2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2018 | 3:00 PM - 3:15 PM | IMPACTS OF A DAM REGULATED FLOW REGIME ON PRIMARY AND SECONDARY PRODUCTIVITY IN THE UPPER EEL RIVER, CALIFORNIA | 420 A
IMPACTS OF A DAM REGULATED FLOW REGIME ON PRIMARY AND SECONDARY PRODUCTIVITY IN THE UPPER EEL RIVER, CALIFORNIA
Flow alterations from dams in northern California watersheds can result in lower primary production into the summer, supporting fewer macroinvertebrates, especially mobile grazers, which make up a disproportionate portion of salmonid diets. The salmonid populations of the Eel River are impacted by the Potter Valley Project, a dam and diversion system on its upper mainstem. Yet, the effects of the dams on the aquatic ecosystem are not known. This comparative observational study examined the algal and benthic macroinvertebrate communities of the mainstem Eel River relative to an undammed river in the same watershed, the Middle Fork Eel River, during the summer of 2017. The steep recession limb in the spring and summer caused by the flow diversions of the Potter Valley Project quickly reduced the channel width relative to the more gradual decline witnessed in the Middle Fork. The Middle Fork Eel had significantly higher percent cover of Cladophora, t(79)=-2.74, p=.008, as well as on significantly higher chlorophyll-a concentrations, t(31)=4.10, p<0.001. By mid-summer, Chironominae and Hydroptilidae, key grazers in filamentous algae were found at abundances that were 12 and 3 times higher than those found in the mainstem Eel River.
- Invertebrate
- Algae
- Bioassessment
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Presenters/Authors
Lara Jansen
(), Humboldt State University, lsj68@humboldt.edu;
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Alison O'Dowd
(), Humboldt State University, alison.odowd@humboldt.edu;
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