Case No. 3:07-cv-08164-DGC Grand Canyon Trust v. U.S. Bureau of Reclamation December 7 2007

• Description: Case No. 3:07-cv-08164-DGC Grand Canyon Trust v. U.S. Bureau of Reclamation December 7 2007
• State: CO
• Date: 12/7/2007
• Title: Case No. 3:07-cv-08164-DGC Grand Canyon Trust v. U.S. Bureau of Reclamation December 7 2007
• Water Supply Pro - Doc Type: Court Documents

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FACTUAL BACKGROUND
I. HUMPBACK CHUB AND ITS RIVER HABITAT
The humpback chub is a three -to -five million - year -old fish native only to the
Colorado River Basin. Exh. 9 (2002 Recovery Goals) at A -1. The chub gets its name from
the dorsal hump that develops behind its head as it matures. With its "prominent hump,"
chub can survive in fast moving water; the hump "cause[s] the fish to be pushed to the
bottom [of the river] where water velocities are lower and less energy is required to hold
[its] position." Exh. 2 (1990 Recovery Plan) at 2.
The humpback chub evolved in a unique desert river environment. Chub live in
river canyons, characterized by both fast - moving waters with rapids, and sheltered
shoreline areas. Exh. 9 (2002 Recovery Goals) at A -4. High spring run -off builds sandbars
and eddies that support shoreline habitats, maintains channel and habitat diversity, flushes
sediments from spawning areas, rejuvenates food production, and forms the gravel and
cobble deposits used for spawning. Id. at viii. High springtime flows also signal the
spawning season for the chub. Exh. 3 (1994 BO) at 10. Low flows during the summer and
fall distribute sediments and allow them to settle and form shoreline habitats. Exh. 11
(SCORE) at 18, 19, 26. Shoreline habitats with low flow velocities and warm water are
extremely important because they act as nurseries for young chub. Exh. 3 (1994 BO) at 11,
23, 27. Sufficient sediment in the river system is necessary to build beaches and create
shoreline habitats. Exh. 11 (SCORE) at 19, 26.
Historically, the chub's habitat range extended throughout the Colorado River Basin,
from the Flaming Gorge on the Green River in Wyoming to below the Grand Canyon on
the Colorado River in Arizona. Exh. 9 (2002 Recovery Goals) at A -1 - A -3. The chub's
current range, however, represents a fraction of that and is limited to approximately six
isolated populations, including one in the Grand Canyon below the Glen Canyon Dam. Id.
at 10, 20. The primary cause of this reduced range is dam construction and operations. Id.
Memorandum in Support of Ms.'
Motion for Summary Judgment
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