat] level4 ,floods c ?us spread out & subm]ge ! walls & deposit silt4 ,if ! walls are c>ri$ up too high x may be necess>y1 9 ord] to give room = floods1 to space !m too f> ap>t1 & ?is1 z w be se5 bel[1 is objectionable4 ,! diff]5ce betwe5 tra9+ walls & groynes is "o ( degree r ?an "o ( k9d4 ,! mat]ial mo/ commonly us$ is1 9 ei!r case1 loose /one--) pit*+1 if desir$1 above l[-wat] level1--b x may be wattl$ /akes4 ,if ! wat] ( ! /ream conta9s silt at all /ages ( ! supply1 gaps c be left 9 tra9+ walls s t silt deposit may occur at all times & n only 9 floods4 ,if ! walls are ( wattl$ /akes1 wat] w pass ?r\gh !m1 & x may n be necess>y to leave any gaps4 ,groynes are frequ5tly made ) ,t-heads 7fig4 #bf71 & !y are ?us equival5t to tra9+ walls ) long gaps 9 !m4 ,! edge ( ! n>r[$ *annel usually =ms some:at z %[n 9 ! figure4 ,if ! groynes are plac$ s ne> toge!r z to give a regul> *annel1 ! co/ is n likely to be mu* less ?an t ( tra9+ walls4 ,! alignm5t ( tra9+ walls or groynes %\ld be su* z w give ! be/ *annel consi/5t ) economy 9 co/4 ,! be/ *annel is g5]ally t :i* is mo/ free f %>p b5ds4 ,x is assum$ = ! pres5t t no cuts or div]sions ( su* l5g?s z to mat]ially alt] ! gradi5t are to be made1 b t a c]ta9 am\nt ( *oice ( alignm5t is af=d$ by ! r$uc$ wid? ( ! tra9$ *annel & by small div]sions or eas+s ( b5ds4 ,x is sometimes said t /raight rea*es are objectionable because ! /ream w t5d to w&] f side to side & cause %oals1 :]eas 9 a b5d !re w be no su* t5d5cy4 ,! difficulty z to %oal+ w be greate/ at l[ wat]1 b x is likely to be s]i\s only :5 ! wid? betwe5 ! tra9+ walls is too great4 ,if ! wid? _c be r$uc$ to su* an ext5t z to d away ) ! tr\ble1 x may be bett] to adopt a curv$ c\rse4 ,! wid? betwe5 ! tra9+ walls %\ld g5]ally be ! same ?r\gh\t1 :e!r ! rea*es are /raight or curv$1 b 9 view ( ! prec$+ rem>ks x may be desirable1 :]e a rea* _c be o!rwise ?an /raight & :]e %oal+ is fe>$1 to give ! /raight portion a r$uc$ wid? ) ( c\rse a great] dep?1 & simil>ly to r$uce ! wid? at rev]se *anges ( curvature4 ,9 curves :i* are at all %>p ! curvature %\ld be r %>p] 9 ! middle ( ! curve ?an at ! ends 7,,*ap4 ,,iv41 ,art4 #h74 #d4 ,alt]ation ( ,dep? or ,wat]-,level4--,:5 ! wid? ( a /ream is alt]$1 ! dep? ( wat]--! gradi5t be+ suppos$ to be un*ang$--mu/ alt] 9 ! opposite mann]4 ,a n>r[+ ( ! *annel by tra9+ necessitates an increase 9 ! dep? ( wat]1 & ! same rem>k applies if an arm ( ! /ream is clos$4 ,! increase 9 dep? may be effect$ ei!r by rais+ ! wat]-level or by l[]+ ! b$--z may be conv5i5t--or bo?4 ,if ! b$ is to be l[]$ & is ( h>d clay1 x may be necess>y to dr$ge x &1 :5 ?is has be5 done1 tra9+ may be unnecess>y4 ,if ! b$ is ( s(t mud1 a dr$g$ *annel is likely to fill up aga91 & tra9+ alone w be ! me?od to adopt4 ,if ! b$ is mod]ately h>d1 say compact s&1 x may be suitable to tra9 ! *annel fir/ & !n to dr$ge if necess>y4 ,9 any case1 %oals ( h>d mat]ial may h to be dr$g$ or rocks1 :e!r ^! =m %oals or lat]al ob/ructions1 to be bla/$ or o!rwise brok5 up 7,art4 #b74 ,9 cases :]e x is desir$ to raise ! wat]-level )\t any l[]+ ( ! b$1 tra9+ is ( c\rse necess>y4 ,9 any case 9 :i* ! b$ is likely to sc\r to a l[] level ?an is desir$1 or if ! b$ is to be rais$1 ! measures describ$ 9 ,,*ap4 ,v41 ,art4 #f1 may be adopt$1 b !y are h>dly likely to be suitable & satisfactory 9 all cases4 #e4 ,tra9+ & ,canalis+4--,! /eps s f> describ$1 toge!r ) any ( ^? describ$ 9 ,,*aps4 ,v4 & ,,vi41 exhau/ ! li/ ( :at c be done s long z only ! cross-section ( a /ream is dealt )4 ,?is is (t5 call$ ! 8regulation0 ( a /ream1 ?\gh 8tra9+0 is a m satisfactory t]m4#aj ,illu/ration3 ,,fig4 #bh4 ,a m]e alt]ation ( ! cross-section ( a /ream w n always af=d a solution ( ! problem to be solv$4 ,frequ5tly a *ange ( gradi5t is requir$4 ,! gradi5t c be /eep5$ by means ( /raight5+s1 or flatt5$ by introduc+ weirs1 or p]haps by adopt+ a c\rse some:at m circuit\s ?an 0 int5d$4 ,?is ext5d$ scope ( op]ations is kn[n z canalis+ 9 ! case ( a riv]1 & remodell+ 9 ! case ( a canal4 ,suppose t x is desir$ to alt] ! cross-section ( a /ream1 at ord9>y wat]-level1 s z to r$uce ! wid? & increase ! dep? 7fig4 #bh74 ,if ! mean dep? is d\bl$1 ! new wid? w be ab\t equal to #a_/7cb7 ( ! old wid? 7,hydraulics1 ,,*ap4 ,,vi41 ,art4 #b74 ,if ?is gives too n>r[ a *annel1 x may be desirable to flatt5 ! gradi5t4 ,if x gives too wide a *annel1 ! gradi5t c be /eep5$ or a great] dep? adopt$4 ,:ile ! wid? & dep? ( ! /ream w be fix$ s z to be suitable = ! navigation1 ! ratio ( dep? to velocity %\ld be s arrang$1 if ?is is possible1 z to m9imise tr\ble connect$ ) silt+ or sc\r 7,,*ap4 ,,iv41 ,art4 #f74 ,a remodell$ *annel is1 9 %ort1 design$ 9 exactly ! same way z a new *annel4 ,! dep? ( wat] ex]cises ! greate/ effect on ! dis*>ge1 & ! gradi5t ! lea/4 ,! weak po9t 9 a s*eme :i* includes weirs is ! difficulty ( deal+ ) floods4 ,a s*eme p]fect 9 all o!r respects may be vitiat$ because ( ! ob/ruction1 caus$ by weirs1 to ! passage ( floods4 ,! difficulty is got ov] by means ( movable weirs4 ,! :ole subject ( weirs is dealt ) 9 ,,*ap4 ,x4 ,tra9+ or canalis+ %\ld n be effect$ 9 any rea* ( a /ream )\t reg>d to o!r rea*es4 ,a m]e local l[]+ ( ! wat]-level by dr$g+ may acc5tuate ! effect ( a %oal at ! upp] end ( ! rea*4 ,:5 ! wat]-level is rais$ by a weir or by n>r[+ ! *annel--?\gh 9 ! latt] case ! rais+ may n be p]man5t--x is g5]ally be/ to comm5ce ! "w f ! up/ream end4 ,! rais+ ( ! wat]-level w !n n int]f]e ) ! execution ( ! re/ ( ! "w4 ,b 9 a case ( wid5+1 :]e ! wat]-level up/ream ( ! "w is l[]$1 ! "w c conv5i5tly be begun at ! d[n/ream end1 & ! rem>k applies also to a case ( /raight5+1 provid$ t ! new *annel is n s small t x at fir/ causes no l[]+4 ,9 any case 9 :i* !re is a d\bt :e!r ! :ole ( ! s*eme w be c>ri$ out1 ! rea* to be dealt ) fir/ c be decid$ on accord+ to circum/ances4 ,!re is no g5]al reason = select+ an up/ream or d[n/ream rea*1 except t any rais+ or l[]+ ( ! wat]-level w ext5d up/ream ( ! rea* & n d[n/ream ( x 7,,*ap4 ,i41 ,art4 #d74 ,tra9+ walls & groynes1 if made ) /akes or fasc9es or any mat]ials except /one1 require c>eful wat*+ & ma9t5ance4 ,,*apt] ,,ix ,,canals ,,& ,,conduits #a4 ,banks4--,all banks :i* h to hold up wat] %\ld be c>efully made4 ,! e>? %\ld be deposit$ 9 lay]s & all clods brok5 up4 ,9 high banks ! lay]s %\ld be moi/5$ & ramm$4 ,! dott$ l9es 9 fig4 #bi %[ two possible c\rses ( p]colation wat]4 ,! v]tical height--f ! wat]-level to ! gr\nd outside ! bank1--divid$ by ! l5g? ( ! l9e ( p]colation is ! hydraulic gradi5t1 z 9 ! case ( a pipe1 & ?is gradi5t is m or less a measure ( ! t5d5cy to leakage4 ,a bank :i* has wat] con/antly aga9/ x ne>ly always becomes almo/ wat]-tight 9 "t4 ,! "t is less or great] accord+ z ! soil is bett]1 & accord+ to ! am\nt ( c>e ) :i* ! bank is made4 ,illu/ration3 ,,fig4 #bi4 ,! side slopes ( banks v>y ) ! soil4 ,g5]ally !y are #a to #a1 b !y are sometimes #b to #a or ev5 #c to #a if ! soil is bad or s&y1 or if great precautions aga9/ brea*es are to be tak54 ,leakage c sometimes be /opp$ by ?r[+ *aff or o!r f9ely divid$ sub/ances into ! wat] at ! site ( ! leak4 ,9 o!r cases x is necess>y to dig up "p ( ! bank1 f9d ! *annel by :i* ! wat] is escap+1 & fill x up by add+ e>? & ramm+4 ,on "s navigable canals 9 ,france x 0 at "o "t ! cu/om to lay ! rea* dry1 :5 a bad leak occurr$1 & to dig away ! bank & lay slabs ( concrete or puddle ov] ! place4 ,?is plan 0 ab&on$1 & in/ead ( x %eet piles are driv5 94 ,!y are !n )drawn "o at a "t &1 if any leakage occurs1 ! space is fill$ ) concrete4 ,! dim5sions ( a bank %\ld dep5d to "s ext5t on ! head ( wat] aga9/ x & on ! volume ( ! /ream ^: wat] x holds up4 ,a brea* is obvi\sly m s]i\s ! great] ! volume ( ! escap+ wat]4 ,?is volume dep5ds on ! size ( ! /ream & on its velocity4 ,9 navigation canals 9 ,engl& ! bank on ! side opposite ! t[+-pa? is usually #d to #f feet wide & #a feet above ! wat]4 ,9 irrigation canals 9 ,india ! bank ( a v l>ge canal is #b feet above ! wat] & #bj feet wide1 :ile t ( a small canal ) #f feet ( wat] is #h or #aj feet wide & #a feet above ! wat]1 & t ( a small di/ribut>y *annel ) #c feet ( wat] is #d feet wide & #a foot above ! wat]4 ,! soil is (t5 poor4 ,fur!r rem>ks1 :i* apply to banks ( special height or special importance1 are giv5 "u ,embankm5ts 7,,*ap4 ,,xii41 ,art4 #f74 #b4 ,navigation ,canals4--,a navigation canal is sometimes all on "o level1 b g5]ally diff]5t rea*es are at diff]5t levels1 ! *ange be+ made by means ( locks4 ,a 8lat]al0 canal--! mo/ common k9d--runs along a riv] valley m or less p>allel to ! riv]4 ,x is frequ5tly *eap] to con/ruct su* a canal ?an to canalise ! riv]4 ,a 8summit0 canal crosses ov] a ridge & connects two valleys4 ,a navigation canal requires a supply ( wat] to make good ! losses :i* occur by lockage1 leakage1 or absorption & evaporation4 ,a canal may be ( any size1 accord+ to ! size ( ! boats :i* are to be us$4 ,!re is always room1 except 9 %ort rea*es :]e ! exp5se ( con/ruction has to be kept d[n1 = two boats to pass "o ano!r4 ,a lat]al canal obta9s wat] f ! riv] or f ! small afflu5ts :i* x crosses4 ,= a summit canal x may be necess>y to provide /orage res]voirs4 ,! canal crosses ! ridge :]e x is l[1 & ! res]voirs are made on high] gr\nd4 ,res]voirs may be requir$ also = o!r canals to hold wat] = use 9 dry seasons or 9 ord] to fill ! canal quickly :5 laid dry = repairs4 ,9 tropical c\ntries we$s gr[ pr(usely 9 canals :i* h /ill or ne>ly /ill wat]4 ,traffic t5ds to keep !m d[n1 b !y h to be cle>$ p]iodically4 ,9 design+ a b>ge canal ! *ief consid]ations g5]ally are t x %all n be 9 su* l[ gr\nd or s ne> a riv] z to be liable to damage by floods1 t x %all n trav]se v p]meable soil or gravel--?is is (t5 f\nd ne> a riv]1--t ! mat]ial excavat$ %all be z ne>ly z possible equal to t requir$1 at ! same place1 = embankm5t1 & t z f> z possible high embankm5ts1 :i* are v exp5sive to con/ruct & are m or less a s\rce ( dang]1 %all be avoid$4 ,! side slopes ( ! banks ( a navigation canal dep5d on ! nature ( ! soil4 ,!y are g5]ally #a to #a1 b ! inn] slope may be #b to #a4 ,! banks are g5]ally #a or #b feet above ! wat]-level1 ! wid? ( ! bank on ! t[+-pa? side rang+ f #h to #af feet1 b be+ g5]ally #ab feet & ! wid? ( ! o!r bank #d to #f feet4 ,! wid? ( a canal is made suffici5t = two boats to pass1 & ! dep? is #a to #b feet great] ?an ! draught ( ! boats us$4 ,9 "s cases ! banks are protect$ by pit*+ = %ort l5g?s1 b g5]ally !y are m]ely turf$4 ,! sides ne> ! wat] surface we> away1 s t ! side slope becomes /eep] 9 ! upp] "p & flatt] 9 ! l[] "p4 ,! resi/ance ( a boat to traction 9 a canal is giv5 by ! =mula ,r r7#hdf7_/7b 7,a_/a771 :]e r is ! resi/ance 9 a l>ge body ( wat] & ,a & a are ! areas ( ! cross-sections ( ! canal & ( ! imm]s$ "p ( ! boat4 ,:5 ,a is six times a1 ,r is only #f p] c5t4 m ?an r4 ,9 practice ,a is nev] less ?an six times a4 ,reg>d+ me?ods ( protect+ banks1 see ,,*ap4 ,,vi4 ,a %ip canal is a b>ge canal on a l>ge scale4 ,! spe$ ( %ips has to be /rictly limit$ to avoid damage to ! banks4 ,! ,man*e/] ,%ip ,canal takes 9 ! wat]s ( ! ,irwell & ! ,m]sey1 & conveys !m = sev]al miles4 ,x is ?us a canalis$ riv] = "p ( its c\rse4 ,bel[ t x is a tidal /ream1 ! tide be+ admitt$ at its l[] end :]e x jo9s ! e/u>y ( ! ,m]sey1 & pass+ out high] up :]e x leaves ! e/u>y aft] skirt+ x4 ,?is circulation ( wat] is b5eficial to ! e/u>y4 ,! ,panama ,canal might h be5 con/ruct$ at "o level1 b ! co/ ( ?is1 & ! "t occupi$1 w\ld h be5 d\ble t ( mak+ x a summit canal4 ,! wat] ( ! riv] ,*agres is to be imp\nd$ to =m a lake ( great ext5t t w n only supply wat] = lockage b w itself =m "p ( ! high-level rea* ( ! canal1 & %ips w be able to trav]se x at great] spe$ ?an 9 ! re/ ( ! canal4 ,"s ,indian irrigation canals h be5 con/ruct$ s z to be navigable4 ,! increase 9 co/ has usually be5 enorm\sly 9 excess ( any result+ b5efits4 #c4 ,locks4--,an ord9>y lock is %[n 9 fig4 #bi;,a4 ,! space above ! head gates is call$ ! 8head bay10 & t bel[ ! tail gates ! 8tail bay40 ,! floor ( ! lock is (t5 an inv]t$ ar*4 ,sometimes ! floor is ( ca/-iron4 ,! 8lift wall0 is g5]ally a horizontal ar*4 ,! gates :5 clos$ press at _! l[] ends aga9/ ! 8mitre sills02 & ! v]tical 8mitre po/s0 at ! edges ( ! gates meet & are press$ toge!r4 ,! gate1 9 op5+ & clos+1 revolves above ! cyl9drical 8heel po/0--:i* /&s 9 ! 8holl[ quo90 ( ! lock wall--& :5 fully op5 is conta9$ 9 ! 8gate recess40 ,a lock is always /rongly built1 ( masonry or concrete4 ,! walls h to )/& ! e>? pressure :5 ! lock is laid dry = repairs4 ,! floor has to )/& ! sc\r+ action f ! sluices4 ,reg>d+ ! upw>d pressure ( ! wat] :5 ! lock is empty1 see ,,*ap4 ,x41 ,art4 #c4 ,! lift or diff]5ce 9 ! wat]-levels ( ! two rea*es ( a b>ge canal is g5]ally f #d to #i feet1 b occasionally x is mu* m4 ,illu/ration3 ,,fig4 #bi;,a4 ,! gates ( small locks are g5]ally ( wood & are c\nt]balanc$4 ,^? ( l>ge locks are ( wood or /eel1 & ! weight is g5]ally tak5 by roll]s4 ,ord9>y wood %\ld n be us$ if ! ,t]$o navalis exi/s 9 ! wat]s4 ,an iron gate1 if enclos$ on all sides by plat+1 is buoyant1 & ! roll]s & an*or /raps :i* hold ! upp] ends ( ! heel po/s are ?us reliev$ ( mu* weight4 ,! gates ( ! ,panama ,canal locks are #aaj feet long & #g feet ?ick1 & ! height ranges f #dh feet to #hb feet4 ,! sluices = fill+ & empty+ a lock are plac$ 9 ! gates or 9 ! walls4 ,! gates & sluices are g5]ally work$ by hydraulic p[] or by electricity4 ,locks are frequ5tly arrang$ 9 flights4 ,!re are1 9 a few in/ances1 #bj to #cj locks 9 a flight1 ! total lift be+ #aej to #bjj feet4 ,by ?is means ! numb] ( gates is r$uc$1 ! tail gates ( "o lock be+ ! head gates ( ! re/1 & !re is a sav+ 9 lab\r 9 work+ ! locks4 ,let ,l be ! volume ( wat] conta9$ 9 a lock betwe5 ! levels ( ! upp] & l[] rea*es1 & let ,b be ! subm]g$ volume ( a boat4 ,! 8lockage0 or volume ( wat] )drawn f ! upp] rea* ( ! canal is %[n 9 ! foll[+ /atem5t3-- ---------------------------------------- ----------------------------------- ,lockage4 ,ref]5ce ,numb] ,direction ,lock or ,lock or ------------------------ ,numb] ( ,boats4 ( ,travel4 ,locks ,locks ,s+le ,flight ( ( ,case4 ,f\nd4 ,left4 ,lock4 m ,locks4 ---------------------------------------- ---------------------------------- #a #a ,d[n4 ,empty4 ,empty4 ,l - ,b ,l - ,b #b #a 0 ,full4 0 - ,b - ,b #c #a ,up4 ,empty4 ,full4 ,l ,b m,l ,b #d #a 0 ,full4 0 ,l ,b ,l ,b #e #bn ,up & ,go+ ,go+ n,l mn,l d[n d[n1 full4 d[n1 alt]nately4 ,go+ up1 empty4 empty4 ,go+ up1 full4 #f n ,d[n4 ,empty4 ,empty4 n,l-n,b n,l - n,b #g n 0 ,full4 0 7n-#a7,l 7n - #a7,l - n,b -n,b #h n ,up4 ,empty4 ,full4 n,ln,b 7mn-#a7,l n,b #i n 0 ,full4 0 n,ln,b n,l n,b #aj n ,d[n4 n ,up4 0 0 7#bn-#a7,l 7m#bn-#b7,l ---------------------------------------- ---------------------------------- ,9 ! case ( a s+le lock1 if two boats are to pass ?r\gh1 "o desc5d+ & "o asc5d+ 7cases #b & #c71 ! desc5d+ boat w\ld be pass$ ?r\gh fir/ if ! lock 7 full1 & ! asc5d+ boat fir/ if empty2 9 ei!r case1 ! total lockage is ,l1 or ,l_/#b = ea* boat4 ,?is also appe>s f case #e4 ,cases #f to #aj %[ t if a long tra9 ( boats desc5ds1 ev5 ?\gh ! lock is full = ! fir/ boat or if a long tra9 asc5ds ev5 ! lock is empty = ! fir/ boat1 ! total lockage is ne>ly ,l p] boat4 ,?us 9 a s+le lock1 boats %\ld pass up & d[n alt]nately s f> z ?is may be possible4 ,9 ! case ( a flight ( m locks1 a s+le boat 9 desc5d+ uses no m wat] ?an if !re 7 only "o lock1 ! same wat] pass+ f lock to lock1 b 9 asc5d+ x uses m4 ,9 ! case ( a numb] 7#bn7 ( boats go+ up & d[n alt]nately 7case #e71 ! lockage is m n ,l1 ! lockage p] lock p] boat be+ ,l_/#b1 b 9 ! case ( a long tra9 ( boats desc5d+ foll[$ by an equal tra9 asc5d+ 7cases #g & #h71 ! lockage is less4 ,if n is suppos$ to be equal to m1 ! av]age lockage p] boat is z foll[s3-- m #a #b #c #d #e #f ,inf9ity ,lockage ,l_/#b ,l #g,l_/#f #e,l_/#d #ac,l_/#aj #d,l_/#c #c,l_/#b p] boat ,?us 9 a case :]e n & m are v l>ge1 ! av]age lockage p] boat1 :5 ! boats pass up & d[n 9 tra9s1 is to ! lockage p] boat1 :5 ! s+le boats pass up & d[n alt]nately ?r\gh m s+le locks all at diff]5t places1 z #c is to m4 ,! reason = ! diff]5ce1 :i* may appe> puzzl+1 is t :5 ! locks are at diff]5t places !y are work$ indep5d5tly ( "o ano!r4 ,sometimes a lock is provid$ ) int]m$iate gates :i* provide a %ort lock = %ort vessels4 ,9 ! ,man*e/] ,%ip ,canal1 alongside ea* lock !re is ano!r ( small] size to be us$ = small vessels & ?us save lockage4 ,at ! ,ea/ham lock1 :]e ! ,man*e/] ,%ip ,canal desc5ds into ! e/u>y ( ! ,m]sey1 !re is1 bel[ ! tail gates1 an extra pair ( gates op5+ t[>ds ! e/u>y1 s t ! lock c be work$ :5 ! wat] ( ! e/u>y is high] ?an t 9 ! canal4 ,wat] c be economis$ by means ( a 8side-pond10 into :i* ! upp] portion ( ! wat] f a lock c be dis*>g$ & utilis$ aga9 :5 ! lock has to be fill$4 ,if two locks are built side by side1 ea* acts z a side-pond to ! o!r4 ,two flights ( locks c be built side by side4 ,sometimes in/ead ( a lock !re is an incl9$ plane1 up or d[n :i* are drawn on rails caissons conta9+ wat] 9 :i* ! boats float4 ,! rails ext5d bel[ ! wat]-levels ( ! two rea*es1 & ! caissons c ?us be run "u ! boats4 8,lifts0 h also be5 con/ruct$ by :i* ! boats c be lift$ bodily & swung ov] f "o rea* to ! o!r4 #d4 ,o!r ,artificial ,*annels4--,! me?od ( calculat+ ! dis*>ges ( *annels 9 :i* wat] is to fl[ is a "q ( hydraulics4 ,! pr9ciples & rules to be foll[$1 9 ! design ( e>!n *annels1 h be5 /at$ 9 ,,*ap4 ,,iv41 ,art4 #f1 & 9 ,,*ap4 ,,viii41 ,art4 #e4 ,! design ( banks has be5 dealt ) 9 ,art4 #a ( ?is ,*apt]4 ,= convey+ wat] = ! supply ( t[ns1 or = o!r purposes1 masonry conduits are (t5 us$4 ,a usual =m is %[n 9 fig4 #cj4 ,! curv+ ( ! pr(ile ( ! cross-section gives an increas$ sectional area & hydraulic radius1 & h5ce an increas$ dis*>ge4 ,illu/ration3 ,,fig4 #cj4 ,,*apt] ,x ,,weirs ,,& ,,sluices #a4 ,prelim9>y ,rem>ks4--,e /ructure :i* int]f]es at all ) a /ream causes an abrupt *ange 9 ! /ream 7,,*ap4 ,,iv41 ,art4 #a74 ,at an abrupt *ange !re are always eddies1 & ^! h a peculi> sc\r+ effect4 ,?is effect is greate/ :]e ! velocity ( ! /ream is abruptly r$uc$ z :]e1 = in/ance1 aft] be+ contract$ by an ob/ruction1 x exp&s aga9 or :]e x falls ov] a weir or issues f a sluice op5+4 ,9 all cases ( ?is k9d ! protection ( ! /ructure f sc\r is ( prim>y importance4 ,! site ( a weir or o!r p]man5t /ructure %\ld1 if ! /ream is un/able1 be 9 a fairly /raight rea*1 or at lea/ n be imm$iately d[n/ream ( a b5d4 ,?is is because ( ! t5d5cy ( b5ds to %ift d[n/ream 7,,*ap4 ,,iv41 ,art4 #h74 ,!re is no p>ticul> advantage 9 select+ a n>r[ place4 ,a n>r[ place is likely to be deep or x may be liable to wid54 ,9 a h>d & /able /ream !re is no re/riction z to site4 ,weirs are frequ5tly con/ruct$ = purposes ( navigation1 z m5tion$ 9 ,,*ap4 ,,viii4 ,!y are also us$ 9 /reams :i* are n navigable 9 ord] t ! gradi5t may n be too /eep1 & 9 irrigation canals = ! same reason4 ,!y are us$ bo? 9 riv]s & canals 9 ord] t ! wat]-level may be rais$ & wat] drawn (f by bran* *annels = purposes ( manufactures1 wat]-p[] or irrigation4 ,up/ream ( a weir !re is m or less t5d5cy = silt to deposit1 b x by no means foll[s t !re w be deposit 7,,*ap4 ,,iv41 ,art4 #b1 la/ p>41 & ,art4 #c1 la/ p>474 ,:5 deposit ( s& or mud is fe>$1 small horizontal passages1 kn[n z 8weep holes10 may be left 9 ! weir at ! level ( ! up/ream b$4 ,9 ! old ,nile b>rages iron grat+s 7 provid$1 b !y 7 ne$lessly l>ge4 ,illu/ration3 ,,fig4 #ca4 ,an inh]5t defect ( an ord9>y weir is t x ob/ructs ! passage ( floods4 ,! ob/ruction may or may n be ( consequ5ce4 ,sometimes x is ( great consequ5ce4 ,attempts h be5 made to p>tially rem$y ! evil by plac+ ! weir obliquely to ! /ream1 ?us giv+ x a great] l5g?4 ,at ord9>y wat]-levels ! fl[ ov] ! cre/ ( ! weir is normal to its l5g?1 or ne>ly s4 ,suppos+ t ! wat] has to be held up to a giv5 level1 ! cre/ ( ! weir mu/ be high]1 because ( its great] l5g?1 ?an if x 7 normal to ! /ream4 ,9 a flood ! wat] has a high velocity & fl[s ov] ! weir 9 a direction ne>ly p>allel to ! axis ( ! /ream1 s t ! effective l5g? ( ! weir is n mu* great] ?an if x 7 normal to ! /ream1 &1 its cre/ be+ high]1 x ob/ructs ! flood z mu*4 ,oblique weirs are usually made z 9 fig4 #ca4 ,if made 9 "o /raight l9e1 !re might be excessive action on ! bank at ! l[] end4 ,if ! weir is l5g!n$1 n by be+ built obliquely b by a wid5+ ( ! /ream at ! site1 ! cre/ has to be rais$ & no?