Agencies that control flows on the Stanislaus River below Tulloch and New Melones reservoirs began increased releases Monday from Goodwin Dam.
The increased flows are intended to supplement spring fish flow requirements set by a National Marine Fisheries Service 2009 biological opinion, according to federal Bureau of Reclamation staff.
The Bureau of Reclamation is acting in conjunction with Oakdale Irrigation District and South San Joaquin Irrigation District to increase flow releases from Goodwin Dam in the Stanislaus River.
Goodwin Dam is downstream from Tulloch and New Melones dams.
As of Monday, Tulloch Reservoir was holding 60,005 acre-feet, 90 percent of capacity, and New Melones was holding 637,441 acre-feet, 27 percent of capacity.
Increased flows from Goodwin are scheduled between midnight and 10 a.m., “to minimize public impact,” Bureau of Reclamation staff said. The flows are expected to range from 1,400 cubic feet per second to 3,200 cfs.
Flows from Goodwin are expected to begin ramping down by Thursday and return to 1,400 cfs by Saturday.
People in and along the Stanislaus River downstream from Goodwin Dam to the confluence of the Stanislaus and the San Joaquin River are advised to take safety precautions due to the increased flows.
On April 1, Bureau of Reclamation staff filed a temporary urgency change petition to modify requirements to the bureau’s water right permits at New Melones, said Reclamation spokesman Shane Hunt said Monday.
“We asked for changes to flow requirements at Vernalis on the San Joaquin River,” Hunt said. “We asked for them to be lower than they normally would be, because of very low storage levels at New Melones Reservoir as a result of the multi-year drought.”
The Bureau of Reclamation also asked for a change in the dissolved oxygen requirement in the Stanislaus River, Hunt said.
“Fish breathe oxygen out of the river,” Hunt said. “So we asked for modifications to that requirement, again to conserve water at New Melones. If we had to meet the existing standard we would have to release more water from New Melones this summer.”
The urgency changes for New Melones were granted April 19 by the State Water Resources Control Board executive director, Thomas Howard.
“The bottom-line message is, without the changes, we estimate we would have needed to release about 300,000 more acre-feet than we will with the changes,” Hunt said. “If we had to release that much water, by the end of September, we estimate New Melones could have been holding as little as 116,000 acre-feet.”
One of the conditions of the State Water Board’s April 19 approval is that, by the end of September, storage at New Melones is required to be at least 415,000 acre-feet, Hunt said.
One acre-foot of water is enough to flood a typical football field 12 inches deep.
Howard issued the April 19 order approving most of the changes requested by Bureau of Reclamation staff, finding that modified flow levels with specified conditions are “a reasonable balance between the need to provide flows for fish and wildlife in the spring and the need to maintain adequate storage to meet flow and other water quality requirements later in the year and going into water year 2017,” State Water Resources Control Board staff said.
In addition, people with the National Marine Fisheries Service and the California Department of Fish and Wildlife have determined the Bureau of Reclamation’s proposed operations would be better for salmonid fish, according to State Water Board staff.
The Bureau of Reclamation is billed as the largest wholesale water supplier in the U.S., and the nation’s second largest producer of hydroelectric power, with operations and facilities in 17 western states.