FLOOD09102

• County: Logan
• Community: Sterling
• Basin: South Patte
• Title: Sterling Flood Control Interceptor Channel Project
• Date: 4/1/2002
• Prepared For: Sterling
• Prepared By: URS
• Floodplain - Doc Type: Project

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SElma.TWO

Ahernatives Considered

be impacted and the cost of moving large quantities of fill material. In addition, this alternative
was perceived to have more unknowns that could potentially increase costs (ICON 1998).

2,1.4 Improve Routing of Pawnee Creek Flood Flows

The alternative, identified as Alternative 5 in the applicant's Flood Hazard Mitigation Feasibility
Study (ICON 1998), would provide flood flow routing activities near Atwood, near the
Highway 6 and UPRR bridges over Pawnee Creek, and near Riverside Cemetery. Culverts and
flood channels would be sized to handle floodwater at Atwood. Culverts, dikes, bridges,
floodwalls, and flood channels would be sized to handle potential floodwater from Pawnee
Creek. Although this alternative was previously considered by FEMA and evaluated in an EA
(URS Greiner Woodward Clyde 1999a), the alternative was dismissed when Logan County
withdrew its support for the project.

2,2 ALTERNATIVES CARRIED FORWARD

The potential environmental impacts for three alternatives are evaluated in this report. These

alternatives include:

. No Action

. Sterling Flood Control Interceptor Channel

. Pawnee Creek Overflow Cutoff

2,2,1 Alternative 1 . No Action

With the No Action Alternative, no improvements would be made to or other work performed
along Pawnee Creek.

2,2,2 Alternative 2 - Sterling Flood Control Interceptor Channel (Proposed
Action)

When the alternative discussed in Section 2.1.4 was originally presented to the public, concern
was expressed by affected landowners that the conveyance channel went through the middle of
several fields. The landowners requested that consideration be given to an alternative where the
conveyance was located along the edge of the fields, thus minimizing impacts to irrigated land.
The City agreed with the request and identified the following alternative. As shown on
Exhibit 3, the conveyance channel would be located along the edge of the agricultural fields.
This alternative would have no effect (adverse or beneficial) on flooding within Atwood and
would provide quite limited flooding control for rural Logan County.

This alternative includes measures to intercept and redirect flood flows to the South Platte River.
A channel would be constructed to collect Pawnee Creek overflow and transport it directly to the
South Platte River. The channel, highway bridge, and railroad bridge would be sized to carry
5,000 cfs floodwater (projected 100-year flood event). Exhibit 2 shows the general location of
the project activities. Specific features are shown in Exhibit 3 and are described below.

2-2