+ is ga9$4 ,! only arrangem5t by :i* a weir c be made to hold up wat] :5 a /ream is l[ & to let floods pass freely1 consi/s 9 hav+ "p ( ! weir movable1 i4e4 consi/+ ( gates1 %utt]s or horizontal or v]tical timb]s1 :i* c be )drawn to let floods pass1 & c be manipulat$ to any ext5t s z to regulate ! am\nt ( wat] pass+4 ,a famili> in/ance ( a movable weir is ! "o :i* is usually plac$ across a mill /ream1 ! wood5 gates work+ 9 grooves 9 ! masonry4 ,above a weir 9 ,java1 #afb feet long1 !re 0 a great accumulation ( %+le 9 ! b$ ( ! riv]1 & ! head ( a canal tak+ (f above ! weir became *ok$4 ,! cre/ ( ! weir on ! side away f ! canal 0 rais$ #e feet & ! cre/ slop$ gradually d[n1 a l5g? ( #dc feet on ! side next ! canal rema9+ z x 04 ,?is 0 q successful4 ,x 0 practically a contraction ( ! riv] ne> ! canal (f-take1 & ?is mu/ h caus$ sc\r1 s t ! b$ became l[] ?an ! floor ( ! canal head & ! %+le 0 n c>ri$ 94 ,! %+le1 h[ev]1 is said to h be5 c>ri$ ov] ! weir 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxv474 ,a lock is an adjunct to a weir1 us$ :5 navigation has to be provid$ =4 ,! lock may be plac$ close to ! weir or x may be 9 a side *annel1 ! up/ream end ( ! lock be+ ab\t 9 a l9e ) ! weir4 ,locks h already be5 discuss$ 9 ,,*ap4 ,,ix41 ,art4 #c4 ,frequ5tly a 8salmon ladd]0 has to be provid$4 ,x consi/s ( a s]ies ( /eps or a zigzag arrangem5t s t ! velocity ( ! wat] is n too great = ! fi% to asc5d4 #b4 ,g5]al ,design ( a ,weir4--,unless ! b$ & sides ( ! *annel are ( rock1 a weir has side walls & re/s on a /rong floor or 8apron40 ,^! ne$ n ext5d f> up/ream1 b mu/ ext5d "s way d[n/ream because ( ! sc\r+ action ( ! wat]4#aa ,a common type ( weir is %[n 9 fig4 #cb4 ,! d[n/ream face is made slop+1 s t ! wat] may n fall v]tically & /rike ! floor bel[ ! weir4 ,! ?ickness & l5g? ( ! floor dep5d on ! volume ( wat] to be pass$ & on ! height :i* x w fall & on ! nature ( ! soil1 & are g5]ally matt]s ( judgm5t1 ?\gh rules reg>d+ !m1 applicable to c]ta9 special cases1 are giv5 9 ! next article4 ,illu/ration3 ,,fig4 #cb4 ,! upp] corn]s ( ! weir %\ld be r\nd$4 ,?is prev5ts _! be+ worn away2 b ! r\nd+ ( ! up/ream corn] has ano!r advantage4 ,if ! corn] is %>p1 ! /ream spr+s cle> f x & ! weir holds up ! wat] high]1 especially 9 floods4 ,) small dep?s ( wat] ! diff]5ce is less1 & x vani%es :5 !re is only a trickle ( wat]4 ,?us a cre/ r\nd$ on ! up/ream side holds up l[-wat] ne>ly z well z a %>p-edg$ cre/1 b lets floods pass m freely4 ,any batt] giv5 to ! up/ream face has a simil> advantage4 ,! r\nd+ is ( m importance z ! batt] is less4 ,= simil> reasons1 ! up/ream w+ walls %\ld be splay$ or ev5 curv$ s z to be tang5tial to ! side wall1 & n built normally to ! /ream4 ,^! advantages are sometimes lo/ sight (4 ,! d[n/ream walls are splay$ to r$uce ! swirl4 ,! body ( ! weir may be ( rubble & ! face-"w ( dress$ /one4 ,9 l>ge weirs ! /ones are sometimes d[ell$ toge!r4 ,:]e1 z 9 _m p>ts ( ,india1 /one is exp5sive1 brick is us$ = small weirs1 ! cre/ & faces be+ brick on edge4 ,d[n/ream ( ! floor1 unless ! *annel is ( v h>d mat]ial1 !re is pav+ or pit*+ ( ! b$ & pit*+ ( ! sides1 & ^! may t]m9ate 9 a curta9 wall4 ,! bank pit*+ may be ( any ( ! k9ds describ$ 9 ,,*ap4 ,,vi41 ,art4 #c1 & ! b$ pav+ z describ$ 9 ,,*ap4 ,v41 ,art4 #f1 b d[n/ream ( a weir ! eddy+ is cont9u\s & ! lap ( ! wat] on ! bank is ceaseless1 & good me?ods are necess>y4 ,sometimes plank+1 laid ov] a wood5 fram+ or atta*$ to piles1 is us$ in/ead ( pav+ & pit*+4 ,9 case ! height ( a weir is great relatively to its ?ickness1 ! dang] ( its be+ ov]turn$ mu/ be consid]$4 ,to be safe aga9/ ov]turn+1 ! resultant ( ! pressure on ! weir mu/ pass ?r\gh ! middle ?ird ( its base 7see fig4 #fb1 ,,*ap4 ,,xiii474 ,illu/ration3 ,,fig4 #cc4 #c4 ,weirs on ,s&y or ,por\s ,soil4--,if ! *annel is v s(t or s&y ! weir may be built on "o or m l9es ( wells4 ,! wells are n s mu* to support ! weir z to =m a curta9 & prev5t /reams1 due to ! hydraulic gradi5t ,a ,e 7fig4 #cc71 f =m+ "u ! /ructure & gradually remov+ ! soil4 ,x is assum$ 9 ! case repres5t$ by ! figure t ! maximum head occurs :5 ! d[n/ream *annel is dry4 ,any removal ( soil f "u ! weir may cause its de/ruction4 ,! wells %\ld be z close toge!r z possible1 & ! spaces betwe5 !m c>efully fill$ up ) brickwork or concrete to z great a dep? z possible1 & bel[ t by piles4 ,in/ead ( wells1 l9es ( %eet pil+--ca/-iron or wood--c be us$4 ,a good fit %\ld be made1 b x is n necess>y t ! jo9ts %\ld be absolutely wat]-tight4 ,! object is to flatt5 ! hydraulic gradi5t by increas+ ! l5g? travell$ by ! wat] f ,b ,e to ,b ,l ,g ,h ,e4 ,( c\rse1 no flatt5+ occurs at a po9t :]e ! curta9 is n wat]-tight1 b if only small int]/ices exi/1 none b small trickles ( wat] c pass1 & ! int]/ices w probably soon be *ok$ up1 j z ! s& 9 a filt] b$ becomes clogg$ & has to be wa%$4 ,9 any case1 no important /ream c\ld develop o!rwise ?an r\nd ! toe ( ! curta94 ,x has be5 /at$ t :5 a curta9 is wat]-tight ! wat] foll[s ! l9e ,b ,l ,m ,g ,h ,k ,e1 b ?is requires pro(4 ,ano!r plan is to cov] ! b$ & sides ( ! *annel ) a cont9u\s %eet ( concrete ext5d+ up/ream ( ! weir f ,b to ,d--?us flatt5+ ! hydraulic gradi5t f ,a ,e to ,f ,e4 ,in/ead ( concrete1 clay puddle c be us$ ) pit*+ ov] x4 ,! *oice betwe5 ! diff]5t me?ods dep5ds l>gely on que/ions ( co/ & facility ( con/ruction4 ,x has be5 said t a c]ta9 am\nt ( leakage occurs "u /ructures su* z ! ,okla weir 7,art4 #d71 :i* nev]!less rema9s undamag$4 ,!re h1 h[ev]1 be5 cases 9 :i* failures ( works h occurr$1 especially :5 !re has be5 a great diff]5ce betwe5 ! wat]-levels ( ! up/ream & d[n/ream rea*es1 f no o!r app>5t cause ?an ! passage ( wat] und]nea? ! works4 ,weirs 9 por\s soils h be5 discuss$ by ,bligh 7,eng9e]+ ,news1 #bi? ,decemb] #aiaj71 :o gives ! foll[+ z safe hydraulic gradi5ts 7s7 or ratio ( ! greate/ head ,a ,b to ! l5g? ,b ,e3-- ,f9e silt & s& z 9 ! ,nile #a 9 #ah ,f9e micace\s s& z 9 ,colorado & ,himalayan riv]s #a 9 #ae ,ord9>y co>se s& #a 9 #ab ,gravel & s& #a 9 #i ,b\ld]s1 gravel & s& #a 9 #d to #a 9 #f ,^! figures are probably q safe en\gh ev5 = ! mo/ important works & = ^? :]e ! head+ up is con/ant4 ,= small works or = regulators 7,art4 #e7 :]e ! head+ up is n con/ant1 /eep] gradi5ts are p]missible4 ,mu* also dep5ds on ! condition ( ! wat]4 ,if x conta9s mu* silt1 all int]/ices w probably become *ok$ up4 ,! hydraulic gradi5t 9 ! case ( ! ,n>ora weir across ! ,ganges 0 #a 9 #aa4 ,! weir fail$ aft] work+ = tw5ty ye>s4 ,x 0 rebuilt ) a gradi5t ( #a 9 #af4 ,9 ! ,zifta & ,assiut regulators on ! ,nile ! gradi5ts are #a 9 #afd & #a 9 #ba4 ,illu/ration3 ,,n>ora ,,weir ,,z ,,orig9ally ,,built4 ,illu/ration3 ,,n>ora ,,weir ,,z ,,recon/ruct$4 ,illu/ration3 ,,f\ndation ,,( ,,! ,,zifta ,,regulator1 ,,riv] ,,nile4 ,reg>d+ ! upw>d pressure on ! floor due to ! hydro/atic pressure f ! head ,a ,b1 !re is a !ory t ! weight ( a portion ( ! floor at any po9t ,p %\ld be able to balance ! pressure due to a head ( wat] ,p ,r4 ,?is1 suppos+ ! masonry to be twice z heavy z wat]1 w\ld give a ?ickness ( floor equal to half ,p ,r4 ,accord+ to ,bligh1 ! !oretical ?ickness ought1 = safety1 to be increas$ by "o-?ird4 ,practically ! ?ickness ne$ n1 9 mo/ cases1 be made ev5 s great z is giv5 by ! !oretical rule4 ,on canals 9 ! ,punjab x is c]ta9ly less4 ,wat] pass+ ?r\gh soil or f9e s& does n ex]t any?+ l ! pressure :i* x ex]ts :5 pass+ ?r\gh a pipe4 ,x acts 9 ! same mann] z 9 a capill>y tube4 ,x is only 9 co>se s& or gravel or b\ld]s t wat] fl[s z 9 a pipe4#ab ,if ! tail wat] cov]s ! floor1 ! weight ( a portion ( floor is r$uc$ by ! weight ( an equal volume ( wat]4 ,if ! f\ndation ( any "p ( ! floor is high] ?an ,b ,e1 ! upw>d pressure on x is r$uc$ because ! wat] has to =ce its way upw>ds ?r\gh ! soil4 ,bligh also /ates z an empirical rule t 9 ord] to provide effici5tly aga9/ sc\r ! l5g? ( floor ,b ,e %\ld be #d_/s 7,h_/#ac71 :]e ,h is ! maximum head ,a ,b2 & he po9ts out t 9 a case :]e ?is l5g? is less--z x usually is--?an t necess>y to give a hydraulic gradi5t ( ! requisite flatness1 accord+ to ! rule previ\sly quot$1 x is bett] to add an up/ream floor ,b ,d1 :i* may be ( puddle & !re=e *eap1 ?an to add to ! d[n/ream floor a l5g? ,e ,c :i* mu/ be ( masonry or concrete1 & t ?is arrangem5t1 by %ift+ ! l9e ( hydraulic gradi5t f ,a ,e to ,f ,e1 gives a r$uc$ upw>d pressure on ! d[n/ream floor4 ,! l5g? ,e ,n to :i* pit*+1 if ( 8rip-rap0 type1 %\ld ext5d is giv5 by ,bligh z #aj_/s 7,h_/#aj7 7q_/#ge71 :]e q is ! maximum dis*>ge 9 cubic feet p] second pass+ ov] a #a-;foot l5g? ( ! weir1 & ,h is ! head ,a ,b4 #d4 ,v>i\s ,types ( ,weirs4--,! type ( weir %[n 9 fig4 #cb may be v>i$ by /eep5+ or flatt5+ ! slopes ( "o or bo? faces4 ,flatt5+ increases ! co/ b gives a great] spread = ! f\ndations4 ,x may1 h[ev]1 be comb9$ ) a decrease 9 ! wid? ( ! cre/4 ,flatt5+ ( ! d[n/ream slope r$uces ! %ock ( ! wat] on ! floor1 b ! slope itself1 especially ! l[] portion1 has to /& a good deal ( we>1 & ! l5g? expos$ to ?is is increas$4 ,flatt5+ ! up/ream slope facilitates ! passage ( floods4 ,! same result is obta9$ by mak+ ! cre/ slope upw>ds 7fig4 #cd74 ,9 a small /ream or 9 an irrigation di/ribut+ *annel1 a weir may be a simple brick wall ) bo? faces v]tical & corn]s r\nd$4 ,illu/ration3 ,,fig4 #cd4 ,weirs 9 ,am]ica are (t5 built ( crib-"w fill$ ) /ones4 ,weirs are also made ( %eet pil+ fill$ 9 ) rubble1 & ! top may be protect$ by %eet iron4 ,a weir made on ! ,m]sey 9 connection ) ! ,man*e/] ,%ip ,canal works 0 s made4 ,!re 7 ?ree r[s ( piles & ! fill+ 9 ! back "p 0 ( clay4 ,sometimes ! d[n/ream faces ( weirs us$ to be made curv$ 7figs4 #ce & #cf71 ! object be+ to r$uce ! %ock ( ! fall+ wat]1 b ! advantage ga9$ is n v appreciable1 & ?is type ( weir is n v common4 ,illu/ration3 ,,fig4 #ce4 ,illu/ration3 ,,fig4 #cf4 ,! ,okla weir 7fig4 #cg7 across ! riv] ,jumna ne> ,delhi 0 built ab\t ?irty-eight ye>s ago on ! riv] b$1 :i* consi/$ ( f9e s&4 ,! dep? ( wat] ov] ! cre/ 9 floods is #f to #aj feet4 ,! mat]ial1 except ! face-"w & ! ?ree walls1 is dry rubble4 ,illu/ration3 ,,fig4 #cg4 ,:5 ! rea* ( *annel d[n/ream ( a weir has a b$-level mu* l[] ?an t ( ! up/ream rea*--?is is (t5 ! case 9 irrigation canals1--! "w is kn[n z a 8fall0 or 8rapid40 ,at a fall ! wat] g5]ally drops v]tically1 & a ci/]n 7fig4 #ch7 is provid$4 ,! fall+ wat] /rikes t 9 ! ci/]n & ! %ock on ! floor is greatly r$uc$4 ,an empirical rule = ! dep? ( ! ci/]n1 measur$ f ! b$ ( ! d[n/ream rea*1 is ,k ,h ,h ,d1 :]e ,h is ! dep? ( ! cre/ ( ! fall bel[ ! up/ream wat]-level1 & ,d is ! diff]5ce betwe5 ! up/ream & d[n/ream wat]-levels4 ,at "s old falls on ,indian canals ! wat]1 z x beg9s to fall into ! ci/]n1 is made to pass ?r\gh a grat+ :i* projects ) an upw>d incl9ation f ! cre/ ( ! weir at ! d[n/ream angle4 ,?is splits up ! wat] & r$uces ! %ock1 b rubbi% is liable to collect4 ,illu/ration3 ,,fig4 #ch4 ,9 ! usual mod]n type ( canal fall 9 ,india ! weir has no rais$ cre/1 & ! wat] is held up by lat]al contraction ( ! wat]way j above ! fall4 ,! op5+ ?r\gh :i* ! wat] passes is trapezoidal 7fig4 #ci71 be+ wide at ! wat]-level & n>r[ at ! b$-level4 ,9 a small *annel !re is only "o op5+1 b 9 a l>ge canal !re are sev]al side by side1 s t ! wat] falls 9 sev]al di/9ct /reams4 ,! curv$ lip %[n 9 ! plan is add$ to make ! wat] spread out & cause less %ock to ! floor4 ,! dim5sions ( ! op5+s are calculat$ s t h[ev] ! supply 9 ! canal may v>y1 !re is nev] any head+ up or draw+ d[n4 ,! detail$ me?od ( calculation = f9d+ ,c ,f & ! ratio ( ,a ,b to ,b ,c is giv5 9 ,hydraulics1 ,,*ap4 ,,iv4 ,9 cases :]e x is only necess>y = ! not* to be accurate :5 ! dep? ( wat] ranges f ,b ,c to ?ree-f\r?s ,b ,c1 x w suffice to calculate z foll[s3--,let b be ! b$ wid? ( ! canal1 & let ,q be ! dis*>ge & ,b ! mean wid? ( ! /ream :5 ! dep? ( wat] is ,b ,c4 ,decide on ! numb] ( not*es1 & let ,w be ! wid? ( a not* calculat$ z if x 7 to be rectangul>1 i4e4 by ! ord9>y weir =mula4 ,increase ! wid? to ,w #aje ,w4 ,!n make ! not* trapezoidal1 keep+ ! mean wid? ,w1 & mak+ ! bottom wid? w 7or ,c ,f71 su* t w_/,w b_/,b4 ,! top wid? ( ! not* is ( c\rse increas$ z mu* z ! bottom wid? is r$uc$4 ,illu/ration3 ,,fig4 #ci4 ,a rapid has a long d[n/ream slope1 :i* is exp5sive to con/ruct & difficult to keep 9 repair1 especially z ! canals c only be clos$ = %ort p]iods4 ,rapids exi/ 9 l>ge numb]s on ! ,b>i ,doab ,canal 9 ,india1 ! face-"w consi/+ 9 _m cases ( r\nd$ undress$ b\ld]s--) ! int]/ices fill$ up by spawls & concrete--:i* /& ! we> well4 ,rapids h aga9 be5 us$ on ! m mod]n canals 9 places :]e b\ld]s are obta9able1 & :]e deep f\ndations w\ld h giv5 tr\ble 9 unwat]+4 ,! up/ream face ( a rapid is v]tical1 or has a /eep slope4 ,illu/ration3 ,,fig4 #dj4 #e4 ,weirs ) ,sluices4--,! long weirs built across ,indian riv]s bel[ ! heads ( irrigation canals g5]ally ext5d across ! great] "p ( ! riv] b$4 ,9 ! rema9+ "p--g5]ally ! "p ne>e/ ! canal head--!re is1 in/ead ( ! weir1 a set ( op5+s or 8"u-sluices0 7fig4 #dj7 ) pi]s hav+ iron grooves 9 :i* gates c slide v]tically4 ,! pi]s may be tw5ty feet ap>t & five feet ?ick4 ,! gates are work$ by "o or m 8travell]s10 :i* run on rails on ! ar*$ roadway4 ,! travell] is provid$ ) screw ge>+ to />t a gate :i* /icks4 ,:5 once />t$ x is easily lift$ by ! ord9>y ge>s4 ,! gates desc5d by _! own weight4 ,! gate 9 ea* op5+ is usually 9 two halves1 upp] & l[]1 ea* 9 its own grooves1 & bo? c be lift$ cle> ( ! floods4 ,9 int]m$iate /ages ( ! riv] ^! gates h to be work$ a good deal4 7,see also ,,*ap4 ,v41 ,art4 #e47 ,usually ! weir has1 all along its cre/1 a set ( h+$ %utt]s1 :i* lie flat at all seasons1 except t ( l[ wat] 9 ! riv]4 ,illu/ration3 ,,fig4 #da4 ,! canal head consi/s ( small] ar*$ op5+s1 provid$ ) gates work+ 9 v]tical grooves & lift$ by a light travell]4 ,if ! floor ( ! canal head is high] ?an ! b$s ( ! riv] & ! canal1 x may be said to be a weir1 b o!rwise ! canal head is m]ely a set ( sluices )\t a weir4 ,! b>rage ( ! ,nile at ,assiut 7fig4 #da71 & ! old b>rages ( ! ,rosetta & ,damietta bran*es1 consi/ ( sets ( sluices )\t weirs4 ,at ,assiut !re are pi]s five metres ap>t & gates work+ 9 grooves l ^?1 above describ$1 at ,indian headworks4 ,illu/ration3 ,,fig4 #db4 ,! 8dam0 across ! ,ravi1 at ! head ( ! ,sidhnai ,canal 9 ! ,punjab1 also consi/s ( sluice op5+s )\t a weir4 ,! pi]s are connect$ by horizontal beams 7fig4 #db71 aga9/ :i*1 & aga9/ a sill at _! l[] ends1 re/ a numb] ( ne>ly v]tical timb] 8ne$les10 fitt+ close toge!r1 :i* c be remov$ :5 necess>y by m5 /&+ on a foot-bridge4 ,9 floods ! ne$les are all remov$ & laid on ! high-level bridge 7n %[n 9 ! draw+71 ! foot-bridge be+ !n subm]g$4 ,) ne$les ! span betwe5 two pi]s c be great] ?an w\ld be possible ) a gate4 ,ne$les c be us$ up to a l5g? ( #ab or #ad feet1 exclud+ ! h&le :i* projects above ! horizontal beam4 ,!y c be ( p9e1 ab\t #e in*es deep 9 ! direction ( ! /ream1 & #d in*es ?ick4 ,:]e a bran* takes (f f a canal 9 ,india !re are usually no fix$ weirs b two sets ( pi]s--"o 9 ! canal & "o 9 ! bran*1--) op5+s & gates l ^? at ! canal heads1 or else ) wid] op5+s & ne$les4 ,^! works are call$ regulators4 ,! gates are work$ by travell]s or by fix$ w9dlasses or racks & p9ions4 ,v small gates = di/ribut>ies are (t5 work$ entirely by screw ge>+4 ,= ! small] bran*es ! gates are replac$ by sets ( planks or timb]s ly+ "o above ano!r & remov$ by means ( hooks4 ,!y are replac$ by means ( ! hooks or by be+ held 9 position "s little height above ! wat]1 & dropp$4 ,!y are f9ally clos$ up by ramm+4 ,9 ! case ( ei!r planks or ne$les1 leakage c be mu* r$uc$ by ?r[+ %av+s or *opp$ /raw into ! wat] up/ream ( !m4 ,ne$les c be provid$ on _! d[n/ream sides ) eye-bolts j above ! level ( ! beam aga9/ :i* _! upp] ends re/4 ,!y c !n be atta*$ by *a9s or cords to ! beam or to ! next pi]1 & _c be lo/ :5 releas$4 ,!y c be releas$ by a lev] :i* c be ins]t$ "u ! eye-bolt4 ,by pu%+ ! head ( a ne$le =w>d & ins]t+ a piece ( wood "u x1 a little wat] c be let ?r\gh4 ,9 ?is way1 or by remov+ ne$les "h & !re1 ! dis*>ge c be adju/$ ) exactness4 ,at a ne$le weir 9 an ,indian canal all ! ne$les 9 "o op5+ are report$ to h brok5 simultane\sly4 ,a possible explanation is t "o ne$le broke & t ! velocity ?us set up 9 ! approa*+ /ream caus$ ! o!rs to break4 ,on ano!r occasion :5 a canal 0 dry all ! ne$les 7 bl[n d[n4 ,sometimes ! beam or b> aga9/ :i* ! upp] ends ( ! ne$les re/ is itself movable4 ,at ,rav5na1 9 ,italy1 ! b> betwe5 any two pi]s has a v]tical pivot at "o pi] & c sw+ horizontally4 ,its o!r end is held by a prolongation ( ! next b>1 ne> to its pivot4 ,if ! end b> ( ! weir is releas$1 ea* b> 9 turn is releas$ automatically4 ,at ,t$d+ton on ! ,?ames ! oblique weir1 #dhj feet long1 has ?irty-five gates1 :i* ext5d ov] half ! l5g? ( ! weir4 ,!y are work$ by travell]s :i* run on a foot-bridge4 ,! op5+s d n ext5d d[n to ! riv] b$1 b are plac$ on ! top ( a l[ weir4 ,! o!r half ( ! weir is fix$4 ,! gates are rais$ to let floods pass4 ,at ,ri*mond on ! ,?ames ! arrangem5ts are simil>1 ! gates be+ c\nt]balanc$ to admit ( easy & rapid rais+4 ,:5 rais$ !y are tilt$ into a horizontal position s z n to ob/ruct ! view4 ,9 ,/oney's sluice gates a set ( roll]s is int]pos$ betwe5 ! gate & ! groove4 ,! roll]s are susp5d$ f a *a91 "o end ( :i* is atta*$ to ! top ( ! gate & ! o!r end to ! groove4 ,! roll]s ?us move up or d[n at half ! rate ( ! gate1 & "s ( !m are always 9 ! prop] position = tak+ ! pressure4 ,escape ( wat] betwe5 ! gate & ! groove is prev5t$ by a rod :i* is susp5d$ on ! up/ream side ( ! gate close to its end1 & is press$ by ! wat] aga9/ ! pi]4 ,/oney's sluice gates1 ) spans rang+ up to #cj feet1 h be5 us$ on ! ,man*e/] ,%ip ,canal = ! sluices by :i* ! wat] ( ! riv] ,weav] is pass$ across ! canal1 & at locks = pass+ ! flood wat]s ( ! ,irwell & ,m]sey d[n ! canal4 ,! gates are balanc$ by c\nt]weights4 ,frame weirs1#ac us$ *iefly on riv]s 9 ,france b also 9 ,belgium & ,g]many1 are a modification ( ! ne$le & plank arrangem5ts above describ$4 ,= ! masonry pi]s !re are sub/itut$ iron frames or tre/les1 :i* are h+$ at ! floor-level s t1 :5 ! timb]s h be5 remov$1 ! frame c be turn$ ov] sideways & lie flat on ! floor1 ?us leav+ ! wat]way absolutely cle> f side to side ( ! /ream4 ,! foot-bridge :i* re/s on ! frames is remov$ piece by piece4 ,! frames are rais$ aga9 by means ( *a9s atta*$ to !m4 ,9 ord] t ! frames may n be too heavy !y are spac$ #c to #d feet ap>t1 or v mu* ne>] ?an :5 masonry pi]s are us$4 ,horizontal planks c ?us be us$ ( %ort] l5g?s ?an ! ne$les1 & !y c be made up into great] wid?s s t ! leakage is less4 ,a fur!r modification consi/s 9 plac+ ! bridge plat=m above flood-level1 & 9 h++ ! frames to x in/ead ( to ! floor4 ,! frame turns ab\t a horizontal axis p>allel to ! l5g? ( ! weir4 ,a weir ( ?is k9d c be us$ = great] dep?s ( wat] ?an ! ord9>y frame weir4 ,9 "s cases ! horizontal planks are connect$ toge!r by h+es s t !y =m a 8curta940 ,! curta9 is rais$ by roll+ x up by means ( a travell]4 ,x admits ( rapid & accurate adju/m5t ( ! wat]-level1 b !re is consid]able sc\r+ action bel[ a curta9 :5 x is some:at rais$4 ,illu/ration3 ,,fig4 #dc4 #f4 ,fall+ ,%utt]s4--,9 ,?n>d's sy/em1 fir/ us$ 9 ,france1 a %utt] 7fig4 #dc7 is h+$ at its l[] edge & is held up by a /rut4 ,:5 ! l[] end ( ! /rut is pu%$ aside x slides d[n/ream & ! %utt] falls flat4 ,to enable ! %utt] to be rais$ aga9 an up/ream %utt]1 :i* ord9>ily lies flat & is held d[n by a bolt1 is releas$1 & x is !n rais$ by ! curr5t to ! ext5t p]mitt$ by a *a9 atta*$ to x4 ,! d[n/ream %utt] is !n rais$4 ,?n>d's sy/em 0 n mu* us$ 9 ,france because ! riv] _h to fall to a level some:at too l[ = navigation be=e ! %utt]s c\ld be rais$4 ,! sudd5 j]k on ! *a9 ( ! up/ream %utt] is also liable to d damage4 ,! sy/em has be5 adopt$ on "s ( ! long weirs :i* cross ,indian riv]s d[n/ream ( ! heads ( irrigation canals4 ,to prev5t damage by %ock1 a hydraulic brake 0 design$ by ,f\racres4 ,x consi/s ( a pi/on :i* travels along a cyl9d] & drives wat] out ?r\gh small holes4 ,! %utt]s are plac$ on ! top ( ! fix$ weir1 :]e !y usually lie flat1 except 9 ! l[ wat] season1 any adju/m5ts ( ! riv] dis*>ge be+ effect$ by means ( ! "u-sluices4 ,9 ! ,*ano9e sy/em ( fall+ %utt]s 7fig4 #dd71 us$ fir/ 9 ,france1 ! %utt] is h+$ at a po9t r high] ?an ! c5tre ( pressure4 ,! h+e is support$ by a v]tical tre/le1 :i* is h+$ at its l[] end & is support$ by a /rut :i* slides 9 a groove & re/s aga9/ a /op4 ,:5 ! wat] rises to a c]ta9 height above ! top ( ! %utt]1 x is turn$ by ! =ce ( ! wat] into a horizontal position4 ,! /ruts c !n be pu%$ sideways out ( ! /ops by means ( a 8tripp+ b>10 :i* lies along ! floor p>allel to ! l9e ( %utt]s & is work$ f ! bank4 ,! /ruts1 tre/les1 & %utt]s !n fall flat4 ,to close ! weir ! %utt]s are fir/ rais$ into ! horizontal position :i* !y occupi$ be=e fall+1 by means ( a hook work$ f a boat or by *a9s atta*$ to a foot-bridge runn+ across ! riv] up/ream ( ! weir4 ,!y c !n be easily clos$ by a boat-hook4 ,! wat] closes !m ( itself if x falls l[ en\gh4 ,illu/ration3 ,,fig4 #dd4 ,:5 ! %utt]s fall a great ru% ( wat] occurs4 ,to obviate ?is a valve is made 9 ! upp] half ( ! %utt]4 ,x consi/s ( a m9iature %utt] on ! same pr9ciple z ! ma9 %utt]4 ,! pivot ( ! ma9 %utt] is made at su* a height t ! %utt] w n turn ov] :5 only a small dep? ( wat] fl[s ov] x4 ,in/ead ( ?is ! valve comes into op]ation4 ,! valve also facilitates ! rais+ ( ! %utt]4 ,aga91 in/ead ( ! tripp+ b>1 :i* w\ld sometimes h to be ( great l5g? or be liable to damage ow+ to /ones jamm+ 9 its tee?1 ! %utt] c be releas$ by pull+ ! /rut up/ream s t x falls into a second groove1 d[n :i* x slides4 ,:5 a tripp+ b> is us$1 its tee? c be s arrang$ t ! %utt]s are releas$ a few at a "t1 fir/ s+ly1 !n 9 twos & ?rees4 ,sometimes !re are gaps ( a few in*es betwe5 "o %utt] & ! next1 & ! gaps c be clos$ by ne$les if necess>y4 ,*ano9e %utt]s c be v rapidly l[]$1 & !y are us$ 9 ,france & 9 ! ,u4,s4,a4 9 places :]e sudd5 floods occur4 ,!y are also us$ = navigation 8passes0 :]e mo/ ( ! heavy traffic is d[n/ream & :]e x is too heavy to be dealt ) 9 a lock4 ,a foot-bridge across ! /ream or across ! navigation pass is always an assi/ance1 b sometimes x _c be us$ :5 !re is mu* float+ rubbi% or ice4 ,) a foot-bridge ! co/ is great] ?an t ( a ne$le weir4#ad ,illu/ration3 ,,fig4 #de4 ,9 ! ,be> ,trap weir 7fig4 #de7 ! up/ream %utt] re/s aga9/ ! d[n/ream "o4 ,bo? are rais$ by admitt+ wat] f ! upp] rea*1 by means ( a culv]t1 ?r\gh an op5+ 9 ! side wall1 & !y are made to fall by plac+ ?is op5+ 9 communication ) ! d[n/ream in/ead ( ! up/ream rea*4 ,?is k9d ( %utt] is only suitable = passes ( mod]ate wid?1 & x is r exp5sive on acc\nt ( ! culv]ts4#ae ,%utt]s ) fix$ supports are us$ on ! ,irwell & ,m]sey4 ,a fix$ frame is built across ! /ream 7fig4 #df7 & ! %utt]s are h+$ to x4 ,:5 ! wat] rises to a c]ta9 height above its top1 ! %utt] turns into a horizontal position1 b z ?is causes a sev]e ru% ( wat] ! %utt] is usually rais$ by a *a9 atta*$ to its l[] end & work$ f ! bank4 ,:5 9 a horizontal position1 x is held !re by a rat*et4 ,:5 ! /ream falls ! rat*et is releas$ & ! %utt] is clos$ by ! /ream4 ,?is k9d ( %utt] _c be us$ :]e !re is navigation4 ,on ! weir #djjj feet long across ! riv] ,*5ab at ,khanki 9 ! ,punjab1 ! fall+ %utt]s1 #f feet high & #c feet wide1 are h+$ at ! base & held up by a tie-rod on ! up/ream side4 ,! trigg] :i* releases ! rod is actuat$ by means ( a wire rope c>ry+ a /eel ball1 & work$ by a w9* f ! abutm5t ( ! weir or f "o ( ! pi]s1 :i* are #ejj feet ap>t4 ,a w9* is fix$ on ! top ( ea* pi]1 & communication ) ! pi]s is effect$ by means ( a cradle slung f a /eel wire rope1 :i* re/s on /&>ds & runs across ! weir4 ,! wire rope :i* c>ries ! /eel ball passes ov] a s]ies ( =ks1 "o on ea* %utt]4 ,:5 "o trigg] has be5 releas$1 t %utt] falls & ! ball hangs loose4 ,a fur!r haul on ! rope causes x to actuate ! trigg] ( ! next %utt]1 & s on4 ,if x is desir$ to drop only "s ( ! %utt]s1 ! rope is pass$ ov] ! =ks ( ^? %utt]s only4 ,! %utt]s c be rais$ by means ( a crane :i* runs along ! weir on rails d[n/ream ( ! %utt]s or1 if ! wat] is too high to all[ ( ?is1 by a crane 9 ! /]n ( a boat :i* is moor$ up/ream ( ! weir & all[$ to drop d[n4 ,illu/ration3 ,,fig4 #df4 ,illu/ration3 ,,fig4 #dg4 #g4 ,adju/able ,weirs4--,drum weirs1 inv5t$ by ,desfonta9es1 h be5 us$ 9 ,france & ,g]many4 ,two paddles 7fig4 #dg7 are fix$ on a horizontal axis & c turn ?r\gh ab\t #ij1 ! l[] paddle1 :i* %\ld be slightly ! l>g]1 work+ 9 a 8drum10 :i* is ro($ ov] & c1 by means ( sluices1 be plac$ 9 communication ) ei!r ! upp] or l[] rea* ( ! /ream4 ,accord+ z ! upp] paddle is to be rais$ or l[]$1 wat] is admitt$ f ! upp] rea* above or bel[ ! l[] paddle1 ! wat] on its o!r side be+ at ! same "t plac$ 9 communication ) ! l[] rea*4 ,on ! weirs fir/ made on ! ,m>ne1 ! height ( ! upp] paddle 0 #c feet #g in*es1 & !re 71 9 a weir1 a numb] ( pairs ( paddles1 ea* be+ #d feet #aa in*es wide4 ,by hav+ sluices at bo? abutm5ts communicat+ ) bo? rea*es1 & by op5+ or clos+ ea* ( !m m or less1 ! v>i\s paddles c be made to take up diff]5t positions1 & ?us p]fect control ov] ! dis*>ge is obta9$ by simply turn+ a h&le to control a sluice gate4 ,a weir has s9ce be5 made ) a s+le pair ( paddles ext5d+ "r across ! op5+ 7#cc feet71 & ! height ( ! upp] paddle is ov] #i feet4#af ,! *ief objection to drum weirs is ! necessity = ! holl[ or drum1 :i* r5d]s ! "w v exp5sive1 except :5 only a small dep? ( wat] is held up4 ,illu/ration3 ,,fig4 #dh4 ,! old sluice gates ( ! ,nile b>rages 7 made segm5tal 7fig4 #dh71 turn$ on pivots 9 ! pi]s1 & 7 rais$ by *a9s4 ,9 "s factories 9 ,bav>ia & ,switz]l& !re are self-act+ %utt]s :i* revolve on a horizontal axis at ! l[] edge1 & are c\nt]balanc$ by cyl9drical weights :i* roll on ways 9 ! side wall4 ,?is arrangem5t is suitable :5 !re is only "o span1 :i* c1 h[ev]1 be z great z #cj feet4 ,an adju/able weir us$ at ,s*we9furt on ! ,ma9e1 consi/s ( a holl[ iron cyl9d]1 #ei feet long & #aj feet 9 diamet]1 runn+ across ! /ream4 ,! cyl9d] is pe>-%ap$ 9 cross-sections1 & c be made1 by means ( me*anism1 to revolve1 ! wat] pass+ ov] x4 ,ano!r k9d us$ at ,mulhaus5 on ! ,rh9e consi/s ( a holl[ iron cyl9d] #he feet long & #ih feet 9 diamet]4 ,! :ole cyl9d] c be rais$ by w9*es 7,m94 ,proc4 ,in/4 ,c4,e41 vols4 cliii4 & clvi474 #h4 ,rem>ks on ,sluices4--,9 all k9ds ( sluice op5+s or regulators1 ! pr9ciples ( design z reg>ds protection ( ! b$ & sides1 splay+ & curv+ ( walls & pi]s1 ?ickness ( floor1 & prev5tion ( ! =mation ( /reams "u ! /ructure are ! same z laid d[n = weirs4 ,9 ord] t a pi] may be safe f be+ ov]turn$ by ! pressure ( ! wat] :5 ! gates or timb]s are d[n1 ! resultant ( its weight1 includ+ t ( any?+ re/+ on x1 & ( ! wat] pressure on x1 mu/ pass ?r\gh ! middle ?ird ( its l5g?4 ,?is g5]ally occurs :5 !re is an ar*$ roadway4 ,o!rwise x mu/ be arrang$ = by prolong+ ! base ( ! pi]s d[n/ream1 & giv+ ! d[n/ream side a batt] or /eps4 ,! floor %\ld usually be plac$ at a level some:at l[] ?an ! mean b$-level ( ! /ream4 ,! b$ may possibly be l[]$ 9 c\rse ( "t4 ,l[]+ ! floor also gives a great] ?ickness ( wat] cu%ion to take ! %ock ( wat] fall+ ov] ! gates or planks4 ,x is conv5i5t to build1 on ! floor1 a l[ wall or sill1 rea*+ up to ! level ( ! b$ or !reab\ts1 & runn+ across f pi] to pi] "u ! l9e ( gates or ne$les4 ,! height ( ! gates or ne$les c ?us be r$uc$1 & !re is little *ance ( silt or /ones collect+ & int]f]+ ) !m4 ,9 ! case ( ne$les ! wall mu/ be /rong en\gh to resi/ _! horizontal pressure4 ,if ev] ! b$ is l[]$1 ! wall c easily be cut d[n or remov$4 ,sluices ) gates are1 ( c\rse1 us$ 9 connection ) works o!r ?an weirs or regulators1 z1 = in/ance1 9 res]voirs or locks1 or g5]ally = communication betwe5 any two bodies ( wat]4 ,! gate may or may n be :olly subm]g$4 ,if x is n :olly subm]g$1 planks c be us$4 ,ne$les c be us$ if ! fl[ is always 9 "o direction & nev] 9 ! rev]se direction4 ,9 all cases protection d[n/ream ( ! op5+ is requir$4 ,9 design+ a set ( sluice op5+s or regulators1 x is sometimes ! cu/om to make ! total area ( wat]way ! same z t ( ! /ream 9 its unob/ruct$ condition4 ,!re is no p>ticul> reason :y x %\ld be ! same4 ,9 a description ( ! ,assiut ,b>rage 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clviii41 p4 #cj71 x is m5tion$ t "o ( ! reasons = plac+ ! floor l[] ?an ! riv] b$ 0 t ! wid? ( ! wat]way ( ! b>rage 0 less ?an t ( ! riv]4 ,! b$ has to be heavily protect$ 9 any case1 & ! prop] pr9ciple is to fix a velocity :i* is consid]$ to be safe &1 ! maximum dis*>ge be+ kn[n1 to det]m9e ! area ( ! wat]way accord+ly4 ,9 ! case ( a v wide riv] l ! ,nile1 ) a well-def9$ *annel1 x is inconv5i5t to make ! di/ance betwe5 ! abutm5ts ( a "w mu* less ?an ! wid? ( ! *annel1 b s f> z velocity is conc]n$1 ! floor ne$ n usually be l[] ?an ! b$4 ,! protection giv5 to ! *annel on ! up/ream side ( ! b>rage 7fig4 #da7 seems to be r great] ?an necess>y4 ,! ?ickness ( ! floor 7#i feet #aj in*es7 seems excessive4 ,! ?ickness orig9ally propos$ 0 mu* less4 ,( ! _m k9ds ( app>atus describ$ 9 ?is *apt] ea* possesses "s advantages & disadvantages4 ,gates require a bridge ) p[]ful lift+ app>atus1 & are suitable = l>ge bodies ( wat] & great dep?s4 ,comp>+ ne$les ) planks1 ! =m] c be work$ by "o man & admit ( rapid removal1 & require f> few] pi]s4 ,planks require two m51 & are sometimes liable to jam1 b ob/ruct float+ rubbi% less ?an ne$les1 & 9 %all[ wat] give rise to less leakage4 ,:e!r ne$les or planks are us$1 masonry pi]s are mo/ suitable :]e s& or gravel are liable to accumulate on ! floor1 or :]e !re is mu* float+ rubbi%4 ,! h+$ frames are suitable 9 o!r cases4 ,fall+ %utt]s ( ! ,*ano9e type admit ( v rapid l[]+1 & c be us$ )\t a foot-bridge4 ,! drum weir is p]fect 9 action1 b its co/ is high4 ,at any sy/em ( sluices ! regulation %\ld be s arrang$ z to m9imise ! *ances ( damage to ! b$ & banks :]e ?is is at all likely to occur4 ,if ! gates are op5$ only ne> "o side ( ! /ructure1 !re w be a ru% ( wat] on t side1 & s]i\s damage may occur4 ,! op5+ %\ld be done symmetrically &1 z f> z possible1 di/ribut$ along ! :ole l5g?4 ,until exp]i5ce has %[n x to be unnecess>y1 s\nd+s %\ld be tak5 at regul> p]iods ( "t d[n/ream ( e important "w :]e sc\r c occur4 ,:5 sc\r is f\nd to h occurr$ at any p>ticul> "p ( ! "w1 ! ru% ( wat] at su* places %\ld1 z f> z possible1 be prev5t$1 & a *ance giv5 = silt+ to occur4 ,unless exp]i5ce %[s t damage is n likely to occur1 a /ock ( concrete blocks1 s&bags1 or o!r suitable mat]ials %\ld be kept on ! spot ready = use4 ,life-buoys %\ld be provid$ on any "w :]e l>ge volumes ( wat] are dealt )1 especially if x is unf5c$ 9 any "p1 or if any ( ! m5 employ$ are casual work]s4 ,reg>d+ works = prev5t+ a riv] f %ift+ its c\rse s z to damage or de/roy a weir or simil> "w1 see ,,*ap4 ,,xi41 ,art4 #c4 ,,*apt] ,,xi ,,bridges ,,& ,,syphons #a4 ,bridges4--,bridges are ( _m k9ds4 ,9 ?is book only ^? p>ts ( !m are consid]$ :i* are expos$ to ! /ream4 ,if a bridge has pi]s1 !re mu/ be "s di/urbance ( ! wat]4 ,! di/urbance w be lea/ :5 ! area ( ! wat]way ( ! bridge is at lea/ z great z t ( ! /ream1 & :5 its %ape is z ne>ly z possible ! same4 ,= small /reams1 a s+le span cle>+ ! :ole /ream may be adopt$1 especially :5 ! *annel is ( s(t mat]ial1 b = a l>ge /ream ! co/ ( int]m$iate pi]s1 ev5 ) a c]ta9 am\nt ( protection = !m or ) deep f\ndations1 w be m ?an c\nt]balanc$ by ! small] ?ickness ( ar* or dep? ( gird]4 ,g5]ally a bridge has v]tical abutm5ts :i* limit ! wat]way1 b x may h l&-spans1 & 9 ?is case ! /ream z x rises c spread out4 ,pi]s & abutm5ts %\ld be s design$ t abrupt *anges 9 ! section ( ! /ream are1 z f> z possible1 avoid$1 ! pi]s be+ r\nd$ or boat-%ap$ at bo? ends & ! abutm5ts suitably curv$ 7fig4 #di74 ,boat-%ap$ pi]s1 besides pres5t+ ! neate/ appe>ance1 cause ! lea/ am\nt ( di/urbance4 ,a bridge c be made safe aga9/ sc\r ei!r by giv+ deep f\ndations to ! pi]s & abutm5ts or by add+ a floor &1 if necess>y1 pit*+4 ,! =m] c\rse is usually adopt$ & is ! be/4 ,b 9 a case 9 :i* ! dis*>ge ( a /ream is to be increas$ or has be5 und]e/imat$1 x is (t5 f> easi] to add a floor to an exi/+ bridge ?an to increase ! span ( ! bridge4 ,9 ord] to increase ! wat]way ! floor c be 8di%$10 i4e4 made at a level l[] ?an ! b$ ( ! /ream#ag & gradually slop$ up--! slopes be+ pit*$--bo? up/ream & d[n/ream ( ! bridge1 to meet ! b$4 ,illu/ration3 ,,fig4 #di4 ,9 any case 9 :i* ! wat] rises above ! cr[n ( ! ar*1 ! bridge becomes a syphon1 & a floor is probably necess>y unless ! f\ndations are v deep1 or unless ! rise ( wat] above ! cr[n is tempor>y4 ,illu/ration3 ,,fig4 #ej4 ,9 ! case ( ,indian riv]s :i* h s(t *annels1 & are ord9>ily ( mod]ate wid? b are subject to occasional floods :5 ! wid? ( ! /ream is multipli$ sev]al times & becomes v great1 x is ! rule to make ! span ( a railway bridge f> less ?an ?is great] wid?4 ,! /ream dur+ floods sc\rs out a deep *annel ?r\gh ! bridge ) great rapidity1 & no head+ up wor? m5tion+ occurs4 ,! f\ndations ( ! pi]s are v deep1 be+ frequ5tly #ej feet bel[ ! l[e/ po9t ( ! riv] b$ :i* c be f\nd any:]e )9 sev]al miles ( ! bridge4 ,! span ( ! bridge c be arriv$ at by consid]+ a g5]al cross-section ( ! riv] z x is :5 9 high flood1 & assum+ t sc\r to ! dep? ( ! l[e/ po9t1 f\nd z j expla9$1 w take place 9 "o-?ird ( ! span ( ! bridge4 ,! span c !n be s fix$ z to give no head+ up4 ,x is n assum$ t !re w be no increase 9 velocity ?r\gh ! bridge4 ,! velocity 9 ! deep sc\r$ portions w be increas$4 ,! pi]s are protect$ by loose /one 7fig4 #ej74 ,! spans v>y f #ajj to #bej feet4 ,! bridge ov] ! riv] ,*5ab at ,wazirabad _h orig9ally sixty-f\r spans ( #ade feet ea*4 ,! numb] ( spans has s9ce be5 r$uc$ to tw5ty-eight4 ,) a v long bridge1 ! curr5t ( ! %ift+ /ream is m likely to /rike ! bridge obliquely1 ?\gh ?is is n ! *ief reason = r$uc+ ! l5g?4 ,long spans1 say #bej feet1 h be5 f\nd to be bett] ?an %ort] spans2 ! co/ ( ! /one protection r\nd ! pi]s is ( c\rse less 7,gov]nm5t ( ,india ,te*nical ,pap]1 ,no4 #aec1 8,riv] ,tra9+ & ,control on ! ,guide ,bank ,sy/em10 by ,sir ,f4 ,j4 ,e4 ,spr+1 ,c4,i4,e41 #aijd74 #b4 ,syphons & ,culv]ts4--,syphons are us$ to pass dra9age *annels or o!r /reams "u canals or o!r l9es ( communication4 ,9 ! case ( a masonry syphon "u a /ream :i* may be dry :ile ! syphon is full1 ! weight ( ! ar* & its solid load mu/ be n less ?an ! upw>d pressure ( ! wat] pass+ ?r\gh ! syphon4 ,! *annel sometimes has a v]tical drop at ! up/ream side 7fig4 #ea7 & a slope at ! d[n/ream side4 ,! slope enables any solid mat]ials to be c>ri$ ?r\gh1 & facilitates clean+ out & unwat]+4 ,! drop at ! up/ream side does n give rise to any %ock on ! floor :5 ! syphon is full1 b a slope is pref]able if !re is room = x1 & x causes less loss ( head4 ,illu/ration3 ,,fig4 #ea4 ,a culv]t :i* is liable to run full & :i* has a /eep approa* *annel 7fig4 #eb7 may become sudd5ly dr[n$ on ! up/ream side4 ,z soon z ! wat] rises to ! cr[n ( ! ar*1 ! wet bord] ( ! culv]t increases & ?is r$uces ! velocity & dis*>ge4 ,! wat] com+ d[n ! approa* *annel !n rises abruptly1 & ! increas$ section ( ! /ream causes a r$uc$ velocity ( approa*1 & ?is fur!r r$uces ! dis*>ge ?r\gh ! culv]t4 ,! head+ up cont9ues until ! diff]5ce 9 ! up/ream & d[n/ream wat]-levels is great en\gh to readju/ matt]s 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxxvi474 ,! possibility ( ?is head+ up occurr+ %\ld be att5d$ to 9 ! design4 ,9 ! case ( a culv]t 9 a railway embankm5t :]e heavy floods h to be pass$1 ! culv]t may be made bell-m\!d by a curv$ embankm5t con/ruct$ on its up/ream side4 ,illu/ration3 ,,fig4 #eb4 #c4 ,tra9+ ,works4--,! object ( ! up/ream & d[n/ream protections already describ$ 7,,*ap4 ,x47 is to prev5t damage to ! /ructure ow+ to ! di/urbance caus$ by ! /ructure itself4 ,:5 a riv] is giv5 to %ift+ its c\rse 7,,*ap4 ,,iv41 ,art4 #i7 & cutt+ away its banks1 protection ( ano!r k9d is requir$4 ,! /ream1 if left to itself1 may cut away "o bank up/ream ( ! /ructure = a long di/ance1 & ev5tually damage1 or de/roy by und]m9+1 ! up/ream pit*+ & ! abutm5t itself4 ,?is is kn[n z outflank+4 ,if 9 ! neighb\rhood ( ! l9e ,a ,b 7fig4 #ec7 !re is no?+ = ! riv] to damage1--if1 = in/ance1 ! /ructure is a weir ) a canal1 if any1 only on ! opposite bank ( ! riv]1--& if ! l& is ( no p>ticul> value1 ! case c\ld conceivably be met by protect+ ! abutm5t on all sides1 b ev5 !n !re might be a *ance ( ! erosion ( ! bank cont9u+ until ! /ream _h =m$ a connection at ,c ) ! d[n/ream rea*4 ,?is1 ( c\rse1 9 ! case ( a weir1 w\ld r5d] ! "w useless & might ev5 de/roy x4 ,illu/ration3 ,,fig4 #ec4 ,9 ! case ( a bridge c>ry+ a road or railway1 or ( a syphon or aqu$uct c>ry+ a canal or o!r /ream1 x is :olly inadmissible to all[ ! /ream to cut away ev5 z f> z ! po9t ,a = fe> ( its sev]+ ! l9e ( communication4 ,?us 9 e case x is practically necess>y to prev5t any s]i\s erosion ( ! bank up/ream ( ! /ructure4 ,9 ord9>y cases x is suffici5t to protect ! bank ,c ,d by any ( ! me?ods giv5 9 ,,*ap4 ,,vi41 ,art4 #c1 ! protection be+ turn$ inw>ds1 z %[n at ,d1 to prev5t ! end ( x be+ damag$4 ,9 ! case ( railway bridges across ! great %ift+ riv]s ( ,india1 protection us$ at "o "t to be af=d$ by v>i\s sy/ems ( spurs4 ,?is has n[ be5 ab&on$ 9 fav\r ( ,bell's guide banks 7fig4 #ed71 :i* are f\nd to be f> m satisfactory4 ,^! guide banks are discuss$ 9 ! pap] by ,spr+ quot$ above 7,art4 #a74 ,! spaces beh9d ! guide banks become fill$ ) wat]1 at lea/ dur+ floods1 & are meant to be silt$ up4 ,an op5+ 9 ! railway embankm5t %\ld be provid$ at ,a1 & ano!r on ! opposite side ( ! riv]1 to ensure a con/ant fl[ ( wat] 7,,*ap4 ,v41 ,art4 #c71 b !y %\ld n be l>ge en\gh to cause high velocity4 ,! *ief dang] to :i* a guide bank is liable is outflank+ :5 ! /ream assumes ! position %[n4 ,to gu>d aga9/ ?is dang] x is necess>y to h v /rong & massive heads to ! guide banks4 ,:5 ! bank ( ! erod+ /ream1 d[n/ream ( ! guide bank head1 becomes a semicircle or !reab\ts1 ! /ream takes a %ort-cut across ! s&bank1 & to enc\rage ?is an artificial cut c be dug1 at ! season ( l[ wat]1 on any suitable l9e4 ,illu/ration3 ,,fig4 #ed4 ,if ! guide banks 7 made ) an increas$ wid? ( op5+ at ! upp] end1 ?is w\ld r$uce ! *ance ( outflank+ b w\ld increase ! dang] f a direct attack su* z indicat$1 9 ! figure1 on ! left bank4 ,x has be5 sugge/$ t ! wid? at ! up/ream end %\ld be less ?an at ! bridge1 b ?is seems undesirable4 ,probably ! =m %[n 9 fig4 #ed is ! prop] "o4 ,! l5g? ( ! guide bank up/ream ( ! bridge is made ab\t equal to ! span ( ! bridge betwe5 ! two guide banks4 ,if made less ?an ?is1 ! riv] might cut into ! l9e ( railway4 ,! l5g? ( guide bank d[n/ream ( ! bridge is g5]ally #cjj to #ejj feet1 be+ great] z ! velocity ( ! riv] is great] & ! s& ( its b$ f9]4 ,illu/ration3 ,,fig4 #ee4 ,! ,b5gal ,doo>s ,railway runs ne> ! foot ( ! ,bhutan ,himalayas1 & crosses "s broad riv] *annels :i*1 aft] ! excessively heavy ra9s :i* occur1 are fill$ by /reams ( v high velocities4 ,"o su* *annel or set ( *annels 7fig4 #ee71 m ?an half a mile wide1 is provid$ ) a bridge ^: wat]way consi/s ( t5 spans ( #fj feet ea*4 ,! railway embankm5t across ! rema9d] ( ! *annel hav+ be5 brea*$ 9 _m places 9 #aijc1 protection 0 af=d$ by ,t-head$ spurs & o!r groynes1 ! fir/ arrangem5t1 :i* )/ood ! floods ( #aijd1 be+ z %[n 9 ! figure4 ,! triangul> apex ( ! ,a-%ap$ groyne1 s\?-ea/ ( ! bridge1 0 add$ 9 #aije because1 9 its abs5ce1 ! wat] /ruck ! bridge obliquely4 ,aft] ! addition !re 0 a great deposit ( silt 9 ! neighb\rhood ( ! f\r ,t-head$ spurs4 ,next ye> ! riv]1 9 a great flood1 rose ov] ! top ( ! railway embankm5t ne> ^! spurs1 & f9ally caus$ a brea* #fjj feet wide4 ,! embankm5t 0 aft]w>ds rais$4 ,! velocity ?r\gh ! bridge seems to h approa*$ #ah feet p] second4 ,! bridge _h at fir/ no floor4 ,a floor 0 add$1 b 0 mu* damag$ by ! floods 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxiii474 ,! level ( ! floor is n giv51 b x w\ld seem to h be5 desirable to make x at a v l[ level4 ,! ris+ ( ! /ream ov] ! railway embankm5t 0 attribut$ to ! silt+ up ne> ! ,t-head$ spurs4 ,! addition ( ! triangul> portion above ref]r$ to w\ld seem to h some:at assi/$ ?is process4 ,if all ! tr\ble c\ld h be5 =ese51 x might h be5 be/ to build an additional bridge #bjjj feet s\?-ea/ ( ! exi/+ bridge4 ,! groynes 7 compos$ ( ! wire-network rolls1 describ$ 9 ,,*ap4 ,,vi41 ,art4 #c1 pil$ pyramid fa%ion4 ,,*apt] ,,xii ,,dra9age ,,& ,,floods #a4 ,prelim9>y ,rem>ks4--,arts4 #b & #c ( ?is ,*apt] deal ) ! calculation ( flood dis*>ges1 ,art4 #b deal+ ) small /reams1 9 :i* ! wat] has to be got rid (1 & ,art4 #c ) l>ge /reams4 ,! rema9+ articles discuss ! me?ods ( pr$ict+ floods & ( prev5t+ !m f do+ damage4 ,:5 ! dis*>ge figures h be5 arriv$ at 9 any case1 ! necess>y masonry works c be design$ 9 accordance ) ! pr9ciples describ$ 9 ,,*aps4 ,x4 & ,,xi4 ,= rem>ks reg>d+ ! design ( *annels & banks1 see ,,*ap4 ,,ix41 ,art4 #d1 & also ,art4 #f ( ! pres5t ,*apt]4 ,9 ,engl&1 l& ne> a /ream or flood$ area is said to be 8awa%0 :5 ! flood wat] rises to )9 #c feet ( ! surface ( ! gr\nd4 ,! dra9age ( su* l& is apt to be unsatisfactory4 ,if l& is flood$ or awa%1 x may be desirable to %ift ! outfall ( a bran* dra9 to a po9t l[] d[n 9 ! ma9 outfall4 #b4 ,small ,/reams4--,9 deal+ ) small /reams1 su* z bran* dra9s or natural /reams n f> f _! s\rces1 ! eng9e] is conc]n$ only ) _! maximum dis*>ges4 ,he has to design culv]ts1 bridges or syphons to pass ! /reams "u roads or o!r works1 or to design *annels or wa/e weirs = !m4 ,9 a settl$ c\ntry !re may be already "s works 9 exi/5ce on ! same /ream1 & ^! may =m a guide1 or x may be possible to obta9 local in=mation z to ! height or volume ( floods4 ,ev5 9 su* a case ra9fall figures w be mo/ useful4 ,9 di/ricts :]e !re is no settl$ population1 & 9 any case :]e ! /ream is ill-def9$1 & ! fl[ fitful1 ! ra9fall figures may af=d ! only1 or at lea/ f> ! be/1 means ( e/imat+ ! dis*>ge4 ,! ra9fall to be consid]$ 9 all ^! cases is ! maximum likely to fall 9 a %ort p]iod ( "t4 ,! cat*m5t areas dealt ) are small1 say #e squ>e miles or less4 ,x mu/ be assum$ t ! fall ( ra9 ext5ds to all p>ts ( ! cat*m5t area1 & t its duration is suffici5t = ! wat] f all p>ts ( x to rea* ! site ( ! "w4 ,! diff]5t valleys or divisions ( ! cat*m5t area %\ld be consid]$ sep>ately1 & reg>d mu/ be _h1 n only to ! area ( ea* division1 b to its l5g? & declivity measur$ along ! c\rse ( ! /ream :i* dra9s x4 ,on ^! two factors dep5d ! "t tak5 by ! ra9 wat] to rea* ! site ( ! "w4 ,! rate at :i* ! ra9 wat] fl[s ov] ! gr\nd into rills or small subsidi>y /reams may be tak5 to be mile p] h\r 9 flat l&1 & #a mile p] h\r on /eep hill sides4 ,! velocity ( ! curr5t 9 ! rills & l>g] /reams is g5]ally #b to #d miles p] h\r4 ,x c1 :5 necess>y1 be calculat$ r\ghly f ! size & slope ( ! /ream4 ,to be on ! safe side1 ! highe/ probable figure c be tak54 ,! "t tak5 by ! wat] to fl[ f ! fur!/ po9ts ( ! cat*m5t area to ! site ( ! "w hav+ be5 arriv$ at z above1 ! next ?+ is to e/imate ! probable maximum int5sity ( ! ra9fall dur+ t "t ov] ! :ole cat*m5t area4 ,! only figures imm$iately available w be ! mean annual ra9fall1 or p]haps ! maximum fall 9 tw5ty-f\r h\rs1 b x has be5 %[n 7,,*ap4 ,,ii41 ,art4 #e7 h[ ! probable maximum fall ov] a %ort] p]iod may be e/imat$4 ,! next ?+ to be calculat$ is ! 8run-(f10 i4e4 ! probable proportion ( ! ra9fall :i* w at once run (f4 ,?is may be less ?an ! proportion :i* w ev5tually become 8available10 because "s ( x may g to fe$ ! und]gr\nd supply f :i* spr+s are f$4 ,! proportion runn+ (f a small area 9 a %ort "t w\ld1 "u mo/ circum/ances1 be r difficult to e/imate1 b 9 ! case "u consid]ation1 only ! probable maximum figure is requir$4 ,?is occurs :5 ! gr\nd is saturat$4 ,"u ^! circum/ances ! ratio ( ! run-(f to ! total fall may be some:at z foll[s3-- ,/eep rocky hillsides #gj to #ij ,ord9>y hills #ej 0 #ge ,undulat+ c\ntry #dj 0 #ej ,flat c\ntry #cj 0 #ce ,! figures c be increas$ :5 ! surface is specially h>d or froz51 & decreas$ :5 x is s(t1 s&y1 cov]$ ) woods or vegetation1 or cultivat$4 ,:e!r or n ! above proc$ure is necess>y 9 its entirety dep5ds *iefly on ! size ( ! propos$ "w & on ! degree ( inconv5i5ce likely to arise f any wrong e/imation ( ! dis*>ge4 ,9 design+ syphons to c>ry torr5ts across ! ,upp] ,jhelum ,canal 9 ! ,punjab1 ! dis*>ge f a cat*m5t area ( #gi squ>e miles 0 f\nd to be ab\t #djjj cubic feet p] second4 ,?is is at ! rate ( ab\t #ejjj cubic feet p] second p] squ>e mile1 & is equival5t to a run-(f ( #gh in*es 9 an h\r4 ,! cat*m5t area 0 among l[ hills1 n f> f ! ,himalayas1 & ! declivities ( ! rills 7 v /eep4 ,! sup]9t5d+ eng9e]1 ,mr ,r4 ,e4 ,purves1 /ates#ah t ! dis*>ge obs]vations 7 reliable1 & t falls ( ra9 ( an in* 9 t5 m9utes occur n infrequ5tly1 ev5 ?\gh ! fall 9 tw5ty-f\r h\rs might n exce$ #b or #c in*es4 ,9 ord] to acc\nt = ! dis*>ge 9 ! case "u consid]ation1 x w\ld at fir/ seem to be necess>y to assume n only t a fall at ! rate ( #gh in*es p] h\r _h occurr$1 b t ! :ole ( x _h run (f4 ,x is n1 h[ev]1 necess>y to assume q s mu*4 ,! gr\nd be+ saturat$1 ! ra9 fall+ 9 a p]iod ( five m9utes might be rea*+ ! dis*>ge site ) little loss4 ,a sudd5ly increas$ fall at ! rate ( #f in*es p] h\r might !n occur1 & ! wat] travell+ m quickly & ) h>dly any loss1 w\ld ov]take t already pass+ ! site4 ,?is case seems to %[ t = a v small cat*m5t area ! :ole ( ! fall1 & m1 mu/ be all[$ =4 ,! ,*ief ,eng9e] ( ! ,punjab did n accept ! above figures4#ai ,he rem>k$ t obs]vations tak5 "u great difficulties z to "t & place are liable to error1 & he consid]$ t an all[ance ( ra9fall at ! rate ( #dh in*es p] h\r--a rate :i* _h be5 obs]v$ else:]e--& a run-(f ( #ge ( ! fall w\ld be suffici5t4 ,he accept$ a dis*>ge ( #bjjj cubic feet p] second = cat*m5t areas ( less ?an #e squ>e miles1 assum+ ! run-(f to be #ge ( ! fall1 b aft]w>ds increas$ ! figure to #bdjj cubic feet p] second4 ,! *ief eng9e] did n ov]look ! fact t 9 ! designs = ! dra9age aqu$ucts a free-bo>d ( #e feet _h be5 all[$1 & p]haps ?is l$ to an acceptance ( an e/imat$ dis*>ge less ?an w\ld o!rwise h be5 accept$4 ,x does n seem to be at all c]ta9 t ! figure put =w>d by ,mr ,purves 0 f> wrong4 ,:5 ! orig9al project e/imate = ! ,upp] ,jhelum ,canal 0 fram$1 ! irrigation eng9e]s _h _h no exp]i5ce ( small & /eep cat*m5ts1 & no "o _h suspect$ t ! dis*>ge p] squ>e mile w\ld be any?+ l ! above4 ,! sums ( money provid$ = works = ! passages ( torr5ts _h to be increas$ 9 ratios v>y+ f #be to #a to #f to #a4 ,! foll[+ /atem5t %[s ! figures = o!r small cat*m5t areas 9 ! neighb\rhood ( ! ,upp] ,jhelum ,canal3-- ------------------------------------- ,cat*m5t ,dis*>ge p] ,run-(f4 ,area4 squ>e mile4 ------------------------------------- ,sq4 miles4 ,cub4 ft4 p] sec4 ,in*es4 4#gi #ejjj #gh #adg #chbe #ehb #bif #bbad #cdf ------------------------------------- ,9 ! s\?-ea/ ( ,new ,s\? ,wales flood dis*>ges ( #ace & #hd cubic feet p] second h be5 f\nd = cat*m5t areas ( #ia & #be squ>e miles respectively 9 brok5 c\ntry4 #c4 ,riv]s4--,x is possible to apply ! me?ods ( ! prec$+ article to l>ge cat*m5t areas1 b ! results w\ld be q unreliable4 ,if ! calculations 7 made s z to err on ! side ( safety1 ! result+ dis*>ges w\ld (t5 be enorm\s4 ,! foll[+ table %[s "s figures bas$ on actual flood dis*>ges4 ,none ( ! localities h excessive ra9falls1 ?\gh mo/ are liable to occasional v heavy falls4 ,9 m\nta9\s di/ricts 9 ! ,nor? ( ,engl& & 9 ,scotl& ! flood dis*>ges p] squ>e mile ( cat*m5t area h be5 f\nd to v>y f #fd to #cbj cubic feet p] second4 ---------------------------------------- ------------------------- ,flood ,dis*>ge ,ref]5ce ,c\ntry4 ,locality4 ,cat*m5t p] sq4 mile ,rem>ks4 ,numb]4 ,area4 ( ,cat*m5t ,area4 ---------------------------------------- ------------------------- ,sq4 miles ,cub4 ft4 p] sec4 #a ,india4 ,upp] #e to #aj #afac ,jhelum4 #b 0 ,nagpur4 #ff #dhj #c ,s\? ,ne> ,cape #cde #gh ,africa4 ,t[n4 #d 0 ,ne> ,port #ce #fdj ,e/imat$4 ,elizabe? #e ,new ,s\?,s\?-,ea/ #di #cg ,wales4 ,di/rict4 #f ,india4 ,upp] #ef #ajjj ,jhelum4 #g 0 0 #agd #eej #h ,new ,s\?,s\?-,ea/ #dah #aab ,wales4 ,di/rict4 #i ,india4 ,kali ,nadi #beic #ea ,e/imat$ ,/ream4 or m r\ghly4 ---------------------------------------- ------------------------- ,! t5d5cy ( ! figures 9 column #e ( ! table is to decrease z ! cat*m5t area increases4 ,?is t5d5cy has long be5 kn[n1 & attempts h be5 made to f\nd on x =mul = calculat+ flood dis*>ges4 ,"o su* =mula is ,q c ,m#c_/d :]e ,q is ! flood dis*>ge 9 cubic feet p] second & ,m is ! area ( ! cat*m5t 9 squ>e miles4 ,! =mula is r\ghly correct1 c be+ a con/ant = cat*m5t areas ( n dissimil> *>act]s & ) ra9falls n diff]+ mu*4 ,b = o!r cases !re is no kn[+ h[ c may v>y1 & ?is r5d]s ! =mula practically useless4 ,! au?or ( ano!r su* =mula quotes cases ,nos4 #e & #h 9 ! above table1 & ! two cases m5tion$ at ! end ( ,art4 #b z agree+ fairly well ) ! result ( 8 =mula4 ,! t5d5cy j m5tion$ is due to ! fact t e riv] is compos$ ( tribut>ies :i* h _! own small cat*m5t areas b are1 :5 measur$ to ! g5]al outlet or po9t :]e ! dis*>ge is "u consid]ation1 ( v diff]5t l5g?s1 to ! improbability ( heavy ra9fall occurr+ ov] all ^! small areas at su* times z to cause ! diff]5t flood waves to arrive simultane\sly at ! outlet1 & to ! facts t 9 ! case ( ! long] tribut>ies ! flood waves flatt5 out 7,hydraulics1 ,,*ap4 ,,ix41 ,arts4 #c & #d7 s z to arrive m gradually1 & t1 unless ra9 is also fall+ all along _! c\rses1 ^! long] tribut>ies und]go losses f evaporation & absorption4 ,b occasionally x happ5s t ! v>i\s flood waves d arrive at ! outlet m or less simultane\sly1 & t ! ra9fall cont9ues s long & is s widely di/ribut$--?\gh n necess>ily ( ! same int5sity z t :i* caus$ ! flood--t ! flood waves d n flatt5 out & t losses 9 ! *annels d n occur4 ,floods c ?us v>y to an extraord9>y degree 9 sev]ity1 & =mul are q useless4 ,?is is :y floods occur surpass+ all previ\s records1 z1 = in/ance1 ! rec5t floods 9 ,p>is4 ,h[ev] sev]e a flood may be1 x c nev] be said t ! maximum has1 ev5 probably1 be5 atta9$ unless x c be %[n t ! ra9fall has be5 s heavy1 s long cont9u$1 & s di/ribut$ t any?+ worse is n likely to occur4 ,! be/ me?od ( e/imat+ ! flood dis*>ge ( a l>ge p]5nial /ream is to asc]ta91 by local inquiry1 ! height to :i* x is kn[n to h ris51 & to take cross-sections ( ! *annel & calculate ! dis*>ge 7,,*ap4 ,,iii41 ,arts4 #d & #e74 ,9 design+ works1 all[ance c be made = a flood exce$+ any kn[n be=e4 ,?is me?od applies also to a case 9 :i* a riv] is =m$ by ! junction ( two or m l>ge tribut>ies4 ,x is possible t ! tribut>ies h n1 )9 ! memory ( man1 be5 9 high flood simultane\sly4 ,if s1 ! *ances ( ?is occurr+ are no great] & no less ?an if ! /ream 0 compos$ m]ely ( a numb] ( small afflu5ts4 ,rem>ks reg>d+ int]mitt5t /reams are giv5 9 ,,*ap4 ,,iii41 ,art4 #g4 ,s9ce an acre conta9s #dc1efj squ>e feet1 & a twelf? ( ?is is #cfcj1 x foll[s t a fall ( #d in*es ( ra91 ( :i* #a in* runs (f1 9 an h\r1 gives a dis*>ge ( #cfcj cubic feet p] h\r1 or ab\t #a cubic foot p] second4 ,?is is #fdj cubic feet p] second = a squ>e mile4 ,! figures 9 column #e ( ! above table %[ t ! run-(f 01 9 ! cases quot$1 g5]ally f> less ?an #a in*4 ,9 case ,no4 #d x 0 #a in*1 & 9 case ,no4 #b x 0 #c_/d in*4 ,9 ! case ( ! ,kali ,nadi 7,no4 #i 9 ! table7 an aqu$uct to c>ry ! ,l[] ,ganges ,canal ov] ! /ream 0 be+ design$4 ,! flood dis*>ge1 e/imat$ f ! suppos$ flood-level & cross-section ( ! /ream 0 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 xcv47 #bf1ceb cubic feet p] second4 ,! dis*>ge1 e/imat$ by assum+ a fall ( #f in*es ( ra9 9 tw5ty-f\r h\rs ov] ! cat*m5t area--!n believ$ to be #cjbe squ>e miles--& a run-(f ( #be ( ! fall1 0 #aad1iej cubic feet p] second4 ,?is figure 0 reject$ on ! gr\nd t ! ra9fall w\ld n be cont9u\s ov] s l>ge an area z #cjbe squ>e miles4 ,an all[ance ( #g cubic feet p] second p] squ>e mile 0 made &1 a fre% survey hav+ %[n t ! cat*m5t area 0 only #beic squ>e miles1 a dis*>ge ( #ah1jjj cubic feet p] second 0 all[$ =4 ,! aqu$uct 0 built1 ab\t ! ye> #ahge1 ) five ar*$ spans ( #ce feet ea*1 ! total area ( ! wat]way be+ ab\t #cjjj squ>e feet4 ,! l5g? ( ! pi]s & abutm5ts 0 #bab feet1 ! wid? ( ! canal c>ri$ ov] ! aqu$uct be+ #aib feet4 ,9 #ahhd ! aqu$uct 0 p>tly de/roy$ by a flood ^: dis*>ge 0 ab\t #dd1jjj cubic feet p] second4 ,9 ,july #ahhe x 0 :olly de/roy$ by a flood ^: dis*>ge 0 e/imat$ at #acb1dge cubic feet p] second1 b 0 probably m4 ,! dis*>ge mu/ h be5 m ?an #ea cubic feet p] second p] squ>e mile4 ,! aqu$uct 0 rebuilt ) a wat]way ( ab\t #ae1jjj squ>e feet4 ,bel[ ! aqu$uct !re 0 a bridge :i* _h be5 /&+ = a hundr$ ye>s4 ,its wat]way 0 only #aadf squ>e feet4 ,x 0 n mu* damag$ by ! flood ( #ahhd1 b mu* ( ! wat] pass$ r\nd x1 break+ ?r\gh ! embank$ roadway or p\r+ ov] x4 ,x is und]/ood t ! bridge 0 de/roy$ by ! flood ( #ahhe4 ,?is case %[s ! necessity = mak+ e possible all[ance 9 calculat+ flood dis*>ges = important works4 ,! smallness ( ! dis*>ge1 z calculat$ f ! cross-section ( ! /ream1 0 probably ow+ to its be+ dry :5 ! survey 0 made1 s t ! velocity c\ld n be obs]v$1 b x is probable t su* a dis*>ge z wreck$ ! aqu$uct _h nev] be=e pass$ d[n ! /ream4 #d4 ,pr$iction ( ,floods4--,at any place high up on ! c\rse ( a /ream1 ! occurr5ce ( a flood c (t5 be pr$ict$ :5 ra9 /orms--(t5 accompani$ 9 ! tropics by lightn+--c be se5 to be occurr+ t[>ds ! s\rces ( ! /ream4 ,= any /ation l[] d[n ! /ream & = precise in=mation 9 any case1 ! read+s ( gauges high] up ! /ream c be telegraph$4 ,if ! /ation is at a great di/ance f ! gauge & if !re is railway communication1 ! read+s c be s5t by po/4 ,9 ord] to be able to pr$ict ! "t ( ! arrival ( a flood at ! l[] /ation ! read+ ( a gauge !re1 & also ( t at ! upp] /ation1 %\ld be tak5 at frequ5t int]vals4 ,9 ! case ( l>ge riv]s & di/ances ( hundr$s ( miles1 ! int]val may be six or ev5 twelve h\rs1 b 9 o!r cases x %\ld be mu* less4 ,if ! read+s are plott$1 z 9 fig4 #ef1 oblique l9es c be drawn to connect ! sali5ces & depressions1 & ! "t tak5 by ea* *ange c ?us be readily se54 ,:5 ! upp] "p ( ! /ream is =m$ by two or m important tribut>ies !re %\ld be a gauge 9 ea*4 ,z to :at con/itutes a flood1 ! gauge diagram ( a riv] 7fig4 #ef7 is g5]ally su* t a l9e c be sket*$ z %[n dott$4 ,! rises above ?is l9e are floods4 ,! maximum flood dis*>ge ( a ,nor!rn ,indian riv] is e/imat$ r\ghly z be+ #ajj times ! l[-wat] dis*>ge4 ,leslie's rule = floods 9 ! ,briti% ,isles is t if all ! daily dis*>ges ( a /ream dur+ ! ye> are rang$ 9 ord] ( magnitude1 ! dis*>ges ( ! upp] qu>t] are consid]$ to be floods4 ,illu/ration3 ,,fig4 #ef4 ,9 ,india x is sometimes arrang$ t a telegram %all1 9 ! l[-wat] /age ( ! riv]1 be s5t f ! upp] /ation :5 a rise ( #b feet occurs 9 tw5ty-f\r h\rs or any less p]iod1 ) a fur!r telegram = any su* subsequ5t rise4 ,! telegram /ates ! exact read+ on ! gauge & :e!r ! wat] is ris+ /eady or fall+4 ,?is is giv5 z indicat+ ! proc$ure t may be foll[$ :]e ! telegraph has to be us$1 b :5 long & frequ5t telegrams are n desirable4 ,! advanc+ end ( a flood wave may1 :ile ! wave is ris+ & be+ =m$1 travel rapidly1 b :5 ! wave has be5 =m$ x travels at ! ord9>y rate ( fl[ ( ! ris5 /ream4 ,! advanc+ end ( a tr\gh may1 :ile x is be+ =m$1 travel rapidly1 b aft] =mation x travels at ! ord9>y rate ( ! fall5 /ream 7,hydraulics1 ,,*ap4 ,,ix41 ,arts4 #c & #d74 ,?us ! rate at :i* a *ange 9 wat]-level travels d[n a /ream dep5ds at fir/ on ! am\nt ( ! rise or fall1 b aft]w>ds on ! wat]-level ( ! ris5 or fall5 /ream4 ,by tak+ ! above facts into consid]ation & not+ ! actual times obta9$ f ! diagram1 x w be possible to arrive at ! probable "t t w be tak5 by any *ange4 ,x w also be possible to pr$ict ! height ( ! flood4 ,if x is wor? :ile1 an empirical =mula c be got out4 ,if !re are tribut>ies1 ea* ) a gauge1 ! matt] w be m difficult4 ,probably ! floods 9 ! tribut>ies w arrive at diff]5t times1 b ev5 9 su* cases empirical =mul h be5 arriv$ at1 especially 9 ,france1 & are m5tion$ 9 v>i\s volumes ( ! ,proce$+s ( ! ,in/itution ( ,civil ,eng9e]s4 ,9 all cases pr$ictions are liable to be m or less upset if ra9 falls 9 ! tract betwe5 ! upp] & l[] gauges4 ,9 v dry wea!r ! spe$ ( a flood wave may be some:at r$uc$1 & ! height to :i* x rises w almo/ c]ta9ly be r$uc$4 ,! full effect ( a *ange w n be felt at ! l[] /ation unless ! *ange at ! upp] /ation is ma9ta9$ = a suffici5tly long p]iod4 ,a %ort wave or tr\gh flatt5s out4 ,?us 9 any empirical =mula or sy/em ( pr$iction1 ! "t ov] :i* ! *ange ext5ds at ! upp] gauge mu/ be tak5 into acc\nt1 or else !re mu/ be sev]al upp] gauges & ! read+s ( all ( !m be tak5 into acc\nt4 ,9 m\nta9\s di/ricts l&slips sometimes occur & block ! valley ( a /ream :i* !n =ms a lake4 ,! wat] gradually rises & ev5tually fl[s ov] ! dam & sweeps x away caus+ a flood1 :i* is ( great sudd5ness & height b decreases v quickly 9 height z x travels d[n ! valley4 ,9 a case :i* occurr$ 9 ! ,himalayas 9 #ahhh ! inhabitants ( ! valleys1 f ! dam to ! po9t :]e ! riv] deb\*es f ! hills1 7 compell$ by ,gov]nm5t to vacate all habitations bel[ ! probable level ( ! flood1 & no loss ( life occurr$4 ,simil> floods1 b on a small] scale1 may be caus$ by ! bur/+ ( ord9>y res]voir dams4 ,9 "s cont95tal riv]s ice may ob/ruct ! /ream & cause floods4 #e4 ,prev5tion ( ,floods4--,! ext5d$ use ( field dra9s has1 9 rec5t ye>s1 done mu* to increase ! sev]ity ( floods 9 ,engl& & o!r c\ntries4 ,"o me?od ( mitigat+ or prev5t+ floods is ! con/ruction ( res]voirs = /or+ ! wat]4 ,res]voirs locally kn[n z 8wa%es10 =m$ by sett+ back ! embankm5ts1 exi/ on ! ,f5 riv]s4 ,"o wa%1 on ! ,n5e1 bel[ ,pet]bor\gh1 is #ab miles long & half a mile wide & is fill$1 9 floods1 to a dep? ( #g feet & holds #a in* ( ra9fall ov] ! riv] bas91 & ?is is f\nd to be suffici5t4 ,res]voir con/ruction is1 h[ev]1 9 mo/ cases1 impracticable ow+ to ! exp5se4 ,to /ore ! wat] :i* is giv5 by #a in* ( ra9 9 ! bas9 ( ! ,?ames1 a res]voir w\ld be ne$$ #ej feet deep & cov]+ ab\t #g squ>e miles4 ,x might co/ #g1jjj1jjj4 ,! af=e/ation or re=e/ation ( riv] bas9s 7,,*ap4 ,,ii41 ,art4 #d7 is also occasionally und]tak51 b is n g5]ally practicable4#bj ,! mo/ practicable me?ods = prev5t+ flood+ are l[]+ ! wat]-level ( ! /ream & con/ruct+ embankm5ts along x4 ,^! w be consid]$ 9 ! next two articles4 #f4 ,l[]+ ! ,wat]-,level4--,! wat]-level ( a giv5 l5g? ( /ream c be l[]$ by l[]+ ! b$1 wid5+ ! *annel or /raight5+ ! *annel4 ,! effici5cy ( ^! processes is 9 ! ord] nam$4 ,z /at$ 9 ,,*ap4 ,i41 ,art4 #d1 ! alt]ation to ! *annel mu/ 9 any case be cont9u$ to "s po9t d[n/ream ( ! rea* "u consid]ation4 ,let ! *annel be suppos$ to be ( 8%all[0 section ) slop+ sides4 ,let ,w be ! mean wid?1 ,d ! dep?1 & ,s ! slope4 ,let x be requir$ to l[] ! wat]-level by an am\nt equal to ,d_/#e4 ,?is c be effect$ by l[]+ ! b$ by ab\t #be p] c5t4 ( ,d1 or by increas+ ! wid? by ab\t #ej p] c5t41 or by increas+ ! slope by ab\t #ajj p] c5t4 ,if ! b$ is l[]$1 ,v is n affect$1 & ! mean wid? is r$uc$4 ,increase 9 ,w r$uces ,d1 & !re=e r$uces ! hydraulic radius & ! velocity4 ,h5ce ! l>ge am\nt ( wid5+ necess>y4 ,:5 ,s is increas$ ! velocity1 if ,r rema9s ! same1 is affect$ only z ,s 7,hydraulics1 ,,*ap4 ,,vi41 ,art4 #b71 b ! dep? ( wat] is r$uc$ & ,r !re=e r$uc$4 ,dress+ ! sides ( a *annel1 s z to make x smoo!r1 produces ! same effect z a slight wid5+4 ,x does n1 ( c\rse1 foll[ t l[]+ ! b$ is always ! be/ plan & /raight5+ ! wor/4 ,any "o ( ! processes may be m or less impracticable because1 = in/ance1 ( ! h>dness ( ! mat]ial to be remov$1 or ! exp5se--includ+ comp5sation--( remov+ ob/ructions4 ,a p>ticul> k9d ( wid5+ consi/s 9 digg+ a new *annel & keep+ bo? ! new & ! old *annel op54 ,if a *annel conta9s a weir1 or a local rais$ portion ( b$ =m+ a k9d ( subm]g$ weir1 or a contract$ place or n>r[ bridge1 ! up/ream wat]-level c be l[]$ by simply remov+ or r$uc+ ! ob/ruction4 ,! l[]+ ( ! wat]-level w be greate/ at ! site ( ! ob/ruction1 & w be z]o at "s po9t f> up/ream 7,hydraulics1 ,,*ap4 ,,vii41 ,art4 #e74 ,if ! rais$ portion =ms a long %oal1 its removal--suppos+ its height above ! g5]al b$ to be ! same--w h m effect ?an if x 7 %ort4 ,if ! height ( ! rais$ portion is small comp>$ to ! dep? ( wat]1 or ! am\nt ( contraction small comp>$ to ! wid? ( ! /ream1 ! removal may h mu* less effect ?an might appe> 7,,*ap4 ,i41 ,art4 #d74 ,9 s(t soils "o advantage ( ! /raight5+ sy/em = l[]+ ! wat]-level is t %ort-cuts c be dug to a small section1 & left to enl>ge !mselves 7,,*ap4 ,,vii41 ,art4 #a74 ,ano!r advantage is t aft] any div]sions h enl>g$ !mselves to ! size ( ! re/ ( ! *annel--or h orig9ally be5 s excavat$--! :ole *annel may sc\r1 & ! wat]-level cont9ue to fall4 ,?is1 ( c\rse1 %\ld be all[$ = if likely to occur4 ,! same ?