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<br />Tahl~ 1
<br />Table 2
<br />TallleJ
<br />Tallie 4
<br />TableS
<br />Tahle6
<br />Table 7
<br />TableS
<br />Table')
<br />TahklO
<br />Tablell
<br />Table 12
<br />TableD
<br />Table 14
<br />Tabl('15
<br />
<br />LIST OF TABLES
<br />
<br />CityofStuling,Colorado
<br />rllwll('eCreekFloodlla7.ardMiti~atioll
<br />hasihilityStudy
<br />
<br />Peak Discharge Estimales July 1997Flood....,."... .,...,...,11
<br />Peak Discharges Alun!,\ PaWTlec Creek Main Channel ......., ,......,.., 13
<br />Unit Costs For Pawnee Creek Improvements. ........._.. ........,..... ,22
<br />Alternative No 2 Estimated Costs,._, ..,....,.... ..,.........,...."...,.... ,23
<br />Alternative No.3 Estimated Costs..."... .,................. ,..,................". .,,24
<br />Alternative No.4 Estimated Costs.. ..........."... ...........,......,................,... __25
<br />Alternative No.5 Estimated Costs........ ,,_..........................,..,...,.._ ............... ,.26
<br />Alternative No.6 EstimatedCosts..."... ,.....,.... ..,...,...,..,.......... ..27
<br />Alternative Cost Summary........" ,..."...."....,...,.......,_.....,..,......"..."...,..28
<br />AltemativeEvalu.ationFactors.............. ...............".. ...............................29
<br />AltemativeSelectionMatrix..,...,.......... ...,.....,........"..,.......,......'.. ....30
<br />Other Damage As A Percent Of Direct Damage.......,... ...,.."..,.. "...43
<br />DamageSummary-1998Dollars. "..,44
<br />Property Protected By Project.."... ".........,... ........._...... .....45
<br />Design and Construction Schedule .....,..."..."....... ,..,................ 46
<br />
<br />l. I:-.'TRO]}t:CT10N
<br />
<br />The e,ty of Sterling, Colorado, is hordered by Sand Creek and I'ione..r ni!~~ ,,-, the north and west, the
<br />South Plal1e River to the east, and Pawnee Creek to the south, Each ofthesc drainage ways provides a
<br />source of flooding for the City during large storm ewnt. Three major floods and at least three other
<br />minor tloods have impacted the City in the last 65 years, Through previous studies, improvemcnts to
<br />the Pawnee Creek tlood plain would create the greate8t bcnefit to the C il)'and portions of the county,
<br />
<br />Th~ objective of this project is to develop a Flood Hazard Mitigation Feasibility Sludy for Pawnee
<br />Creek and to provide a report to be included with the Colorado Walcr Conservation Board (CWeB)
<br />loan application, This report is formatted 10 meellhe criteria outlined hy the C\\iCB for their Waler
<br />Project Construction Loan I'rogram,
<br />
<br />[I. l'i\.o.lF:cr SPONSOR
<br />
<br />The City of Sterling is the county scat lv, ;''-'5'''' :::U,",,;:j'. ;:;~ City is located approximately 125 miles
<br />northeast of Denvcr, and 126 milc~ southeast of Cheyenne, Wy"ming. A general location map "fthe
<br />[,o!!an County/Stcrling area is ~h\)",n on fij!ure I, Sterling is the largest eommunit), in Lugan County,
<br />having a population of nhout 11,000 (l995 estimate), The total p0p\ll~li'm within 1,c\gal1 COllnty i~
<br />about 19.000 (1995 e"tjmat~). The City operal"" with s"urc~s of revenuc from taxcs, licenses and
<br />permitting, intergovernmentul, charges for servi,;es. and fine~. Approximately 75% of the Cily'~ lOlnl
<br />revenue comes from t~-::es of which apprmimalo:-ly 70% ot'tl", lax rcvenuc eome, from sales tax.
<br />
<br />The climate of Sterling is primarily afleck'li by northwestern wmds, The' average annual precipitation
<br />i~ 19 in,;hes and the average aIUlual snowfall is 39.4 inches. The mean mlllu.allemperature is 48,60 r"
<br />and the average annual number of elear days is 299. The coldest monlh is Jmllmry Wilh a mean
<br />temperature of 38.80 F. and the warmest monlh is Ju.ly with an average tcmperatu.re of ~9.0o F. The
<br />topography of the City consists of high rolling plains, with the predom\ll~te feature being the South
<br />P' n' ,. , " . ....~ "c ,.. ,-.,... ~ C ~ .. .. h h Th S '0'
<br />lall" fl.1Vt'1 """....n HU"'~ ,,,w'-'5" ,,,;; LH] an... _"umy ,ron'> tuc :>Gut" te t"c :lOft... ...e 0Ut:l ....:lttc
<br />
<br />River floodplain is hroadand relatively flat. Sterling is bisected from southwe,t to nonheastby Sta'"
<br />HIghway 6 and a parallel railroad track ()('Craled joimly by 13SRRiUPRR,
<br />
<br />Pu\.\nee Creek i~ a left bank tnbutary to lhe South Platte I\.iverand drams an area of about 645 square
<br />miles, The upper portions of the basin arc h)Cat~>d in Wc!d County. and the [ower IXlrtion. along witlt
<br />thl." c()[}l1ucncc with the Soulh Plane River are located inl,ogan County. The mouth of the creck is
<br />loeated about 5 miles southwest of Sterling and about I mile northeast of To....n llf Atwood in Logan
<br />C"unty, The watershed elcvation mnges Irom about 3.9HO fcet to 5.400 feet. The soils in the basin arc
<br />~,~",;!ly h'a~~1" aml cbv 1"!\!'1~. w;t!1 <~'''_!<'''''':' <b.,I., ~n.-l ~ilt~tOT'" ""Irmnnin~'_ Land use consists of
<br />. ..., .. -
<br />"pen rallge land and a significam amount of irrig,llcd cropland in the lowel pon "f the bd.~in, Several
<br />:llajor und many milwr irrigali"tl ~"n";, "lid dildll.'" ero" the study arca_ g';llerally !1,)winB p~r~llcll"
<br />the Soulh Plane Rivcr. Signiticant among the canals an: the l'awnee Ditch. SpringJak Ditch. and lhl'
<br />Sterling No, I Ditch,
<br />
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