Works of Thomas Downloads in Dams Reservoirs-Ingles

8/20/2019 Works of Thomas Downloads in Dams Reservoirs-Ingles

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WORKS OF THOMAS DOWNLOADS IN DAMSRESERVOIRS

1. INTRODUCTION

The water reservoir of a dam is released thro!h two mai" t#$es of str%tres&

• Landfills: To 'e $rovided for stora!e a"d dete"tio" dams to release e(%ess water or floodi"!

that %a" "ot 'e %o"tai"ed i" allo%ated stora!e s$a%e) a"d diversio" dams for the derivatio" ofhi!her flows to the %o"verted i" the '#$ass s#stem*

• Intake Works: The# re!late or release water im$o"ded '# a dam* +o %a" free i"flows

slowed to a $a%e) li,e a dam of dete"tio"- +o %a" divert i"%omi"! flows i" %ha""els or

$i$es) as well as a diversio" dam- or water %a" 'e stored i" release rates im$osed '# the"eeds of dow"stream %o"sideratio"s eva%atio") or a %om'i"atio" of mlti.$r$osere/ireme"ts*


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The headwor,s %o"sist of a %om'i"atio" of featres 0ie) ma,i"! str%tres) tra"s$ort%hara%teristi%s) s%h as d%ts) %o"trol str%tres) et%*1 a"d o$eratio" 0ele%tri%al a"dme%ha"i%al1 e/i$me"t re/ired for the o$eratio" a"d %o"trol safet# of water released from areservoir to meet dow"stream re/ireme"ts* The wor,s of shots serves several $r$oses)s%h as flow %o"trol a"d water /alit#) the release of flood water) $ower !e"eratio")

emer!e"%# eva%atio") a"d $rovide irri!atio" a"d i"dstrial water* 2hara%teristi%s of theheadwor,s are illstrated i" the followi"! fi!re&

Example: Combination of outlet: works penstock tunnel and energy, highlighting a number of features such as intake

structure upstream and downstream from the structures. Theodore Roosevelt am, !ri"ona.

2.-WORKS OF TO!"S IN STOR"#$ D"!S

Dow"loads i"ta,es are so %alled 'e%ase the# release water ot of the reservoir* Some of these are

e/i$$ed with a" i"ta,e str%tre if water feeds a %ha""el or %o"dit for a"# s$e%ifi% $r$ose asservi"! the "eeds of irri!atio" or h#dro$ower !e"eratio") et%*

Sometimes dis%har!e otlets %a" 'e $la%ed at a hi!h e"o!h level to s$$l# water to a %ha""el)

while a referral to the river %o"ti"es to $rovide "e%essar# flows 'elow the dam) flows S%h

derivatives ma# 'e re/ired to meet $rior ses sed dow"stream or to mai"tai" a" e%olo!i%al flow for

the $reservatio" of a/ati% life) or for other $r$oses* Dams are 'ilt $rimaril# to store water a"d also

for re%reatio" or for 'reedi"! fish a"d wildlife %o"servatio" re/ires fairl# %o"sta"t level reservoir* For

s%h a $ower dams dow"load ma# 'e "e%essar# to release o"l# the mi"imm flow "e%essar# to

mai"tai" the e%olo!i%al flow 'elow the dam* I" some %ases) dis%har!e otlets $re# are sed i"stead

of a servi%e s$illwa# %om'i"ed with a"%illar# or se%o"dar# s$illwa#* I" this %ase) the sal ma,i"!

i"stallatio" dow"load %old 'e modified to i"%lde a '#$ass flows sr$ls so that the str%tre %a"serve as 'oth the dis%har!e otlet a"d s$illwa#

A dis%har!e $ort %a" a%t as a re!lator of flood %o"trol to release the water tem$oraril# stored i" the

stora!e or flood %o"trol to e(hast a reservoir stora!e i" a"ti%i$atio" of the i"fl( of flood* I" additio")

sam$les %a" 'e sed to em$t# the ta", for i"s$e%tio" to allow "e%essar# re$airs) or to ,ee$ the


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$stream fa%e of the dam a"d other str%tres "ormall# flooded* The shots ma# also hel$ lower

stora!e ta", if desired to %o"trol the "a%%e$ta'le a/ati% life i" the reservoir* Sometimes) the

reservoirs are lowered a"d raised i" a se/e"%e to %o"trol the threat of malaria

%. O&'$CTI($S:

The !oal of a dis%har!e de%isio" is to ma,e %o"trolled release reservoir water stored 'ehi"d the dam*The dis%har!e $ort is a" i"ta,e str%tre havi"! o$e"i"!s at differe"t hei!hts valve that allows waterto flow i" reservoir str%tre to a sele%ted flow rate* The water the" flows dow" to the tower i"let a"da" otlet %o"dit thro!h the 'ottom of the 'a%, dam i" a river or %a"al*The mai" $r$ose of a" i"ta,e is to e"a'le a"d %o"trol the e(tra%tio" of stored water i" the dam i" a"

amo"t a"d whe" re/ired* The headwor,s mst 'e a'le to ot$t the water e($e"ses de$e"d o" the "eeds dow"stream of thedam- i" the %ase of a re!lati"! dam) #o %a" leave ot the %o"tri'tio"s of a !radal


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). FUNCTIONS OF DISC"R#$ T"K$S ON R$S$R(OIR D"!S


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The type and design of an intake easier to be strongly inuenced by the

project, its objectives and functions of specic structures. It is absolutely

necessary assessment of each function in any design structure selected.

a) Flood control. An intake for ood control projects usually reuire

designs !ith large o! capacities and less regulation capacity.

"sually, the discharges are performed by gates to regulate o!.#o!ever, the ducts may be uncontrolled $no doors) by vacuum

reservoirs that are not ooded or lo! during periods.

b) Irrigation. %ates and valves for irrigation reuires close regulation

and lo!er ranges controls discharge outlet !orks discharge the ood

control. The releases can be do!nloaded in a channel or conduit

instead of the original riverbed.

c) Water s*++l,. Ti%,ets m"i%i$al water s$$l# are !e"erall# a f"%tio" of se%o"dar# $ro3e%t*

Relia'ilit# a"d water /alit# are im$orta"t i" the desi!"* The h#dra"ts are lo%ated a"d

%o"trolled to e"sre that water is free of silt a"d al!ae) to o'tai" desired tem$eratres a"d to

allow %lea"i"! of e"tr#*

d) $ner,. 4ates of $ower withi" i"ta,e str%tres shold 'e lo%ated so that "o "desira'le

flow %o"ditio" i"$ts s%h as swirls that %old im$air the o$eratio" of the tr'i"e does "ot

o%%r* E"er!# i"ta,e o$e"i"!s ma# re/ire smaller !rids to limit the si5e of the waste that

e"ters the $e"sto%,*


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e) Te sedi/ents. 6ro3e%ts desi!"ed for the rete"tio" of sedime"ts mst 'e desi!"ed to $ass

flows a"d the level of sedime"t reservoir level rises a"d to $reve"t sedime"t from $assi"!thro!h the e"tries a"d is harmfl or 'lo%, 'oth i"$t a"d ot$t itself * Mi"or dis%har!es are

%o"trolled '# wor,s mltilevel otlets are %losed '# !ate or sto$ re%ords as the level of

sedime"t i" the ta", rises*

0. $L$!$NTS OF WORKS OF !"KIN#

A dis%har!e $ort mai"l# has the followi"! eleme"ts or %o"stite"t $arts&

0.1.-entr, str*t*re.

This t#$e of str%tre ma# 'e !rit %ham'ers) ve"ts) holes i"%ldi"!&

4rids& 4rids are "eeded to $reve"t dama!e a"d de'ris %lo!!i"! the %o"trol !ates a"d tr'i"eot$t* The !rid si5e a"d t#$e of the o$e"i"!s de$e"d o" the $ool elevatio") elevatio" of

admissio") the si5e of the otlet d%t) !ar'a!e de$osit %o"ditio"s) the t#$e of %o"trol devi%e

sed) water se a"d the "eed to e(%lde the trash*


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0.2.-Driin Works

Drivi"! wor,s are the str%tres that %arr# water to the dow"stream of the i"ta,e* The# %a" 'e

%lassified i"to&

O$e" %ha""els

'ried d%ts

TUNN$L &7# its i"here"t adva"ta!es) t""el dow"load a $ower wor,s is $referred that the%o"ditio"s of the $illars a"d fo"datio" $ermit its se a"d is %hea$er tha" other t#$es of

otlet wor,s* A t""el is "ot i" dire%t %o"ta%t with the em'a",me"t dam a"d) therefore)

$rovides a m%h safer a"d more dra'le desi!" that %a" 'e a%hieved with a $i$e %tter a"d