+ may occur 9 ! case ( ! removal ( a weir1 %oal1 or contract$ piece ( *annel4 ,! sc\r w act at fir/ close to ! site ( ! ob/ruction1 b x may "w up/ream4 ,9 wid5+ or deep5+ a *annel = ! purpose ( mitigat+ floods1 x is a good plan to beg9 "w at ! d[n/ream end1 because ! l[]+ ( ! wat]-level w ext5d up/ream beyond ! rea* 9 :i* "w is done1 & ?is may facilitate "w fur!r up/ream4 ,z reg>ds any t5d5cy = a wid5$ rea* to silt up aga91 any su* silt+ is n likely to be great 9 a %ort p]iod ( "t1 & ne$ n prev5t ! c>ry+ on ( "w 9 v>i\s rea*es1 if ?is is conv5i5t4 #g4 ,flood ,embankm5ts4--,a flood embankm5t may be close to ! edge ( ! riv] or x may be set back4 ,if set back x ne$ n foll[ all ! w9d+s ( ! /ream4 ,! sett+ back ( an embankm5t gives an increas$ wat]way to ! /ream dur+ floods1 & !re=e a l[] flood-level1 b ! effect ( ?is is trifl+ 9 cases :]e ! dep? ( ! wat] on ! flood$ l& is small1 especially if su* l& is cov]$ ) vegetation1 or is o!rwise mu* ob/ruct$4 ,sett+ back is g5]ally necess>y 9 cases :]e ! /ream is liable to erode ! banks to any consid]able ext5t4 ,9 su* a case ! embankm5t %\ld n be s ne> to ! riv] z to be 9 mu* dang] f erosion1 b ! gr\nd1 z already /at$ 7,,*ap4 ,,iv41 ,art4 #i71 g5]ally falls1 9 go+ away f ! riv]1 s t :5 an embankm5t is set well back x is 9 l[] gr\nd1 m exp5sive & m liable to brea*4 ,! mo/ suitable alignm5t is a matt] ( judgm5t1 & dep5ds l>gely on ! ext5t to :i* ! riv] is likely to %ift4 ,embankm5ts %\ld1 :]e possible1 be made 9 /raight or prop]ly curv$ rea*es4 ,a flood embankm5t1 at lea/ at its up/ream end1 %\ld t]m9ate 9 gr\nd :i* is above flood-level4 ,! top ( an embankm5t %\ld be1 9 ! case ( a l>ge riv]1 #b or #c feet above ! high flood-level ( ! riv]4 ,x %\ld1 ( c\rse1 be grad$ p>allel to ! g5]al high flood-level1 b nei!r ! gradi5t nor ! height ( ! flood is usually kn[n ) accuracy 7,,*ap4 ,,ii41 ,arts4 #a & #b74 ,!re is g5]ally a record or m>k ( "s high flood1 & ?is is tak5 provisionally z ! flood-level4 ,or ! level is calculat$ approximately f ! flood read+s on ! ne>e/ riv] gauge4 ,if exp]i5ce %[s t ! embankm5t is too l[1 x is rais$4 ,! cross-section ( an embankm5t dep5ds on ! soil1 on ! ext5t ( damage :i* results if a brea* occurs1 on ! funds available1 & on ! value ( ! l& :i* ! embankm5t has to occupy4 ,:]e an afflu5t ent]s ! riv] x w probably be necess>y to run out bran* embankm5ts4 ,sometimes cross embankm5ts are run f ! ma9 embankm5t to high l&4 ,_! object is to localise ! damage if a brea* occurs4 ,along ! back ( ! embankm5t !re may be a dra9 & x c be made to dis*>ge its wat]1 :5 ! riv] is n 9 flood1 ?r\gh ! embankm5t by means ( sluices or by pipes clos$ by flap valves :i* w n all[ flood wat] f ! riv] to pass ?r\gh4 ,!re may be sluices 9 ! embankm5t = ! purpose ( irrigat+ ! l& at ! back4 ,! imm$iate effect ( ! con/ruction ( flood embankm5ts along a riv] is to raise ! wat]-level1 because ! floods c no long] spread out ov] ! c\ntry1 b ?is effect w n be great if ! sectional area ( ! flood wat] 0 small or its velocity l[4 ,! riv] may or may n t5d1 aft] ! con/ruction ( flood embankm5ts1 to raise or l[] its b$4 ,x has already be5 rem>k$ t que/ions ( silt+ or sc\r+ _c be answ]$ 9 a g5]al mann]4 ,9 ! case1 h[ev]1 ( floods spill+ ov] a piece ( c\ntry1 ! dep? ( ! flood wat] is g5]ally small & ! c\ntry m or less ob/ruct$4 ,"s deposit ( silt g5]ally occurs4 ,! con/ruction ( an embankm5t r$uces ! area ( ! flood wat]1 & ?us g5]ally r$uces ! silt+ & leaves m silt 9 ! riv] prop]4 ,! dep? & velocity 9 ! riv] are increas$4 ,ev]y?+ dep5ds on :i* is increas$ mo/4 ,mo/ likely ! /ream is ( %all[ section & ! velocity is increas$ mo/ 7,,*ap4 ,,iv41 ,art4 #f1 p>4 #f71 & ! increas$ silt-support+ p[] may make up = ! increas$ *>ge ( silt4 ,sometimes :5 a ma9 embankm5t is set f> back1 a subsidi>y embankm5t ( small] section is con/ruct$ clos] to ! /ream4 ,?is is (t5 objectionable4 ,! small] embankm5t is liable to brea*1 & ! wat] !n rises sudd5ly in/ead ( gradually aga9/ ! ma9 embankm5t1 :i* is ?us endang]$ to "s ext5t1 especially z x is dry in/ead ( be+ soak$4 ,x is (t5 said t "o effect ( embank+ a rea* ( a riv] is to increase ! sev]ity ( floods fur!r d[n/ream4 ,! importance ( ?is is g5]ally exagg]at$4 ,! n>r[+ ( ! flood /ream 9 ! embank$ portion causes ! flood to travel m quickly & rise high] 9 t p>ticul> rea*4 ,at a place fur!r d[n/ream ! same effect is produc$1 b 9 a less degree & only because ( ! increas$ velocity & consequ5t r$uction 9 ! flatt5+ out ( ! flood wave1 especially :5 ! rise is soon succe$$ by a fall4 ,:5 !re is a gradual rise la/+ = a consid]able "t--& ?is is mo/ likely to cause a high flood--!re is no rise ( ! flood-level d[n/ream ( ! embank$ rea*1 except su* z is due to ! increase 9 ! dis*>ge ( ! /ream consequ5t on ! absorption & evaporation be+ less ?an be=e1 ow+ to ! r$uc$ area ( flood+ 9 ! embank$ rea*4 ,9 ! case ( a long-cont9u$ rise1 su* z t j m5tion$1 x is ! rea* imm$iately up/ream ( ! embank$ rea* :i* w1 to "s ext5t1 %>e 9 ! increas$ height ( ! floods4 ,an embankm5t may suitably h side slopes ( #d to #a on ! riv] side & #c to #a on ! l& side1 ) a top #aj feet wide & #c feet above high flood-level4 ,on ! ,irrawaddy ! top wid? is g5]ally #h feet4 ,= v high & v l[ embankm5ts x is #aj feet & #c feet respectively4 ,9 ,holl& #a foot above high flood-level 0 at "o "t suppos$ to be ! rule1 b 9 practice x 0 usually #d feet4 ,) s&y soil ! riv]w>d slope prescrib$ 0 #f to #a4 ,su* flat slopes are n necess>y if fasc9+ or /iff soil is us$ z a protection4 ,on ! ,rh9e ! top wid? ( embankm5ts consi/+ ( gravel & s& has be5 made ab\t #ae feet1 b ! side slopes 7 #a to #a & #a to #a4 ,! embankm5ts _h spurs to keep (f ! curr5t4 ,s&1 protect$ z above1 makes a good embankm5t1 & rats d n burr[ into x4 ,( c\rse1 if a brea* occurs 9 an embankm5t consi/+ ma9ly ( s&1 x w enl>ge v quickly4 ,9 "s cases an embankm5t has a core wall ( s& or ( clay puddle4 ,9 ,holl&1 on s&y soil1 a tr5* #h feet wide is made & tak5 d[n to ! clay4 ,embankm5ts require to be made ) great c>e4 ,! e>? %\ld be deposit$ 9 lay]s4 ,9 ,holl&1 horses are driv5 up & d[n ov] ea* lay]4 ,9 "s p>ts ( ,india ! e>? = embankm5ts is br\ght f ! borr[ pits by scoops drawn by bullocks4 ,! e>?work is ( s excell5t a "*1 ow+ to ! e>? be+ trodd5 d[n1 t no settlem5t has to be all[$ =4 ,:]e ! soil is s& ! top & faces ( ! embankm5t %\ld be ( good /iff soil1 if x c be obta9$1 = a ?ickness ( #i in*es or a foot1 or else ! face next ! riv] %\ld be protect$ by fasc9+ 7,,*ap4 ,,vi41 ,art4 #c7 = #b feet above1 & sev]al feet bel[ high flood-level4 ,su* protection may be necess>y 9 any case :]e waves are liable to occur4 ,9 ,holl& embankm5ts are turf$1 & trees & %rubs are n all[$ to gr[4 ,9 ! ,punjab ! gr[? ( all k9ds ( jungle is enc\rag$4 ,x b9ds ! soil toge!r & protects x f ! wa% ( waves & f w9ds :i* bl[ away s& & du/1 & s we> ! embankm5t sl[ly away4 ,9 embank+ a long rea* ( a riv] x is conv5i5t to beg9 f ! up/ream end1 because o!rwise floods may get beh9d ! f9i%$ "p ( ! embankm5t &1 becom+ imp\nd$ 9 a 8pocket0 =m$ by ! embankm5t & high l&1 rise to an abnormal height &1 unless gaps 9 ! embankm5t h be5 left or are subsequ5tly made1 cause brea*es4 ,dur+ high floods pegs %\ld be driv5 9 at frequ5t int]vals1 to m>k ! high flood-levels4 ,if a high] flood occurs1 ! peg is %ift$4 ,! levels ( ! pegs c be obs]v$ at leisure4 ,:5 a brea* occurs 9 an embankm5t1 ! fir/ ?+ to d is to protect ! ends s t ! brea* %all n l5g!n4 ,if ! wat] pass+ ?r\gh a brea* becomes pocket$1 ! embankm5t may h to be cut to let x out4 ,reg>d+ ! /oppage ( leakages1 see ,,*ap4 ,,ix41 ,art4 #a4 ,reg>d+ ! closure ( brea*es1 see ,,*ap4 ,,vii41 ,art4 #b4 ,= a description ( flood embankm5ts along ! great %ift+ riv]s ( ,nor!rn ,india1 see ,punjab ,riv]s & ,works4 ,note to ,art4 #e4--;,floods c sometimes be mitigat$ by s9k+ pits 9 ! flood$ area s t ! flood wat] comes 9 contact ) p]meable /rata & is absorb$ by !m4 ,,*apt] ,,xiii ,,res]voirs ,,& ,,dams #a4 ,res]voirs4--,! object ( a res]voir is to /ore wat] = t[n supply or = irrigation or o!r purposes4 ,res]voirs = ! wat] supply ( t[ns are divid$ into 8imp\nd+ res]voirs0 & 8s]vice res]voirs10 ! latt] be+ ( comp>atively small size1 & _! object be+ to /ore1 ne> to ! t[n1 a supply suffici5t = a %ort p]iod4 ,in/ead ( "o imp\nd+ res]voir !re may be sev]al1 =m$ by v>i\s dams & "o dis*>g+ into ano!r4 ,:5 a res]voir is m5tion$ )\t qualification1 an imp\nd+ res]voir is meant4 ,a res]voir is g5]ally made by block+ up a valley by means ( a dam ( e>? or masonry4 ,! site ( ! dam %\ld be select$ at a place :]e ! valley is n>r[4 ,! l[e/ portion or 8bottom wat]0 ( a res]voir is usually n drawn ^u1 because x is less pure ?an ! re/1 & x has to be left1 9 dry wea!r1 = ! fi%4 ,x is n includ$ 9 calculat+ ! capacity ( ! res]voir4 ,9 ,great ,brita91 :5 ! wat] ( a /ream is imp\nd$1 8comp5sation wat]0 has to be giv5 back to ! /ream l[] d[n4 ,?is comp5sation wat] is g5]ally giv5 9 ! =m ( a con/ant supply1 & am\nts to p]haps a qu>t] ( ! available supply4 ,x has to be includ$ 9 calculat+ ! daily supply tak5 out ( ! res]voir4 ,! advantage to ! /ream 9 hav+ ?is addition to x dur+ dry wea!r is v great4 ,x has already be5 se5 7,,*ap4 ,,ix41 ,art4 #a7 t 9 an e>!n bank :i* has to reta9 wat] ! leakage g5]ally decreases rapidly & ! bank becomes almo/ imp]meable4 ,! same is true ( ! surface ( a valley1 9 ! case ( mo/ ord9>y soils1 provid$ t x is kept subm]g$4 ,any portions :i* become expos$ to ! sun & wea!r are likely to crack & give rise to p]colation4 ,?us a res]voir =m$ by ! con/ruction ( a dam re/+ on ! surface ( ! gr\nd may be m or less wat]-tight accord+ to circum/ances4 ,!re are _m :i* are suffici5tly wat]-tight4 ,b 9 mo/ cases ! dam--or an imp]vi\s core-wall--is c>ri$ d[n to an imp]vi\s /ratum4 ,a masonry dam is c>ri$ d[n to rock4 ,9 ! case ( dams ( consid]able height ! soil %\ld be exam9$ by bor+s4 ,if !re is an incl9$ /ratum n well connect$ ) t bel[ x1 unequal settlem5t ( ! dam may occur2 & ?is may also happ5 if !re is a ?ick /ratum ( clay1 ow+ to its compressibility4 ,except = v high dams--^?1 = in/ance1 m ?an #aaj or #abj feet 9 height measur$ f ! gr\nd to ! wat]-level--an e>!n dam is *eap] ?an a masonry dam4 ,x is also m easily rais$ & /r5g!n$--?\gh ?is op]ation has also be5 effect$ on masonry dams--9 case1 = in/ance1 ( ! silt+ up ( ! res]voir1 a process :i* is sl[ 9 ,engl&1 b n s sl[ :5 wat] conta9+ mu* silt is dealt )1 z 9 ! case ( irrigation res]voirs 9 ,india4 ,sometimes a dam consi/s ( a wall ( masonry or concrete ) e>? beh9d x z a support4 ,:atev] k9d ( dam is us$1 its con/ruction always dem&s v great c>e4 ,s]i\s disa/]s1 ) mu* loss ( life1 h occurr$ ow+ to failures ( dams4 ,a res]voir ) an e>!n dam is provid$ ) a wa/e weir = ! purpose ( pass+ (f flood wat]1 :i* might o!rwise ov]top ! dam & de/roy x4 ,g5]ally ! wa/e weir is a cont9uation ( ! l9e ( ! dam4 ,its cre/ has to be bel[ ! high-wat] level ( ! res]voir1 b n l[] ?an c be help$1 & its l5g? has !re=e to be consid]able4 ,sometimes x is provid$ ) groov$ pi]s betwe5 :i* planks are plac$ 9 ! season :5 floods are n likely to occur4 ,9 connection ) irrigation res]voirs 9 ,we/]n ,india1 x has be5 po9t$ out by ,/range 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 cxxxii47 t a long high-level wa/e weir is be/ suit$ to cases 9 :i* ! repl5i%m5t ( ! res]voir is unc]ta91 & t 9 cases :]e x is ne>ly c]ta91 ! high-level weir prev5ts ! wat]-level 9 ! res]voir be+ quickly l[]$ 9 ! case ( an accid5t or = ! purpose ( effect+ repairs1 imp\nds ! e>lie/ floods1 :i* are mo/ *>g$ ) silt1 & causes ! wat] area to be a maximum1 & !re=e gives all floods ! maximum "t 9 :i* to deposit silt4 ,he accord+ly sugge/s t ! cre/s ( wa/e weirs 9 ^! res]voirs %\ld be %ort5$ & l[]$ & provid$ ) fall+ %utt]s 7?is _h be5 done 9 "o res]voir & has s9ce be5 done 9 ano!r71 & t sluices be add$ ) sills at a /ill l[] level ?an ! l[]$ cre/4 ,^! proposals seem to be entirely reasonable1 ?\gh ( c\rse x w\ld be necess>y to h skill$ sup]vision ov] ! work+ ( ! sluices4 ,sometimes ! wa/e weir is made 9 a sep>ate place1 be+ sep>at$ f ! dam by a saddle4 ,a masonry dam may act z its own wa/e weir1 ! flood wat] fl[+ ov] ! cre/ & d[n ! re> slope2 b 9 cases :]e heavy floods are liable to occur x is usual to provide a sep>ate wa/e weir by cutt+ away ! side ( ! gorge ei!r close to ! dam or at "s o!r place4 ,:ile a dam is 9 c\rse ( con/ruction arrangem5ts mu/ be made to deal ) flood wat]4 ,g5]ally ! con/ruction ( "s "p ( ! dam has to be def]r$ to let ! wat] pass4 ,9 ! case ( a masonry dam x does n mu* matt] :at "p is ?us def]r$ provid$ ! usual proc$ure ( /epp+ ! "w back is foll[$4 ,9 ! case ( an e>!n dam x is be/ to def] a portion1 n 9 ! l[e/ gr\nd :]e ! dam is highe/1 b to "o side ( x1 ?us all[+ ! highe/ "p ( ! dam to be br\ght up cont9u\sly4 ,tempor>y embankm5ts & weirs c be con/ruct$ to cause ! wat] to trav]se ! desir$ r\te )\t do+ damage4 ,/epp+ ( ! e>?work %\ld be avoid$ z f> z possible4 ,if x has to be adopt$1 ! /eps %\ld be small4 ,sometimes ! flood wat] is convey$ away by means ( a 8by-wa%10 by an entirely diff]5t r\te4 ,illu/ration3 ,,fig4 #eg4 ,9 ,indian res]voirs ! dis*>ge ov] ! wa/e weir may at times be great4 ,! wa/e weir is sometimes 9 ! position %[n 9 fig4 #eg1 a e be+ ! weir4 ,9 su* a case a special hydraulic problem arises4 ,9 a case :]e a /ream ^: velocity is ,v issues f a res]voir or takes (f at "r angles f a l>g] /ream !re is 7,hydraulics1 ,,*ap4 ,,ii41 ,arts4 #ai & #bj7 a fall 9 ! wat] ( ab\t ,v#b_/b;g4 ,! same ?+ occurs d[n/ream ( a weir1 at lea/ :5 !re is a cle> fall :i* is v]tical or ne>ly s1 s t ! wat] aft] fall+ has no horizontal velocity4 ,! wat] has to be />t$ afre% on its c\rse4 ,9 ! case repres5t$ by ! figure1 ! wid? ( ! *annel is (t5 re/rict$ because ( high gr\nd beyond f1 & ! velocity 9 ! *annel may be v high4 ,suppose ! *annel bel[ e f to be ( brickwork ) v]tical sides1 & to h a #bj-;foot b$1 a slope ( #a 9 #ejj1 & a dep? ( wat] ( #aj feet4 ,! velocity may be #ae feet p] second1 & ,v#b_/b;g is #cdi feet4 ,if ! wat] has a cle> fall ov] ! weir at e1 all[ance mu/ be made = a dep? ( wat] ( #acdi feet1 n #aj feet1 9 ! *annel at e4 ,ord9>ily ! l5g? a e w be mu* great]1 relatively to e f1 ?an %[n 9 ! figure4 ,suppose t a e is #cjj feet & t ! slope ( ! floor ( ! *annel is c>ri$ on at #a 9 #ejj f e f up to a1 b1 c1 & d1 foll[+ 9 ea* case ! l9es m>k$ on ! figure :i* repres5t ! directions ( fl[4 ,! l5g? f a w be ab\t #caj feet1 & ! floor level at a w be ab\t #fb feet high] ?an at e f4 ,! wat]-levels bel[ ! weir w be 9 ea* case #acdi feet above ! floor4 ,?is %\ld be all[$ = 9 ! design4 ,x is true t ! /ream on fir/ />t+ into horizontal motion bel[ ! weir moves m or less at "r angles to x1 & has ?us a l>ge sectional area & a l[ velocity2 b x v soon has to turn p>allel to ! weir & acquire ! full velocity ( #ae feet p] second1 & !re mu/ be ! requisite extra head to give ?is velocity4 ,if ! weir is dr[n$1 ! wat] on pass+ ov] x may h a high horizontal velocity1 b x w be at "r angles to ! axis ( ! *annel1 & its effect w be wa/$ 9 eddies4 #b4 ,capacity ( ,res]voirs4--,a res]voir dep5ds = its supply on ! yield ( a p>ticul> valley or valleys :i* =m its cat*m5t area1 & ! capacity ( ! res]voir or res]voirs c be alt]$ by alt]+ ! height or numb] ( ! dams4 ,! ne$ = a res]voir is entirely ow+ to ! inequality 9 ! di/ribution ( ! ra9fall4 ,if ! ra9 fell 9 equal quantities week by week1 ! daily fluctuations c\ld probably be equalis$ by ! s]vice res]voirs4 ,! imp\nd+ res]voir c\ld be q small4 ,actually1 a res]voir is ne$$ to 8equalise0 ! fl[--t is1 to give a /eady fl[ = an int]mitt5t "o4 ,! small] ! res]voir1 ! soon] x w g dry 9 a dr\ght & ! soon] x w ov]fl[ 9 wet wea!r & cause wa/e ( ! wat]4 ,9 o!r words1 ! l>g] ! res]voir ! bett] x w fulfil its function ( equalis+ ! fl[ & ! great] ! degree to :i* ! cat*m5t area w be utilis$4 ,illu/ration3 ,,fig4 #eh4 ,9 ! ,briti% ,isles ! di/ribution ( ! ra9fall :i* is mo/ try+ = a res]voir1 occurs :5 ! ra9 is heavy dur+ ! w9t] & v light 9 summ]4 ,fig4 #eh %[s a diagram = a res]voir 9 ! drie/ ye>1 :5 ! ra9fall is 7,,*ap4 ,,ii41 ,art4 #a7 #fc ( ! mean annual fall4 ,! di/ribution ( ! fall is suppos$ to be unfav\rable z j describ$4 ,! l[] "p ( ! figure %[s ! wat]-level at ! end ( ea* mon?1 ! res]voir be+ suppos$ to h v]tical sides s t ! quantity ( wat] 9 x is proportional to ! dep? ( wat]4 ,! upp] "p ( ! figure %[s ! wat] imp\nd$ 7available fall multipli$ by area ( cat*m5t7 9 full l9es1 & ! consumption 9 a dott$ l9e4 ,! di/ance betwe5 ! two l9es 9 any mon? is ! same z ! rise or fall ( ! res]voir 9 t mon?4 ,!re is suppos$ to be no ov]fl[1 & ! total consumption ( wat] 9 ! ye> is equal to ! quantity imp\nd$ 9 ! ye>1 s t ! levels ( ! res]voir wat] surface on #a/ ,janu>y & #ca/ ,decemb]1 z %[n by ! horizontal l9es ,a1 ,b at ! left & "r ( ! figure1 are ! same4 ,deacon1 :o has inve/igat$ ! subject1 has f\nd 7,ency4 ,brit41 ,t5? ,edition1 vol4 #cc1 8,wat] ,supply07 t1 9 ord] to satisfy ! above conditions1 ! capacity ( ! res]voir mu/ be #cj p] c5t4 ( ! wat] imp\nd$ dur+ ! ye>1 or ab\t #aaj days' consumption4 ,on #a/ ,janu>y ! res]voir mu/ be ab\t two-?irds full4 ,at ! end ( ,febru>y x is ready to ov]fl[4 ,at ! end ( ,augu/ x is j becom+ dry4 ,! daily consumption is suppos$ to be /eady ?r\gh\t ! ye>4 ,z an in/ance1 suppose ! cat*m5t area to be #ajjj acres1 ! mean annual fall #fj in*es1 ) a loss f evaporation & absorption ( #ad in*es4 ,! available ra9fall ( ! ye> is 7see la/ column ( table bel[7 #bch in*es1 or #aihc feet4 ,! wat] imp\nd$ & consum$ dur+ ! ye> is #ajjj #dc1efj #aihc #fbe #eci1ifb1jjj gallons4 ,! res]voir capacity mu/ be #c_/aj?s ( ?is1 or #afa1ihh1fjj gallons4 ,?is is repres5t$ by ! height ,c ,e4 ,if ! mean available ra9fall 9 ,janu>y & ,febru>y is #fc in*es1 or #ebe feet1 ! wat] imp\nd$ dur+ ^? mon?s is #ajjj #dc1efj #ebe #fbe #adc1ica1jjj gallons1 & ! consumption is #eci1ifb1jjj_/f #hi1iic1ffg gallons4 ,! diff]5ce1 #ec1icg1ccc gallons1 repres5ts ! addition ,a ,c1 to ! res]voir4 ,simil>ly1 ! light summ] ra9fall causes ! depletion ,a ,e1 & ! heavy ra9fall 9 ! la/ f\r mon?s ( ! ye> ! addition ,e ,b4 ,if ! height ( ! res]voir above ,a ,b 7 less ?an ,a ,c1 !re w\ld be ov]fl[ at ! end ( ,febru>y2 & if ! dep? bel[ ,a ,b 7 less ?an ,a ,e1 ! res]voir w\ld g dry be=e ! dr\ght end$4 ,if ! capacity ( ! res]voir 7 increas$ ei!r at ! top or bottom1 ! co/ w\ld be increas$ & no?+ w\ld be ga9$4 ,x is n meant t ! highe/ & l[e/ levels ( any res]voir design$ z above w\ld always1 9 ! drie/ ye>1 exactly correspond ) ! po9ts ( ov]fl[ & go+ dry1 b !y w\ld d s ne>ly4 ,deacon /ates t su* a res]voir w\ld fail only once 9 fifty ye>s1 & !n only = a %ort "t4 ,! res]voir consid]$ above does n1 z already rem>k$1 fully utilise ! yield ( ! cat*m5t area4 ,9 a wett] ye> !re w\ld be ov]fl[ & ! yield f ! res]voir w\ld n be mu* increas$4 ,9 ord] to equalise ! fl[ ( ! two drie/ ye>s ! capacity ( ! res]voir mu/ be increas$1 its yield be+ also increas$1 & s on = l>g] gr\ps ( ye>s4 ,by collect+ in=mation = l>ge numb]s ( places 9 ! ,briti% ,isles1 ,deacon has prep>$ diagrams & tables :i* %[ ! capacities & yields ( res]voirs4 ,! foll[+ table gives ! figures = ! case :]e ! ra9fall is #fj in*es & ! loss by evaporation & absorption #ad in*es3-- ---------------------------------------- ---------------------- ,numb] ( ,column #b ,drie/ ,net ,capacity ,column #c ,consecutive ( ,res]voir or ,numb],ratio ( ,ye>s ! = a ,daily ( ,days' ,ra9fall,available ,fl[ ( ,cat*m5t ,yield ( ,supply to ,mean ,ra9fall4 :i* ,area ( #ajj ,res]voir4 conta9$ ,annual is to be acres4 9 ! ,fall4 ,equalis$4 ,res]voir4 ---------------------------------------- ---------------------- ,gallons4 ,gallons4 ,in*es4 #a #aff1jjj1jjj #a1dge1jjj #aac #fc #bch #b #beh1jjj1jjj #a1hae1jjj #adb #gb #bib #c #cbi1jjj1jjj #a1ihg1jjj #afe #gg #cbb #d #cij1jjj1jjj #b1ajc1jjj #aij #hj #cdj #e #dda1jjj1jjj #b1ahg1jjj #bja #hb #ceb #f #dhg1jjj1jjj #b1bee1jjj #baf #hce #cfa ---------------------------------------- ---------------------- ,! figures 9 ! fif? column are ^? giv5 9 ,,*ap4 ,,ii41 ,art4 #a4 ,! figures 9 ! la/ column %[ ! correspond+ available falls1 aft] d$uct+ ! loss ( #ad in*es4 ,x w be se5 t1 ow+ to ?is d$uction1 ! available falls = ! %ort] p]iods are r$uc$ 9 a great] ratio ?an ! figures 9 ! fif? column4 ,9 arrang+ = ! supply ( t[ns 9 ! ,briti% ,isles x is usual to design ! res]voirs s z to equalise ! fl[ ( ! ?ree drie/ consecutive ye>s4 ,exi/+ res]voirs1 old & new1 usually conta9 f #adj to #agj days' supply1 b "s conta9 less4 ,! above table %[s t = ! assum$ fall ( #fj in*es & loss ( #ad in*es1 ! capacity ( a res]voir1 to all[ = a six-ye> dry p]iod1 has to be #di p] c5t4 m ?an = a ?ree-ye> dry p]iod1 :ile ! daily supply f x is only #ac p] c5t4 great]4 ,! foll[+ /atem5t gives ,deacon's figures = mean annual ra9falls rang+ f #cj to #ajj in*es4 ,! columns m>k$ ,r %[ ! res]voir capacities 9 millions ( gallons1 & ^? m>k$ ,s ! daily yields ( ! res]voirs 9 ?