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<br />Practically all d~ms ins~ected in the Cache la Poudre River ~~ln
<br />fall Lnto the high hazard and lnterrocdlate or large she c"t"e~ry.
<br />Ther"for<!, 1n the Inspection r<!sult8 pre"..nt~d in this repon, da..s
<br />with the ~yJrologic ~apability to pa~~ 100 p~rcent of ~he p'fr' ~lthQ~t
<br />ov"rtol'ping are ter\lled "ad<8quut,,"". Altern,,~iv~ flood~ '~~re !",""ed
<br />thr<>ugh the daas, ,~tth discharges being vart<}us percentago>s of the I'M,'
<br />discharges. DaIllsthat pass SOp"rcent of thePMF but less thp.nlOO
<br />p"rc~"t of it are termed "inadequate"", Da"", that Cannot pa"s SO per-
<br />cent of the PMF' Il.r~ consIdered "aer1ously inadequate".
<br />
<br />wa" ~lven ~o itp.m6 related to c~han~~ent ~tability s~ch ~s leakage,
<br />~rosion, seepage, .lope ln6tahility, undue qettle~ent, dis~laccment,
<br />tilting, cracking, dHedoraUon, and l"'~roper funcUonlng of dr~ins
<br />and relief wells.
<br />
<br />Although the ca~acity to paS5 a PMF is a principal factor,
<br />strLlctural defiden~ies should be ~onsideted, Soro.e of the~e are
<br />Id~ntifl~d in the next section, which discus5es dam ~afety inspect1en
<br />prClcedures,
<br />
<br />Con<lltio"s relating to $tructur,~l "deq~acy were observed during
<br />the d<\r.\ t".p..cUon$, These ,,-ondltions included a spillway dh,,-harge
<br />positioned ~o it ~ould erode the embankment, a 13~k of riprap or vegeta-
<br />tion which could promote erosion, an uneven "pill~ay or embankment
<br />level which could cause flows to conce"tra~e and rapidly erode, erosion
<br />at the outlet ~orks discharge, and excessively steep slop~s. Another
<br />potentialhazardis"pip1ng";withthiscondition,..."terunderpre9"Ure
<br />can find 3 path through the embankment byway of 9l1\allopenings. These
<br />"penings Can rapidly be enlarged by erodon, The possibility of thi6
<br />~ondHion 11"3 indi~ated by trees on the embankment, whi~h ~ould leave
<br />root holes; by rodent holes; or by seepage.
<br />
<br />INSPECTION PROCEDURES
<br />
<br />A Ph.."" L Lnspect 10n Report 1l!',~ lx>en ?r<'pared "nd~r the ~ational
<br />Dam Sdfety Program for dbo~t 30 dAro.~ in the Ca~he la Poudre River
<br />bas In. The purpose of the ~napect1on "'MI ~o raalr.e s gencnl S"$es~ment
<br />of str"~tur"l integrity "<l.d op"raUonal adeqLlacy. I[\ "rder to Identify
<br />h~,~"d",,~ 1~,,< ~~,,~~ttb"~~7, t~.~ ~copc ~~ the "le<ise 1 i\l.;lcd-,-"" "aa
<br />
<br />RESULTS OF DAM INSPECTIONS
<br />
<br />The results of th.. d"", ioape~t1orlS are summari~ed io table. 11 and
<br />
<br />12. T!1~ ",,::.ber p~ccee~ln;; ~!1~ :u:.::.c of ~"'cr, ~a::: c3n ~~ ""~~ to l..,~"te
<br />
<br />b~.ed on .vailable engineering data, a detailed visuaL field inspec-
<br />tion, and a !1ydrologLc analysb. The Ln"p"~tion deterllcneJ ne"d~ for
<br />el""rgen~y lIle"sur<'s or additional studies.
<br />
<br />the d~ms on plate 12.
<br />
<br />7he hydroiogi~ atudie. 1I"~e "",d<' to deter:nl~" th.. ~apabll1ty of
<br />harldUng the P'lF. Durl[\g the f1eld insp~~tton, iof"r'Mtton on eo""truc.-
<br />tlon, maintenan~e hi6tory, and I)pora.ti~z prl)~edllre. "as g~ther~d. ,\
<br />d~t"il~J insp<'~ti()" che~klta( cover"d ~ach I'drt of th", dd'!l, lncL",Urlg
<br />ttle C<cl"t, upst~..ar" slor~, d(l~.""tr"a", s 10"" , .~"ut_nont C01\~uct", Int~k~
<br />str\lctur':, outLH lIor~$ ~""d"lt, ..ril1i"-l h"sin, ~1'11,-"",', fJ,H~ "~rlJ~-
<br />tllres, ~he 'cs~rvoir ,He,\, ,,,,<I i""~rHlnO>~l~tt"n, "ani~"hr .'tte1\cl"n
<br />
<br />Elevations in tables 11 and 12 usually refer to a local datuQ,
<br />gen..ra11y the lOll point lit the lIpstre~rn "ide of the darn, In tllble 11,
<br />th" inventory number t~ II. d".lgnRt1on us~d in Corps of ~ng.in"".... and
<br />St"t~ of Colorado records and should be used if <~questin~ funh~r
<br />infor"",tion about a purti~uhr datil, A da~ lo~,Hed "offHrMm" is
<br />".uaUy in " nor:nally dry gul~h and Hs lIater "()Llr~.. i. a can,,-l or
<br />another upstream da~.
<br />
<br />Tb" ldt",," "~,A."" r~(~r tD the dr,<l\\Il;';~ .,r~a. contrlbut1n~ to the
<br />
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