FS0018X Feasibility Study 11/01

• Contract/PO #: FS0018X
• Contractor Name: Sterling, City of
• Contract Type: Loan
• Loan Projects - Doc Type: Feasibility Study

The Pawnee Creek/South Platte River confluence is located approximately 4 miles
southwest of the City of Sterling along U.S. Highway 6 (HWY 6) and the Union Pacific
Railroad (UPRR). During large storm events, stormwater overtops the banks of Pawnee
Creek and flows into the City. These overflows are estimated to be 5,000 cfs during the
100-year storm. This study focuses primarily on the reach along Pawnee Creek from its
confluence with the South Platte River upstream to County Road 29 (CR. 29), a distance
of about 7.5 miles. The Vicinity Map (Figure 2)presents the lower portion of the Pawnee
Creek Basin with respect to the City of Sterling. The Pawnee Creek Basin Map (Figure
3) shows the overall Pawnee Creek Drainage Basin, along with a tabulation of pertinent
basin characteristics.
Previous Reports
Several studies have been completed to investigate the existing flooding conditions in the
City of Sterling and surrounding Logan County. Some of these studies address
alternatives for mitigation to the flooding problems. The City of Sterling is subject to
flooding from four major sources which include the South Platte River, Pawnee Creek,
Sand Creek, and the Pioneer Drainage Ditch. One recent study, "City of Sterling
Drainage and Flood Control Implementation Plan" dated June 1997, by ICON
Engineering, Inc. concluded that addressing the flooding problems associated with the
Pawnee Creek should be given the City's highest priority, and would result in the most
feasible and economical plan of improvements for the area. As a result of flooding
events that occurred in 1997 and discussed in detail within this report, the City and
County have determined that resolution of the Pawnee Creek drainage problems must be
appropriately implemented. The following reports were reviewed as a part of this study:
Reference Reports:
1. Flood Hazard Mitigation Reconnaissance Study Pawnee Creek Basin, by ICON
Engineering, Inc. dated August 2000.
2. City of Sterling Drainage And Flood Control Implementation Plan, by ICON
Engineering, Inc. dated June 1997.
3. Pawnee Creek - Logan County, Colorado: Flood of July 1997, (Draft) by Colorado
Water Conservation Board, dated October 1997.
4. Flood Plain Information and Drainage Plan for Sand Creek and the Pawnee Creek
Overflow at Sterling, Colorado by Charles F. Leaf and Resource Consultants, Inc.,
dated May 1983.
5. Sand Creek Watershed, Sterling, Colorado by the U.S.D.A. Soil Conservation
Service, dated August 1984.
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