BOARD01565

• Board Meeting Date: 5/22/2000
• Description: WSP Section - Colorado River Basin Issues - Aspinall Operations/Flow Recommendations
• Board Meetings - Doc Type: Memo

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STATE OF COLORADO

Colorado Water Conservation Board

Department of NaturaI Resources
1313 Sherman Street, Room 721
Denver, Colorado 80203
Phone, [phone]
FAX, [phone]

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Bill Owens
Governor

Greg E. Walcher
Executive Director

MEMORANDUM

Peter H. Evans
ewes Director

Dan McAuliffe
Depu ty Director

TO:

Colorado Water Conservation Board Members

FROM:

Randy Seaholm, ~
Chief, Interstate Streams Investigations Section

DATE:

May 16, 2000

SUBJECT: Agenda Item 17f, May 22-23, 2000 Board Meeting
Colorado River Issues
Aspinall Operations/Flow Recommendations

Introduction

This is an informational item that deals with the draft final flow recommendations to
benefit Endangered Fishes in the Gunnison River and the Colorado River downstream of
the Gunnison River confluence.

Background

On January 27, 1999 the United States Fish and Wildlife Service (FWS) released their
draft final flow recommendations to benefit endangered fishes in the Gunnison and
Colorado Rivers. This draft final report compiles information from various studies that
were carried out within the Gunnison and Colorado River Basins to determine the effects
of operation of the Aspinall Units on endangered fish. The studies concentrated on the
humpback chub, Colorado pikeminnow and razorback sucker.

Mimicry of the natural hydrograph is the foundation of the flow recommendation for the
Gunnison and Colorado rivers. Flow recommendations were developed for six hydrologic
categories that correspond to the April - July unregulated inflow to Blue Mesa Reservoir
based on the 1937-1997 period of record. The following tables reflect the proposed flow