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<br />Basin <br /> <br />G-l <br /> <br />G-2 <br /> <br />G-3 <br /> <br />G-4 <br /> <br />G-5 <br /> <br />G-6 <br /> <br />G-7 <br /> <br />G-8 <br /> <br />G-9 <br /> <br />G-lO <br /> <br />G-ll <br /> <br />G-12 <br /> <br />G-13 <br /> <br />G-14 <br /> <br />G-15 <br /> <br />TOTAL <br /> <br />Area <br />Sq. Mi. <br />.253 <br /> <br />.390 <br /> <br />.448 <br /> <br />.603 <br /> <br />.620 <br /> <br />.781 <br />.884 <br /> <br />.210 <br /> <br />.333 <br /> <br />.884 <br /> <br />1. 00 <br /> <br />.264 <br /> <br />.568 <br /> <br />.385 <br /> <br />.362 <br /> <br />7.985 <br /> <br />TABLE 3 <br /> <br />Drainage Basin Parameters <br /> <br />Length <br />Mi. <br />.606 <br /> <br />.530 <br /> <br />.568 <br /> <br />.568 <br /> <br />.549 <br /> <br />1. 33 <br /> <br />1.12 <br /> <br />.322 <br /> <br />.852 <br /> <br />.909 <br /> <br />.852 <br /> <br />.511 <br /> <br />1. 23 <br /> <br />.852 <br /> <br />.758 <br /> <br />Centroid <br />Length <br />Mi. <br />.359 <br /> <br />.246 <br /> <br />.189 <br /> <br />.322 <br /> <br />.246 <br /> <br />.568 <br /> <br />.625 <br /> <br />.095 <br /> <br />.398 <br /> <br />.492 <br /> <br />.445 <br /> <br />.321 <br /> <br />.530 <br /> <br />.549 <br /> <br />.246 <br /> <br />Slope <br />Ft/Ft <br />.0076 <br /> <br />.0087 <br /> <br />.0055 <br /> <br />.0077 <br /> <br />.0055 <br /> <br />.0171 <br /> <br />.0084 <br /> <br />.0067 <br /> <br />.0222 <br /> <br />.0069 <br /> <br />.0081 <br /> <br />.0116 <br /> <br />.0204 <br /> <br />.0122 <br /> <br />.0325 <br /> <br />Proj. Dev. <br />Perv. Ct. <br /> <br />60 .29 <br /> <br />35 <br /> <br />58 <br /> <br />67 <br /> <br />60 <br /> <br />58 <br /> <br />63 <br /> <br />57 <br /> <br />62 <br /> <br />50 <br /> <br />65 <br /> <br />70 <br />60 <br /> <br />65 <br /> <br />60 <br /> <br />.24 <br /> <br />.29 <br /> <br />.32 <br /> <br />.29 <br /> <br />.29 <br /> <br />.30 <br /> <br />.28 <br /> <br />.27 <br /> <br />.27 <br /> <br />.31 <br /> <br />.32 <br /> <br />.26 <br /> <br />.31 <br /> <br />.26 <br /> <br />5 <br /> <br />Table 4 <br /> <br />Flood Frequency and Discharge <br /> <br />CP <br /> <br />Location <br /> <br />2-Year <br />(cfs) <br /> <br />10-Year <br />(cfs) <br /> <br />100-Year <br />(cfs) <br /> <br />.50 <br /> <br />Goldsmith Gulch <br /> <br />Confluence with Cherry Creek <br />Hampden <br /> <br />Below I-225 <br />Above I-225 <br /> <br />Belleview <br />Dayton <br /> <br />Southmoor Park Tributary <br />Mouth near Dartmouth <br /> <br />West Tributary-Arapahoe Co. <br />Mouth near Orchard Road <br /> <br />1230 <br /> <br />1040 <br />810 <br />600 <br />620 <br /> <br />380 <br />240 <br /> <br />3880 <br />2800 <br />1900 <br />1990 <br />1250 <br />760 <br /> <br />5310 <br />3940 <br />2750 <br />2900 <br />2250 <br />1090 <br /> <br />.45 <br /> <br />.50 <br /> <br />.53 <br /> <br />.50 <br /> <br />.49 <br /> <br />280 <br /> <br />490 <br /> <br />490 <br /> <br />.51 <br /> <br />80 <br /> <br />670 <br /> <br />.49 <br /> <br />.56 <br /> <br />A detailed, technical appendix covering the hydrologic analysis is <br />available at the offices of the Urban Drainage & Flood Control Dis- <br />trict. <br /> <br />.47 <br /> <br />.52 <br />.54 <br /> <br />Hydraulic Analysis <br /> <br />Hydraulic analyses were completed to determine the water surface <br />elevations for the 100-year storm event. The elevations were com- <br />puted using the Corps of Engineers HEC-2 Water Surface Profiles <br />computer program. Valley cross sections were measured on the 1" = <br />100' scale, 2-foot contour topographic mapping provided by the <br />District. Estimates of channel and overbank roughness factors were <br />made after field investigation of the study area. Typical roughness <br />or Manning's "n" values used in this study are: <br /> <br />.55 <br /> <br />.52 <br /> <br />.55 <br /> <br />channel <br />overbank <br /> <br />.030 to .045 <br />.035 to .055 <br /> <br />The computed flood profiles are plotted on the Flood Hazard Area <br />Delineation Map Drawings. Also, the computed flood elevations for <br />Goldsmith Gulch and tributaries are tabulated at each reference <br />point in Tables 5 and 6. <br /> <br />A detailed, technical appendix with all the hydraulic calculations <br />is available at the Urban Drainage & Flood Control District. <br />