7142

• UCREFRP Catalog Number: 7142
• Author: Joseph, T. W., et al.
• Title: Evaluation of the Status, Life History, and Habitat Requirements of Endangered and Threatened Fishes of the Upper Colorado River System.
• USFW Year: 1977.
• USFW - Doc Type: \
• Copyright Material: NO

recent water resources data, published annually. This information is
well supplemented by works based largely on U.S. Geological Survey data
by the Department of Interior (1977), the U.S. Water Resources Council
(1976), the Utah Water Research Laboratory (1975), and the Upper Colo-
rado Region State-Federal Inter-Agency Group (1971). Many other reports
provide additional information on the water-related resources of the
upper basin; however, a thorough review of the literature on abiotic
components of the rivers in the upper basin is not within the scope of
this evaluation report.
The analysis of abiotic components in this report is intended to
identify only those major changes in the upper basin that impact sig-
nificantly on the fishery. General trends are emphasized, but studies
of specific problems are also used to support the general character
description. The objective of this analysis is to present an overview
of the major changes in abiotic components in the upper basin and
identify the causative factors.
The abiotic components discussed in this report which may be of
major consequence to the resident fishes of the upper basin include:
water flow, salinity, sediment, temperature, pH, dissolved oxygen, and
various other water quality parameters. The historic or virgin condi-
tion of each of these parameters is described in order to assess the
magnitude of change. The causative factor behind each permutation will
be identified whenever data or reliable professional speculation per-
mit.
Water data on the upper Colorado basin are presented in this re-
port as traditionally considered according to three hydrologic sub-
regions (Iorn's et al. 1965): Green River, San Juan-Colorado, and
Upper Main Stem (Figure 1.1). These subregions coincide closely to
the 1401-1403 aggregated subareas (ASA) of region 14 as designated
by the U.S. Water Resources Council (1976).
The Green River Subregion consists entirely of the Green River
drainage and encompasses the greatest area of the upper basin
(44,744 mi2). The San Juan-Colorado Subregion is the drainage area
between the junction of the Green River and Lee's Ferry (38,644 mi2).
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