American River Common Features Project
The American River Common Features Project involves significant
levee improvements on the American River and Sacramento River, as
well as in the Natomas area. When completed in late 2004, the work
on the American River levees will reduce a portion of the Sacramento
area’s flood risk to 1 chance in 100 in any given year. Additional
work has been completed on Sacramento River levees and in the Natomas
Basin, and more levee work is in the planning stages for these areas.
The American River Common Features Project is
part of the integrated Watershed Project to reduce the risk of flooding
in the Sacramento area to a 1-in-213 chance in any one year. This
overall effort also includes modifications to the outlet gates at
Folsom Dam and the Folsom Dam Raise.
Soon after the record storm of 1986, the Army Corps of Engineers
(Corps), California Reclamation Board (Reclamation Board) and the
Sacramento Area Flood Control Agency (SAFCA) formed a partnership
to find ways to reduce Sacramento’s flood risk.
At one time the Corps, Reclamation
Board, and SAFCA proposed a flood control dam near Auburn along
with the levee improvements downstream of Folsom Dam. There was
no community consensus for the dam, and Congress told the Corps
to focus instead on the downstream flood control system, and to
combine a number of features common to three different flood management
proposals into one plan to reduce the flood risk to Sacramento.
is the American River Common Features Project, a comprehensive effort
that includes levee work on the Lower American River, levee work
on the east bank of the Sacramento River adjacent to downtown, levee
work in the Natomas Basin, additional upstream river flow gages,
and an improved flood warning system along the lower American River.
These common features are an interim measure to reduce the flood
risk. Future measures include modifying the outlet gates at Folsom
Dam and raising Folsom Dam so that it can hold back additional floodwater.
The main element of the originally authorized
common features project was to install an impervious barrier along
almost 20 miles of American River levees. The barrier consists of
a mixture of soil, clay, cement, and water, called a slurry cut-off
wall. Other elements include: