The Santa Clara Valley Water District has been lowering the water level on the Anderson Dam since Oct. 1 to keep the region safe from potentially catastrophic flooding in the event of a major earthquake.
The Anderson Reservoir can hold up to 90,000 acre-feet of water and is now at three percent capacity, which is the lowest feasible level given the position of the existing outlet tunnel. At its current level, even a heavy rainy season would not pose dam failure and flooding risk; keeping some water in the reservoir helps preserve some wildlife habitat. Beyond immediate safety, one of the main reasons for lowering the water level is to allow for construction to begin on a major seismic retrofit project for the dam. The reservoir has been closed for recreational use since October and is expected to remain shuttered for the duration of the project.