\s&s ( gallons4 ,! figures = o!r falls c be int]polat$4 ,= a fall (1 = in/ance1 #ej in*es1 ! figures1 :e!r ( ,r or ,s1 are practically a mean betwe5 ^? = falls ( #dj & #fj in*es4 ---------------------------------------- ----------------- ,numb] ,f #cj4 ,f #dj4 ,f #fj4 ,f #ajj4 ( ,ye>s ^: ,supply is to be ---------------------------------------- --- ,equalis$4 ,r4 ,s4 ,r4 ,s4 ,r4 ,s4 ,r4 ,s4 ---------------------------------------- ------------- #a #ce #cjj #gi #fie #aff #adge #cde #cjdj #b #he #dgj #adj #ijj #beh #ahae #die #cfjj #c #abj #efj #aij #ajej #cbi #aihg #faj #cijj #d #aej #fbj #bcj #aaaj #cij #bajc #gaj #dajj #e #age #fej #bfj #aagj #dda #bahg #hjj #dbcj #f #aie #fhj #bij #abbj #dhg #bbee #hhg #dcbj ---------------------------------------- ------------- ,9 all cases ! loss is suppos$ to be #ad in*es annually4 ,if x is #ae or #ac in*es1 ! res]voir capacity is less or m by ab\t five1 t51 or fifte5 million gallons1 accord+ z ! numb] ( ye>s 9 column #a is #a1 #c1 or #f4 ,& ! daily yield is less or m by ab\t #ej1jjj gallons4 ,) a l[ ra9fall ! advantage ( a l>ge res]voir is some:at increas$4 ,! capacity ( ! six-ye> res]voir = a fall ( #cj in*es is #fc p] c5t4 m ?an t ( ! ?ree-ye> res]voir1 b ! supply is #bb p] c5t4 great]4 ,! figures giv5 above = res]voir capacities are suitable = ! ,briti% ,isles4 ,!y assume t ! di/ribution ( ! ra9fall is ! lea/ fav\rable t is at all likely to occur4 ,deacon /ates t ! figures d n relieve ! eng9e] ( ! ex]cise ( judgm5t4 ,z reg>ds ! ,briti% ,isles1 ! *ief que/ions on :i* judgm5t has to be ex]cis$ are :e!r to equalise ! fl[ ( ?ree ye>s or ( ano!r numb]1 & h[ mu* to all[ = loss4 ,z already /at$1 ?ree ye>s is ! p]iod usually tak54 ,! figures are suitable = mo/ places 9 ,europe1 b 9 "s places1 e4g4 on ! ,m$it]ranean coa/1 ! di/ribution ( ! ra9fall is some:at less fav\rable ?an 9 ! ,briti% ,isles4 ,9 o!r p>ts ( ! _w1 & notably 9 or ne> ! tropics1 ! di/ribution ( ! ra9fall mu/ be specially /udi$1 & a diagram be prep>$ on ! same pr9ciple z 9 ! case ( fig4 #eh4 ,! diagram %\ld be ext5d$ to cov] ! desir$ numb] ( ye>s4 ,9 hot c\ntries loss by evaporation f ! surface ( ! res]voir %\ld be all[$ =4 ,9 ,india dur+ ! hot dry mon?s ?is loss may be half an in* 9 tw5ty-f\r h\rs4 ,9 ! article above quot$ x is %[n t if1 z commonly happ5s1 ! consumption ( wat] is1 9 summ]1 great] ?an ! mean1 & 9 w9t] less1 ! conditions are /ill m try+ = ! res]voir2 & t 9 ! case :]e ! summ] consumption is #ac p] c5t4 great] ?an ! mean1 ! capacity ( ! res]voir :i* imp\nds ! wat] ( ! drie/ ye> mu/ be #cc p] c5t41 in/ead ( #cj p] c5t41 ( ! total supply imp\nd$ dur+ ! ye>4 ,x w\ld !n conta9 #aba days' in/ead ( #aaj days' mean supply4 ,9 ! table on page #agj ! numb] ( days' supply is #aac4 ,f ?is x appe>s t ! tables f :i* extracts h be5 giv5 are calculat$ on ! basis ( a con/ant consumption4 ,?is1 h[ev]1 9 ! case :]e ! numb] ( ye>s ^: supply is equalis$ is great] ?an "o1 makes1 ow+ to ! increas$ size ( ! res]voir1 no practical diff]5ce4 ,! calculations = ! great res]voirs 9 ,radnor%ire = ! supply ( ! city ( ,birm+ham are z foll[s 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxx474 ,! ratio ( ! mean fall 9 ! ?ree drie/ ye>s to ! mean annual fall 0 tak5 z #hj in/ead ( #gg4 ,!re is "s diff]5ce ( op9ion z to ! be/ figure3-- ,mean annual fall det]m9$ f read+s ( v>i\s gauges #fe in*es ,mean fall ( ?ree drie/ ye>s #eb 0 ,d$uct loss f evaporation & absorption & losses dur+ floods #ae 0 ,available ra9fall #cg 0 ,?is multipli$ by #dd1jjj acres1 ! area ( ! cat*m5t1 gives #ajb million gallons p] day4 ,( ?is1 #bg1jjj1jjj gallons is comp5sation wat]1 leav+ #ge1jjj1jjj gallons = ,birm+ham4 ,capacity ( res]voirs1 #ag1bej1jjj1jjj gallons1 or #afi days' supply4 ,illu/ration3 ,,fig4 #ei4 #c4 ,e>!n ,dams4--,be=e an e>!n dam is made1 any s(t soil on ! site %\ld be remov$ & ! gr\nd d[n/ream ( ! site %\ld be dra9$4 ,a few tr5*es1 runn+ p>allel to ! axis ( ! dam1 c be dug s z to give ! dam a hold1 ?\gh !re is nev] any dang] ( its be+ mov$ horizontally by ! ?ru/ ( ! wat]4 ,if ! gr\nd has a side-long slope x %\ld be b5*$ z %[n 9 fig4 #ei4 ,! front slope ( an e>!n dam is g5]ally ab\t #c to #a1 & ! re> slope ab\t #b to #a4 ,! top has a wid? ( to ! greate/ dep? ( wat] held up1 & is #e to #aj feet above ! highe/ wat]-level4 ,! borr[ pits f :i* ! e>? = ! dam is got %\ld n be ne> en\gh to x to 9 any way affect its /ability4 ,illu/ration3 ,,fig4 #fj4 ,9 ,engl&1 & g5]ally 9 o!r c\ntries1 an e>!n dam has a core-wall 7fig4 #fj7 :i* is c>ri$ d[n to an imp]vi\s /ratum1 & is key$ into x to a dep? ( a foot or m 9 ! case ( h>d rock & sev]al feet 9 ! case ( clay4 ,on ?is core-wall ! imp]meability ( ! dam *iefly dep5ds4 ,! core-wall may be ( clay puddle1 concrete1 or masonry4 ,9 ,engl& x is g5]ally ( clay puddle4 ,! core-wall sometimes ext5ds d[n to a dep? ( #ajj or #bjj feet4 ,its top is horizontal & ab\t level ) ! highe/ wat]-level4 ,x is desirable n to make ! f\ndation /epp$1 b to let x foll[ ! pr(ile ( ! imp]vi\s /ratum4 ,! wall is key$ at its ends into ! sides ( ! valley or gorge4 ,a core-wall ( concrete or masonry is1 9 a high dam1 necess>ily a comp>atively ?9 /ructure1 & x may be subject$ to great /ra9s by unequal pressures ( ! e>? :i* surr\nds x4 ,x is !re=e to "s ext5t liable to crack4 ,a core-wall ( concrete us$ = ! wat]-works ( ,bo/on1 ,u4,s4,a41 is #ajj feet high1 #h feet ?ick at ! base1 & #d feet ?ick at ! top4 ,a clay-puddle wall1 be+ pla/ic & moi/1 at lea/ dur+ ! p]iod imm$iately succe$+ ! con/ruction ( ! "w1 is n v liable to crack4 ,! top wid? ( a puddle wall may be #d to #aj feet1 & ! batt] ( ! sides f #a 9 #bj to #a 9 #h4 ,! clay us$ = ! wall above ! gr\nd-level %\ld conta9 ab\t #cc p] c5t4 ( s& & /ones4 ,?is dim9i%es its %r9kage if x dries4 ,x %\ld n be giv5 too mu* wat] 9 mix+4 ,x %\ld be ?or\ghly mix$ & work$ up & trodd5 d[n4 ,! clay puddle & ! e>? ( ! dam %\ld be c>ri$ up uni=mly4 ,! all[ance = settlem5t may be #a_/cj to #a_/ej4 ,! e>? %\ld be deposit$ 9 ?9 lay]s1 moi/5$ & ramm$1 & all clods brok54 ,9 ,india & "s o!r c\ntries1 in/ead ( ! e>? be+ ramm$1 cattle or %eep are driv5 ov] x repeat$ly4 ,?is makes e>?work ( mo/ excell5t quality1 & ! settlem5t1 if any1 is v small4 ,9 cases :]e1 ow+ to a fissure 9 ! rock bel[ ! bottom ( ! puddle tr5*1 wat] comes ?r\gh "u ! puddle1 x is usual to c>ry x away 9 a pipe runn+ v]tically 9 a groove up ! side ( ! tr5* & !n horizontally till x em]ges f ! dam4 ,su* wat]1 & any o!r leakage1 c (t5 9 ,great ,brita9 be us$ z "p ( ! comp5sation wat]4 ,!re is1 h[ev]1 a c]ta9 *ance1 :5 !re are wat]-be>+ fissures 9 ! rock bel[ ! bottom ( ! tr5*1 t "s p]colat+ /ream ( wat] may wa% away ! puddle1 & x is pref]able to use a concrete core-wall 9 su* cases1 c>ry+ x up to ab\t gr\nd-level & key+ x into a mu* ?ick] wall ( puddle :i* is c>ri$ up to ! wat]-level4 ,x has be5 sugge/$ t ! clay puddle or o!r imp]vi\s lay] %\ld be plac$1 n v]tically & 9 ! middle ( ! dam1 b ly+ on ! up/ream face ( ! dam1 s z to keep out wat] f ! :ole dam in/ead ( f only half ( x4 ,objections to ?is1 if clay puddle is us$1 are t v]m9 may bore holes 9 x1 & t1 ) "s clays1 x w\ld slip4 ,^! objections might be ov]come to "s ext5t by lay+ a pit*+ ( concrete blocks ov] ! puddle4 ,o!r objections1 apply+ also :5 masonry or concrete is us$1 are t ! sup]ficial area & co/ are increas$1 & t cracks w\ld occur f settlem5t ( ! e>? & f *anges ( temp]ature :5 ! wat] 9 ! res]voir 0 l[4 ,a good _m cases h occurr$ 9 :i* an imp]vi\s lay] laid on ! slopes has fail$ f "o cause or ano!r4 ,9 ,france x is usual to rely on su* a lay]--concrete is us$--& to disp5se ) a core-wall4 ,! practice ( hav+ a v]tical wall appe>s to be ! be/1 & is ! mo/ widely adopt$4 ,:5 puddle is us$ ! weight ( ! mass above x =ces x to completely fill ! tr5*1 & :5 once x is 9 position & cov]$ up x is n at all likely to be damag$4 ,illu/ration3 ,,fig4 #fa4 ,! out] portion ( a high embankm5t sometimes slips 7fig4 #fa71 & precautions %\ld be tak5 aga9/ ?is4 ,a slip may occur if ! site ( ! dam has n be5 c>efully select$ z to geological =mation1 or if !re is unequal settlem5t ow+ to ! "w hav+ be5 done at diff]5t times4 ,"o cause ( slips is sudd5 & p>tial *anges 9 ! degree ( saturation1 & ano!r cause is excessive saturation4 ,"s clays :5 wet require extremely flat side slopes1 & w n /& ev5 at #e to #a4 ,! out] p>ts ( ! embankm5t are n requir$ = /opp+ p]colation 7?is w be fur!r consid]$ 9 ! foll[+ p>agraph71 &1 ?\gh !y mu/ be c>efully laid & consolidat$1 !y %\ld be ( por\s mat]ial1 & ! "p on ! d[n/ream side ( ! dam mu/ be well dra9$4 ,a s]ies ( surface dra9s may be arrang$ & fill$ ) loose /one & gravel4 ,!re is also a di/9ct advantage 9 us+ heavy mat]ial su* z small /one = ! l[e/ portion ( ! out] p>ts on bo? sides ( ! dam4 ,:5 good mat]ial _c be obta9$1 ! side slope on ! d[n/ream side ( ! dam may be flatt5$4 ,a side slope />t+ at ! top ) #c to #a & becom+ #d to #a l[] d[n1 & f9ally #e to #a at ! base1 is a v good =m = prev5tion ( slipp+ & g5]ally = ! safety ( a dam4 ,! "p on ! side next ! res]voir is n likely to slip4 ,x becomes soak$1 b x has ! pressure ( ! wat] aga9/ x & is pit*$4 ,9 ,madras1 :]e res]voirs are v num]\s1 ! slope on ! side next ! wat] is g5]ally only #a to #a4 ,! diff]5t p>ts ( an e>!n dam fulfil two di/9ct functions4 ,"s p>ts1 :i* may be call$ ! /aun*es1 h to /op ! p]colation ( wat] f ! res]voirs4 ,o!r p>ts1 :i* may be call$ ! supports1 h m]ely to hold up ! /aun*es4 ,9 ! ,briti% type ( dam ! portion ne>e/ ! core-wall on ei!r side 7fig4 #fj7 is g5]ally made ( e>? specially select$ = imp]meability4 ,! di/ance to :i* x ext5ds f ! wall dep5ds p>tly on ! quantity ( su* e>? available4 ,9 any case x has to be v c>efully made & consolidat$1 to avoid unequal pressures on ! core-wall1 or unequal settlem5t :i* might cause x to "p f ! wall4 ,"o ( its functions is to keep ! core-wall moi/ :5 ! wat]-level 9 ! res]voir falls4 ,:e!r x is also to be consid]$ z a /aun* or a support might at fir/ appe> to be ( no consequ5ce1 b x is ( importance z affect+ ! "q ( dra9age4 ,! support on ! d[n/ream side ( ! dam mu/1 z has j be5 se51 be made ( por\s mat]ial & be well dra9$2 b obvi\sly a /aun* mu/ n be por\s1 nor c x be p5etrat$ by dra9s4 ,! "q mu/ be decid$ 9 ea* case accord+ to judgm5t4 ,9 a discussion :i* took place on ! above-m5tion$ pap] by ,/range1 at ! ,in/itution ( ,civil ,eng9e]s1 mu* div]sity ( op9ion 0 express$ among em95t eng9e]s z to ! desirability ( dra9+ ! d[n/ream half ( ! dam1 i4e4 ! "p d[n/ream ( ! core-wall4 ,by "s x 0 urg$ t dra9age is necess>y to less5 ! *ance ( ! e>?work slipp+4 ,o!rs cont5d$ t any dra9 :i* p5etrates ! dam mu/ facilitate ! p]colation ( wat] f ! res]voir4 ,x is cle> t "s ( ! speak]s reg>d$ ! dam d[n/ream ( ! core-wall z be+ p>tly /aun*1 & "s z be+ :olly support4 ,if = any reason !re seems a *ance ( wat] leak+ ?r\gh ! core-wall1 x is desirable to reg>d ! e>?-fill+ next to x z /aun*4 ,9 ,we/]n ,india a k9d ( puddle is made by mix+ ?ree p>ts ( 8black cotton soil0 ) two ( s&4 ,! object ( ! puddle wall is only to prev5t wat] f f9d+ its way along ! surface ( ! gr\nd4 ,x is c>ri$ d[n only to a fairly wat]-tight /ratum & is c>ri$ up only to #a foot above ! gr\nd4 ,above t ! mass ( ! dam is made ( black cotton soil z a /aun*1 ) m por\s mat]ial on bo? sides ( x4 ,9 ord] to af=d full protection aga9/ waves & _! spla%es1 ! pit*+ on ! up/ream face ( a dam %\ld ext5d up to a height ( #e feet1 measur$ v]tically1 above ! highe/ wat]-level4 ,9 ! case ( a dam 9 :i* ! 8fet*0 or di/ance ov] :i* ! waves h be5 9 process ( =mation exce$s two miles1 ! above height %\ld be slightly increas$4#ba ,! pit*+ is usually ( /ones r\ghly squ>$ at _! out] ends & laid on a lay] ( brok5 /ones4 ,! wat] f a res]voir is usually drawn (f by means ( pipes :i* are laid inside a masonry culv]t built "u ! dam4 ,! pipes c ?us be inspect$4 ,! culv]t is block$ at its up/ream end by a ?ick masonry wall ?r\gh :i* ! pipes pass4 ,accid5ts :i* h happ5$ 9 ! pa/ h be5 due to weakness ( ! culv]t or to wat] f9d+ its way along ! outside ( ! masonry4 ,! culv]t c be made ( prop] /r5g?1 & x %\ld h a ?ick coat+ ( clay puddle :i* is work$ into ! clay-puddle core-wall ( ! dam4 ,if ! core-wall is ( masonry or concrete1 ! masonry ( ! culv]t is prop]ly jo9$ to x4 ,9 _m cases ! culv]t & pipes are tak5 ?r\gh a cutt+ or tunnel & n "u ! dam4 ,at ! up/ream end ( ! culv]t !re is a masonry t[]--access to x is obta9$ f ! top ( ! dam by a foot-bridge1--& f x valves = op5+ & clos+ ! pipes are work$4 ,if ! res]voir is = ! wat] supply ( a t[n1 x is arrang$1 by means ( a v]tical pipe1 t ! draw-(f c be at v>i\s levels s t ! surface-wat] c always be us$4 ,9 ! case ( "s ( ! t[]s at ! res]voirs :5ce ,birm+ham is n[ suppli$1 ! v]tical pipe consi/s ( a numb] ( /eel cyl9d]s ) gun-metal faces :i* are s accurately made t ! jo9t is wat]-tight :5 "o cyl9d] m]ely /&s on ano!r4 ,! draw-(f is obta9$ f a giv5 level by lift+ a p>ticul> numb] ( cyl9d]s4 ,sometimes ! t[] is made ( re9=c$ concrete4 ,:5 x is l(ty x %\ld be /rong en\gh to resi/ a /rong w9d1 bl[+ :5 ! res]voir is empty4 #d4 ,masonry ,dams4--,= heights mu* exce$+ #aaj or #abj feet a masonry dam may be *eap] ?an an e>!n dam2 & 9 case a flood occurs :ile "w is 9 progress ! masonry might suff] little injury1 :ile e>?work might be swept away completely4 ,masonry dams are usually built ( r&om rubble masonry ) faces ( dress$ /one4 ,su* masonry weighs ab\t #adj lbs4 p] cubic foot1 & is ord9>ily q safe :5 subject$ to pressures ( #bj tons p] squ>e foot1 b 9 a masonry dam a high factor ( safety is necess>y1 & #ae tons p] squ>e foot may be all[$4 ,9 a wall ( su* masonry ) bo? faces v]tical1 ! pressure1 ow+ to ! weight ( ! wall1 w rea* ! above limit :5 ! wall has atta9$ a height ( ab\t #bbj feet4 ,9 a masonry dam1 al?\gh ! masonry is always ( ! be/ quality1 x is a rule to calculate ! dim5sions s z to give no t5sion on any "p ( ! masonry4 ,any crack or op5+ ( a jo9t1 occurr+ p]haps be=e ! masonry _h h>d5$1 w\ld let 9 wat]1 & its pressure w\ld t5d to gradually ext5d ! crack & ev5tually to ov]turn ! portion above ! crack4 ,fig4 #fb %[s ! upp] "p ( a masonry dam4 ,! l9es ) arr[s %[ ! v]tical =ce due to ! weight ( ! masonry above ,a ,b1 ! horizontal =ce due to ! wat]-pressure on x--act+ at two-?irds ( ! dep?1--& ! resultant ( ^! two4 ,9 ord] t !re may be no t5sion on ! masonry1 ! resultant mu/ always fall )9 ! middle ?ird ( ! ?ickness ( ! dam4 ,9 ord] to prev5t its fall+ outside ! middle ?ird1 ! d[n/ream face mu/ be splay$ out1 & ! splay w g on increas+ some:at4 ,suppose1 n[1 t ! res]voir is laid dry4 ,x w be f\nd t 9 ! case ( a dam m ?an #ajj feet high ! pressure due to ! weight ( ! wall alone w fall outside ! middle ?ird--to ! up/ream side ( x1 ( c\rse--( ! ?ickness ( ! wall1 & a slight splay mu/ be giv5 to ! up/ream side4 ,! v]tical pressure ( ! wat] on ?is splay$ "p mu/ be tak5 into consid]ation4 ,! limit ( pressure1 #ae tons p] squ>e foot1 may ev5tually be rea*$ ow+ to ! height ( ! dam1 & additional splay may h to be giv5 = ?is4 ,:5 ! outside splay becomes consid]able a fur!r all[ance is made = x1 because ! /ress at ! edge ( a horizontal section is tang5tial to ! face4 ,9 ord] t ! tang5tial /ress may n exce$ #ae tons p] squ>e foot1 ! v]tical /ress at ! out] edge ( a horizontal section ( ! dam mu/ n exce$ ab\t #ab tons4 ,by foll[+ ! above rules ! section ( ! dam c be calculat$1 beg9n+ f ! top & work+ d[nw>ds4 ,! result+ pr(ile ( ! dam is some:at z %[n 9 fig4 #fc4 ,if a masonry dam is design$ on ! pr9ciples giv5 above--t is1 s z to be safe z reg>ds cru%+ & ov]turn+--x w be safe z reg>ds %e>+ or slid+ horizontally1 b a te/ calculation c easily be made = ?is4 ,illu/ration3 ,,fig4 #fb4 ,illu/ration3 ,,fig4 #fc4 ,calculations ( ! above k9d d n1 ( c\rse1 enable all ! /resses 9 a solid mass ( masonry to be f\nd4 ,great /resses are caus$ by expansion & contraction ow+ to *anges 9 temp]ature4 ,o!rs are caus$ by ! connections ( ! dam ) ! rock on :i* x re/s & ) ! sides ( ! gorge4 ,! me?od ( calculation describ$ above indicates a suitable =m = ! pr(ile ( a dam4 ,! l>ge factor ( safety adopt$ all[s = o!r /resses4 ,! sections ( ! olde/ dams1 made 9 ,spa91 7 some:at z %[n 9 fig4 #fd1 & conta9$ ab\t twice z mu* mat]ial z 0 necess>y4 ,! object ( ! calculations is to save ?is ne$less exp5diture4 ,masonry dams design$ on ! above pr9ciples h be5 con/ruct$ = heights rang+ up to ne>ly #cjj feet1 measur$ f ! f\ndation to ! top4 ,! f\ndation is always on h>d rock free f fissures4 ,g5]ally a f\ndation tr5* is cut4 ,! ends ( ! dam are c>ri$ into ! rock on ! sides ( ! gorge4 ,!y %\ld n1 h[ev]1 if ! sides ( ! gorge are /eep1 be built 9 ) mort>1 b be all[$ to exp& & contract v]tically1 a wat]-tight jo9t be+ made by means ( asphalt 7,ency4 ,brit41 ,t5? ,edition1 vol4 #cc1 8,wat] ,supply074 ,?is obvi\sly r$uces ! /ra9+4 ,a dam %\ld be built 9 cool wea!r1 s t any /resses to :i* x w ev5tually be subject$ ow+ to *anges 9 temp]ature w be *iefly compressive4 ,! up/ream face %\ld be z wat]-tight z possible4 ,!re %\ld n1 h[ev]1 be too sudd5 a *ange 9 ! "* ( ! masonry f ! face "w to ! inside "w4 ,if !re are any spr+s1 !y mu/ be c>efully connect$ to pipes & c>ri$ outside ! dam4 ,no wat] mu/ be p]mitt$ to get "u or inside ! dam1 ei!r f spr+s 9 ! sides ( ! gorge or f ! wat] 9 ! res]voir4 ,_m exi/+ dams leak slightly :]e !y jo9 ! sides ( ! valley1 & mo/ h develop$ "s v]tical cracks normal to ! face4 ,illu/ration3 ,,fig4 #fd4 ,out ( "s hundr$ high masonry dams :i* h be5 erect$1 only ?ree are kn[n to h fail$4 ,( ^!1 ! ,pu5tes dam 0 p>tly f\nd$ on piles2 & 9 two1 ! ,habra & ,b\zey dams1 ! rule ( ! middle ?ird 0 n att5d$ to4 ,ano!r dam1 n s high1 ! ,au/9 dam1 9 ,texas1 ,u4,s4,a41 fail$ sev5 ye>s aft] con/ruction4 ,x 0 #fe feet high & f\nd$ on lime/one1 ! wid? ( ! base be+ #ff feet4 ,spr+s 9 ! b$ & sides ( ! gorge _h1 dur+ ! con/ruction ( ! dam1 giv5 mu* tr\ble1 & _h1 aft] its completion1 =c$ _! way ?r\gh ! und]ly+ rock4 ,at ! "t ( failure #aa feet ( wat] 0 pass+ ov] ! dam1 :i* %e>$ 9 two places1 a l5g? ( #ddj feet ( x be+ pu%$ =w>d = #dj or #ej feet )\t ov]turn+1 b subsequ5tly break+ up4 ,! dam 0 f\nd$ 9 a tr5* cut 9 ! rock4 ,! rock on ! d[n/ream side ( ! f\ndation tr5* appe>s to h be5 worn away by ! wat]1 s t !re 0 no long] a tr5* 7,sci5tific ,am]ican1 #bh? ,april #aijj74 ,! above1 h[ev]1 does n seem to be suffici5t to acc\nt = failure4 ,! horizontal wat]-pressure on a #a-;foot l5g? ( ! dam w\ld be #ahj1jjj lbs4 & ! weight ( masonry to be mov$ p]haps #cbj1jjj lbs4 ,x seems probable t wat] f up/ream f\nd its way "u ! dam & ex]cis$ a lift+ =ce on x & s caus$ x to slide4 ,if a masonry dam1 in/ead ( be+ /raight1 is made curv$ on plan1 ) its convexity up/ream1 x acts z an ar*1 & its ?ickness c1 9 ! case ( a fairly n>r[ gorge1 be greatly r$uc$4 ,?is type ( dam is a suitable "o to use :5 ! sides ( ! gorge are ( firm & solid rock & !re is no d\bt ab\t _! be+ able to /& ! ?ru/ )\t yield+4 ,sev]al dams ( v consid]able size h rec5tly be5 built 9 ?is way4 ,! ?ickness ( ! upp] "p ( ! dam & ! ratio ( ! v]s$-s9e ( ! ar* to ! span c be decid$ on by ! me?ods us$ = ar*es 9 g5]al4 ,! l[] "p ( ! dam is made ?ick]4 ,! l[e/ "p _c act z an ar*1 because x is atta*$ to ! f\ndation4 ,x is1 h[ev]1 assi/$ by ! portion above x1 :i* acts z an ar*1 & ?us ne$ n be s ?ick z 9 a 8gravity0 section4 ,! ,be> ,valley dam1 :i* is #fd feet high1 is only #c feet ?ick at ! top4 ,! ?ickness increases gradually to #h feet at #dh feet f ! top4 ,! *ord ( ! curve is #bej feet & ! radius ( curvature #cce feet4 ,if ! gorge is wide1 ! ?ickness ( ! ar* comes out s great t no?