Aquatic Invertebrate Dam Removal Monitoring

Project Description: A primary uncertainty concerning the removal of four dams on the Klamath River is how such actions will affect native biota, including salmon stocks. Dam removal is expected to mobilize millions of cubic yards of stored sediment, functionally shifting river dynamics and changing channel morphology. Removal of the dams will also force biota from reservoirs and enable them to invade the riverine environment. Such changes will elicit a strong biological response. In order to understand the impact and subsequent recovery of native species, before- and after-dam removal studies are necessary. Quantifying changes to river biota through time is critical to inform adaptive management and define the response trajectory of the Klamath River post dam removal. Quantifying the response of dam removal and communicating how the river is changing to tribal members, local constituents, stakeholders, rural communities, and those contemplating dam removal in other river systems is fundamental to measuring dam removal success.

The primary goal of this task is to determine the species composition and relative abundance of macroinvertebrates in the Klamath River. It is anticipated that after dam removal, this study could be repeated and the results compared to previous data collections. Our specific objectives for this task are to quantify the relative amount and types of benthic organisms over time and space for mainstem Klamath River environments and analyze the data and make it available for use in determining effects of management actions such as dam removal, and to refine future management actions.



In order to achieve project outcomes, we propose to collect macroinvertebrate relative abundance data from the bed (benthos) of the river. This data will be collected four times per year at approximately ten different study locations. The exact locations of study sites will be chosen based on their geographic locations and accessibility. Sampling sites will be more numerous in the first ten miles downstream of Iron Gate Dam as this is where we expect the greatest amount of habitat change to occur.



Macroinvertebrate benthic samples will be collected using a kick net with a mesh size of 500 µm and a one by one-foot sampling square. All rocks within this square will be rubbed for 60 seconds, with the invertebrates floating into the kick net. Macroinvertebrate samples will be preserved in bottles using a 90% ethanol solution for later processing. Sample processing will be conducted by the Center for Watershed Sciences at the University of California, Davis (or other qualified contractor) and this project will allow the YTFP to process any previous collections made related to this study. All samples will be quantified and have a taxonomic breakdown provided for the invertebrates contained in the collections

The benefit of this project will be shown through the high-quality data that we plan to collect. This data set will be extremely important to researchers and river managers before, during and after dam removal is complete. Information gathered during this venture will help inform adaptive management, fish re-population efforts and river restoration projects. Data from these invertebrate collections can inform researchers and river managers of baseline riverine conditions before and during dam removal.



An extremely important measure of the project’s success will occur after dam removal is complete. River managers will be closely monitoring how fish (especially salmonids) are responding to the changes that come with dam removal. It is imperative that biological data from the pre-dam removal period exists in order to make assumptions regarding the response of Klamath River fish stocks. For example, if SONCC ESU Coho Salmon populations seem to be suffering after dam removal, this baseline data set can help to ascertain whether the food web has recovered or if the problem lies elsewhere.