Storms Raise Hydro Prospects

By Published On: February 20, 2009

After one of the driest Januarys on record, the recent storms were welcomed by utilities dependent on hydropower supplies. “The recent series of storms was very good news,” said Paul Moreno, spokesperson for Pacific Gas & Electric, which has 4,000 MW of hydropower supplies in average precipitation years. The water supply levels in the reservoirs that feed the utility’s power houses are at 95 percent of normal, he said. The Sacramento Municipal Utilities District reported that water levels following the storms raised water supplies to 73 of percent of normal. Last week’s precipitation raised a key reservoir’s level by 5 inches. About 15 percent of the muni’s power supplies come from hydropower. Just how much the foul weather increased water supplies in other reservoirs, as well as the state-wide snow pack that feeds them as the weather warms, won’t be known until early next month. “The recent storms have helped but we will not know exactly how much until the first week of March,” said Paul Klein, Southern California Edison spokesperson. Edison’s main hydropower plant is Big Creek, which supplies about 1,100 MW. The utilities and Department of Water Resources conduct monthly snow surveys that measure the water content of the snow pack. Lots of powdery snow produces far less water than heavy wet snow. DWR’s next survey is scheduled for March 2. Statewide water supplies have increased from 61 percent of normal to about 74 percent of normal, according to the Department of Water Resources. The northern part of the state was estimated to be at 69 percent of normal, Central California at 75 percent of the annual average, and Southern California at 76 percent of normal as of February 18, according to DWR’s Cooperative Snow Survey. PG&E isn’t concerned about water supply at this time because about one-third of the state precipitation has yet to fall. In addition, the utility is cushioned because its hydropower supplies along the McCloud and Pitt Rivers are fed by underground aquifers, not high mountain snow pack. These aquifers in northeastern California supply about 38 percent of the utility’s hydropower on average. “In dry years, when less hydro from our other systems is available it will make up a greater portion of our hydro output,” Moreno said. In late January, the Department of Water Resources issued water supply shortage warnings after releasing its snow survey findings. Much of the water supply concern arises from serious ecosystem problems in the San Francisco-San Joaquin Bay Delta, which is the largest source of water supply in the state. Pumping water from this area, which is critical habitat for the endangered Delta Smelt and Chinook Salmon, particularly in dry years, wreaks havoc on the fish. It also resulted in a court recently slapping on pumping restrictions at the heart of the state’s water power system.

Share this story

Not a member yet?

Subscribe Now