Mike Zweifel: Downstream effects must be considered in regulating flows from dams

Regarding the very high water levels at Don Pedro Reservoir and the ongoing threat of additional flooding, it’s worth remembering that only eight weeks ago many of the state’s large reservoirs were less than 30 percent full. In most years, MID and TID maintain a minimum of 30 feet below the spillway for spring runoff and flood control. It has been very difficult to maintain reservoir space this year since two-thirds of this year’s above-average snow- and rainfall has come in the last eight weeks. Many storm systems were very warm, resulting in heavy rains and big melt-offs of high-elevation snow resulting large inflows to reservoirs.

MID and TID must abide by the Army Corp of Engineers regulations governing river flows and releases from Don Pedro. The Corp is entrusted to manage flood control, which is particularly complicated in the Central Valley. Every west-slope Sierra Nevada and east-slope Coast Range waterway from Redding to Visalia ultimately empties into the Sacramento/San Joaquin Delta, so downstream impacts must be considered.

This winter’s concentrated rains made it abundantly clear that we desperately need more water storage (and levee reinforcement), not just to ride us through inevitable droughts but also for flood control to insure public safety.

This story was originally published February 27, 2017 at 1:22 PM with the headline "Mike Zweifel: Downstream effects must be considered in regulating flows from dams."