%over* A little seated fo"datio") differe"tial moveme"t) a"d str%tral dis$la%eme"ts is

e($erie"%ed with a t""el drilled thro!h the material of %om$ete"t s$$ort) a"d filteri"!

alo"! the oter srfa%es of t""el li"i"! or lea,s i" the material srro"di"! the t""el is less

severe* It is also less li,el# that the failre of some $ortio" of a t""el wold %ase the failre

of the dam failre %t a d%t a"d the %over that !oes "der or thro!h the dam*


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CUTTIN# "ND DUCT CO($R: If a %losed %o"dit mst 'e !ro"ded a"d $rovided their

%o"ditio"s are "ot sita'le for a t""el) or if the re/ired si5e of the waterwa# is too small to


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3stif# the mi"imm si5e of the t""el) a %t a"d %over d%ts mstIt is sed* 7e%ase this

t#$e of d%t $asses thro!h or "der the dam) #o shold se %o"servative a"d safer

desi!"s* Nmeros failres earth fill dam otlet d%ts %ased '# %t a"d %over wro"!l#

desi!"ed or 'ilt have demo"strated the "eed for %o"servative $ro%edres

0.%.-Re*lator, /eanis/ and e/eren,.

Devi%e sele%tio" otlet wor,s mst 'e 'ased o" the se of relativel# sim$le desi!"s !ates

a"d !ate where $ossi'le or %ommer%iall# availa'le valves* The se of s$e%ial devi%es that

i"volve e($e"sive desi!" a"d ma"fa%tri"! %osts shold 'e avoided* 2ast iro" slidi"!

doors) whi%h %a" 'e sed to %o"trol !ates a"d srveilla"%e) are availa'le for 'oth re%ta"!lar

a"d %ir%lar o$e"i"!s a"d to the heads of desi!" to a'ot 89 meters* However) s$erior

fa%ilities re/ire s$e%ial desi!"s head !ate* Sim$le radial !ates are availa'le for %ommo"

srfa%e fa%ilities) a"d radial.seal !ates %a" 'e assred of to$ ma"fa%trers o" the 'asis of

sim$le desi!"s a"d s$e%ifi%atio"s* For low heads $ to a'ot 89 meters) !ate valves a"d

%ommer%ial 'tterfl# the# are sita'le for %o"trolli"! the dow"stream e"d of the $ressret'es if the# are desi!"ed to o$erate "der free dow"load with the 3et well ve"tilated all

aro"d* 4ate a"d 'tterfl# valves are also sita'le for se as !ard li"e valves a"d %a" 'e

ada$ted to %o"trol valves o"li"e if air ve"tilatio" a"d ade/ate aeratio" dis%har!e stream is

$rovided immediatel# dow"stream of the valve*The %o"trol !ate for a" otlet wor,s %a" 'e $la%ed o" the $stream e"d of the %o"dit) at a"

i"termediate $oi"t alo"! its le"!th) or at the lower e"d of the str%tre* Where the flow of a

%o"trol !ate is released dire%tl# i"to the o$e" so free dow"load) o"l# the $ortio" a'ove water


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d%t dam$er is "der $ressre* Wherei" a %o"trol !ate or valve at the lower e"d of the

str%tre is $la%ed) the i"ter"al total $ressre shold 'e %o"sidered i" desi!"i"! the t""el

%o"dit or $i$e* However) whe" a %o"trol d%t dis%har!i"! i"to a free flow) the lo%atio" of the

%o"trol !ate 'e%omes im$orta"t i" the desi!" of the ot$t* 4ate %o"trols $stream d%t are

sall# $la%ed o" a tower str%tre with !ate elevators mo"ted o" the de%, of o$eratio"

0Fi!re :1* With this arra"!eme"t) the tower mst e(te"d a'ove the srfa%e of waterma(imm* If the %o"trols are lo%ated at some i"termediate $oi"t alo"! the d%t) hi!h

$ressre !ates slidi"!) seali"! a"d radial !ates at the to$ %a" 'e sed* These %o"trols ma#

'e lo%ated o" a" a(is wet a"d e(te"di"! verti%all# from the level of the d%t to the to$ of the

dam* T#$i%al arra"!eme"ts of these fa%ilities are show" i" Fi!res 8 to ;*


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0.).-Deies for dissi+ation of ener,.

