FLOOD01374 - Laserfiche WebLink

Home Browse Search

I I I I I I I I I I I I I I I I I I I calculated to be 1,500 cfs. The 100-year existing condition discharge in Tri-Area Drainageway at !VCR 13 is 2,590 cfs, WC:R 16 C:ulvert The crossing at WCR 16 is a 6'H x 10'W reinforced concrete box culvert. At this location, overtopping of the right bank and associated flooding of adjacent property and WCR 16, occurs 50 feet upstream at a depth of approximately 10.3 feet above the invert of the culvert. The capacity of the culvert prior to overtopping is 710 cfs, The 100-year existing condition discharge in Tri-Area Drainageway at WCR 16 is 1,940 cfs. Main Street Frederick Culvert The crossing at Main Street is a 6'H x 8'W reinforced concrete box culvert. At this location, overtopping of the right bank occurs at the upstream face . of the culvert, at a depth of approximately 8.6 feet above the invert. The capacity of the culvert prior to overtopping is 520 cfs, The lOa-year existing condition discharge in Tri-Area Drainageway at Main Street is 1,940 cfs, State Higbway 52/Eighth Street C:ulverts. This crossing of State Highway 52 and Eighth Street in Dacono is comprised of a cluster of corrugated metal pipes. Two CMPs with diameters of 3.5 feet and 4,0 feet convey flow under Eighth Street. One 3.5-foot CMP and two arched CMPs (2.5'H x 4'W) convey flow under State Highway 52, At this location, roadway overtopping occurs at a depth of approximately 6.0 feet from the invert of the most upstream culvert, Due to the potential debris loading, all of these pipes were assumed to be ineffective during large events, The lOO-year existing condition discharge in Tri-Area Drainageway at State Highway 52 is 1,520 cfs, 3.3 Open Channels 3.3.1 Godding Hollow Rasin At WCR 24V2, the Godding Hollow major drainageway confluences with the Rural Ditch. Stormwater runoff within the Godding Hollow channel combines with the water conveyed in the Rural Ditch and continues northeast for approximately 1,800 feet before emptying into the Rural Ditch Wasteway at the end of the Rural Ditch. This reach of the Rural Ditch is incapable of conveying stormwater runoff from even minor storm events within the Godding Hollow Basin. Similarly, the other irrigation ditches, namely the Coalridge Ditch, Godding Ditch, and the Last Chance Ditch, offer limited value as drainage features that will capture and convey stormwater out of the basin. Furthermore, the major drainageway of the Godding Hollow Basin is typically incapable of conveying stormwater runoff generated from any event in excess' of the 2-year existing condition storm event. T:iOPEMCoweldO/\CoweldOJ Inl rpt.wpd 3.10 Septernber8,1999