BOARD00038 ‎(2)‎

• Board Meeting Date: 9/20/2006
• Description: WSP Section - San Juan River Recovery Implementation Program Document Revisions
• Board Meetings - Doc Type: Memo

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CHAPTER 3: SAN JUAN RIVER BASIN RECOVERY
IMPLEMENTATION PROGRAM

Impacts to Fish Species

In 1922, representatives of the seven Colorado River Basin states of Arizona, California,
Colorado, Nevada, New Mexico, Utah and Wyoming signed a compact dividing the consumptive
use of water from the Colorado River system between the Upper Basin and the Lower Basin. The
compact was ratified by the legislatures of all the states except Arizona, and the President of the
United States proclaimed the compact effective in 1929. Arizona later ratified the compact in
1944. In 1948, the Upper Basin states, including Arizona, Colorado, New Mexico, Utah and
Wyoming, signed the Upper Colorado River Basin Compact to apportion among them the
consumptive use of water available to the Upper Basin pursuant to the Colorado River Compact.
The Colorado River Storage Project (CRSP) Act in 1956 subsequently authorized for
construction Glen Canyon Dam and Lake Powell on the Colorado River, Navajo Dam and
Reservoir on the San Juan River, Flaming Gorge Dam and Reservoir on the Green River, and the
Aspinall Unit on the Gunnison River.

The construction of these impoundments was essential for the development of water storage and
flood control and to allow the Upper Basin States to develop their compact apportionments while
complying with Article III of the Colorado River Compact. However, physical and biological
changes to the environment, such as the modification of the natural flow regime and changes in
water temperature and quality resulted from the construction of such large impoundments within
the Upper Basin. This contributed to the endangerment of four native fish species ofthe Colorado
River system. Within the San Juan River Basin, two of these species, Colorado pikeminnow and
razorback sucker, inhabit the San Juan River. The other two species, bonytail chub and
humpback chub, may have occurred historically in the river.

Other human-induced impacts in the San Juan River Basin included the use of selective chemical
treatments applied in the San Juan River to eradicate native species and introduction via stocking
of non-native sport fish species. In addition, contamination of waterways in the Basin resulting
from oil and gas development, grazing and other watershed land uses, agricultural return flows
and urban development, along with attendant contaminants from urban runoff and sewage
effluent, has affected the aquatic environments of the San Juan River system. The effects of these
and other impacts resulted in extremely low population levels of Colorado pikeminnow and
razorback sucker in the San Juan River.

Pre-Program Consultation History

Species Listings

The Colorado pikeminnow and the humpback chub were listed in 1967 as endangered. Since the
passage of the Endangered Species Act of 1973, two other species of Colorado River fishes have
been listed as endangered. The bonytail was listed in 1980, and razorback sucker was listed in
1991. As required under section 7 of the Endangered Species Act, federal agencies whose actions
may affect listed species must consult with the U.S. Fish and Wildlife Service. This is to insure

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