This issue is a little more complex.
(please note: this data is dated, but I doubt you will be able to find much true data on releases in the past few years, since this has turned into a hot button issue. All I can testify to is that I was moving a friend from Folsom to Granite bay a few weeks back and the spillways were open on more than a few days (she has alot of stuff!)... When the lake was no where near full.)
Sacramento River Portal and Library
"Jeff McCracken, Bureau of Reclamation spokesman, claims the federal agency is doing everything it can to balance the interests of different water users in the midst of a low precipitation year. He attributes the low state of Folsom Lake to the driest spring in 80 years and the need to meet water quality requirements for Delta smelt.
“We never got the spring melt that we anticipated,” said McCracken. “We had projected 870,000 acre-feet of water, when all we got was 650,000 acre-feet in Folsom.”
He said the state and federal governments have to meet waterquality requirements for Delta smelt, as well as provide water fore xport purposes. 100,000 acre feet was taken from Folsom for Delta smelt this year, according to McCracken."
The function of a government is control. Eventually, a governing body controls growth of towns, communities, and finally individuals.
We are no where near that level yet, but it is a natural progression as a country ages.
Regrettably, that is the true issue. Fresh water has always been the ultimate control over the masses. What is brilliant, is that the issue is masked in the oldest religion, that of "Nature"... We will run our reservoirs dry, in the the name of a tiny little "ultimately important" fish.