In 2017, the San Francisco Bay Regional Water Quality Control Board adopted the Vineyard General Permit to improve water quality in local watersheds. The General Permit regulates pollutant discharges from vineyard properties located in the Napa River and Sonoma Creek watersheds. It requires implementation of best management practices (BMPs) to control sediment discharge and storm runoff increases from farms and unpaved roads, and actions to control discharge of pesticides and nutrients.
The General Permit's Monitoring Plan requires monitoring of vineyard properties to evaluate the effectiveness of these BMPs to reduce sediment discharge within the vineyard footprint and from unpaved roads. The Water Board also requires the monitoring of sediment levels in streambed sections that provide habitat for steelhead and/or salmon.
This story focuses on the results of monitoring the effectiveness of unpaved road BMPs to prevent road-related sediments from getting to streams.
Napa County and Sonoma RCD staff monitored the four road BMPs that were most commonly recommended to help vineyard properties reduce sediment delivery from unpaved roads- critical dips, trash racks, waterbars, and rolling dips.
Staff visited a total of 484 BMP implementation sites spanning the four types of underlying bedrock known to exist in the Napa River and Sonoma Creek watersheds.
Overall, RCD staff found that the effectiveness of all four types of BMPs was extremely high; over 90% of the BMPs of each type were observed to be effective at reducing sediment delivery after experiencing heavy storms.
To see examples of the BMPs and read more, head over to our website!
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