+ is sav$ by adopt+ ! curv$ =m4 ,b 9 su* a case1 & 9 any case1 a dam c be made slightly curv$ s z to (f] a greatly increas$ resi/ance to ov]turn+4 ,x ne$ n act z an ar*1 & c be prev5t$ f s act+1 9 ord] t excessive /resses may be avoid$1 by lett+ ! ends ( ! dam1 aft] !y h ent]$ ! grooves cut 9 ! sides ( ! gorge1 /op %ort ( ! ends ( ! grooves4 ,illu/ration3 ,,fig4 #fe4 ,dur+ ! la/ few ye>s mu* att5tion has be5 giv5 to ! inve/igation ( ! /resses to :i* a masonry dam is subject$4 ,"s inve/igations h be5 !oretical & o!rs practical1 models ( india-rubb] & o!r sub/ances hav+ be5 us$ = exp]im5t4 ,! inve/igations %[ t g5]ally ! /resses 9 a model ( a dam are v mu* ! same z w\ld be expect$1 b t !re is a t5sile /ress1 previ\sly ov]look$1 ne> ! po9t ,m 7fig4 #fe71 :]e ! dam re/s on its f\ndation4 ,! t5sion is on ! f\ndation1 on ! l9e ,m ,n1 & is due to ! horizontal ?ru/ ( ! wat]4 ,x is natural t 9 an ela/ic model ?is /ress %\ld manife/ itself by de=mation4 ,9 ! case ( an actual dam re/+ on rock1 matt]s are diff]5t2 b ?is t5sile /ress des]ves consid]ation4 ,= ! pres5t let x be suppos$ t !re is no tr5*1 ! dam m]ely /&+ on ! rock4 ,suppose t ! rock has only ! ?ickness ,m ,r4 ,!re is t5sion 9 ,m ,n1 & probably compression 9 ,n ,r4 ,x is assum$ t1 along ! base ,m ,p1 !re is p]fect union betwe5 ! dam & ! rock4 ,! t5sion to :i* ! rock is occasionally subject$ ow+ to *anges ( temp]ature may exce$ any t5sion due to ! wat]-pressure1 b x is conceivable t ! t5sion occurr+ f bo? causes might cause a crack at ,m ,n1 & t ?is might ext5d to ,r4 ,?is implies a m9ute slid+ ( ! dam & ( ! rock bel[ x1 movem5t tak+ place on ! plane ,r ,q4 ,! ?ru/ ( ! wat] is n[ resi/$ by ! rock d[n/ream ( ,p ,q4 ,! dam1 ) ! rock ,m ,r ,q ,p adh]+ to x1 t5ds to rotate ab\t ! po9t ,p4 ,! t5d5cy to rotate w be enhanc$ if wat] ent]s ,m ,r1 & /ill m if x ent]s ,r ,q4 ,no rotation c1 h[ev]1 take place unless ! rock at ,m ,r is spl9t]$ away4 ,! rock w\ld also h to fracture at ,p ,q4 ,x has be5 sugge/$ t ! up/ream face ( ! dam be made curv$ z %[n by ! dott$ l9e4 ,?is w\ld %ift ! *ief t5sion to m n1 & ! dam1 ) ! rock b5ea? x & ! weight ( ! wat] above ! curv$ portion1 w\ld obvi\sly (f] an increas$ resi/ance to rotation ab\t ,p4 ,! co/ ( ! dam w\ld ( c\rse be increas$4 ,! dang] ( a crack =m+ at ,m ,n seems to exi/ only :5 !re is a ?9 upp] /ratum ( rock n firmly connect$ to rock bel[4 ,:5 ?is condition is believ$ to exi/1 a masonry dam1 if built at all1 %\ld h ! up/ream face curv$ z above describ$4 ,9 ! case ( any exi/+ dam ( great height1 :5 ! above condition is suspect$ to exi/1 ! res]voir might be laid dry1 & if any crack at ,m ,n is discov]$ a curv$ portion c\ld be add$2 b 9 ?is case ! union betwe5 ! new & ! old "w w\ld be imp]fect1 & ! curve %\ld />t f high up on ! up/ream face ( ! dam4 ,x has be5 sugge/$ t asphalt or "s imp]vi\s mat]ial be laid on ! rock to prev5t wat] f ent]+ any crack4 ,x w\ld1 h[ev]1 n only h to be laid up/ream ( ! dam1 b to ext5d "u "p ( ! dam1 & ?us weak5 x to "s ext5t4 ,9 ! case 7fig4 #fc7 9 :i* ! dam is f\nd$ 9 a deep tr5*1 ! build+ up ( ! up/ream triangul> space & unit+ ! mat]ial bo? to ! dam & to ! side ( ! tr5*1 might be ( "s use1 b a crack might =m 9 x4 ,x w\ld be desirable to add a curv$ portion1 z above describ$1 on ! top ( ! rock if s\nd1 or to remove ! uns\nd rock & wid5 ! tr5* & !n add ! curv$ portion4 ,add+ mat]ial to ! d[n/ream triangul> space1 & unit+ x well1 w\ld also increase ! resi/ance ( ! dam to ov]turn+1 n s mu* because ( ! additional weight1 z because ( ! rais+ ( ! po9t ab\t :i* ! dam w\ld h to revolve 9 ov]turn+4 ,sev]al rec5t dams h be5 built ( cyclopean concrete1 blocks ( rock z heavy z #aj tons be+ sometimes us$ 9 ! "w4 ,su* blocks are laid on "o ( _! flat faces4 ,9 ! ,u4,s4,a4 "s res]voirs h be5 made ) walls ( re9=c$ concrete1 back$ by e>? embankm5ts 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxxxix471 & also ( cyclopean masonry re9=c$ ) /eel rods4 ,ano!r k9d ( dam :i* has be5 us$ 9 ! ,u4,s4,a4 is ! rock-fill dam ) a core--correspond+ to ! puddle wall 9 an e>!n dam--( /eel plates rivet$ toge!r & made wat]-tight & ins]t$ into ! rock at ea* side4 ,9 ! case ( ! ,ea/ ,canyon ,creek ,res]voir1 ,morgan1 ,utah1 ! dam is #aaj feet high4 ,! /eel plates v>y 9 ?ickness f #c_/h-;in* at ! bottom to -in* at ! top1 & are emb$d$ 9 asphaltum concrete & re/ on a concrete base4 ,! dry-/one "w ( ! dam is h&-pack$ on bo? faces1 & also on bo? sides ( ! core4 ,! re/ is ?r[n 94 ,! up/ream face is #a to #a1 & ! d[n/ream face #b to #a4 ,! wa/e weir is at "o end ( ! dam & is cont9u$ by a flume1 s t ! wat] falls cle> ( ! dam4 ,! outlet is a tunnel 9 ! rock4 ,,*apt] ,,xiv ,,tidal ,,wat]s ,,& ,,works #a4 ,tides4--,! tides or 8tidal waves0 are caus$ by ! attraction ( ! moon & ! sun4 ,! ph5om5a are complex1 & a full discussion ( _! causes ne$ n be giv5 "h4 ,:5 ! tide rises x is said to 8fl[10 & x is call$ ! flood tide2 :5 x falls x is call$ ! ebb tide4 ,! p]iod betwe5 "o tide & ! next1 e4g4 f high wat] to high wat]1 is ab\t twelve h\rs1 tw5ty-five m9utes4 ,at a spr+ tide ! range ( ! tide is great] ?an usual2 at a neap tide less4 ,:]e !re are *annels1 z1 = in/ance1 ! seas :i* surr\nd ! ,briti% ,isles1 ! tidal waves run up !m z ! tide rises 9 ! neighb\r+ ocean1 & run back z x falls4 ,at "s places1 z ,s\?ampton1 ! tide comes 9 f two directions1 & !re is a d\ble tide4 ,! times & levels ( high & l[ wat] at v>i\s places h be5 asc]ta9$ by obs]vation1 & are record$4 ,! levels are1 h[ev]1 liable to be affect$ by w9ds4 ,a w9d bl[+ t[>ds ! %ore raises ! level ( bo? high & l[ wat]2 a w9d bl[+ (f %ore l[]s bo? levels4 ,a sev]e /orm 9 ! ,nor? ,sea has caus$ a d\ble tide at ,london ,docks1 by accel]at+ ! ,nor? ,sea tidal wave4 ,9 a funnel-%ap$ e/u>y1 especially if x faces ! direction ( ! tidal wave 9 ! sea1 ! tide 9 go+ up ! *annel increases 9 velocity1 & ! mom5tum ( ! wat] causes x to rise high] & high] z ! wid? decreases4 ,at ! upp] end ( ! ,bri/ol ,*annel ! range ( ! tide is d\ble ! range 9 ! sea outside ! *annel4 ,! ,bay ( ,fundy is ano!r place :]e a simil> ph5om5on occurs4 ,:5 a riv] or e/u>y is %all[ & ! range ( ! tide is great1 s t its rise is rapid1 ! flood tide 9 "s cases advances 9 ! =m ( a wave or 8bore10 caus+ a sudd5 rise 9 ! wat]-level & a sudd5 rev]sal ( ! fl[ ( ! /ream4 ,a bore is mo/ pron\nc$ at spr+ tides4 ,t ( ! ,sev]n is well kn[n4 ,9 ! case ( a tide runn+ along a coa/ or up an e/u>y1 ! wat] ( ! flood tide1 aft] x has ceas$ to rise1 cont9ues = a %ort "t1 ow+ to its mom5tum1 to fl[ 9 ! same direction z be=e4 ,! same ?+ happ5s :5 ! ebb tide ceases to fall4 ,! tide also acquires special velocity1 j z a riv] does1 r\nd any project+ headl&4 ,! rise & fall ( ! tide are lea/ rapid ne> ! turns ( ! tide4 ,if ! "t f ! beg9n+ to ! end ( ! fl[ be divid$ into six equal p>ts1 ! proportional rise ( ! wat] w be approximately z foll[s4 ,& simil>ly ) ! fall dur+ ! ebb4 ,"t #a #b #c #d #e #f ,rise ( wat] #jfg #be #e #ge #icc #a ,tidal wat]s are frequ5tly *>g$1 m or less1 ) silt1 obta9$ f ! %ore or f %all[s ne> x1 ei!r by curr5ts or tidal waves sweep+ along x1 or by ! action ( ord9>y waves4 ,tidal wat]s fl[+ up & d[n ! l[] portions ( riv]s r5d] !m to an enorm\s degree m capable ( c>ry+ navigation &1 especially if !y become enl>g$ & =m e/u>ies1 m capable ( be+ alt]$ by tra9+ works4 ,a tide-gauge is con/ruct$ on ! same pr9ciple z a self-regi/]+ /ream-gauge4 ,! rise & fall ( ! wat] are r$uc$1 by me*anism1 to a conv5i5t range1 & are record$ on a b& c>ri$ on a drum1 :i* is caus$ to revolve by clockwork4 ,ano!r k9d1 :i* dep5ds on ! use ( an inv]t$ syphon fill$ ) air & a syphon ( m]cury1 is describ$ 9 ,m94 ,proc4 ,in/4 ,c4,e41 vol4 clxiv4 ,illu/ration3 ,,fig4 #ff4 #b4 ,tidal ,riv]s4--,let ,a ,b 7fig4 #ff7 be ! surface ( ! l[] "p or m\? ( a riv]1 suppos$ to be ( uni=m wid?1 & let ,b be ! mean sea-level4 ,z ! tide rises to ,d ! wat] ( ! riv] is head$ up & assumes ! l9e ,a ,d4 ,:5 ! tide falls to ,f !re is a draw1 ! riv] surface tak+ ! l9e ,a ,f4 ,if ! rise ( ! tide ,b ,h is s great t ! dis*>ge ( ! riv] _c keep pace ) x1 s z to fill up ! :ole space betwe5 ,a & ,h to ! level ( ,h1 !re w be a fl[ ( sea wat] f ,h to "s po9t ,m1 & ( riv] wat] f ,a to ,m4 ,! po9t ,m w be l[] ?an ,a & ,h4 ,if ! tide n[ turns & ! wat]-level ,h beg9s to fall1 !re w /ill be a fl[ along ,h ,m4 ,= a brief p]iod x w be due to mom5tum1 b x w cont9ue until1 by ! rise ( ! wat]-level at ,m & ! fall at ,h1 ! surface has assum$ ! =m indicat$ by ! dott$ l9e ,a ,n ,j4 ,:ile ?is is happ5+1 ! po9t correspond+ to ,m--:]e ! concave curve ( ! upl& wat] meets ! convex curve ( ! tidal wat]--rises high] & %ifts seaw>d4 ,! "* ( ! two curves rema9s ! same1 b !y become flatt] & ! surface ,n ,j ne>ly level4 ,?us ! "t ( high tide at ,m is lat] ?an at ,h4 ,x is lat] = ea* po9t pass$ 9 go+ up ! riv] f ,h t[>ds ,a4 ,ev5tually a po9t ,a is rea*$ :]e !re is no tide1 t is1 no rise or fall4 ,f> bel[ ?is po9t1 betwe5 ,a & ,b1 !re is a po9t above :i* !re is no upw>d curr5t b only a slack5+ ( ! d[n/ream fl[4 ,at ,h a diagram %[+ ! rise & fall ( ! tide is symmetrical1 at ,n ! rises & falls are less ?an at ,h1 & ! p]iods ( _! occurr5ce lat]4 ,9 go+ up ! riv] ! duration ( ! flood tide decreases & t ( ! ebb tide increases4 ,! flood tide atta9s its greate/ velocity soon aft] its comm5cem5t1 ! ebb tide t[>ds its close4 ,! di/ances to :i* ! tidal influ5ce ext5d are ( c\rse great] ! great] ! range ( ! tide & ! flatt] ! slope ( ! riv]4 ,! dis*>ge ( ! riv] ( c\rse v>ies4 ,! great] ! dis*>ge ! m ! rise ( ! riv] t5ds to keep pace ) t ( ! tide & ! less ! di/ance to :i* ! tidal influ5ce ext5ds4 ,on a longitud9al section ( ! riv]1 ! high-wat] l9e w be %[n z ,a ,n ,h4 ,?is is m]ely done = conv5i5ce4 ,x is nev] high wat] at all po9ts simultane\sly4 ,to %[ ! actual /ate ( affairs at v>i\s /ages ( ! tide1 s]ies ( l9es mu/ be drawn z 9 fig4 #fg1 :]e ! firm l9es %[ ! flood1 & ! dott$ l9es ! ebb tide4 ,! fl[ 9 ! tidal rea* ( a riv] is ! same z if ! wat] 0 alt]nately head$ up by a movable weir & !n all[$ to fl[ freely & be drawn d[n4 ,if ! wat] c>ries silt1 ! t5d5cy = deposit to occur is 7,,*ap4 ,v41 ,art4 #b7 no great] ?an if !re 0 no head+ up or draw+ d[n4 ,! t5d5cy dep5ds *iefly on :e!r !re is1 on ! av]age1 any r$uction 9 velocity or increase 9 dep? z comp>$ ) ! non-tidal up/ream rea*1 & :e!r ! wat] 9 t rea* is fully *>g$ ) silt4 ,if bo? ! answ]s are 9 ! negative1 no deposit due to riv] silt is likely to occur 9 ! tidal rea*4 ,illu/ration3 ,,fig4 #fg4 ,if ! sea wat] is *>g$ ) silt1 x w ( c\rse c>ry silt into ! riv] z x fl[s up1 b ! :ole volume ( wat] :i* ent]s has to fl[ out aga94 ,on ! :ole1 ! t5d5cy = silt to be deposit$ 9 ! riv] is due only to ! p]iod ( 8slack tide0 ne> ! "t :5 ! fl[ ceases4 ,! t5d5cy is seldom m>k$4 ,if ! sea wat] c>ries silt & ! riv] wat] is cle>1 ! latt] assi/s ( c\rse 9 remov+ any deposit--t is1 x t5ds to keep ! *annel cle>4 ,if ! riv] *annel is s(t & if ! sea wat] c>ries no silt1 x may1 9 pass+ up & d[n ! riv]1 become *>g$ ) silt & return to sea /ill c>ry+ x4 ,x ?us has a sc\r+ effect on ! *annel1 & may deep5 or wid5 x4 ,if1 ow+1 = in/ance1 to ! flatt5+ ( ! b$ slope 9 its l[] rea*es1 ! riv] t5ds to deposit its own silt 9 its tidal rea*1 ! sea wat] may prev5t ?is deposit4 ,?us1 z reg>ds silt+ 9 ! tidal rea* ( ! riv]1 ! tidal wat] ( ! sea has little prejudicial effect if x is silt-lad51 & a b5eficial effect if x is n4 ,silt is likely to deposit 9 ! tidal rea* ( a riv] ( uni=m wid?1 only 9 a case 9 :i* ! riv] wat] c>ries mu* silt1 & ! slope is flat or cross-section great comp>$ to t ( ! upp] rea*4 ,sea wat] is heavi] ?an fre% wat] by ab\t #bd p] c5t41 & ?is1 to "s ext5t1 prev5ts _! mix+4 ,at all /ages ( ! flood tide ! t5d5cy at ! po9t :]e ! fre% wat] meets ! salt wat] is = ! fre% wat] to accumulate t[>ds ! surface & ! sea wat] t[>ds ! bottom4 ,:5 ! tide beg9s to fl[ up ! riv] !re may be a l[-level salt wat] curr5t mov+ l&w>d & a high-level fre% wat] curr5t mov+ seaw>d1 b ?is is q a tempor>y /ate ( affairs4 ,! surface slope is l&w>d1 & ! wat] mov+ seaw>d is n mov+ 9 ob$i5ce to ! surface slope4 ,x is only mov+ z a result ( mom5tum previ\sly acquir$4 ,! l[-level curr5t may h "s extra velocity & extra sc\r+ p[]1 b ?is _c be mu*1 because ! mean l&w>d velocity ( ! :ole /ream mu/1 ow+ to ! int]nal resi/ances caus$ by ! two curr5ts1 be less ?an x w\ld be if !re 7 n two curr5ts4 ,moreov]1 ! /ate ( affairs is tempor>y4 ,! two k9ds ( wat] mix ev5tually1 & _! tempor>y sep>ation has no consid]able effect on ! g5]al t5d5cy ( ! riv] 9 ! tidal rea* to sc\r or to silt4 ,a body ( wat] includ$ at any mom5t betwe5 any two cross-sections ( ! tidal portion ( a riv] may n rea* ! sea dur+ ! next ebb tide4 ,9 ?is case x w fl[ back up ! *annel ) ! next flood tide1 & s be kept mov+ up & d[n1 gett+ ne>]1 h[ev]1 to ! sea at ea* tide4 ,de ,fran*imont has %[n 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clx47 h[ a diagrammatic r\te-guide c be prep>$ = any tidal riv] to %[ pilots or capta9s ( vessels ! be/ times = />t+ on voyages up or d[n ! riv]1 & = pass+ ea* po9t on x4 #c4 ,works 9 ,tidal ,riv]s4--,if any works are requir$ 9 ! tidal portion ( a riv]1 ! pr9ciples to be foll[$ 9 design+ !m are ! same z if ! riv] 0 non-tidal4 ,all t has be5 said 9 ,,*ap4 ,,viii41 ,arts4 #a to #c1 applies to !m4 ,! riv] may be /raight5$ or tra9$ or dr$g$4 ,g5]ally tra9+ & dr$g+ are comb9$4 ,any dr$g+ 9 ! portion ( ! riv] ne>e/ ! sea w n1 ( c\rse1 alt] ! wat] levels ne> ! m\?1 b x w alt] !m fur!r up4 ,! tide w come up 9 great] volume & w rise high] & ext5d fur!r up4 ,! ebb w be facilitat$1 & ! l[-wat] level w be l[]$4 ,if any n>r[+ ( ! *annel ne> its m\? is effect$ by tra9+ walls = ! purpose ( l[]+ ! b$1 ! effect on ! volume ( tidal wat] ent]+ ! riv] mu/ be tak5 into consid]ation4 ,if ! n>r[+ is conf9$ to a rea* ne> ! m\?1 & if ! result+ deep5+ is n suffici5t to c\nt]act ! effect ( ! n>r[+1 ! volume ( tidal wat] rea*+ ! unn>r[$ portions ( ! *annel w be r$uc$1 & ?is may be injuri\s4 ,its sc\r+ action may be insuffici5t4 ,! prop] c\rse may be to cont9ue ! n>r[+ up/ream4 ,if ?is is done1 !n x is obvi\s t ! wid? ( *annel 9 :i* deep wat] is to be ma9ta9$ at high wat]1 or :i* is to be kept free f deposit1 is r$uc$ 9 ab\t ! same proportion z ! volume ( tidal wat] is r$uc$1 & no h>m is likely to result4 ,any weir or simil> /ructure :i* abruptly /ops ! fl[ ( ! tide up a riv] *ecks x ( c\rse = a long di/ance back1 p]haps to ! m\?4 ,old ,london ,bridge us$ to ob/ruct ! tide1 & its removal increas$ ! range ( ! tide1 & 0 b5eficial4 ,tidal riv]s g5]ally wid5 out to "s ext5t ne> _! m\?s1 & are ?us r e/u>ies ?an riv]s4 ,! works 9 su* riv]s are m fully discuss$ 9 ,art4 #e4 #d4 ,tidal ,e/u>ies4--,if1 in/ead ( a riv] ( uni=m wid?1 !re is an e/u>y ^: wid? increases /eadily t[>ds ! sea s t x is funnel-%ap$1 ! conditions describ$ 9 ,art4 #b are modifi$4 ,an e/u>y is =m$ fir/ by ! waves ( ! sea1 :i* we> away ! angles at ! m\? ( ! riv] & all[ ! tide to ent] 9 great] volume1 & !n by ! fl[ & ebb ( ! tides4 ,! slope ( ! b$ ( ! e/u>y is usually mu* flatt] ?an t ( ! riv]1 & ! wat] surface is z %[n 9 fig4 #fg4 ,! tidal movem5ts ext5d fur!r up/ream ?an 9 ! case ( a riv]1 n only because ( ! great] difficulty exp]i5c$ by ! upl& wat] 9 fill+ up ! wide *annel ( ! e/u>y1 b because ( ! mom5tum ( ! tidal wat] driv+ its way up ! funnel-%ap$ *annel 7,art4 #a74 ,! capacity ( ! e/u>y is ( c\rse mu* great] ?an is requir$ = ! dis*>ge ( ! upl& wat] alone4 ,if ! sea-level rema9$ always at "o height & if ! upl& wat] conta9$ silt1 x w\ld t5d to deposit 9 ! e/u>y & w\ld c]ta9ly deposit 9 x to "s ext5t4 ,! action ( ! sea wat] is ! same z describ$ 9 ,art4 #b1 sc\r+ if x is cle> :5 ent]+1 ( less acc\nt if x is n cle>4 ,ow+ to ! funnel %ape ( ! e/u>y1 ! tide rises high] at its upp] end ?an if ! e/u>y 7 replac$ by a riv] *annel1 & ! tide also ext5ds fur!r up4 ,?is may p>tly or :olly comp5sate = ! great] t5d5cy ( silt to deposit 9 an e/u>y z comp>$ ) a riv] *annel4 ,! ebb tide 9 an e/u>y does n always foll[ exactly ! same c\rse z ! flood tide4 ,( c\rse ! l[e/ p>ts ( ! e/u>y are fill$ fir/ & empti$ la/1 b ! *annels are n all cont9u\s4 ,a *annel op5 at its l[] end may h a dead end at its upp] t]m9ation1 & vice v]sa4 ,also1 at %>p b5ds 9 ! *annels1 ! mom5tum ( ! wat] may cause diff]5ces 9 ! pa?s trav]s$ by ! fl[+ & ebb+ curr5ts4 ,:]ev] !re is a deep *annel ! wat] f ! adjac5t s&banks t5ds1 t[>ds ! close ( ! ebb1 to fl[ cross-wise into ! *annel1 & 9 do+ ?is x to "s ext5t wa%es d[n ! banks into ! *annel4 #e4 ,works 9 ,tidal ,e/u>ies4--,e/u>ies1 :5 %all[1 (f] great facilities = tra9+4 ,x us$ at "o "t to be said t any *ange :i* r$uces ! volume ( tidal fl[ mu/ be injuri\s4 ,x w\ld be injuri\s to re/rict ! m\? ( ! e/u>y1 unless x 7 exceptionally wide1 & leave ! re/ unt\*$4 ,if ! :ole e/u>y is n>r[$1 & a suitable funnel %ape pres]v$1 ! wid? to be kept op5 is1 relatively to ! size ( ! m\?1 no great] ?an be=e1 & ! tide may fl[ up z f> z be=e1 & rise to z high a level4 ,! n>r[+1 if prop]ly arrang$1 w improve ! %ape ( ! e/u>y & cause an increas$ sc\r4 ,! effect ( ! upl& wat] is also great] 9 ! n>r[] *annel4 ,improvem5ts to e/u>ies are n1 h[ev]1 re/rict$ to tra9+4 ,!re is always "o or m deep *annels1 & ! be/ ( ^! c be select$ & improv$ by dr$g+4 ,! *annel %\ld be "o along :i* bo? ! flood tide & ! ebb tide w run4 ,! above rem>ks z to tra9+ d n apply to a case 9 :i* !re is a b> outside ! m\? ( ! e/u>y4 ,tra9+ might *eck ! sc\r at ! b>4 ,b>s are treat$ ( 9 ,,*ap4 ,,xv4 ,if an e/u>y is n funnel-%ap$1 if1 = in/ance1 x wid5s out v rapidly1 ! tidal fl[ is mu* less effective 9 keep+ ! *annel op54 ,9 ?is case1 tra9+ works1 :i* w\ld give ! necess>y funnel %ape1 are indicat$ r ?an dr$g+4 ,if an e/u>y is n>r[ at ! entrance1 ! fl[ is mu* less p[]ful1 unless ! n>r[ "p is ( great] dep?1 b ev5 !n ! =ce ( ! tide is r$uc$ ow+ to ! *ange 9 ! %ape ( ! *annel4 ,! b$ ( an e/u>y may be ( su* s(t or s&y mat]ial t a dr$g$ *annel w\ld be likely to be quickly fill$ up aga9 by ! slipp+ 9 ( mat]ial at ! sides 7,art4 #d74 ,9 su* a case an untra9$ *annel c only be kept op5 to its full dep? by con/ant dr$g+1 & probably ! be/ c\rse is to con/ruct a tra9$ *annel1 al?\gh x may be m exp5sive ?an 9 ! case ( a h>d] *annel1 because ( ! dep? to :i* ! f\ndations ( ! walls mu/ be sunk into ! s(t b$4 ,also1 if ! b$ ( ! e/u>y is con/antly %ift+1 a dr$g$ *annel alone w n succe$1 & tra9+ mu/ be resort$ to4 ,aga91 ! b$ may be ( su* h>d mat]ial t tra9+ walls w\ld n cause x to sc\r4 ,9 ?is case a *annel %\ld be dr$g$ & ne$ n be tra9$4 ,= ! great body ( int]m$iate cases 9 :i* ! deep *annel c be =m$ ei!r by dr$g+ or tra9+1 bo? me?ods c be adopt$4 ,a common plan is to tra9 ! upp] "p & to dr$ge ! l[] "p :]e ! e/u>y is wid] & ! tra9+ walls w\ld be m expos$ to ! waves4 ,illu/ration3 ,,fig4 #fh4 ,:5 an e/u>y is ?us p>tly tra9$1 ! deep5+ due to ! tra9+ does n ext5d f> beyond ! po9t :]e ! walls t]m9ate4 ,! deposit ( mat]ial along ! sides ( ! e/u>y may1 h[ev]1 ext5d "s di/ance fur!r d[n 9 places :]e ! tide c no long] h free play4 ,?is occurr$ 9 ! ,se9e e/u>y 7fig4 #fh74 ,! au?orities ( ,havre1 :i* lies at "o side ( ! e/u>y n f> f its m\?1 fe>$ t if ! tra9+ walls 7 br\ght fur!r d[n1 ! deposits might ext5d to _! neighb\rhood4 ,! r$uction 9 ! capacity ( ! e/u>y1 due to ! deposits1 caus$ x to become fill$ up m quickly1 & ! "t ( high wat] at ,havre 0 advanc$4 ,! dott$ l9es %[ a good arrangem5t ( tra9+ walls propos$ by ,h>c\rt4 ,!re is no d\bt t x is always feasible to c>ry tra9+ walls "r ?r\gh an e/u>y1 or at lea/ d[n to a po9t :]e deep wat] is rea*$1 & if a prop] funnel %ape is giv5 to ! *annel ! r$uction ( ! tidal fl[ & silt+ up ( ! spaces beh9d ! walls ne$ n cause any tr\ble4 ,tra9+ ! complete e/u>y 0 c>ri$ out 9 ! case ( ! ,tees1 :]e1 h[ev]1 ! e/u>y 0 n ( great l5g?1 & 0 n ( a good %ape = keep+ itself op54 ,any afflu5ts ent]+ ! e/u>y c be provid$ ) sep>ate tra9$ *annels4 ,difficulty may1 h[ev]1 arise if !re are t[ns :i* w\ld be %ut (f f ! e/u>y by ! silt banks4 ,g5]ally ! l9e select$ = ! tra9$ or dr$g$ *annel %\ld1 ?