Pacific Northwest Projects:

Hydropower Projects

Limnological Studies Associated with Hydropower Relicensing


Hydropower field studies are crucial in describing existing conditions of a river or lake and involve a variety of data collection activities ranging from hourly water samples to seasonal population surveys.  These studies help determine the effects hydropower development can have on a river system and evaluate the effectiveness of proposed mitigation and enhancement measures.  

To maintain contact and open communication, public and technical working group meetings are held with various interested parties, such as Native American Tribes, environmental groups, citizen groups, and federal and state agencies. These group meetings provide a forum to present information, review study plans, develop mitigation measures, negotiate license conditions, and generally ensure a cooperative and coordinated process for project relicensing.

Thorough data acquisition and analysis in the field, laboratory, and office contribute to fulfilling the needs of regulatory agencies and meeting the requirements for state certification under Section 401 of the Clean Water Act. E&S scientists have conducted numerous environmental studies for hydropower projects, including:

  • Water quality reconnaissance of North Fork Reservoir and the Clackamas River, Oregon.
  • Limnological studies of Lake Billy Chinook and Lake Simtustus, Oregon.
  • Water quality and biota of the lower Deschutes River, Oregon.
  • Conditions affecting dissolved oxygen in the lower Deschutes River, Oregon.
  • Effects of hydropower development on water quality in the lower Deschutes River, Oregon.
  • Effects of hydropower development on temperature and water quality in the Sandy and Bull Run rivers, Oregon.
  • Modeling the effect of proposed mitigation measures on the limnology of Roslyn Lake, Oregon.
  • Effects of the Sullivan hydropower development on temperature in the Willamette River near Oregon City, Oregon.
  • Development of measures to mitigate extreme pH excursions in Lemolo 2 Forebay, North Umpqua Hydroelectric Project.
  • North Umpqua River water quality and paleolimnological analysis.
  • North Umpqua hydropower project supplemental chlorophyll sampling.
  • Current limnological conditions in the Klamath River hydropower project in Oregon and California.
  • Determination of sediment oxygen demand in reservoirs of the Klamath River hydropower project in Oregon and California.

E&S scientists have also provided technical and regulatory assistance for a number of hydropower projects. Some of the projects are as follows:

  • Pelton Round Butte Project, FERC No. 2030, 400 MW, Deschutes River, Oregon
  • North Fork Project, FERC No. 2195, 127 MW, Clackamas River, Oregon
  • Oak Grove Project, FERC No. 135, 44 MW, Clackamas River, Oregon
  • Bull Run Project, FERC No. 477, 22 MW, Sandy River, Oregon
  • Willamette River Project, FERC No. 2233, 16 MW, Willamette River, Oregon
  • North Umpqua Project, FERC 1927, 185 MW, North Umpqua River, Oregon
  • Klamath Project, FERC No. 2082, 151 MW, Klamath River, Oregon and California