Petaluma River Bacteria TMDL
Petaluma River is listed on the Clean Water Act 303(d) list of impaired water bodies due to elevated fecal indicator bacteria levels (e.g., E. coli). High fecal indicator bacteria levels indicate presence of pathogenic organisms that are found in warm-blooded animal (e.g., human, cows, horses, dogs, etc.) waste and pose potential health risks to people who recreate in contaminated waters. Petaluma River is also listed as impaired due to excessive algae growth, known as eutrophication, which is caused by high nutrient (nitrogen and phosphorus) levels. Eutrophic waters can significantly alter dissolved oxygen and pH levels, which are critical to aquatic wildlife and can impact recreational beneficial uses.
The Petaluma River Bacteria and Nutrients TMDL was initiated to address the current impairment of aquatic wildlife and recreational beneficial uses in this water body. Potential anthropogenic nutrients and bacteria sources in the watershed include livestock, municipal stormwater runoff, septic systems, sanitary sewer systems, pet waste, and vessel marinas. We conducted an impairment analysis for nutrients and pathogens as documented in the project report below. Nutrient concentrations and algae biomass were not consistently elevated in the Petaluma River and tributaries, therefore, we do not have data to warrant a nutrient TMDL at this time. However, fecal indicator bacteria exceeded the applicable water quality standards in Petaluma River and tributaries. Consequently, we are in the process of developing a bacteria TMDL to identify sources of fecal contaminations, and specify actions to reduce sources to levels that will support recreational beneficial uses.
Project Documents and Notices
The Petaluma River Bacteria TMDL is available for public review and comment. The comment period ends on September 3, 2019.
Please Join Our Mailing ListThe Water Board maintains an email notification list for our TMDLs called: “ALL Basin Planning/TMDL Notices and Information.” To ensure you receive future information on this TMDL, we encourage you to subscribe to this list. The instructions for subscribing to the list are provided on the subscriptions page, which you can reach by clicking here.
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