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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placement of stabilization measures to control the potential erosion in the vicinity
of the crossing.

4. Regional Detention Pond To reduce the peak flows within the major drainageway,
a regional detention pond is proposed to be located east of WCR 13 and south of
WCR 20. At this location, approximately 43 acre-feet of storage is required which
will necessitate the acquisition of approximately 9 acres of land along with the
construction of an improved outlet structure.

5.2.14 Tri-Town Basin Reach T4: FirestoneiFrederick

The improvements in Reach T 4 involve the stabilization of the existing conveyance channel
located east of WCR 13. Stabilization efforts should include the channel reach from Firestone in
the vicinity of Wooster A venue to the southern limits of Frederick, a distance of approximately
6,600 feet. In this reach, channel sides lopes should be regraded to a more stable slope (3H: 1 V)
and vegetated. These improvements are presented in Figure 5.15.

5.2.15 Tri-Town Basin Reach T5: Frederick/Dacono

The improvements in Reach T5 are focused on: (a) construction of a regional detention
pond; (b) construction of channel improvements along the major drainageway between Frederick
and Dacono; and (c) installation of crossing structures beneath State Highway 52. The specific
improvements to Reach T5 are presented below and also in Figure 5.16.

1. Regional Detention Pond To reduce the peak flows within the major drainageway,
a regional detention pond is proposed to be located immediately south of Frederick.
At this location, approximately 136 acre-feet of storage is required which will
necessitate the acquisition of approximately 35 acres of land along with the
construction of an improved outlet structure. In addition, improvements to an
existing berm and swale which will convey stormwater into the regional pond are
required.

2. Channel Improvements This improvement consists of the construction of channel
improvements from the regional pond to State Highway 52. Approximately 2,400
feet of channel improvements will be required. The channel improvements should
include a compound channel configuration, i.e., a low flow channel along with an
overbank area to convey flood flows. In addition, the channel incorporates a grass
lining, bottom width of 20 feet (low flow channel), maximum top width of 100
feet, sideslopes of 4H:IV, and design depth of 4 feet.

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5.28

September 8, /999