At a hearing in Watsonville, Calif., Monterey County officials said proposed state water regulations could take several thousand acres of farm land out of production and reduce crop values by $100 million to $167 million annually in the county.

Citing risks to drinking water supplies and aquatic habitat from fertilizer and pesticide runoff, the Central Coast Regional Water Quality Control Board has drafted new rules for irrigated farming to succeed an expiring conditional discharge waiver.

At the March 17 board meeting, Farmers for Water Quality spoke on behalf of a grower-supported alternative plan that would report efforts collectively rather than farm-by-farm, and be overseen by a third-party auditor. Abby Taylor-Silva of the Grower-Shipper Association of Central California and Danny Merkley of the California Farm Bureau Federation were among those who spoke.

At the hearing, Monterey County Agricultural Commissioner Eric Lauritzen submitted a letter saying agency staff had underestimated the impact of the draft rules.

The plan’s alternatives for 30- or 50-foot waterway buffers could take 5,663 or 9,438 acres, respectively, out of production, according to the county. The water board had estimated 56 to 154. The county pegged average crop value per acre at $17,748; the board, $9,389.

“They only looked at a few crops,” Bob Roach, the county’s assistant agricultural commissioner, said later. “We think what was presented to this committee of the board was really not reflective of the actual impact. They said seven growers would be affected; we thought more land than that might be taken out of production.”

Board and county documents both said projections were based on the county’s 2009 crop report.

The board delayed a vote until an April date yet to be announced. Still unresolved, among other issues, is the nine-member panel’s lack of a quorum. Three seats are vacant, and two members recused themselves to avoid potential conflicts of interest.

Besides Monterey County, the Central Coast region stretches to Santa Cruz, San Benito, San Luis Obispo and Santa Barbara counties.