9473

• UCREFRP Catalog Number: 9473
• Author: Anderson, R. and G. Stewart.
• Title: Riverine Fish Flows Investigations.
• USFW Year: 2001.
• USFW - Doc Type: Fort Collins.
• Copyright Material: NO

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filings were based on recommendations made by the U. S. Fish and Wildlife Service

(USFWS) in regard to recovery of endangered fish species [Modde and Smith (1995) and
Osmundson et al. (199S)]. In a more recent study Modde et al. (1999) used an infection point

method to assess minimum stream flow needs for Colorado pikeminnow (Ptychocheilus

lucius) on the Yampa River. Even though the intent of these studies was the same, to

determine stream flow requirements for endangered fish, the methods in each study were

different. The CWCB expressed a desire to have a more standardized approach for instream

flow filings and it is hoped that recommendations using this approach will be acceptable to

agencies involved with endangered species recovery.

Study Objectives:

1). Model fish habitat availability on warm water sections of three rivers (Yampa,
Colorado and Dolores) using the established methods (ld models) and evaluate the
practically of using 2d flow models to quantify fish habitat.

2). Determine community structure, density and biomass for fish assemblages for
river reaches listed above.

3). Test for relationships between habitat availability and fish abundance.

4). Develop and validate methodologies that use I-D and 2-D flow models for the
Division of Wildlife to use for minimum instream flow recommendations for the warm
water sections of the Yampa and Colorado rivers.

Study Area

Yamna River

A new study site was added to the Yampa River in 2000 increasing the total number of

study areas to three. The two sites established in 1998 are Sevens and Duffy and are

described in earlier reports. The Sevens station is located at River Mile (RM) 63 and Duffy is

3