Water Management Study: Phase 1 Report

• File Number: 8461.100
• Description: Adaptive Management Workgroup
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 1/29/2008
• Author: Boyle Engineering, Ecological Resource Consultants, BBC Research & Consulting, Lytle Water Solutions
• Title: Water Management Study: Phase 1 Report
• Water Supply Pro - Doc Type: Report/Study

1.0 INTRODUCTION AND PURPOSE
Phase I of the Water Management Study (WMS) for the Platte River Recovery
Implementation Program (PRRIP or Program) evaluates the ability of the Program to achieve
pulse flows of Program water during the low demand period on the Platte River in central
Nebraska for the benefits of four threatened or endangered species. Phase I also evaluates the
potential to provide a maintenance flow to the same habitat during the summer irrigation
months. This report presents the results of this Phase I evaluation. The study will be used by
the Governance Committee of the PRRIP to meet certain Program water supply objectives,
including the determination of water delivery timing and quantities, and additional water
supply and conservation project needs.
Figure 1-1 entitled, "Study Area and Locations" illustrates key locations on the Platte River
in central Nebraska which are referenced in this report. Figure 1-1 is located at the end of the
main report section.
The Phase I study objective is to evaluate the feasibility of ineeting the following water
supply goals by December 31, 2011:
1. Provide 5,000 cubic feet per second (cfs) pulse flow of Program water for three
days to the Overton gage on the Platte River in central Nebraska when other
demands that may be competing for river channel and irrigation system capacity
are low (normally September 1 through May 31). Program water is intended to
supplement existing flows to achieve pulse flows in excess of 6,000 cfs two out of
three years. If these flows are achieved entirely or partially by flows without
Program water, deliveries of Program water would be eliminated or reduced,
respectively.
2. Provide 800 cfs of Program water at the Overton gage during the irrigation season
continuously from May 1 through September 30. The target period for the 800 cfs
flow evaluated corresponds to May 1 to September 30. USFWS indicated that the
800 cfs flow is intended to augment flows from May 11 to September 15 as
B042E Page 1 of 58 January 29, 2008
PRRIP - Draft Water Management Study, Phase I