Dow"loadi"! to a" ot$t) either a !ate valve or free flow d%t) arise at hi!h s$eed) sall# i" a"

almost hori5o"tal dire%tio"* If there 'ed erosio".resista"t ro%, at shallow de$th) the flow %a" 'e

dow"loaded dire%tl# i"to the river* Otherwise) it mst 'e dire%ted awa# from the ti$ of the dam '# a

defle%tor* Where erosio" mst 'e mi"imi5ed) immersio" 'asi" %a" 'e e(%avated a"d li"ed with ri$ra$

or %o"%rete* Whe" it ta,es more e"er!# dissi$atio" for free flow d%ts) #o %a" se the termi"al

str%tres des%ri'ed for s$illwa#s* The h#drali% 3m$ 'asi" are most ofte" sed to dissi$ate the

e"er!# of the otlet wor,s dis%har!es* However) the flow emer!i"! from the otlet as a free 3et) s%h

as %o"trolled release $ressre d%t valve shold 'e dire%ted to the tra%, tra"sitio" a$$roa%hes 'asi"

so 'e%ome eve"l# distri'ted 'efore e"teri"! the 'asi"* Otherwise) a$$ro$riate e"er!# dissi$atio" is

"ot o'tai"ed*

3. !"KIN# WORKS TROU# CONCR$T$ D"!S


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I" the %ase of %o"%rete dams) the irri!atio" i"let str%tre %a" 'e lo%ated i" the foot whe" the

o$erati"! head is low or i" the 'od# of the dam itself whe" the o$erati"! head is medim or hi!h*

T#$i%al i"$t se%tio" i" the fi!re 'elow

Whe" a" i"ta,e i" a !ravit# dam is 'ilt) %ommo"l# the# $la%ed thro!h the %o"%rete se%tio") alo"!

hori5o"tal li"es or slo$i"! dow"stream) i" order that the e"er!# !radie"t at a"# time i"terse%ts the a(is

d%t*


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D%ts thro!h the 'od# of a %o"%rete %rtai" "ormall# are of %ir%lar %ross.se%tio") it ma# 'e re/ired i"

some %ases re%ta"!lar se%tio" for the i"stallatio" of %ertai" t#$es of valves or !ates) so if this is

"e%essar#) it shall 'e $rovided 'ildi"! tra"sitio"s* D%ts for dow"loads with low level i" the dam %a" 'e

'ilt with o"l# the hole i" the %o"%rete) "ot whe" the level te"ds to NAME) ie hi!h loads) i" whi%h %ase

%oati"! is re/ired steel $late over its e"tire le"!th *

3.1.-#eo/etri Desin of onrete da/s sots.

I" the !ravit# dams) t#$i%al i"stallatio"s of the headwor,s are show" i" the followi"! fi!re show" 'elow)

i" the headwor,s is hosed i" the 'od# of the %rtai" whi%h %o"sists of&

A %alli"! %ha""el) whi%h %o""e%ts the stored water from the dam to the i"ta,e str%tre) its %o"str%tio"

de$e"ds o" the threshold elevatio" of the i"ta,e*

I" setti"! $ the water %rtai" s$$orti"! str%tre of the $rote%tive !rilles lo%ated i"side whi%h are

hosed slide !ates) whi%h are o$erated from the %row" of the %rtai"- d%ts sall# wor, $ressre) 'e!i"

i" this str%tre a%ross the 'od# of the %rtai"- the e"d of the d%ts is the e"er!# dissi$ati"! str%tre or%o"%e"trator a"d ma# eve" start


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4. !"KIN# WORKS TROU# $"RT D"!S "ND ROCKFILL OR #ROUND

Whe" the reservoir is formed '# a" earthe" dam) the irri!atio" t""el $la%ed "der"eath it or o" the

$illar* Ma,i"! str%tre for s%h sitatio"s will 'e a de%isio" or i"%li"ed tower t#$e i"ta,e* T#$i%al

desi!"s for i"%li"ed tower shots a"d t#$e are show" i" the followi"! fi!res res$e%tivel#*


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The wor,s of ta,i"! %o"%rete %o"dit i" shades of earth or earth.ro%,fill mst desi!" a"d 'ild o" the

srfa%e of rde"ess) i" 'edro%,) or tre"%h d! o" firm !ro"d* All wor, mst 'e !ro"ded otlet

'elow the srfa%e of the dam a"d rde"ess i" la"dfills where it %a" "ot 'e dama!ed '# differe"tial

settleme"t of the la"d*

I" hi!h %rtai"s it is a$$ro$riate for ma,i"! d%ts remai" !ro"ded i" solid ro%,- i" these) it is

