(LATimes) - Malibu vintners and grape growers will try Tuesday to persuade the Los Angeles County Board of Supervisors to lift a temporary ban on new vineyards, or extensions of existing ones, in the north Santa Monica Mountains.

The ban was imposed last month when supervisors saw an increase in new vineyard applications just as residents in other parts of the county were being asked to cut back water use because of the statewide drought.

County officials have received 51 applications for new vineyards in the last 10 months, whereas the previous year generated three. The mountain area includes unincorporated Malibu, Agoura, parts of Calabasas and Topanga.

"The number of applications for new vineyards worried me in the aggregate because of the overall amount of additional water that could be drawn down, as well as there being no information about what chemicals or pesticides might be added to runoff," Supervisor Sheila Kuehl said. "These were not just half an acre or small backyard vintners, but applicants for larger vineyards. People just drill wells. They draw water."

Kuehl said a study found that in vineyard-rich Central California, the water table had been lowered significantly. "And in the mountains, we don't have a way to measure the impact of vineyards drawing off water upstream."

Dan Fredman, owner of a small backyard vineyard and a spokesman for the Malibu Coast Vintners & Grape Growers Alliance, said, "When we saw the proposed measure, we were down at the planning commission offices as quickly as we could, to provide them with correct information on grapevines and viticulture as it's practiced in Malibu."

Vine growers believe the moratorium is unnecessary because they've already begun working with the county's Department of Regional Planning to address concerns about vineyards in the area.

Some landowners applied for vineyards for their entire property and may have only planted on a small portion of their land.

When the grape growers alliance investigated, it found that all those applications had been made as the result of a meeting with planning commission representatives a year ago, during which property owners in the Triunfo/Lobo area were advised to get in their applications if they were even thinking about planting a vineyard in the future. They took the advice to heart, fearing they'd be shut out in the future unless they had a permit for a vineyard grandfathered in.

"The real hardship is directed at the landowners who have already submitted applications for vineyard permits and are legally entitled to plant crops on their agriculturally zoned land," said Montage Vineyards' John Gooden, president of the Malibu Coast Vintners & Grape Growers Alliance.