The Schlatter family, owner of Merryvale winery in St. Helena, has secured Napa County approval to start a smaller winery at their vineyards in the hills to the east.

This new venture will be much smaller. The Schlatters want to establish what Napa County calls a microwinery.

Schlatter Family Estate microwinery is to produce a maximum of 5,000 gallons of wine annually and host a maximum of 18 visitors daily. It will be located inside a planned, 4,998-square-foot wine cave.

Wineries meeting Napa County microwinery standards are eligible to have a Zoning Administrator hearing before planning staff instead of a Planning Commission hearing. Standards include producing no more than 5,000 gallons of wine annually,

On Aug. 27, county Planning Manager Michael Parker sat as zoning administrator and approved the microwinery to be located at 1111 Conn Valley Road.

A Napa County report found the application met county standards, though the county granted an exception to its road rules to address driveway sections constrained by steep slopes and a seasonal stream.

The project well is 1,570 feet from the Conn Creek, which drains into the city of Napa's Lake Hennessey reservoir. That's just beyond the 1,500-foot limit from a significant stream that triggers stricter groundwater testing.

One issue arising was the potential presence of Clara Hunt's milk-vetch, a state-listed endangered plant.

The plant has been found less than a half-mile away. The Schlatter site has rocky, clay soil derived from volcanic or serpentine materials, Erin Chappell of the state Department of Fish and Wildlife wrote to the county.

"Thus, there may be suitable habitat for Clara Hunt's milk-vetch within or adjacent to the project site," Chappell wrote.

Napa County agreed that a qualified biologist should survey the site prior to any earthmoving or construction. If there is suitable habitat in construction areas, another survey should be done during the plant's blooming period.

If the plant is found, the Schlatters would work with Fish and Wildlife to avoid the plants or obtain an incidental take permit.

A neighboring couple raised concerns about the planned placement of a trash enclosure, as well as light and noise. Parker found no reasons to deny the project for these reasons.

Napa County has approved four micowineries since the program began three years ago. They are Goel Estate Vineyards, Chaix, Stewart Ranch and now Schlatter Family Estate.

The county is reviewing its microwinery law. The Planning Commission on Aug. 20 recommended finding ways to make obtaining a microwinery permit more affordable and quicker, as well as addressing what can be costly roads requirements.