SAN FRANCISCO (CN) – A California appeals court affirmed the State Water Resources Control Board’s decision to ease regulations on how much the discharge from a wastewater treatment plant along Deer Creek may change the water temperature.
California Sportfishing Protection Alliance and the DeltaKeeper Chapter of BayKeeper claimed the adoption of an amendment exempting Deer Creek from temperature regulation violated the Porter-Cologne Act and the Clean Water Act by failing to “protect Deer Creek’s native cold water fish.”
The seasonal stream in the Sierra Nevada foothills flows through El Dorado and Sacramento Counties. Because it often runs dry in the summer, the El Dorado Irrigation District built the Deer Creek Wastewater Treatment Plant in 1974 to help provide flow for aquatic habitat.
Treated water makes up about 90 percent of the creek’s flow during the summer months, and the discharge causes the water temperature to increase in “highly variable” spurts.
A water quality control plan adopted in 1975, called the Basin Plan, provided that the discharge could not increase the water temperature more than 5 degrees Fahrenheit. This 5-degree increase limitation applied to “all water bodies” in the Sacramento and San Joaquin River basins, not just Deer Creek.
When it became apparent that the discharges from the Deer Creek plant regularly exceeded the 5-degree limit, the district proposed an amendment to the Basin Plan that would exempt Deer Creek from the temperature cap. The proposal asserted that the 5-degree limit is neither “supported by current science regarding the effects of temperature on aquatic life” nor “consistent with U.S. (Environmental Protection Agency’s) current approach to regulating temperature in ambient waters.”
The amendment required Deer Creek to use seasonal daily maximum and monthly average temperature goals instead of the 5-degree cap.
The California Department of Fish and Game reviewed the temperature data and found that the daily maximum temperatures upstream of the plant were routinely higher than what rainbow trout could tolerate. The department concluded that “it is highly likely that Deer Creek did not have a self-sustaining rainbow trout population,” even before the plant was built.
The study also showed that the creek downstream of the plant contained a more diverse native fish community than the upstream water, suggesting that the plant has no adverse impact on aquatic life.
The appeals court cited these findings in determining that the regional board “considered all significant implications on the environment” before adopting the amendment.