%ommo" for !ates or emer!e"%# valves remai" lo%ated i" %ham'ers or verti%al shots that mat%h the

a(is of the %rtai") to elimi"ate the "eed to 'ild towers too hi!h ta,es the foot of the slo$e $stream

a"d 'rid!es A%%ess to the %o"trol room*

Valves or dam$ers are i"stalled i" the dow"stream e"d of the emer!e"%#) with the $ossi'ilit# of

i"%ldi"! e"er!# dissi$ati"! devi%es o" dis%har!e* The sha$e of the se%tio" li"es are sed mostl#

%ir%lar a"d horseshoe* Re!ardi"! low %rtai"s) ma,i"! fo"datio"s i" soft !ro"d a%%e$ted after

i"vesti!atio"s stre"!th* With re!ard to $riso"ers of !raded materials) it is $ossi'le that the

%o"str%tio" of the i"ta,e t""el.sha$ed 'od# sta# lod!ed i" the shade or o" the hillside* The mai"


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$arts of a wall i" dam !raded materials are as show" i" Fi!res i"%lde&

The a%%ess %ha""el) with its wor,for%e to the threshold elevatio" of the shot) the !atehose) where the

!rilles) !ates a"d servi%e o$eratio") e/i$$ed with its lifti"! devi%es are hosed*

The headwor,s thro!h t""els o" the slo$es of the reservoir) sall# the most %o"ve"ie"t i" shades of

earth) earth.ro%,fill a"d thi" ar%s) whe" the dis%har!e rate is %o"sidera'le) however) %a" 'e %om'i"ed


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with a"# t#$e of $re# whe" slo$es are formed '# 'edro%,* The se of diversio" str%tre 0se of t""els1

to desi!" de%isio" allows for low.%ost desi!"s*

I" the fi!res 'elow) we see&

The t""el ma,i"!) fo"ded o" stro"! slo$es*

The hose a"d $oi"ts of o$eratio" of !ates a"d valves* emer!e"%# !ates a"d re!lator# or servi%e* emer!e"%# valves a"d %o"trol or servi%e*


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4.1#eo/etri desin 5orks takes earten da/ and rokfill.

The %o"dit ma# 'e formed '# o"e or more 'odies of re%ta"!lar %ross se%tio") %ir%lar or horseshoe*

The ot$t tra"sitio" to !radall# 3oi" the d%t se%tio" with the dis%har!e start* The !eometri% form

de$e"ds o" the $arti%lar %ase i" /estio"*

Dissi$ati"! e"er!# str%tre) whi%h aims to red%e the e"er!# that draws water ot of the %a"al*

The ot$t %ha""el '# whi%h water is led to its se*

The a%%ess 'rid!e) whi%h is esse"tial for %omm"i%atio" 'etwee" the %row" of the !atehose a"d lifti"!

!ear to o$erate the !ates*

I" the wor,s of ta,i"! awa# the 'od# of the %rtai" is !reater safet# i" its %o"str%tio" that d! i"to the

hillside* A" e(am$le of this t#$e of headwor,s is $rese"ted i" the illstratio" 'elow)* I" the first fi!re the

i"ta,e %o"sists of a !rid str%tre where the %o"d%tio" thro!h the 'od# of the %rtai" 'e!i"s) drivi"!

thro!h a steel $i$e wor,i"! $ressre) 3a%,eted a"d $rovided %o"%rete $rese"ts de"tello"es ste$ to

red%e the lea,s* Dow"stream e"d of the $i$e) has a" emer!e"%# valve a"d a %he%, valve o$eratio" todow"load a %o"%e"trator 'o( from whi%h drivi"! starts*

A"other e(am$le of a" i"ta,e hillside a"d i"%reased s$e"di"! i" the $revios %ase we have i" the

followi"! fi!re* I" this t#$e of wor, ta,es) the d%t wor,s as a %ha""el) that is) #o have freedom of

moveme"t a"d the %o"dit is hosed i" a dit%h) whi%h o"%e 'ilt the %a"al is filled with the same


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water$roof material sed i" %rtai") es$e%iall# %om$a%ted form to avoid t'ifi%a%io"es i" %o"ta%t with the

t'e*

As a" additio"al se s%h t""els to 'e 'ilt i" some of them the i"ta,e %o"sisti"! of a tower that

re%eives the $rote%tio" !rids) where he 'e!a" drivi"! i" a t""el wor,i"! "der $ressre* O" the site

where the a(is of the shaft short %rtai" drivi"! swit%hi"! from o"e %ha""el to wor, to free srfa%e a"d

e($e"ditre %o"trol is !ai"ed thro!h slidi"! doors lo%ated o" a $ort* At the e"d of the %o"dit it has a

'ffer str%tre a"d starts drivi"!


