Folsom Dam

Folsom Lake SRA














































The Folsom Dam

Folsom Lake was created in 1955 by Folsom Dam,
a concrete dam flanked by earth wing dams and
dikes with a total length of about 9 miles. The
lake features some 10,000 surface acres of water
when full and has 75 miles of shoreline. It extends
about 15 miles up the north fork, and about 10
1/2 miles up the south fork of the American River.
The Lake level normally varies from 466 feet elevation
in early summer to a low of 426 feet in early
winter.

• Nimbus Dam and Powerplant
  
  During a 24-hour period, the releases of
  water from Folsom Dam can vary greatly to meet
  changing demands for water and power. Nimbus
  Dam, seven miles down stream from Folsom Dam,
  stores these releases and re-regulates them
  to a steady flow downstream in the American
  River. Nimbus is a straight concrete gravity
  structure, 87 feet high and 1,093 feet long.
  
• Lake Natoma, formed by the waters held
  by Nimbus Dam is an afterbay or regulating reservoir
  for Folsom Dam. Two 6,750 kilowatt generators
  produce power from Nimbus Dam water releases.
  Nimbus also serves as a diversion dam to direct
  water into Folsom South Canal.
  

The Folsom Project on the American River in California
is a unit of the Central Valley Project (CVP).
The CVP network includes dams, reservoirs, canals,
powerplants and pumping plants. The project extends
500 miles southward from the Cascade Mountains
and stretches 100 miles from the foothills of
the Sierra to the coastal mountain ranges.
Folsom Dam is located about 23 miles northeast
of Sacramento. The multipurpose project was built
by the US Army Corps of Engineers and is operated
by the Bureau of Reclamation. Although its primary
function is flood control, Folsom stores water
for irrigation and domestic use and for electrical
power generation. Preservation of the American
river fishery, downstream control of salt water
intrusion in the Sacramento-San Joaquin Delta
and water-related recreation are also important
activities.
The main dam consists of a 340-foot high concrete
center section flanked by long earthen wing dams
extending to high ground at either end. This along
with other project features, holds over a million
acre-feet of water in Folsom Lake.
Directly below the dam is the Folsom Powerplant.
Its three generators produce 198,207 kilowatts
of power. Each year Folsom Dam prevents potential
flooding downstream from winter storms and spring
snow runoff.

• In 1955, during the construction phase and
  in 1964 and 1986, Folsom Dam saved the Sacramento
  area from major flooding when torrential rain
  and heavy snows fell in the Sierra Nevada/American
  River Basin.
  
• During the December 1964 storm, the inflow
  into Folsom Lake reached a record high of 280,000
  cubic feet per second, with a river release
  of 115,000 cubic feet per second. That was 15,000
  cubic feed per second over the downriver levee
  design capacity.
  
• Up to February 1986, the estimated flood savings
  totaled $438 million. In February 1986, Folsom
  Dam prevented an estimated $4.7 billion in flood
  damages.