FLOOD05819

• County: Logan
• Community: Sterling
• Basin: South Platte
• Title: City of Sterling Drainage and Flood Control Implementation Plan
• Date: 6/1/1997
• Prepared For: Sterling
• Prepared By: ICON Engineering, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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estimate for the proposed roadway crossings. The proposed crossings are presented in Table 4 along
with their priorities, the estimated 1988 cost and the updated 1996 cost.

Table 4. Cost Summary for tbe 1988 Leaf Summary Report

Location Proposed Crossin~ Priority Estimated 1988 Cost Updated 1996 Cost
($) ($)
Phelps Street 108" CMP I 34,500 46,841
HWYI4 108" CMP 1 348,000 472,481
1/2 mile North of 15'-4"X9'3" 1 64,500 87,572
HWYI4 Pipe Arch
Franklin Street 17'-II"X9'-4" 2 114,000 154,778
Steel Box Culvert
North Seventh 20'-11" X 10'-4" 2 150,000 203,656
A venue Steel Box Culvert

Flood Insurance Study, City of Sterling, Colorado, Logan County by Federal Emergency
Management Agency, dated September 19,1989 (Reference 6).
This study investigates the existence and severity of flood hazards in the City of Sterling. The report is
used as an aid in the administration of the National Flood Insurance Program. The hydrology and
hydraulics used in this study for Pawnee and Sand Creek were adopted from the 1983 Leaf/RCI
Report.

Flood Plain Management Study, Pawnee Creek in Logan County, Colorado by U.S. Department of
Agriculture, Soil Conservation Service, dated Apri/1991 (Reference 7).
The objective of this study is to provide detailed floodplain management information. Mapping was
prepared for the Pawnee Creek area and the report includes detailed hydrology and hydraulics. Seven
potential dams and reservoirs were considered for the purpose of reducing flooding on Pawnee Creek.
In addition, a system of levees was proposed to prevent overflows from reaching the City of Sterling.
The report recommends considering the system of levees to prevent overflows and suggests that the
seven proposed dams may not be cost effective in terms of benefit cost relationships. A summary of
the estimated cost for the propose alternatives is presented in Table 5.

Table 5. Cost Summary for the 1992 SCS Report

Alternative Estimated] 992 Cost ($) Updated 1996 Cost ($)
Seven Dams and Reservoirs 23,080,577 27,365,885
System of Levees 867,570 1,028,649

Section 11 Planning Assistance, Major Drainageway Plan Pioneer Ditch at Sterling, Colorado by
U.S. Army Corps of Engineers, dated December 1995 (Reference 8).
The focus of this study was to provide technical information to the City of Sterling regarding flood
reduction measures along the Pioneer Ditch. The hydrology used in this study was adopted from the
1988 Leaf/RCI Report, The HEC-2 models prepared for the 1983 Leaf/RCI Report were updated and
modified to analyze proposed bridge and channel improvements and a spreadsheet was prepared to

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