Baykeeper Update

Full of it: Keeping Horse Manure out of the Petaluma

One of the largest horse boarding facilities in the country lies on the banks of the Petaluma River (pictured, above). For years, there's been nothing to stop the horse manure from flowing straight into the river and downstream to San Francisco Bay. 

Manure runoff contains unlawfully high levels of bacteria, nitrogen, ammonia, phosphorus, and toxins, all of which are hazardous to public health and wildlife.  

"Dangerous levels of bacteria have shown up in every water sample from the Petaluma River taken by agencies since the 1970s," says Baykeeper Staff Attorney Ben Eichenberg. "We suspected that the fouled runoff from hundreds of horses at Sonoma Horse Park had contributed to the problem."

Last rainy season, Baykeeper scientists conducted an extensive field investigation in the area. Our water sampling confirmed that runoff from Sonoma Horse Park was indeed contaminated and flowing into the Petaluma River and nearby wetlands.

Despite the fact that the Petaluma has the potential to be an idyllic recreational resource for the community, the river has a long history of neglect from government regulators.

The pollution is particularly troublesome since the Petaluma is critical habitat for many protected species, such as steelhead trout, Chinook salmon, longfin smelt, and green sturgeon, as well as the California brown pelican. Too much phosphorous and nitrogen in the water causes algae to thrive, which drains vital oxygen and suffocates fish.

That’s why Baykeeper filed a lawsuit under the Clean Water Act. We now have a legally binding agreement with the owner of Sonoma Horse Park to stop the facility’s manure and other pollutants from flowing into the river.

Under our agreement, the facility will use a large pond to capture runoff before it enters the river, contain and cover all of its manure piles, and implement other pollution controls as needed to prevent manure from contaminating the environment. In addition, Sonoma Horse Park agreed to direct $40,000 to the Rose Foundation for Communities & the Environment to mitigate damage caused by its past pollution. The Rose Foundation will award these funds to other local nonprofits for specific projects to restore the watershed.

We'll keep monitoring to make sure the new runoff controls at the horse park are effectively stopping pollution—to give the Petaluma River a fighting chance at being a healthy and safe waterway for local communities and wildlife.

Photo of the Sonoma Horse Park and Petaluma River by Baykeeper, thanks to LightHawk Conservation Flying