WSP05781

• File Number: 8200.750
• Description: San Juan River General
• State: CO
• Basin: San Juan/Dolores
• Water Division: 7
• Date: 4/1/1994
• Author: Robin Abell
• Title: San Juan River Basin - Water Quality and Contaminants Review - Volume I - April 1994
• Water Supply Pro - Doc Type: Report/Study

2.6 Water Use

2.6 WATER USE
Water use statistics for the basin as a single unitwere unavailable. The best data, approximated
here, ~st for New Mexico. In 1992, 497,414 acre- feet (about 613 million m') of water were withdrawn
for use in the basin within New Mexico; 99% of these depletions were surface water. Water depletions
totaled 337,760 acre-feet (about 417 million m'). Irrigation consumed the most water, with 78% of
withdrawals and 74% of depletions. Mining and power generation constituted the next largest users of
water, together accounting for 10% ofbasin withdrawals in New Mexico and 12% of depletions. Of these
depletions, nearly 100% were of surface water. Livestock, commercial, and industrial uses of water totaled
less than 1% of basin withdrawals, with 73% of withdrawals from surface water sources; these uses
resulted in 1% of basin depletions in New Mexico (Wilson 1992).
Goetz et al. (1987) detennined water use statistics for the New Mexico and Colorado portion of
the basin upstream from Shiprock, NM. In 1965 agriculture accounted for almost 93 % of water depletions
in the area and was projected to equal 77% by 1980. Power generation alone totaled 4% of depletions in
1965 and was projected to reach 16% by 1980. These projections closely match the 1992 New Mexico
statistics, suggesting that water use is fairly unifonn in the basin, at least throughout New Mexico and
Colorado.

2.7 BIOTA
Within the New Mexico portion of the basin, Meneely and Duzan (1979) documented 99 species
of mannnals, 311 species of birds, 14 species of amphibians, 34 species of reptiles, and 50 species of fish.
This review focuses on those species of fish that are native and especially those that are considered rare.
Colorado squawfish (Ptychocheilus lucius) and razorback sucker (Xyrauchen texanus) are both listed as
federally endangered species. Roundtail chub (Gila robusta) and flannelmouth sucker (Catostomus
latipinnis) are federal candidate species, and the roundtail chub is on the New Mexico state list of
endangered species. Other native fish in the basin include. speckled dace (Rhintchthys osculus), bluehead
sucker (Catostomus discobolus), and mottled sculpin (Cottus bairdi).
Factors identified in the decline of San Juan basin native fish include habitat alteration,
fragmentation, and degradation from dam construction as well as competition and predation from exotics
(U.S. Bureau of Indian Affairs 1991). Navajo Reservoir, which was built in 1962 as part of the Colorado
River Storage Project (CRSP), eliminated 35 miles of endangered fish habitat in the San Juan River by
inwlllation and an additional 40 miles by changing the water quality (U.S. Bureau of Reclamation 1992a).
In recent years the Colorado squawfish has only been verified in the San Juan River main channel below
Shiprock, and the razorback sucker has been verified.in the San Juan ann of Lake Powell and near Bluff,
Utah. Roundtail chub have not been identified in the Animas River since the 1970s but have been taken
in the Florida River and the San Juan River at its confluence with the Animas (Figures 8a-c) (Platania
1990,U.S. Fish and Wildlife Service 1993).

3. METHODS
Three questions guided the collection of infonnation for this review: I) What are the contaminants
and water quality problems in the San Juan River basin? 2) What are the sources of the contaminants and
problems? 3) What are the effects of these contaminants and problems on the basin's native fish fauna?
Documents that attempted to answer these questions were'considered for inclusion in this review. For the
purposes of this report, a contaminant is considered any material with the potential, directly or indirectly,
to impair fish health or reproduction. Water quality parameters identified as potential threats to fish health
include temperature, pH, dissolved oll:ygen, salinity, and sediment. No distinction has been made between
anthropogenic and natural contamination, as the mandate of the San Juan River Fisheries Seven Year
Research Plan was to identify any and all threats to the native fish fauna.

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