FLOOD02883 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I HYDRAULIC ANALYSES TABLE 9 SUMMARY OF DISCHARGES Location Quai 1 Creek South 124th Street Downstream from Tributary 0 Lowell Boulevard Downstream from Tributaries B&C Zuni Street Huron Street Confluence with Big Dry Creek Tributary A Zuni Street Confluence with Quail Creek Tributary B Upstream from 144th Avenue Confluence with Quail Creek Tributary C Upstream Limit of Study Confluence with Tributary B Tributa ry 0 South 124th Street Confluence with Quail Creek McKay Lake Basin Downstream from W. l44th Ave. Huron Street Interstate 25 Confluence with Southern Drainageway Confluence with Big Dry Creek General 10-Year (cfs) 100-Year (cfs) - The water surface profiles for all streams under study were computed using the U.S. Army Corps of Engineers HEC-2 computer model (Reference 7). Cross sections for streams analyzed herein were taken directly from the two foot contour mapping prepared for this study (References 8 and 9). Field surveys were conducted where more detailed elevation data were required. 190 400 830 1,480 1,730 1,840 1,770 360 830 1,730 2,990 3,510 3,790 3,690 Geometric measurements and invert elevations for bridge and culvert crossings were obtained in the field as required. Photographs were taken of each crossing and a sketch of the crossing was prepared showing appropriate dimensions, This material is on file as backup information to the project. During these field investigations, estimates of roughness coefficients, i.e. Manning's "n" values, were also noted. 30 100 70 190 320 50 610 820 60 280 110 540 The "n" values utilized in the hydraulic analyses ranged from .030 to .045 for the channel and from .025 to .070 for the overbanks. 110 170 220 360 Hydraul ic runs were completed for the lO-year and lOO-year events for streams analyzed in this study. In addition, a floodway was computed for all streams under study. Thi s floodway is based on the Urban Drai nage and Flood Control District criteria allowing for no more than a one-half foot rise in the energy grade line with encroachment during the 100-year event. 440 800 960 1,530 1,580 910 1,670 1,920 2,980 3,080 Culvert blockage was considered at each crossing structure. With the exception of the Osage, Kalamath, and Huron crossings, all culverts were assumed to be com- pletely blocked. McKay Lake IlIpouOOlent McKay Lake is a man-made reservoir constructed for storage of irrigation water. The reservoir is created by two earthen entlankments located along the southern and eastern sides of the reservoir. There is no emergency spillway structure at this reservoir. The configuration of the McKay Lake impoundment presents some 17