Though little known, the two candidates for District 4 supervisor have been at odds for years behind the scenes.

Dominic Grossi, a fourth-generation dairy farmer, has clashed with Dennis Rodoni, a six-term North Marin Water District director, over the effect that manure runoff from Grossi’s farm has had on Stafford Lake outside Novato.

According to a study commissioned by the district in 2015, the Grossi farm is the “most substantial external source of phosphates” entering the reservoir. Phosphates and other nutrients polluting the lake fuel the growth of algae blooms, which sometimes cause drinking water from the lake to have an unpleasant taste, color and odor.

“My feeling is people should know about this problem,” said Gerald Meral of Inverness. “The reservoir is the principal source of drinking water for Novato and we have someone who is running for supervisor, who will represent a good piece of Novato, and he has not cooperated fully with the district to reduce the pollution going in the reservoir.”

Grossi, however, says he has cooperated fully, and officials with the San Francisco Bay Regional Water Quality Control Board, which issues permits to dairies, say the farm is complying with state law. The Water Quality Control Board inspected Grossi’s farm in February after receiving an anonymous complaint about odor in the vicinity and found no violations.

“We’ve never been cited for a violation by the board,” Grossi said.

Grossi said scrutiny of his farm’s manure disposal procedures has blossomed since he announced his candidacy for supervisor in December.

“The whole thing is politically motivated,” he said.

Denies motive

Meral, who has endorsed Rodoni for supervisor, brought the existence of the 2015 study to the attention of the Independent Journal, but he denies having any ulterior motive in raising the issue. Meral is the California water director for the Natural Heritage Institute and served as deputy director of the state Department of Water Resources from 1975 to 1983.

Meral cited excerpts from North Marin Water District board minutes over the years to bolster his case that the Grossi farm is problematic for the reservoir. The minutes show that as early as 2010 Rodoni was suggesting that the water district should consider purchasing the Grossi farm to resolve the issue.

“Nutrients in the lake have been a taste and odor problem for as long as I’ve been on the water board,” Rodoni said Friday, “and we’ve been working really hard with everyone in the watershed including the Grossi farm to reduce that.

“But as the report indicates, a majority of that nutrient is coming from the Grossi dairy facility,” Rodoni said. “The bottom line is it is costing the customers tens of thousands of dollars a year to remove the taste and odor influent.

“I think the ultimate long-term solution is to figure out a way to either purchase the ranch outright or at least cooperate with the owner to get it out of dairying and into beef cattle or something else,” Rodoni said.

Grossi shocked

The Grossi farm abuts water district land. Grossi’s grandfather sold about 64 acres of the family’s land to the North Marin Water District in 1950, leading to the creation of Stafford Lake.

Grossi said he was never contacted by San Francisco-based SRT Consultants, which conducted the 2015 study, and had no idea such a study had been done.

“It was shocking to me,” Grossi said. “They did this whole report on our ranch, and they never talked with us.”

Grossi said the study contains numerous inaccuracies. For example, the report states that the dairy has failed to implement a number of best management practices to avoid runoff of pollutants.

These include: constructing holding ponds for liquid animal waste, sloping dairy land to direct runoff away from cattle areas and manure collection structures, removing manure for land application elsewhere, and use of dairy waste lagoons for biological treatment and long-term waste storage.

“We do all these things,” Grossi said.

Chris DeGabriele, North Marin’s general manager, confirmed that the Grossi dairy has implemented those best management practices.

In 2012, the water district entered into an agreement with the Grossi dairy pledging to help pay for it to haul its manure to other ranches located farther from the lake for disposal. In 2012, the water district paid Grossi $16,000 and in 2013 it paid him $12,000.

But DeGabriele said the water district stopped underwriting the manure relocation because it failed to see a significant reduction in algae blooms as a result.

Next year, the Water Quality Control Board will require dairies to begin testing runoff into waterways on their land to better assess the level of pollutants escaping.

And in December, the Grossi farm will begin operating as an organic milk producer. Grossi plans to sell his existing herd of 250 cows, buy back 50 and gradually build the herd back up to 125 or 130.

Grossi said the transition will result in less manure and make it easier for him to avoid spreading manure on the fields bordering water district land along Novato Boulevard.

“We don’t want to sell our ranch,” he said. “This is our home.”