California’s Lake McClure reservoir surpasses historic average. Water levels remain uncertain

California Department of Water Resources data indicates that the Lake McClure reservoir, which supplies water downstream to the Merced County waterways, is currently more than 100% of the historical average for this time of year.

As of 12 a.m. Feb. 3, the reservoir had 646,621 acre-feet of water, which is roughly 63% of the reservoir’s total storage capacity of 1,024,600 acre-feet. The reservoir is currently at 131% of the historical average for this date.

Even with the level above the historical average, Mike Jensen, Merced Irrigation District public and government relations manager., said it’s too early to tell what that means for the reservoir later this year.

“We’ve still got a couple of months winter left, so we’ll see what develops with the snow and rain,” Jensen said. “I think like most people, we’re watching to see what’s going to happen over the next couple months here.”

Due to the state experiencing both wet and dry years, Jensen said it is difficult to determine an average to compare the current precipitation data to. It is also to early to tell at this time if the reservoir will have an abundance of water in the coming months or if the reservoir will experience a water deficit this spring and into the summer months.

“We’re watching is where we’re at,” Jensen said. “Again we still have a couple months of winter left, it could be dry it could turn out to be really wet and we’ll find out as we get further along here.”

According to the California Department of Water Resources through the California Data Exchange Center and the California Cooperative Snow Surveys, the Northern Sierra/Trinity area last reported an average snow water equivalent of 18.1 inches which is 70% of the April 1 average and 110% of normal for the date as of Feb. 4. The Central Sierra area reported an average snow water equivalent of 11.9 inches which is 41% of the April 1 average and 63% of normal for the date. The Southern Sierra area reported an average snow water equivalent of 6.5 inches which is 29% of the April 1 average and 45% of normal for the date.

As of Feb. 4, the statewide average snow water equivalent was 12.3 inches, 46% of the April 1 average and 71% of normal for the date. The Merced River was last recorded flowing at a rate of 251 cubic-feet per second below Merced Falls with a river stage of 3.96 feet, according to the California Department of Water Resources.

Jensen said the irrigation district is required to make releases downstream as well as maintaining capacity for inflow of water that comes down the river from the Sierra’s.

“The reservoir is not really moving up or down right now,” said Jensen. “What’s coming in is going out.”

Jensen said the irrigation district must maintain a certain amount of space within the reservoir for flood control, allowing water to go into the reservoir.

“We have mandatory flow requirements that we have to follow for various times of the year and that’s what we’re doing,” said Jensen. “As we get closer to spring, we know what the inflow has been how much water has come into the reservoir. We look at how much snow is left on the mountain that’s going to come into the reservoir. That’s really when we start to make determinations of how much water will be available for our irrigation users.”

Jensen said the reservoir is about as full as the irrigation district can allow for this time of year and the district is waiting to see how the weather develops in the coming months.