FLOOD01374

• Designation Number: 521
• County: Weld
• Community: Erie, Firestone, Dacono
• Stream Name: Tri-town drainageway, Godding Hollow Basin
• Title: South Weld I-25 Corridor Master Drainage Plan
• Date: 9/8/1999
• Prepared For: Weld County
• Prepared By: Anderson Consulting Engineers, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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in the Rural Ditch for approximately 1,800 feet before emptying into the Rural Ditch wasteway
at the end of the Rural Ditch. Large flow events will spill out of the Rural Ditch and flow north
to WCR 2414. Channel improvements may limit the localized flooding problems in this area and
may isolate the stormwater runoff from the Rural Ditch.
WCR 24 Culvert' This culvert crossing lacks the capacity to convey the 100-year peak
discharge of 4,490 cfs at this location. The capacity of the existing structure was estimated to be
240 cfs prior to overtopping the roadway. Large flow events will overtop WCR 24 west of this
crossing. An improved crossing structure could reduce the localized flooding problems at this
location.
WCR 22 Culvert The 100-year existing conditions discharge in Godding Hollow at Weld
County Road 22 is 4,51O cfs. This compares to a culvert capacity, prior to overtopping the
roadway, of 300 cfs. The road will overtop along both sides of the culvert. An improved crossing
structure could significantly reduce the localized flooding problems at this location.
Godding Ditch BridgefFlume At this location, the Godding Ditch is conveyed over
Godding Hollow in a steel flume. The capacity of the bridge prior to overtopping the canal
embankment is estimated to be 3,000 cfs. The 100-year existing condition discharge in Godding
Hollow at the Godding Ditch is 4,510 cfs. Large flows will flow into and out of the ditch. An
improved crossing. structure could reduce the localized flooding problems at this location and
prevent overtopping of the canal embankment.
WCR 20 Culvert The capacity of the culvert prior to overtopping is 210 cfs. The 100-
year existing condition discharge in Godding Hollow at Weld County Road 20 is 4,580 cfs. Flows
will spread out east and west along the road before overtopping. An improved crossing structure
could reduce the localized flooding problems at this location.
WCR ] 8 Culvert The capacity of the culvert prior to overtopping is 190 cfs. The 100-
year existing condition discharge in Godding Hollow at Weld County Road 18 is 4,730 cfs. Flows
will spread out east and west along the road before overtopping. An improved crossing structure
could reduce the localized flooding problems at this location.
WCR ] 6 Culvert The capacity of the culvert prior to overtopping is 160 cfs. The 100-
year existing condition discharge in Godding Hollow at Weld County Road 16 is 4,740 cfs. Flows
will spread out east and west along the road before overtopping. An improved crossing structure
could reduce the localized flooding problems at this location.
State Highway 52 (WCR 14) Culvert The capacity of the culvert prior to overtopping is
1,000 cfs. The 100-year existing condition discharge in Godding Hollow at State Highway 52 is
4,010 cfs. Some of the flows will be detained behind the large highway embankment before
overtopping occurs to the west of the culvert. Additional detention along with an improved

T:10PENlCoweidO/lcoweldOl Inl rpt.wpd

4.16

September 8, 1999