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6. STRUCTUR$ OF $NTR7

I"$t str%tres) form a ma3or $art of the eleme"ts of wor,s of dis%har!e) a"d %o"sist $rimaril# of a

%om'i"atio" of !rids a"d %o"trol !ates a"d !rilles*

De$e"di"! o" the $arti%lar desi!" at ea%h dam) the i"ta,e wor,s mst %orres$o"d to the %o"ditio"sof fo"datio") o$erati"! loads re/ired dow"load) variatio"s i" water levels of reservoirs a"d amo"t

of floati"! solids that %a" tra$ the e(it*

6.1.-#rid

The s%ree"s ,ee$ traili"! solids stream e"teri"! the water i"ta,e) avoidi"! $ro'lems s%h as valves

affe%t me%ha"isms a"d !ates lo%ated dow"stream* The !rids a"d si5e of the o$e"i"!s de$e"d o" the

t#$e of de$osit elevatio") elevatio" i"ta,e d%t si5e ot$t) trash de$ositio" %o"ditio"s) the t#$e of%o"trol devi%e sed) water se) a"d the "eed to e(%lde !ar'a!e* The followi"! im$orta"t $oi"ts

a'ot the se of the !rids a"d the t#$e of it is*

3a%,s flow re!latio"* A sim$le str%tre trash) sall# of rei"for%ed %o"%rete) with %lear

hori5o"tal a"d verti%al o$e"i"!s "ot more tha" two thirds of the width of the door shold 'e

$rovided at the $stream e"d of the otlet wor,s to tra$ trees a"d other lar!e !ar'a!e %a" at

the e"tra"%e a"d 'e a'le to 'lo%, the %losed $assa!es* Lar!e i" the t""el waste o%%rs

most ofte" whe" a $erma"e"t $ool is o"l# sli!htl# a'ove the e"tr# if the $erma"e"t

%o"sortim is well a'ove the e"tra"%e* O"l# i" s$e%ial %ases where trees a"d floati"! de'ris

are a'se"t i" the reservoir a"d watershed shold 'e omitted !ar'a!e str%tre* %losel# s$a%ed metal !rids of 'ars are !e"erall# sed for small d%ts with %o"trol valves

a"d ma,i"! water s$$l# whi%h re/ire the dete%tio" of small de'ris* To fa%ilitate removal of trash immediatel# after a flood) the wor, $latform o" to$ for ra,i"!

a"d dis$osal of waste shold !e"erall# "ot 'e lower tha" the elevatio" of the to$ of

%o"servatio" $ool or ma(imm $ower* The sal !ar'a!e str%tre %o"sists of verti%al

'eams) sli!htl# i"%li"ed dow"stream from the verti%al to $rovide ra,e a"d hori5o"tal 'eams* The area of the o$e"i"!s i" the str%tre of the !ar'a!e shold limit the lo%al area "et

rate of less tha" 8< to 89 feet = se%*

The eleme"ts of a !rid are mai"l# iro" sla's) 'eams s$$orted o" %o"%rete or str%tral steel 'eams*

S%reeds are sall# 8 to > %m wide '# 9 to 89 %m) with s$a%i"! of 9 to 89 %m %e"ter to %e"ter

0de$e"di"! o" the si5e of the me%ha"isms are i"stalled 'elow water1) a"d a total si5e L whi%h %a"

rea%h 9 m) de$e"di"! o" the $arti%lar %ir%msta"%es of ea%h %ase*


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6.2.-#ates


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A h#drali% dam$er is a h#drali%.me%ha"i%al devi%e desi!"ed to re!late the flow of water or other

flid i" a $i$e i" a %a"al) dams) sli%es) diversio" wor,s or other h#drali% str%tre*

(ertial #ate&Similar to that sed for doors rid!e t#$e) 't sall# dee$ e"d as the flow %o"trol i"ta,e

h#dro$ower) whether those wheels rolli"!) or slidi"! . withot a"# wheels are sed *

