Water-Quality Monitoring and Modeling of the Keno Reach of the Klamath River

Aerial photo of Keno impoundment (Photo by T. Roninger, USFWS, 24-Aug-2006)

The Klamath River from Link River to Keno Dam (map) experiences poor water-quality conditions on a seasonal basis, creating inhospitable conditions for fish and other aquatic organisms. The Link River, the Klamath Straits Drain, and the Klamath River at Keno all were classified as having "very poor" water quality in summer by the Oregon Water Quality Index (Mrazik, 2006). The Klamath River in this reach also was included on Oregon's 2004/2006 list of impaired waterbodies for problems related to ammonia, chlorophyll (algae), dissolved oxygen, and pH. These problems mean that the Oregon Department of Environmental Quality will need to prepare a plan, or TMDL, to bring the river back into compliance with water-quality standards.

Although particular attributes of water-quality impairment have been identified, certain processes still need to be quantified to explore the full range of restoration options. While inflows of water from Upper Klamath Lake and agricultural drains are known to affect water quality, instream processes also can be significant drivers of water quality in this reach. This study will include extensive data-collection and water-quality modeling components to build on previous efforts (e.g., monitoring by Bureau of Reclamation, modeling by PacifiCorp [Watercourse Engineering, Inc.]) to improve the understanding of processes affecting water quality in this reach and give insight into pathways for water-quality improvement.

This study focuses on the 21-mile reach from the Link River and Lake Ewauna to Keno Dam and is projected to last for several years beginning in 2006. In 2007 and 2008, field data will be collected to characterize inflows of nutrients (nitrogen and phosphorus), organic carbon, algae, zooplankton, and biochemical oxygen demand (BOD) from Upper Klamath Lake. Additional samples collected at downstream locations and at major inflow points will characterize changes in these constituents as the water moves through the reach to Keno Dam. Directed research will be conducted in 2007 and 2008 to examine the transport, health, growth, death, settling, and decomposition of algae as they move from Upper Klamath Lake downstream through the study area, as well as the conditions originating within Keno Reservoir.

Results from the field data and associated research will be used to construct or modify a model to evaluate the dynamics of water quality in the Keno reach. Modeling work will include development of both a conceptual model and a quantitative hydrodynamic and water-quality model. Scenarios that could be considered with the selected model include simulations of the effects of increased flows, lower water levels, treatment wetlands, in-reservoir activities (e.g., management plans, modification), and changes in the composition (nutrients, organic carbon, algae) of the inflows.

This study is a joint collaborative effort between the Bureau of Reclamation, Watercourse Engineering, Inc., and the U.S. Geological Survey's Oregon Water Science Center. All three partners have significant roles and will contribute to the study's results.