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<br />:. .'. ever. 2t pre cent, Dendin- the ~pme C` [h, ~_-
<br />Clcial dclav preciously re re n, tn, many 2" -.e:, r;
<br />in Ki'~t ut. ~, designed srdin2nC ,', d.'e imali enovn CG
<br />2VJid [`.C -~: ro ri :J roJ: yru G?C'dr`-'~ r2 G'.;i red S. 2
<br />h bil. da-.. ;i ;ho.ch this voc'p lc•:er tn? ri s~ n`
<br />51..-^+ fei;t,res 3~d [U%~3 eGu?^ilti +~: rUVe Safety,
<br />s.'~'. ~:r Gu ,!i;y his chviously suffered.
<br />?h~_xttiC;: ut tenficr. Ti.-,=
<br />Fs <.. n.:n in Tabl_ 2, r,i nima~ "ihcoretica! de-
<br />r. -~:ion n-es" are specified Sy CSn. Sectien ttl5.-j
<br />~cj o' t.~e regula[i ons states that:
<br />"Theo'etieal detention tine is dafined
<br />a: t-_ average ;ine that :he design `low
<br />is d~;aiced in the pond; and is further
<br />defined as the ti ce difference teu+een
<br />tha <°ncrcid of the ir.r!gv, t:yd regraph
<br />and tha ca: [told of the outflow hydro-
<br />graph for [he design event-"
<br />Th_ regulations reGui re a theo rr;i cal de tension
<br />time of "mc less than 24 hours, or any hither
<br />a~T~ount regal red by [he regulatory authority". There
<br />are ccceu!inns ^.o this, ho>:e ve r. Detenti Jn tines :.
<br />n;,] Ica ;[ 1C hours may ba allo+:?d ii suCFicien:r
<br />tcchni cal evidence is provided to ju5 [ify such z
<br />re~uc [ion. Such evidence would be in [he fern of
<br />prWnsEd efficiency i¢proveoen is (i. e., baffles,
<br />e;:.) and analytical proof of zchi evi ng effluent
<br />lini cations [h rough se:L7ing rate ana 11's is. and so
<br />fee [h. D_:an[icn ti.,res of any magnitude nay be
<br />a ppreved if chemical [tea [Went is Droposed. 7Se
<br />d 2sigr.er r;~s[ demni:rate [ha[ effluent Limi Cations
<br />.,'ill bz zchi eyed zn•! maintained, and also must cer-
<br />tify that the chemical agent employed is envirsn-
<br />mcn[ally safe. it is stressed th roug SOU[ the regu-
<br />la:inns [hat detention tines alone do not necessar-
<br />ily assure compliance. The bottom line is always
<br />water quali LY- .
<br />Design Precedu res
<br />Si ng !e Da~DesiGn Under DSM
<br />A typical sedicen[ Cam in profile is shown in
<br />Figure I, and a typical plan view in Figure 2. The
<br />TJ W:'JiF : ~' S?~ ~ t' i95t A?i.TJ . h'. SE' _r ~,••
<br />iw _1 ~~n:-t'.' _ ";_'_°``._Ji_-5.:°^i'r=`yy~jfi~-•l+a~ Hoed [
<br />: p , o4~P,.~. _ _ - _._ .:-- ettiP.._=PGCti (o hionyl)
<br />4rrWw~~ sw .~;- sroatiE Ss.d:.'nC rt+
<br />~aL saq~wc, ... ... _• _
<br />7YPICA! SEC'M_!.r Gs!`~% i-RJFIL~
<br />• ~IIII~II~IIIII~~~I~
<br />SPdi^I (anC ~Anl Ci.'~-'• r- d=rv, gDg - _
<br />s[a,^_ - czp aci .. - -v2 Lh? ~_. ...r =. c...-.-_
<br />_ .t5 h.
<br />wIu'>2. Tnr top e' - - ',- -_ .. ..
<br />at this eieva;ipn ..r ~i-'=-. ..- o Ihac :r. -e: __
<br />LICns r2':Ul re st2; 'E :::.:1 ..r ~~ _
<br />3va i'a!I vo lurx ,- .. ._. (`--_ Ta c._ <''), ._
<br />vUl `..a _a Nd:er :.E l:.r :- -'P '~E/_. ~-~ SPS ~::__.~
<br />pool and the cr,st _ :-_ rite ._ d?s -=-te. is
<br />(nil Ua pa- di Che CEr-_~_nt DC [.i. T-.?5 water -_.
<br />or .,,ay net ~^_ sloth r_~=_=.sed ..- the c~^ Se ;..,ee_.
<br />rd:nCall eve r,ts.
<br />Section °.t6.4o (g) r 'c.^.P ra__ia:ic-s stares:
<br />'There Shall be nD outrio-~ thrc_.^ [he e''e rc^^c/
<br />s; it h::ay duel r.- :hr pa'se:e cr - rue==: resc[tir_
<br />frc':, thz ;i. year/24 r,_ oreci;.!_~- nn." Thrrc fc:?,
<br />[he i~r,E [i'al 5[eo in ~ _esi gr. :. r_ss 'S [o tw:-
<br />5[ruc[ tha 'unpfi .".. r _- fJr ;pie i:, yea ri2(r
<br />hou' stet- and rx :c i, :-nougn :': ris_r and pN --
<br />tipal sailLcay.
<br />Pu ^off Hyd roc: aphs
<br />There are 5everz! t_ .`..n iG~_cs availa^!^_ to the
<br />tlesigner for [he co^strue:ion o`. runoff nyd ro5•aahs.
<br />The runo,`( hyd: og rata ie this oaxr ..ere oene ra :^_'
<br />by a m?pater eadci [hat ?-.^ __ the Spil Cor>='-
<br />vatipn Scrvi is [. %~i: i~rd tog rat;. Ie. h: icq^, 25 out-
<br />lined ir, the fire: a:ure.l'Z (+-.;rc edent !'ois;urc
<br />Cor.di lion II aas asscr.ed, ru^oir t'-eve ^~-.bets for
<br />various cover co ndi[ions were estimato?, and rain-
<br />fall hye[og raohs were ce ne ra [ed from tha SCS Typc
<br />11 24-Hour synthetic tai r.fall d sari bution, Tne
<br />only deparba re fro^• SCS ;eehn:c-es v:as :~'•at o` the
<br />sha pc of the dimen5io^less uni; ^'. drogresh, v.herp
<br />the equalions pro?osed b/ Haag (i5j~) ~_ applied.
<br />The unit hyd rojra:h's :ea s. rl p:: ra !° a-d ntir.e to
<br />peak .re re [hose of .•_ '_~S [rie-.gular u:.it hyd:p-
<br />graph..
<br />'TSe cJ :pu ;a: ~.dei c.._c gE :~r ces tie rc ne.`
<br />h ydrof.-zphs ~zs p:nra mad 'ot~a :eiac:ve iy spa ii
<br />office coopu[er :r. a~ "E x[a :'_°+•~ 6.S IC :Depute:
<br />language. It is 5iritar to et^er rotle;i that ''ave.
<br />beer, reD^rted of in [.`e li to ra !: -e, an? the t -.-
<br />pared results have Sa?~ cui [r - cse. ?i~ical~prc-
<br />gram outputs zee ine Faded vii tc sxe of the case
<br />studies discussed in this paper,
<br />F inure I, -:pieai Pep .rile Y i?di^ent Das Y_-_; g CS.° _if ica;ions,
<br />333
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