Sediment Sampling Results for Heavy Metals
Sediment transport resulting from the Lower Klamath Dam Removal Project (Project) has resulted in turbid river waters, prompting public concern over potential health effects of elevated heavy metals within the water column and riverbed sediments. Residents and recreators alike have expressed their unease at using Klamath River water for irrigation and agricultural purposes, as well as the deleterious effects of exposure to the water from activities such as fishing, boating, and swimming. The Project proponent, the Klamath River Renewal Corporation (KRRC) is responsible for monthly continuous water quality monitoring and collection of grab samples of Klamath River water. However, results of these efforts are delayed through the Federal Energy Regulatory Commission (FERC) process, and KRRC has denied Siskiyou County’s request for the monitoring results in a timelier manner. Therefore, in response to the public’s concerns, Siskiyou County Environmental Health Division has been directed by the County Board of Supervisors to perform quarterly water quality and sediment sampling.
The following memo to the Siskiyou County Board of Supervisors discusses in detail the analytical results from the County’s July 2024 sediment sampling effort. These results indicate that the pre-dam removal heavy metal concentration in the Klamath Riverbed below the Iron Gate Dam footprint is similar to the post-dam removal concentration. However, due to limited baseline data, and post dam removal data, it is not possible to derive any trends in heavy metal concentration post-dam removal. In some cases, such as with iron and aluminum, the pre-dam removal concentration is higher than at post-dam removal concentration. Table A shows the concentration of heavy metals during pre-dam removal conditions and after dam removal.
The following memo outlines the background, methodology, baseline information, and results of the County sediment sampling that occurred in July 2024.
Please view the full Memorandum below for more information.
