Best Management Practices Improve Water Quality on the Point Reyes Peninsula

Through a collaborative effort, the historic ranches on the Point Reyes peninsula put in place a total of 30 best management practices. These included adding manure management infrastructure, fencing, and livestock watering facilities, and covering cattle concentration areas.

Voeller, D. J., Ketcham, B. J., Becker, B. H. 2021. Improved Microbial Water Quality Associated with Best Management Practices on Coastal Dairies and Livestock Grazing Operations. Rangeland Ecology and Management, 76(1), 139-149.

April 2021 - Dairy and cattle ranching can contaminate streams with fecal indicator bacteria like E. coli. Such bacteria can harm human and ecosystem health. But changing ranching practices can dramatically reduce this risk. In 2019, Point Reyes National Seashore staff worked on a case study showing how water quality improved concurrent with grazing management practice implementation in the Olema Creek watershed. Now, they’ve published a new case study. This one looks at trends in water quality on the Point Reyes Peninsula where grazing management practices were also being implemented.

The case study, Improved Microbial Water Quality Associated with Best Management Practices on Coastal Dairies and Livestock Grazing Operations, involved analysis of 13 years of fecal indicator bacteria data. From 2000–2013, park scientists collected the data from monitoring stations in the Kehoe Creek, Abbotts Lagoon, Home Ranch Creek, and East Schooner Creek watersheds. Meanwhile, the historic ranches in the area were hard at work. Through a collaborative effort, they put in place a total of 30 best management practices. These included adding manure management infrastructure, fencing, and livestock watering facilities, and covering cattle concentration areas. Each action served to better control manure, runoff, and cattle access to streams.

Overall, fecal indicator bacteria concentrations declined by 54-99% over the course of the study. The scientists also found that water samples met regulatory criteria six times more often. Reductions were more pronounced within watersheds containing dairies (Abbotts and Kehoe). In the watershed with few livestock and no management practices put in place (East Schooner Creek), there was a slight upward trend. Rainfall events also caused fecal indicator bacteria concentrations to increase.

Bacteria concentrations may still periodically exceed regulatory objectives. Nonetheless, these findings add to the growing body of literature demonstrating the effectiveness of targeted agricultural management practices. Informed by monitoring, such practices reduce fecal indicator bacteria concentrations in waterways. They are, in short, powerful tools for meeting water quality targets across mixed-use watersheds.

For more information

• Voeller, D. J., Ketcham, B. J., Becker, B. H. 2021. Improved Microbial Water Quality Associated with Best Management Practices on Coastal Dairies and Livestock Grazing Operations. Rangeland Ecology and Management, 76(1), 139-149.

• Contact Point Reyes Range Program Manager/Ecologist Dylan Voeller

• Pacific Coast Science & Learning Center Water Quality webpage

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