FLOOD10325

• County: Douglas
• Community: Hayman
• Stream Name: Horse Creek, Fourmile Creek, Trout Creek
• Title: Hayman Fire Area - Contract
• Date: 5/30/2003
• Prepared For: Douglas County
• Prepared By: Moser Engineering
• Floodplain - Doc Type: Contract

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Scope of Services
February 26, 2004
Post-Wildfire Flood Hazard Delineation for the Hayman Burn Area

Objective:
The purposes of this work is to provide assistance for a technical effort related to post-
wildfire flood hazard delineation related to the Hayman Bum area in Douglas County,
Colorado.

Performance Period:
This scope is valid for services performed during the period through June 30, 2004.

Funds Recipient:
The work will be administered by Douglas County. The CWCB's funding for this
project is $15,000. Additional project funds will be provided by the County and the U.S.
Geological Service for completion of this work.

Summary of Requested Work:
This scope of work includes the hydrologic modeling of the Trout Creek, West Creek,
and Four Mile Creek watersheds within the Hayman Fire Area. The intent of the
modeling will be to use the USGS provided "long-term" Curve Number (CN) values for
each of the subwatersheds and include this parameter in the existing SCS (Natural
Resource Conservation Service, formerly Soil Conservation Service) rainfall-runoff
method within HEC-HMS. The results of the modeling will be used to identify peak flow
rates from the tributaries.

It is anticipated that no other hydrologic methods (stream gage statistical analysis, a
different rainfall runoff model, etc.) will be required by FEMA. It is also anticipated that
FEMA will accept the USGS CN determination methodology and use of the SCS rainfall-
runoff method without any comments that affect the modeling completed as part of this
scope of work.

Completion of Work/Payment Schedule:
Funds will be provided to the County solely for the purpose of completing tasks related to
this Scope of Services. In the event the project is not invoiced within the specified
performance period, the funds will not be available to the County. The CWCB will pay
Douglas County $15,000 when the work is completed and the final invoice has been
received.

Deliverables:
A draft report will be prepared and delivered to the CWCB on or prior to May 30, 2004.
The report will summarize the methodologies and results of the study and comments
from CWCB will be incorporated prior to final publication.