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Febrttary 27, 1997 -2- 963-2178 <br />• hour. Rainfall depth for the 10-year, 24hour storm event in the vicinity of the proposed <br />work was determined to be 1.90 inches [National Oceanic and Atmospheric Administration <br />(NOAA) AUas 2, Precipitation -Frequency Alas of the Western United States, Volume III - <br />Colorado, & Previous Reports]. <br />SedCAD+ soil input parameters unique to each site include Land Use Condition (LUC), <br />Curve Number (CN), Hydrograph Response Shape (HRS), Length of Overland Flow, <br />Control Practice Factor (CP), and acreage. Values for LUC, CN, HRS, Flow Length and <br />CP used in the analyses are presented in the following tables (referenEe SedCAD+ guide). <br />Acreages were calculated from base mapping and are included in the SedCAD+ inpudoutput <br />documentation. <br />TABLE 1 <br />LUC VALUES <br />• <br /> <br /> <br />......:...:.......:..:...:......::..:..... <br />S~Z:<:)(9it8:Usc~~€<€`>;~=>~:~~<~:<<~::~<"'~~~>!.:"::';;:' <br />s ......... <br />:;s::~':Oserf~d':~:<~~:':::.; ... <br />y< ...... <br />~;,y:Ce~enfiiated~ .:.. <br /> '::...~'t. .COIf CQRdlUOp <br />Undisturbed portions of the watershed (oak bnuh and 3 9 <br />grass woodland) <br />Cut and fill slopes (bare soil) 5 7 <br />Compacted areas (bare soil, unvegetated) 5 7 <br />Graveled aeeas (bare, unvegetated) 5 7 <br />TABLE 2 <br />CN VALUES <br />r1 <br />• :....:..:... ..........u :: '::i::::;.;:;:i.:s:' <br />:.:.:.:..:::.Type :.'."::'::: dCAD+: Iasstilt~rhon:::::::::;s:;;::: :::;•::: ~ :.: aloe:.;<.:::;:::: <br />Undisturbed portions of the watershed, Oak 30% Oak-Aspen Cover Deasiry 68 <br />Cover <br />Undisturbed Portions of the Watershed, Pine 40% Pine Cover Deasiry 71 <br />Cover <br />Fill slopes, bare (worst case), and vegetated Developing Urban Area (No 91 <br />areas subject to disturbance by traffic Vegeta[ion) <br />Cut slopes, Soil Guard An estimated value, between a 88 <br /> classification of a Fully Developed <br /> Urban Impervious Area of Din and <br /> Gravel Sweet and Roads <br />Gravel hardstands and roads Fully Developed Urban Areas, 89 <br /> Impervious Areas, Streets and Roads, <br /> Gravel, Hydrologic Soil Group C <br />nenaaznaa ner~z.~~x Golder Associates <br />