Radial 4ate& The radial !ates) also %alled Tai"tor !ates) i" ho"or of a %a$tai") who was its%reator) have the sha$e of a %#li"der $ortio") a"d rotate or $ivot aro"d a hori5o"tal a(is

lo%ated i" the lo"!itdi"al a(is the %#li"dri%al srfa%e* 7# the wa#) sometimes the# are %alled

!ate se%tor* See Fi!re


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4e"erall#) i" the radial !ates water a%ts o" the %o"ve( side a"d) de to h#drostati% $ro$erties of a

%#li"dri%al srfa%e) the a%tio" li"e the reslti"! h#drostati% thrst $asses thro!h the $ivot or rotatio"

%e"ter* A%%ordi"!l#) the for%e re/ired to lift the !ate is the re/ired to over%ome the ow" wei!ht of

the same a"d fri%tio" at the s$$orts* This t#$e of !ate is sed i" la"dfills of $re#) i" headwor,s a"d

i" irri!atio" %a"als*

8. LOSS$S


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Flo5 +ress*re o*tlet d*ts

If a %o"trol $ort is $la%ed dow"stream of the i"let d%t) the $art a'ove the %o"trol !ate will flow "der

$ressre* A %losed %o"dit ma# also flow !ates %om$lete de$e"di"! o" the i"$t !eometr#* A"d

h#drali% $he"ome"a e/atio"s for flow thro!h a %o"dit "der $ressre doors %losed* The

h#drali% desi!" of a %losed $ressre li"e mst 'e similar to that of a $ressre li"e %losed !ates*

For flow i" a %losed $i$e) 7er"olli?s e/atio" %a" 'e writte" as follows&

H T =h L+hv2

Where&

H T @ Hei!ht re/ired to over%ome the varios losses to $rod%e the dis%har!e)

h L @ The a%%mlated losses of the s#stem) a"d

hv2 @ Load s$eed valve*

The e/atio" %a" 'e e($a"ded to list ever# loss as follows&

H T =ht +he+hb5

+hf 5

+hex(5−4)+h f 4+hc(4−3)+hg3+hex(3−1)+hf 1+hb1+hc (1−2)+hg2+hv2(4)

5ere:

ht @ the loss !rids)

he @ the loss i"$t

hb @ is the loss de to %ha"!e of address)

h f @ is the fri%tio" loss)

hex @ it is the loss '# e(te"sio")

hc @ shri",a!e is the loss)

hg @ losses are !ates or valves) a"d


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hv @ the velo%it# head loss to the e(it*

I" e/atio" 0;1) the "meri%al s's%ri$ts refer to the varios %om$o"e"ts) tra"sitio"s) a"d rea%hes

that $ressre losses are a$$lied*

Ot$t for free dow"load) HT is measred from the srfa%e of the water ta", toward the %e"ter ofthe e(it or otlet o$e"i"!* If the 3et flowi"! ot is s$$orted o" a dow"stream floor) the hei!ht ismeasred at the to$ of the emer!i"! 3et at the $oi"t of !reatest %o"tra%tio"- if the e(it $ortal dives) thehei!ht level measred dow"stream*

Whe" the varios losses are related to the i"dividal %om$o"e"ts) e/atio" 0;1 %a" 'e writte"&

H T = K t ( v62

2g )+ K e ( v52

2g )+ K b5( v52

2 g )+ f L5 D5

( v52

2g )+ K ex( v52

2 g−

v42

2g )+ f L4 D4

( v 42

2 g )+ K c( v32

2g−

v 42

2 g )+ K g( v32

2g )+

5ere:

K t @ loss %oeffi%ie"t !rids)

K e @ e"tr# loss %oeffi%ie"t)

K b @ loss ratio %rves)

f @ fri%tio" a%tor i" the Dar%# . Weis'a%h for $i$e flow*

K ex @ loss %oeffi%ie"t of e($a"sio")

K c @ loss %oeffi%ie"t of %o"tra%tio")

K g @ door a"d loss %oeffi%ie"t

K v @ door a"d loss %oeffi%ie"t

E/atio" 091 %a" 'e sim$lified '# e($ressi"! the i"dividal losses i" terms of a hei!ht of ar'itraril#

%hose" s$eed* The hi!h s$eed is ofte" %hose" i" a si!"ifi%a"t se%tio" of the s#stem* If the varios

heads to s$eed the s#stem show" i" Fi!re 8< to 88 relate to the %o"dit dow"stream of area 081)