\gh x mu/ be z %ort & direct z possible1 co9cide z ne>ly z possible ) t :i* ! wat] naturally t5ds to keep op54 ,?is may be t[>d "o side ( ! e/u>y or ! o!r1 accord+ to ! direction f :i* ! tidal wave approa*es4 ,9 ! case ( ! ,dee1 ! be/ l9e 0 n adopt$1 att5tion hav+ be5 *iefly giv5 to ! "q ( silt+ up ! spaces outside ! walls & s reclaim+ l&1 a matt] :i* %\ld always be treat$ z ( q second>y importance4 ,tra9+ walls 9 e/u>ies are g5]ally built only up to half-tide level4 ,7 x n = ! exp5se !y might be built up to high-wat] level4 ,9 ! ,se9e e/u>y ! walls 7 made ( blocks ( *alk4 ,:e!r a tra9$ *annel w keep itself op5 or w ne$ p]iodical dr$g+ dep5ds1 ( c\rse1 on ! am\nt ( silt 9 ! wat] & on its velocity & dep?4 ,! "q mu/ be work$ out & calculat$ z 9 ! case ( a non-tidal riv]4 ,! e/u>y ( ! ,m]sey diff]s f mo/ o!rs4 ,t[>ds ! m\?1 ne> ,liv]pool1 x is n>r[ & x wid5s out fur!r inl&4 ,! tides1 runn+ ?r\gh ! n>r[ portion1 to fill up ! l>ge inl& bas9 & to empty x aga91 keep ! n>r[ "p sc\r$ to a great dep?4 ,x 0 propos$ to tra9 ! wide portion = ! ,man*e/] ,%ip ,canal4 ,! tra9+ w\ld1 no d\bt1 h succe$$1 b1 ow+ to ! silt+ up ( ! great] "p ( ! e/u>y1 ! sc\r+ ne> ,liv]pool w\ld h be5 v greatly r$uc$ & s]i\s damage done to t port4 ,,*apt] ,,xv ,,riv] ,,b>s #a4 ,deltaic ,riv]s4--,:5 a riv] fl[s into a tideless sea its silt deposits & =ms a %oal or b>4 ,?is %oal may 9 "t ext5d & rise up to ! wat]-level4 ,! curr5t ( ! riv] makes its way ?r\gh x 9 v>i\s directions1 & 9 ?is way a delta is =m$ & con/antly ext5ds seaw>ds4 ,?is flatt5s ! slope ( ! l[] portions ( ! riv]1 & causes rais+ ( ! b$ 9 ! rea*es up/ream1 & ?is aga9 may cause ! wat] to break out fur!r up/ream & =m fre% *annels to ! sea4 ,! b>s at ! m\?s ( deltaic riv]s are g5]ally =m$ ) great rapidity1 & !y are apt to =m a complete h9drance to navigation4 ,!y are sometimes p>tly sc\r$ away by floods 9 ! riv]1 b 9 ?is case ! sc\r$ mat]ial may deposit on ! out] slopes ( ! b>4 ,if a riv] :i* c>ries silt has no delta1 x is probably because !re is a littoral curr5t1 :i* prev5ts ! silt f deposit+4 ,on ! o!r h&1 if a riv] br+s d[n v heavy s$im5t1 a delta may be =m$ ev5 :5 tidal fl[ is n :olly abs5t4 ,?is occurs 9 ! case ( ! ,ganges4 ,! b>s at ! m\?s ( deltaic riv]s _c usually be kept d[n by dr$g+ except at great exp5se4 ,! usual me?od ( deal+ ) !m is to run out two p>allel jetties1 9 cont9uation ( ! riv] banks1 s z to br+ ! m\? ( ! riv] out to ! b>4 ,! riv] !n sc\rs a *annel ?r\gh ! b> &1 if ! walls are n too f> ap>t1 ! dep? w probably become z great z 9 ! riv] & suffici5t = navigation4 ,! riv]1 h[ev]1 t5ds to at once =m a new b> fur!r out4 ,! rapidity ) :i* ! new b> =ms w be great] or less z ! specific gravity ( ! mat]ials c>ri$ by ! riv] is great] or less1 & z ! /r5g? ( any littoral curr5t is less or great]4 ,clay is spread f> out :ile s& quickly s9ks4 ,all deposits are1 h[ev]1 swept away if !re is a /rong littoral curr5t4 ,! /eep] ! slope ( ! b$ ( ! sea away f ! b> ! long] ! new deposit w take 9 =m+ a fre% b>4 ,also ! less ! dis*>ge ( ! riv] ! less ! deposit w be4 ,! bran* ( a deltaic riv] select$ = improvem5t by hav+ ! b> at its m\? remov$1 %\ld be "o :i* has a small dis*>ge & ^: m\? is 9 a position :]e !re is a /rong littoral curr5t4 ,9 ! case ( ! ,rhone1 ! bran* select$ 0 ! ea/]n "o1 ^: m\? 0 n expos$ to any littoral curr5t4 ,moreov]1 ! o!r bran*es ( ! riv] 7 clos$1 & ?is increas$ ! dis*>ge ( ! bran* :i* 0 left op54 ,! "w did n succe$4 ,9 o!r cases1 ! p>allel jetty me?od has succe$$1 & notably 9 ! case ( ! ,mississippi4 ,9 ?is case will[ mattresses weight$ ) /ones 7 us$4 ,! "q ( keep+ d[n ! dis*>ge does n1 h[ev]1 appe> to h always receiv$ suffici5t att5tion4 ,9 ! case ( ! ,mississippi ! 8,s\? pass0 0 select$ = improvem5t4 ,9 ord] to remove a %oal its upp] end 0 n>r[$ & its dis*>ge r$uc$4 ,! upp] ends ( ! o!r 8passes0 7 !n ob/ruct$ s z to re/ore ! dis*>ges ( all ! passes to _! =m] am\nts4 ,! wisdom ( ?is /ep is que/ionable4 ,x is desirable to keep d[n ! dis*>ge ( ! bran* :i* is to be improv$ to ! l[e/ limit consi/5t ) free navigation4 ,if ! wid? ( ! riv] ne> its m\? is great] ?an is desirable = ! wid? betwe5 ! jetties1 ! latt] are sometimes made to conv]ge ?\gh _! out] ends are made p>allel4 ,9 ! case ( ! ,mississippi ! jetties 7 made ) a slight curve to ! "r4 ,x w\ld seem desirable always to make ! jetties ) q a consid]able curve4 ,! jetty :i* 0 convex to ! *annel c\ld !n probably be %ort5$4 ,9 a case :]e !re is a littoral curr5t1 say to ! "r1 ! curve ( ! jetties c\ld be to ! "r1 s t ! /ream on issu+ w\ld t5d to m]ge into ! curr5t & assi/ x4 #b4 ,o!r ,riv]s4--,x (t5 happ5s t ! mat]ials--s&1 gravel1 & %+le--( :i* a sea bea* is compos$ %ift gradually along ! %ore4 ,?is is kn[n z 8littoral drift40 ,x is by "s suppos$ to be due to ! action ( ! tides1 & by o!rs to ! action ( waves1 ! drift tak+ place 9 ! direction ( ! prevail+ w9ds1 exclud+ ^? :i* are (f %ore4 ,! latt] cause is ! m probable4 ,mo/ riv]s h b>s at _! m\?s4 ,9 ! case ( deltaic riv]s ! b>1 z already /at$1 is caus$ by ! heavy silt c>ri$ by ! riv]1 ?\gh x may be assi/$ by littoral drift4 ,9 ! case ( non-deltaic riv]s fl[+ into tideless seas1 ! quantity ( silt is n en\gh to =m a b>1 & ! same is g5]ally true 9 ! case ( tidal riv]s :]e ! volume ( tidal wat] is usually mu* great] ?an t ( ! upl& wat]4 ,9 bo? ^! classes ( riv]s ! =mation ( ! b>s is due *iefly to littoral drift or to s$im5t br\ght 9 by ! sea wat]4 ,! b>1 z 9 ! case ( deltaic riv]s1 may be p>tly sc\r$ away by a flood 9 ! riv]1 & ! sc\r$ mat]ial may deposit on ! seaw>d slope ( ! b>4 ,g5]ally1 ! navigation *annel across a b> ( ?is k9d c be kept suffici5tly deep by dr$g+1 b sometimes jetties1 l ^? m5tion$ 9 ! prec$+ article1 h be5 con/ruct$1 & 9 ?is case !re is ! great advantage t ! b> is n liable to =m fur!r out4 ,if littoral drift t5ds to accumulate1 ! jetties1 or at lea/ ! "o on ! side :5ce ! drift comes1 c be l5g!n$4 ,?is 0 done1 z m5tion$ by ,h>c\rt 7,riv]s & ,canals1 ,,*ap4 ,,ix471 9 ! case ( ! riv]s ,*icago1 ,buffalo1 & ,oswego1 :i* fl[ into ! ,great ,lakes ( ,am]ica4 ,! same writ] /ates t ! jetties at ! ,sw9e m\? ( ! tideless riv] ,od] 7 made to curve to ! left1 ! convex or left-h& jetty be+ ! %ort]1 b t ?is expos$ ! m\? to littoral drift com+ f ! left4 ,! riv]1 up/ream ( ! jetties1 _h a slight curve t[>ds ! left1 b ?is c\ld h be5 correct$ or1 at all ev5ts1 ! jetties made to curve to ! "r4 ,a case 7fig4 #fi7 :]e p>allel jetties 7 rec5tly con/ruct$ 9 a tidal sea is t ( ! m\? ( ! ,ri*mond ,riv]1 ,new ,s\? ,wales 7,m94 ,proc4 ,in/4 ,c4,e41 vol4 clx474 ,illu/ration3 ,,fig4 #fi4 ,9 ! case ( a b> at ! m\? ( an e/u>y1 p>allel jetties w\ld be too f> ap>t4 ,9 su* cases conv]g+ breakwat]s 7fig4 #gj7 are sometimes made1 especially if ! tidal capacity ( ! e/u>y is small4 ,! entrance is g5]ally #ajjj to #bejj feet wide4 ,if made n>r[1 x w\ld r$uce ! tidal fl[ too mu*4 ,! space inside ! breakwat]s adds to ! tidal capacity1 & ?us induces sc\r at ! b>4 ,! case is simil> to t ( ! ,m]sey e/u>y 7,,*ap4 ,,xiv41 ,art4 #e71 ! breakwat]s assi/+ sc\r at ! b>1 ?\gh p]haps slightly int]f]+ ) ! tidal fl[ 9 ! e/u>y4 ,illu/ration3 ,,fig4 #gj4 ,conv]g+ breakwat]s also t5d to /op littoral drift1 & ! space inside !m acts z a h>b\r ( refuge 9 /orms & z a %elt]$ place :]e dr$g]s c "w 7,riv]s & ,canals1 ,,*ap4 ,,xi474 ,!y h to be heavily built & are v exp5sive1 & !y are g5]ally adopt$ only :5 !re is an important seaport1 & :5 !y c be put to all ! uses above indicat$4 ,,app5dix ,a ,fallacies 9 ! ,hydraulics ( ,/reams 7,,*ap4 ,i41 ,art4 #d1 & ,,*ap4 ,,vi41 ,art #b74--;,9 an inundation canal 9 ,india ! supply dur+ floods 0 excessive4 ,ord]s 7 giv5 t a flume be made at ! head1 z %[n 9 fig4 #ga4 ,! sides 7 to be revett$1 z %[n 9 fig4 #ai 7,,*ap4 ,,vi41 ,art4 #c72 ! l5g?1 exclud+ ! splay$ p>ts1 0 to be #bjj feet1 & ! floor 0 to be a mattress well /ak$ or pegg$ d[n4 ,! ord] /at$ t 8by ?is means we _c get into ! canal mu* m ?an its true capacity40 ,) #i feet ( wat]1 a surface fall ( #d in*es 9 #cjj feet w\ld give a velocity ( "s #fe feet p] second1 & a fur!r fall ( ab\t #h in*es w\ld be requir$ at ! head ( ! flume to impress ?is velocity on ! wat]4 ,! flume w\ld r$uce ! dep? ( wat] 9 ! canal by #a foot1 i4e4 f #i feet to #h feet4 ,?is w\ld n be 9 any?+ l ! proportion desir$4 ,moreov] ! flume1 unless ! b$ 0 extremely well protect$1 w\ld be de/roy$4 ,! above is a case ( exagg]at+ ! effect ( an 8ob/ruction40 ,illu/ration3 ,,fig4 #ga4 ,aga91 on a bran* canal x 0 obs]v$ t 8:]ev] cattle cross+s exi/ !re is a deep silt deposit :i* practically blocks ! bran*40 ,! deposit exi/s because ! sides ( ! *annel are worn d[n4 ,a wide place always t5ds to %oal 7,,*ap4 ,,iv41 ,art4 #i74 ,if ! deposit ob/ruct$ ! fl[ ( wat] !re w\ld be a ru% ( wat] pa/ x1 & x c\ld n exi/4 ,! ,gag]a bran* ( ! ,l[] ,*5ab ,canal--! left-h& bran* 9 fig4 #gb--0 f\nd to silt4 ,x 0 propos$ to make a divide wall 7fig4 #gb7 ext5d+ up to full supply level4 ,! idea is un9telligible4 ,! silt does n travel by itself b is c>ri$ or roll$ by ! wat]4 ,z long z wat] ent]$ ! ,gag]a bran*1 silt w\ld g ) x4 ,! au?orities1 :o _h app>5tly accept$ ! proposal1 alt]$ ! e/imate :5 !y receiv$ x1 & ord]$ ! wall to be made z %[n dott$ & ( only half ! height4 ,?is 0 done4 ,! idea seems to h be5 t ! wall w\ld act z a sill & /op roll+ silt4 ,?is is intelligible1 b see ,,*ap4 ,,iv41 ,art4 #b1 la/ p>agraph4 ,moreov]1 !re 0 a l>ge gap1 ,a ,b1 9 ! wall4 ,! "w is said to h prov$ useless1 & proposals h be5 made to cont9ue ! wall f ,a to ,b4 ,9 ?is =m x is conceivable t x may be ( use4 ,illu/ration3 ,,fig4 #gb4 ,9 a riv]1 ! rises & falls at diff]5t places are n1 ( co>se1 ! same1 ev5 :5 !y are long cont9u$4 ,9 ! riv] ,*5ab1 at ! railway bridge at ,%]%ah1 ! rise f l[ wat] to high flood is g5]ally a foot or two m ?an ! rise at a po9t #be miles up/ream4 ,x has be5 sugge/$ t ! railway embankm5ts1 :i* run across ! flood$ area1 cause a head+ up ( ! /ream4 ,if ?is 7 ! case1 to any appreciable ext5t1 !re w\ld be a 8rapid0 ?r\gh ! bridge1 :i*1 if x did n de/roy ! bridge1 w\ld at lea/ be visible & audible4 ,! exagg]at$ ideas :i* (t5 prevail reg>d+ ! t5d5cy ( a riv]1 :5 9 flood1 to sc\r out a new *annel1 h be5 m5tion$ 9 ,,*ap4 ,,iv41 ,art4 #h4 ,spr+1 9 8 pap] on riv] control1 admits1 :5 m5tion+ ,d]a ,ghazi ,khan1 t !re 0 little dang]1 b 9 m5tion+ ! ,*5ab ,bridge at ,%]%ah he quotes1 )\t disput+ x1 an op9ion ( ! opposite k9d 7,gov]nm5t ( ,india ,te*nical ,pap]1 ,no4 #aec1 8,riv] ,tra9+ & ,control on ! ,guide ,bank ,sy/em074 ,= "s o!r fallacies1 see ,hydraulics1 ,,*ap4 ,,vii41 ,arts4 #i & #ae4 ,,app5dix ,b ,pit*+ & ,b$ ,protection 7,,*ap4 ,,vi41 ,art4 #c1 & ,,*ap4 ,x41 ,art4 #b74--;,any sc\r up/ream ( a weir is m]ely due to ! eddies =m$ up/ream ( ! cre/ 7,hydraulics1 ,,*ap4 ,,ii41 ,art4 #g71 & is n s]i\s4 ,&1 simil>ly1 z to sc\r up/ream ( a pi]4 ,a hole =m$ alongside a pi] or ob/ruction1 if !re is no floor1 may "w up/ream4 ,! *ief use ( a floor ext5d+ f> up/ream is to flatt5 ! hydraulic gradi5t 7,,*ap4 ,x41 ,art4 #c74 ,= pit*+ ( ! sides1 monoli?ic concrete is n v suitable1 because x may settle unequally & crack4 ,= heavy pit*+1 concrete blocks c be us$4 ,!y c re/ on a lay] ( #c to #f in*es ( ramm$ balla/ or gravel4 ,! toe wall1 z %[n 9 fig4 #ac1 page #fe1 is sometimes disp5s$ )1 ! pit*+ be+ m]ely cont9u$ to a suitable dep? bel[ ! b$1 & ! bottom edge be+ at "r angles to ! slope in/ead ( horizontal4 ,! portion bel[ ! b$ may be ( concrete4 ,,index ,abrupt *anges 9 /reams1 #bh4 ,alt]ations 9 a *annel1 up/ream effect1 #d4 ,aqu$uct1 ,kali ,nadi1 #adi4 ,available ra9fall1 #i4 ,bank protection1 #fj4 -- -- artificial we$s1 #gj4 -- -- b]ms1 #gj4 -- -- bu%+1 #fh4 -- -- fasc9+1 #ff4 -- -- heavy /one pit*+ ) apron1 #ga4 -- -- on ! ,adige1 #fg4 -- -- re9=c$ concrete1 #gj4 -- -- rolls ( wire-nett+1 #gj1 #adj4 -- -- /ak+1 #fi4 -- -- trees1 #fh4 -- -- twig revetm5t1 #fh4 -- -- ,villa sy/em1 #fi4 ,banks1 #ib4 -- ,bell's guide1 #acg4 -- cont9u\s l9+ (1 #fd4 -- dim5sions (1 #ic4 -- guide1 #acg4 -- side slopes (1 #ib4 ,b>rage ( ! ,nile1 ,assiut1 #aag4 ,b>s1 riv]1 #bjc4 ,b$1 protection (1 #eh4 -- -- ,villa sy/em1 #ei4 ,bell's guide banks1 #acg4 ,b5ds1 effect (1 #dd4 -- %ort cuts (1 #dd4 ,b5gal ,doo>s ,railway1 bridge & floods1 #aci4 ,bifurcation ( a *annel1 #ec4 ,birm+ham wat] supply1 #agc4 ,borr[-pits 9 b$ ( *annel1 #ec4 ,breakwat]s1 conv]g+1 #bjg4 ,bridges1 #acb4 -- f\ndations or floor1 #acb4 -- on ,indian riv]s1 #acd4 -- pi]s & abutm5ts1 #acb4 -- protection (1 #acg4 -- at ,wazirabad1 #acd4 ,briti% ,ra9fall ,organisation1 #i4 ,canalisation ( riv]s1 #hd4 ,canals1 #ib4 -- fall1 #aac4 -- headworks1 #ed4 -- navigation1 #ic4 -- rapid1 #aac4 -- ,%ip1 #ie4 ,cat*m5t area1 8yield10 #i4 ,*annel1 alt]ations 91 #d4 ,*ano9e fall+ %utt]s1 #aba4 ,*5ab ,riv] at ,%]%ah1 #baj4 ,*oice ( types ( "w1 #c4 ,closures ( /reams1 ,colorado ,riv]1 #hj4 -- -- cradle =1 #gh4 -- -- ,ti/a ,riv]1 #ha4 ,collection ( in=mation conc]n+ /reams1 #ah4 ,colorado ,riv]1 closure (1 #hj4 ,conduits1 #ib1 #ajj4 ,cradle = clos+ /reams1 #gh4 ,culv]ts1 #ace4 -- flood+ (1 #acf4 ,dams1 culv]t (1 #ahj4 -- design ( masonry1 #aha4 -- e>!n1 #agd4 -- masonry #aha4 -- -- con/ruction (1 #ahe4 -- -- design1 #aha4 -- -- failures (1 #ahe4 -- -- /resses 91 #ahe4 -- pit*+ (1 #agi4 -- res]voir1 #afb4 -- ,sidhnai ,canal1 #aag4 -- t[] = culv]t1 #ahj4 ,dee e/u>y1 #bja4 ,d]a ,ghazi ,khan1 ,indus at1 #ga4 ,dis*>ge curves1 #bc4 -- obs]vations1 #ba4 -- tables1 #bd4 ,divide wall1 ,gag]a bran* canal1 #bji4 ,dra9age1 #ada4 ,dr$g+ & excavat+1 #hd1 #hh4 ,drift1 littoral1 #bje4 ,eddies1 sc\r+ p[] (1 #bh4 ,embankm5ts1 #aef4 -- design (1 #aeg4 -- ,holl&1 #aei4 -- ,irrawaddy1 #aei4 -- ,rh9e1 #aei4 -- slips 91 #agg4 ,e/u>ies1 ,dee1 #bja4 -- ,m]sey1 #bjb4 -- ,se9e1 #bjj4 -- tidal1 #aig4 ,fall1 canal1 #aac4 ,fallacies 9 hydraulics1 #e4 ,fall+ %utt]s1 ,*ano9e1 #aba4 -- -- ,f\racres1 #aba4 -- -- ,khanki1 #abd4 -- -- ,?n>d's1 #aba4 ,flood dis*>ge1 e/imat+1 #adh4 ,floods1 #ada1 #adf4 -- ,b5gal ,doo>s ,railway1 #aci4 -- =mul =1 #adg4 -- pr$iction1 #aej4 -- prev5tion1 #aec4 ,fl[+ /ream1 closure (1 #ge4 ,=d 9 a riv]1 #dc4 ,=e/s & vegetation1 influ5ce (1 on ra9fall1 #ad4 ,=mul = floods1 #adg4 ,groynes or spurs1 #eh1 #fj1 #fa4 -- on ! ,indus1 #ec4 ,guide banks1 #acg4 ,headworks ( a canal1 #ed4 ,holl&1 embankm5ts1 #aei4 ,hurdle dykes1 #gi4 ,hydraulics ( op5 /reams1 #d4 -- -- fallacies 91 #bji4 ,important works1 precautions at1 #acj4 ,indian riv]s & bridges1 #acd4 ,indus1 groynes on1 #ec4 ,in=mation conc]n+ /reams1 collection (1 #ah4 ,inundation canal1 flume 91 #bji4 ,irrawaddy1 embankm5ts1 #aei4 ,irrigation *annels 9 embankm5t1 #eb4 ,irwell1 weir on1 #abd4 ,jetties1 9 cont9uation ( riv] banks1 #bjd4 -- ,mississippi1 #bje4 -- ,ri*mond ,riv]1 ,new ,s\? ,wales1 #bjf4 ,kali ,nadi1 aqu$uct1 #adi4 ,khanki1 fall+ %utt]s at1 #abd4 ,leakage1 /oppage (1 #gh4 ,lockage1 #ih4 ,locks1 #if4 -- 9 flights1 #ih4 ,m]sey e/u>y1 #bjb4 ,mississippi jetties1 #dh4 ,n>ora weir1 #aji4 ,navigation canals1 #ic4 ,ne$les1 regulator1 #aag4 ,new ,s\? ,wales1 available ra9fall1 #ab4 ,ob/ruction1 effect (1 #e4 ,ob/ructions 9 /reams1 #bh4 ,okla weir1 #aab4 ,op5 /reams1 hydraulics (1 #d4 ,p]i%able mat]ials1 use (1 #d4 ,p]man5t rgime ( /reams1 #bi4 ,pit*+1 #fd4 ,pr$iction ( floods1 #aej4 ,prev5tion ( floods1 #aec4 ,protection ( banks 7see ,bank protection74 ,ra9fall1 #f4 -- available1 #i1 #bf4 -- -- ,new ,s\? ,wales1 #i4 -- -- ,sudbury ,riv]1 ,massa*usetts1 #ab4 -- -- v>i\s c\ntries1 #aa4 -- ,briti% ,organisation1 #i4 -- 8cat*m5t area10 8bas910 #i4 -- di/ribution (1 #g4 -- drie/ ye>1 #g4 -- evaporation1 #i4 -- heavy falls 9 %ort p]iods1 #ae4 -- influ5ce ( cultivation1 #ae4 -- -- ( =e/s & vegetation1 #ad4 -- local figures1 #h4 -- measurem5t (1 #ac4 -- obs]vations1 p]iod (1 #g4 -- /ati/ics1 #f4 -- v>iation (1 #f4 ,ra9-gauge1 #h1 #ac4 ,rapid1 canal1 #aac4 ,regulators1 #aah4 ,res]voirs1 #afb4 -- capacity1 #afg4 -- comp5sation wat]1 #afb4 -- leakage1 #afc4 -- wa/e weir1 #afd4 ,rsum ( ! subject1 #a4 ,rh9e1 embankm5ts1 #aei4 ,ri*mond riv]1 jetties1 #bjf4 -- weir at1 #aai4 ,riv] b>s1 #bjc4 -- tra9+ groynes1 #he4 -- -- walls1 #he4 ,riv]s1 deltaic1 #bjc4 -- floods 91 #adf4 -- non-deltaic1 #bje4 -- tidal1 #aib4 -- tra9+ & canalisation1 #hd1 #hi4 ,run-(f 9 small /reams1 #adc4 ,salt wat]1 effect (1 #bi4 ,s& sep>ator1 #cd4 ,s&banks1 #dg4 ,sc\r 7see ,silt & sc\r74 ,se9e e/u>y1 #bjj4 ,set ( /ream1 effect (1 #e4 ,%ip canals1 #ie4 ,%utt]s1 self-act+1 ,switz]l& & ,bav>ia1 #abg4 ,silt+ & sc\r+1 #bg4 ,silt & sc\r1 action at b5ds1 #db4 -- -- -- on sides ( *annel1 #dj4 -- -- effect ( regulator or movable weir1 #di4 -- -- 9 ! ,sirh9d ,canal1 #cb1 #ed4 -- -- increas+ or r$uc+1 #dh4 -- -- mat]ials c>ri$ 9 susp5sion1 #c4 -- -- me?ods ( inve/igation1 #cc4 -- -- practical =mul & figures1 #cg4 -- -- production (1 #dh4 -- -- roll$ mat]ials1 #bi4 -- -- s& sep>ator1 #cd4 -- -- scrap]s or h>r[s1 #dh4 -- clay & s&1 #cf4 -- deposit1 production (1 #ea4 -- 9 riv] ,sutlej1 #ce4 -- 9 riv] ,tay1 #ce4 -- quantity & di/ribution (1 #ce4 -- up/ream ( weirs1 #ajc4 ,sidhnai ,canal1 dam1 #aag4 ,sirh9d ,canal1 silt & sc\r 91 #cb1 #ed4 ,slips 9 embankm5ts1 #agg4 ,sluice gates1 ,/oney's1 #aai4 ,sluices1 #ajb4 ,small /reams1 floods 91 #ada4 ,s\nd+s1 #ba4 ,spurs or groynes1 #eh1 #fj1 #fa4 ,/ream gauges1 #ai4 -- div]sions (1 #gc4 -- g5]al t5d5cies (1 #de4 -- in=mation conc]n+ int]mitt5t1 #be4 -- -- -- small1 #bd1 #be4 -- ov]fl[1 #df4 -- %ift+1 #bj1 #dg4 ,sudbury ,riv]1 ,massa*usetts1 available ra9fall1 #ab4 ,surface slope obs]vations1 #bb4 ,survey ( a /ream1 #ba4 ,sutlej ,riv]1 silt 91 #ce4 ,syphons1 #acb1 #ace4 ,tay ,riv]1 silt 91 #ce4 ,t$d+ton1 weir at1 #aai4 ,tidal e/u>ies1 works 91 #aih4 -- riv]1 diagrammatic r\te-guide1 #aif4 -- riv]s1 #aib4 -- works 91 #aif4 ,tide-gauges1 #aib4 ,tides1 #aij4 ,ti/a ,riv]1 closure (1 #ha4 ,tra9+ ( riv]s1 #hd4 ,types ( "w1 *oice (1 #c4 ,upp] ,jhelum ,canal1 syphons to c>ry torr5ts1 #add4 ,velocities :i* enable a /ream to sc\r1 #dj4 ,villa sy/em ( bank protection1 #fi4 -- -- b$ protection1 #ei4 ,wa/e weir1 hydraulic problem1 #afe4 ,wat] supply1 ,birm+ham1 #agc4 ,wat]way1 area (1 9 regulators1 #abi4 ,wave1 travel (1 d[n a /ream1 #aeb4 ,waves1 effect (1 #bi4 ,wazirabad1 bridge at1 #acd4 ,we$s1 artificial1 #gj4 -- gr[? (1 #bi4 ,weirs1 #ajb4 -- adju/able1 #abf4 -- ,be> ,trap1 #abc4 -- drum1 #abg4 -- frame1 #abj4 -- g5]al design (1 #aje4 -- ,n>ora1 #aji4 -- oblique1 #ajc4 -- ,okla1 #aab4 -- on s&y or por\s soil1 #ajf4 -- ,ri*mond1 #aai4 -- silt deposit1 up/ream (1 #ajc4 -- types (1 #aaa4 -- wa/e1 #afd4 -- ) sluices1 #aae4 ,wire-nett+ = bank protection1 #gj1 #adj4 ,works1 design & execution (1 #c4 ,zifta ,regulator1 #aji4 ,,pr9t$ ,,by ,,neill ,,& ,,co41 ,,ltd41 ,,ed9burgh4 ,,footnotes3 #a ,m94 ,proc4 ,in/4 ,c4,e4 #b ,eng9e]+ ,news4 #c ,encyclopdia ,britannica4 #d ,! pap] by ,spr+--9 size x is a book--w repay p]usal by eng9e]s engag$ on railway bridges ov] l>ge %ift+ riv]s4 ,london ,ag5ts1 ,con/able ,co4 #e ,hydraulics ) ,work+ ,tables4 ,spon1 #aiab4 #f ,irrigation canals are dealt ) 9 ,irrigation ,works 7,spon1 #aiac74 #g ,see also ,app5dix ,a4 #h ,! regulator runs across ! canal head2 ! "u-sluices are a cont9uation ( ! weir1 betwe5 ! divide wall & ! regulator4 #i ,see also ,app5dix ,b4 #aj ,on ,indian canals ! t]m 8regulation0 is appli$ to ! control ( ! dis*>ge at ! regulators or (f-take works4 #aa ,see also ,app5dix ,b4 #ab ,irrigation ,works1 ,,*ap4 ,i41 ,art4 #d4 #ac ,m94 ,proc4 ,in/4 ,c4,e41 vols4 lx4 & lxxxv4 #ad ,riv]s & ,canals1 ,h>c\rt4 #ae ,riv]s & ,canals1 ,h>c\rt4 #af ,riv]s & ,canals1 ,h>c\rt4 #ag ,! f\ndations ( pi]s & abutm5ts %\ld be deep en\gh to all[ ( ?is4 #ah ,report on ! ,revis$ ,e/imate1 ,upp] ,jhelum ,canal4 #ai ,revis$ ,e/imate ( ! ,upp] ,jhelum1 ,upp] ,*5ab1 & ,l[] ,b>i ,doab ,canals4 #bj ,see also ,note on p4 #afa4 #ba ,! height ( a wave is suppos$ to be #ad7;fet*71 b ?is all[s no?+ = spla%+4 ,transcrib]'s ,note3 ,obvi\s pr9t] errors correct$ sil5tly4 ,inconsi/5t spell+ & hyph5ation are z 9 ! orig9al4