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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.en'.THREE AUected Environments and Environmental Consequences

hydrologic modeling performed by Sterling's consultant, the benefits would be substantial.
Based on this study, the City has completed and submitted a Conditional Letter of Map Revision
(ICON 2001) in which the City requested FEMA remap the area downgradient from the
proposed channel because they believe a large area would no longer be within the 100-year
floodplain. Since the proposed action would not be expected to result in any adverse impacts on
the hydrology and/or hydraulics of the floodplain within the stndy area, no mitigation measures
would be needed. Therefore, it was determined that the alternative would comply with the intent
ofE.O. 11988 and would be in full compliance with the regulations of the NFIP. It would be
expected that floodplain permits and variance requirements would be issued in a timely manner.

The Proposed Action would reduce the magnitude and duration of future Pawnee Creek flood
events. The exact effect would depend on the magnitude ofthe flood event and the location
within the floodplain. Based on the modeling of the flood flows associated with the 1997 flood,
this alternative would protect Sterling from the 100-year flood event. Based on these modeling
results, a Conditional Letter of Map Revision was completed for this alternative (ICON 2001).
Based on this report, the City has requested that FEMA remap the area downgradient from the
proposed conveyance channel because they believe that much of the area would no longer be
within the 100-year floodplain.

Personal communication (January 14, 2002) with George Good, Planning and Zoning
Commissioner for the City of Sterling, verified that Sterling is in full compliance with the NFIP.
He also verified that the proposed project would be in full compliance with the regulations ofthe
NFIP and that any and all floodplain permits, variances, and requirements would be issued for
the project in a timely manner.

3,2.1.3

Alternative 3 -Improve Routing of Pawnee Creek Flood Flows

Several features of this alternative would be developed within the 100-year floodplain of either
Pawnee Creek or the South Platte River. Issues and procedures followed in the evaluation ofthis
alternative are the same as discussed for Alternative 2 in Section 3.2.1.2. Since this alternative
would be constructed further downgradient (closer to Sterling), the amount of land that would be
removed from the 100-year floodplain is lower than Alternative 2.

Personal communication (January 14,2002) with George Good, Planning and Zoning
commissioner for the City of Sterling, verified that Sterling is in full compliance with the NFIP
(Appendix C). He also certified that the proposed project would be in full compliance with the
regulations of the NFIP and that any and all floodplain permits, variances, and requirements
would be issued for the project in a timely manner. As stated previously, Logan County and
Sterling have implemented controls, zoning, and development regulations, along with effective
land use planning to reduce and control development within the floodplain associated with the
Pawnee Creek bypass flows.

This alternative would be expected to protect Sterling from the lOO-year flood event.

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