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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5.2.3 Godding Hollow Basin Reach G3: WCR 24 to Godding Ditch

Improvements in Reach G3 focused on the alleviation qf flooding problems at three
locations: (a) WCR 24; (b) the channel reach upstream of WCR 24; and (c) WCR 22. The specific
improvements to Reach G3 are presented below and also in Figure 5.4.

1. WCR 24 Crossing. Replace the existing 6'H x 8'W arch CMP crossing of WCR
24 with a bridge structure with a minimum opening of 12'H x 58'W. Transitions
from the existing channel to the bridge crossing are required along with placement
of stabilization measures to control the potential erosion in the vicinity of the
crossmg.

2. Channel Improvements. In conjunction with the improvements to the crossing at
WCR 24, construct approximately 3,000 feet of channel improvements upstream
from WCR 24. The channel improvements should incorporate 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 400 feet, sideslopes of 4H:IV, and
design depth of 4 feet. At the upstream end of the channel improvements, a berm
is required to capture the stormwater runoff and direct the flows into the proposed
improvements.

3. WCR 22 Crossing Replace the existing 6'H x 7.5'W arch CMP crossing ofWCR
22 with a bridge structure with a minimum opening of 6.5'H x 80'W. Transitions
from the existing channel to the bridge crossing are required along with placement
of stabilization measures to control the potential erosion in the vicinity of the
crossing.

5.2.4 Godding Hollow Basin Reach G4: WCR 20

The proposed improvements to Reach G4 focus on the replacement of the existing 6'H x
8'W arch CMP crossing ofWCR 20 with a bridge structure with a minimum opening of 4.5'H x
135'W. Transitions from the existing channel to the bridge crossing are required along with
placement of stabilization measures to control the potential erosion in the vicinity of the crossing.
In conjunction with the replacement of the existing structure, approximately 850 feet of the
roadway should be raised to a maximum height of I foot. Figure 5.5 presents the improvements
for Reach G4.

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5.22

September 8, 1999