Two environmental groups on opposite sides of the Santa Maria River Bridge have sued the custodians of the water system in an effort to prevent extinction of the endangered Southern California steelhead in a drying river channel.
On Wednesday, San Luis Obispo Coastkeeper and Los Padres ForestWatch filed a 19-page lawsuit in Santa Barbara County Superior Court against the Santa Maria Valley Water Conservation District seeking water releases from Twitchell Dam.
The groups contend the much-needed releases will help save a dying species and won't adversely affect water supply, for either agriculture or domestic users.
"Santa Maria can have both steelhead (trout) and its water supply with straightforward changes to water management," said San Luis Obispo Coastkeeper Executive Director Gordon Hensley, who added it's estimated 4 percent of reservoir water would be affected by releases for the fish.
Since the 1950s when Twitchell Dam was constructed, the Conservation District has managed it in such a way that it prevents water flows from the river to the ocean, severely limiting migration and stranding endangered steelhead — a form of rainbow trout that spawns in coastal streams and, then, migrates to the ocean to mature — in the drying channel, according to the lawsuit.
State law requires dam operators to release sufficient water to keep fish stocks in good condition, yet several large dams, including Twitchell, have historically blocked steelhead runs along the Pacific Coast. As a result, steelhead are now one of the most endangered fish species in the United States, according to the lawsuit.
The Water Conservation District hadn't been served by the end of Thursday and declined to comment until members had reviewed the litigation, said Tom Gibbons, district board director and current vice president.
Seventy years ago, the Santa Maria River had the second-largest steelhead run in Santa Barbara County. Some estimates put as many as 10,000 fish travelling up the watershed in wet years, with the Sisquoc River in the Los Padres National Forest being the most important spawning tributary within the stream network.
"Endangered steelhead have nearly disappeared from river systems throughout the Central Coast," ForestWatch Executive Director Jeff Kuyper said. "(Yesterday's) legal action seeks to restore one of our region's most prolific fisheries, while maintaining reliable water supplies for our farms and communities."
Twitchell Dam on the Cuyama River — the northern tributary to the Santa Maria River — has been identified as a major obstacle to steelhead passage, but not in a conventional sense, Kuyper said.
Data suggests the fish don't migrate into the Cuyama River in significant numbers. Instead, they migrate to and from Sisquoc spawning grounds via the Santa Maria River.
The lawsuit argues rather than physically blocking fish passage, it is the operation of Twitchell Dam that limits the timing and quantity of flow to the mainstream of the Santa Maria River, preventing steelhead fry from reaching the Pacific Ocean and ocean-dwelling steelhead from reaching the Sisquoc spawning habitat.
Twitchell Dam is designed to replenish the groundwater, which it does by trapping all stream flow during the winter and spring months, with slow, timed releases during the summer. The schedule rarely leaves any water in the channel for the fish to migrate upstream in the winter and spring, according to the litigation.
"Our lawsuit seeks to bring the Santa Maria Valley Water (Conservation) District out of the 1950s and into the 21st century," Hensley said.
California Coastkeeper Alliance sued in 2007 to compel state officials to initiate stream flow studies as required by law. A resulting study by Stillwater Sciences recommended an improved flow system at Twitchell Dam, but the district has failed to implement any of the recommendations.
The latest lawsuit aims to implement those recommendations.