Blog: Drastic measure to meet Delta outflow
For seven days in mid-March 2021, the Bureau of Reclamation substantially increased Folsom Lake storage releases. Roughly, the releases tripled in volume (Figure 1). The release of over 20,000 acre-feet of water is significant for a year in which Folsom storage is not much better than it was in the worst year on record – 1977 (Figure 2).1 With the release in mid-March, the lake level dropped 3 feet. Yes, there was rain in the forecast and a decent snowpack, but certainly no flood concerns. So why? The reason was to meet state water quality requirements for Delta outflow. Delta outflow increased from 7,000 cfs to 12,000 cfs for a few days (Figure 3).