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Predicting the thermal effects of dam removal on the Klamath River

Environmental Management

By:
, , and
https://doi.org/10.1007/s00267-004-0269-5

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Abstract

The Klamath River once supported large runs of anadromous salmonids. Water temperature associated with multiple mainstem hydropower facilities might be one of many factors responsible for depressing Klamath salmon stocks. We combined a water quantity model and a water quality model to predict how removing the series of dams below Upper Klamath Lake might affect water temperatures, and ultimately fish survival, in the spawning and rearing portions of the mainstem Klamath. We calibrated the water quantity and quality models and applied them for the hydrometeorological conditions during a 40-year postdam period. Then, we hypothetically removed the dams and their impoundments from the models and reestimated the river’s water temperatures. The principal thermal effect of dam and reservoir removal would be to restore the timing (phase) of the river’s seasonal thermal signature by shifting it approximately 18 days earlier in the year, resulting in river temperatures that more rapidly track ambient air temperatures. Such a shift would likely cool thermal habitat conditions for adult fall chinook (Oncorhynchus tshawytscha) during upstream migration and benefit mainstem spawning. By contrast, spring and early summer temperatures could be warmer without dams, potentially harming chinook rearing and outmigration in the mainstem. Dam removal might affect the river’s thermal regime during certain conditions for over 200 km of the mainstem.

Additional publication details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Predicting the thermal effects of dam removal on the Klamath River
Series title:
Environmental Management
DOI:
10.1007/s00267-004-0269-5
Volume:
34
Issue:
6
Year Published:
2004
Language:
English
Publisher:
Springer
Contributing office(s):
Fort Collins Science Center
Description:
19 p.
First page:
856
Last page:
874