Napa County Planning Commissioners reviewed county conservation regulations for streams, woodlands and drinking water-providing reservoirs while avoiding the hot-button aspects that have divided the community.

The Measure C watershed and oak woodlands protection initiative that narrowly lost last June would have strengthened environmental rules. Commissioners didn’t wade into the post-election controversies.

“We’re not setting policy,” Commissioner Dave Whitmer said.

Rather, commissioners held a study session to brush up on the conservation regulations as they apply to Planning Commission decisions. The commission looked at how far the existing rules go, not at whether they go far enough.

“Con-regs 101,” Commissioner Jeri Hansen said.

The county established its conservation regulations in 1991 and has since updated them. The goals include keeping eroded sediments and pollutants from reaching reservoirs that provide drinking water to Napa, St. Helena and Calistoga.

Supervising Planner Brian Bordona explained the 60-40 rule. It states that, when clearing land in areas that drain to reservoirs, at least 60 percent of the tree canopy that existed as of June 1993 must remain. At least 40 percent of the grassland and shrub-land must remain.

That rule is designed to stop erosion and protect water quality, Bordona said. But it also helps with such things as preserving wildlife habitat.

Geotechnical reports must be done for projects in the watersheds of Lake Hennessey, Bell Canyon Reservoir, Kimball Reservoir, Rector Reservoir and other municipal reservoirs, he said. Projects must be designed for 100-year storms.

He described the winter rainy season grading shutdown. Earth-moving in reservoir watersheds in most cases must cease from Sept. 1 through March 31. In other parts of the county, the winter shutdown begins Oct. 15.

Another rule protects slopes greater than 30 percent—24 percent of the county—from any meaningful amount of development, he said. Steeper slopes can be prone to landslides and erosion.

Stream setbacks for development are 35 feet to 150 feet, based on the slope. The steeper the slope, the wider the setback to keep eroded soils from washing into the local water system.

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People developing land for vineyards and other uses in the county’s watersheds must follow these and other county rules, as well as state and federal regulations. Bordona called this interplay the “regulatory blender.”

The Planning Commission sometimes sees a request for a conservation regulation exception come with an application for a new winery or winery expansion. For example, it has allowed improvements to roads and driveways within stream setbacks to meet fire safety regulations.

“You have an existing road,” Bordona said. “That road now needs to be expanded and you’re kind of in a tough position. You’re not going to have them put a brand new road somewhere else.”

When such cases arise, the county tries to have applicants restore or improve some other aspect of the stream, he said.

“Variances and exceptions aren’t always the worst thing,” Hansen said.

The commission took public comments. Resident Chris Benz asked whether the county monitors projects for compliance with its conservation regulations.

Bordona said Napa Resource Conservation District soil scientists inspect properties subject to county erosion control plans each year prior to winter rains. Out of 50 inspections so far this year, there have been no violations.

Michelle Benvenuto of Winegrowers of Napa County said it’s important to understand the data-driven, scientific approach and high level of detail that goes into the conservation regulations.

“This is not a simple process,” Benvenuto said.

Michelle Novi of Napa Valley Vintners mentioned the voluntary Napa Green environmental program for wineries and vineyards. The vineyard program requires participants to create detailed farm plans addressing such issues as reducing erosion.

Almost 55 percent of the vineyard acreage in Napa County is certified Napa Green, she said.

Measure C sought to give more protections to oak woodlands and watersheds. It would have bolstered stream setbacks. It would have capped how many acres of oak woodlands could be removed for vineyard development in the watershed.

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Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He has worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield.