3110

• UCREFRP Catalog Number: 3110
• Author: Sublette, J. E.
• Title: Survey Of The Fishes Of the San Juan River Basin, With Particular Reference To The Endangered Species.
• USFW Year: 1976.
• USFW - Doc Type: Albuquerque, New Mexico.
• Copyright Material: NO

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Olsen (l967) stated, "prior to June 27, 1962, the San Juan River supported

a marginal warm-water fishery. The water level fluctuated drastically and

turbidities were high throughout the year.

At this time the Navajo Dam was completed and the waters of the San

Juan and Pine Rivers were impounded to form Navajo Reservoir with the lake

acting as a settling basin and subsu~face water release through the dam, the

San Juan River, below Navajo Dam, was transformed into an' excellent trout water."

From the standpoint of game fish management the construction of Navajo

Dam undoubtedly was a significant advance. However, it is no small coincidence

that the native fish fauna, with the exception of four species (bluehead and

flannelmouth suckers, speckled dace, and Colorado mottled sculpin), has been

eradicated or reduced to a point of eradication.

The construction of dams, per,se, has not beeneocally responsible. A

history of deliberate and accidental stocking of game and pan fish and bait

minnows extending back into the last century has undoubtedly also been a

contributing factor.

The downstream effects of Navajo Dam are pronounced to well below

Farmington. According to a report "Water Quality in New Hexico" (Anon. 1975)

the following water quality parameters are recorded for che period 1966-1974:

Station Ave. Ann. Suspended Turbidity Sulfates Chloride TDS TDS
Flow Sediments (JTU) (Mg/ I) (Hg/ l) (Mgl1) (Tons/day)
(CFS) (Mg/l)
San Juan nr
Archuleta 1070 8 46 3 161 766
Animas at
Farmington 915 5288 95 96 9 260 l081
San Juan at
!armington
San Juan at
Ship rock 2045 24337 278 184 10 376 38(':0
San Juan nr.
!luff. Utah 2520 33l0l 313 19 616 9497

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