7378

• UCREFRP Catalog Number: 7378
• Author: Wydoski, R. S.
• Title: Potential Impacts of Alterations in Streamflow and Water Quality on Fish and Macroinvertebrates in the Upper Colorado River Basin.
• USFW Year: 1980.
• USFW - Doc Type: 77-147
• Copyright Material: YES

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Table 7. Water Depth and Velocity Used for Spawning by Warm-Water
and Cool-Water Fish

of these depletions are from irrigation and associated uses (U.S, Water

Resources Council. 1971). These depletions often occur in rather small

amounts but cumulatively can have a large impact overall. Further re-

Depth Velocity
Species (meters) ( feet) (em/see) (feet/see)
Paddlefish variable variable 49-91 1.6-3.0
Shove1nose sturgeon 0.3-0.9 1.0-3.0 75-150 2.5-4.9
Creek chub -- -- 49-91 1.6-3.0
Longnose dace 0.03-0.3 0.1-0.7 15-45 0.5-1.5
Longnose sucker 0.2-0.3 0.7-1.0 31-45 1.0-1.5
White sucker 0.2-0,3 0.7-1.0 31-45 1.0-1.5
Shorthead redhorse 0,3-0,9 1.0-3.0 31-61 1. 0-2. 0
Smallmouth bass 0.9-1.8 3,0-5,9 11 0.36
Largemouth bass 0.3-1. 8 1.0-5,9 0 0
Walleye 1. 2-1.5 3,9-4.9 0-50 0-1.6
Sauger 1.2-1.5 3.9-4,9 0-50 0-1.6

duct ions are anticipated for the system in the near future, For example.

the U.S. Water Resources Council estimated that the water exported

from the Green River will increase from 0.12 to 0.65 million acre-feet

and on-site depletions will increase from 0.87 to 1.67 million acre-feet

between 1965 and 2020. The Council estimated similar depletions for the

upper main stem of the ColoradO River--from 0,43 to 0,88 million acre-

feet by export and from 0.97 to 1.35 million acre-feet by on-site deple-

tions for the same time period.

At the present time. it is not possible to make many predictions on

the responses of fish to changes in streamflow because the requirements

of many species or the life stage of a particular species may not be known.

Source: K. D. Bovee. The Determination, Assessment and Desi2Q of
"In-Stream Value" Studies for the Northern Great Plains Rel!:ion. Final
Report. EPA Contract No. 68-01-2413 (Missoula. Mont.. University of
Montana. 1974).

It is particularly important to emphasize that quantitative data be ob-

tained on the streamflow requirements by species and for each life sta~e

if predictions of fish responses to changes are to be made with accuracy.

Responses of Macroinvertebrates to Streamflow

Water flows can greatly affect the invertebrates that are a major

source of food for fish. Reduced water flows can limit the abundance

and diversity of swift-water invertebrates. and excessive flows can

scour the substrate and become detrimental (Giger. 1973; Ward. 1976),

A summary of several studies comparing the relationship between water

velocity in riffles and the numbers of bottom organisms shows that the

numbers of organisms can differ considerably in different streams for a

given water velocity (table 8). Large differences can also exist in

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