%o"versio" to the area of ( is as follows&

Q=a1 v1=a x v x ; a12

v12=a x

2

v x2

;

y a 1

2

v12

2g =

a x2

v x2

2g


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the"&

v x2

2 g=( a1a x )

2

v12

2 g

E/atio" 091 %a" 'e writte"&

H T =v1

2

2 g [( a1a6)2

K t +( a1a6)2

( K e+ K b5+ f L5 D5

+ K ex)+( a1a4 )2

( f L4 D4

− K ex− K c)+( a1a3)2

( K c+ K g+ K ex )+( f L1 D1

− K

If the 'ra%,eted $ortio" of the e($ressio" is re$rese"ted '# b y # K L ) to e/atio" %a" 'e writte"&

H T = K Lv12

2g

(7)

the"&

Q=a1√ 2 g H T K L (8)


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19. LOC"TION OF T$ WORK OF D$CISION R$#"RDIN# R$S$R(OIR L$($LS

The esta'lishme"t of the level of de%isio" a"d elevatio"s dow"loads %o"trol a"d tra"s$ort ste$ i"

their relatio"shi$ with reservoir stora!e levels are i"fle"%ed '# ma"# fa%tors* First) to a%hieve the

re/ired dis%har!e %a$a%it#) dis%har!e shold 'e $la%ed sffi%ie"tl# 'elow the mi"imm level*

The wor,s ma,i"! small dams dow"load for dete"tio" are !e"erall# %o"str%ted %lose to the level of

the river'ed) for $erma"e"t stora!e s$a%e) e(%e$t for the rete"tio" of sedime"ts) !e"erall# is "ot

$rovided* These headwor,s dis%har!e %a" 'e $artiall# %losed to retard the otflow) while the reservoir

tem$oraril# stores the 'l, flow of r"off) or ma# 'e %losed to re!late the release of the tem$oraril#

stored water* If the $r$ose of the dam is for raisi"! the dam a"d divert i"flows i" the low e"tries)

$ri"%i$al of a" i"ta,e dis%har!e shold !e"erall# 'e a $ower or the %o"trol str%tre at a hi!h level* Afle or dis%har!ed '#$ass shold also 'e $rovided to s$$l# water to the river dow"stream or drai"

the water from 'ehi"d the dam dri"! $eriods of low seaso"* The dams that im$o"d water for

irri!atio") domesti% se or for other $r$oses of %o"servatio") mst have headwor,s dow"load low

e"o!h to e(tra%t water 'elow the dam to the 'ottom of allo%ated stora!e s$a%e- however) the

dis%har!e otlet wor,s %a" 'e $la%ed a'ove the river'ed) de$e"di"! o" the mi"imm level of

reservoir stora!e set* It is %ommo" $ra%ti%e to fore%ast a stora!e reservoir for the i"a%tive stora!e to

a%%ommodate settli"! ta",s for fish a"d wildlife %o"servatio") a"d re%reatio"* The de%isio" threshold


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$ositio" the" 'e%omes a" im$orta"t %o"sideratio"- mst 'e hi!h e"o!h to $reve"t i"terfere"%e of

sedime"t de$osits) 't at the same time) low e"o!h to allow either $artial or %om$lete red%tio"

'elow the $$er stora!e i"a%tive*

Headwor,s with elevatio"s levels a"d %o"trols the dis%har!e a"d tra"s$ort %o"dit) whi%h relate to

the stora!e reservoir levels are i"fle"%ed '# ma"# fa%tors* First) to a%hieve the re/ired dis%har!e

%a$a%it#) the dis%har!e otlet mst 'e $la%ed far e"o!h 'elow the mi"imm o$erati"! level of the

reservoir to $rovide the %har!e to dis%har!e the flows*

The si5e of a" otlet %o"dit for a re/ired dis%har!e varies with a" i"verse relatio"shi$ with that

availa'le for the $rod%tio" of the dis%har!e head* This relatio"shi$ %a" 'e e($ressed '# the

followi"! e/atio"&

H T = K 1hv∨ H T = K 2Q

2

a2

where& H T =Totalload available ,

K 1 y K

2=coefficients,

hv=height , ,

Q=¿ dis%har!e rate for the i"ta,e) a"d

a=arearequired by theconduit

The a'ove relatio" for a $arti%lar desi!" show" i" Fi!re 8


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The reservoir %a$a%it# %rve i" Fi!re 8


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Works of Thomas Downloads in Dams Reservoirs-Ingles

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