The two sides in a lawsuit that once threatened to shut down the Carnegie off-road vehicle park have agreed to terms that will keep the park open while offering more protection for Corral Hollow Creek.

A stipulated judgment filed in Alameda County Court on May 29 dismissed a lawsuit by the California Sportfishing Protection Alliance against the California Department of Parks and Recreation.

The Alliance, which filed the suit in September 2009, claimed motorcycles and other off-road traffic in the 1,540-acre Carnegie State Vehicular Recreation Area caused erosion that polluted the creek, which flows seasonally and empties into the valley floor southwest of Tracy.

The settlement allows off-road use to continue in the park on the San Joaquin-Alameda county line in Corral Hollow Canyon southwest of Tracy, as long as certain areas, including the creek, are off-limits to traffic.

It also affirms that new Central Valley Regional Water Quality Control board permits, plus new deadlines for the state park to prove that it has met the terms of those permits, are sufficient to protect water quality in Corral Hollow Creek.

The court issued an ultimatum in September 2009 that required the state to either prohibit off-road use or get a Water Quality Control Board permit to allow sediment in the creek.

But Sportfishing Alliance Executive Director Bill Jennings said that his group’s only goal was the protection of water quality.

“We weren’t trying to get (the state) to close the park. We were trying to get them to control the pollution,” Jennings said.

The park stayed open as the state worked toward a new permit that defines how much sediment is allowed in the creek. In the meantime, the park has continued to be a destination for recreational riders and competitive motorcycle hillclimb events.

Advocates for off-highway vehicle recreation consider the settlement a victory.

Don Amador of Oakley, the western representative for the nationwide BlueRibbon Coalition, said that the California Department of Parks and Recreation and the Central Valley Regional Water Quality Control Board were already able to control runoff into the creek prior to the lawsuit.

“I believe the suit had more to do with the plaintiffs fronting their anti-OHV (off-highway vehicle) agenda than accomplishing any meaningful environmental protection measures,” Amador wrote in an email to the Tracy Press. “The park already had been working with sister agencies on various water quality and erosion measures, such as settling ponds and wet weather closures.”

Bob Williamson, superintendent of the State Parks Off-Highway Motor Vehicle Recreation Division, affirmed those are goals that the parks department had in its sights even before the lawsuit was filed.

“From the beginning, we have worked with the water boards to be placed into a stormwater program,” Williamson said. “We’re all happy with the settlement, and the terms are quite reasonable. It moves us in a direction we were already going.”

The hills on the south side of Corral Hollow Canyon have seen off-road competitive events and recreational riders since the 1920s. The state park was established in 1979, and in 2011 about 65,000 riders visited the park, a decline from previous years.

Corral Hollow Creek is a seasonal waterway, and the channel disappears after it reaches the valley floor, and the water seeps into the ground.

State agencies banded together to study the effects of off-road traffic on the Corral Hollow Canyon watershed in 2001, and in August 2011 the Central Valley Regional Water Quality Control Board created a plan to reduce the sediment, found to contain heavy metals and other pollutants, created by off-road traffic.

The plan defines areas within the park that are off-limits to riders, including the creek itself, with the exception of specific places where riders can cross the creek. The plan also calls for restoring areas that have been heavily damaged by trails.

The board followed up the release of that plan with an order in February that calls for detailed studies, and sets deadlines to make sure water quality goals are met.

Jennings said that the order, plus the $65,000 in attorney fees the state had to pay to the Alliance, makes it a win for his group.

“They have to live within the permit limitations. They’ve already had to do studies on how to control sediment,” he said. “The lawsuit has driven them toward compliance. Whether we get there, we will see.”