Presenter/s: Desiree Tullos
Symposium Session: 2024 - 09 Different Dam Problems with Different Dam Solutions
Topics covered: instream structure (culvert/bridge/dam), traditional ecological knowledge, and water quality
ABSTRACT
Water quality is an often-underappreciated aspect of river health. In northern California’s Klamath River, the world’s largest dam removal is expected to improve water quality, but how the dam removal will affect current high rates of primary production is less clear. The removal of four hydroelectric dams is somewhat unique due to the scale of the project and anticipated impacts on water quality: The project will release 13M cy of mostly fine mineral and organic sediments and re-establish longitudinal transport of sediment and nutrients. The dam removal will eliminate reservoir-derived cyanobacterial blooms, but the interacting changes to nutrients, turbidity, and winter scour make predicting changes to production challenging. Primary production in the Klamath River contributes to sags in dissolved oxygen and pH that impact ESA-listed salmon, and algal proliferations clog boat motors and tribal fishing nets, and decline perceived aesthetics and recreational access.
The broad goals of this research are to document seasonal progression of primary producer assemblages and habitat associations and to compare changes to primary production dynamics before, during, and after dam removal. This research is part of a larger project examining the ecological and socio-cultural dimensions of water quality, primary production, and river health in the Klamath Basin throughout dam removal. The project includes partnership across multiple institutions, including the Yurok Tribe, with a core emphasis on exploring multiple ways of knowing in making decisions about water quality management.
The presentation will include a summary of methods and results from 2023 field observations of biomass and % cover of periphyton, filamentous algae, and macrophytes, along with their water quality and habitat correlates (turbidity, PAR, substrate, nutrient concentrations). In addition, this presentation will include summaries of Tribal perspectives and knowledge on water quality and algae, documented during interviews with elders and leaders within the Yurok Tribe. Collectively, these results translate to conceptual models and hypotheses based on multiple ways of knowing, which will be presented, regarding expected changes for the river following drawdown and removal of the largest dams, set to begin in January 2024.