The Sacramento Weir opened its gates Jan. 10 to reduce water levels in the Sacramento River, but now those gates may begin closing as early as Monday.
Thirty-five of the 48 gates are open.
The weir acts as a bridge between West Sacramento and Interstate 5 on Old River Road.
Most bridges are over water, but this one is blocked with 1,824 wooden planks — each six feet long, one foot wide and four inches thick.
There are 48 sections of 38 planks each. A heavy beam that weighs more than a ton keeps each of the sections in place.
Jon Ericson, chief of the Hydrology and Flood Operations Office with the California Department of Water Resources, says beams are held in place with a cable, which is released to allow a gate to open and the planks to float into the Yolo Bypass.
"Once we cut them loose from the weir itself, from their tethering cable, then we catch them with a boat," Ericson says. "It would be hard to move in the mud out there if the water levels drop too low. So, it's easier to cut them loose, catch them with a boat and then pull them to the side and lift them with a crane on a trailer."
To replace the planks, each section of the weir must be blocked with a 40-foot-wide log.
"For each gate, we have to go gate-by-gate," Ericson says. "We have to put in a stop log so to speak that stops the flow to that particular gate. Then, a worker actually has to get in there, a couple of workers actually to lift that gate and set that block behind it so that we can close the gate itself."
This is the 23rd time the weir has been opened since the mid-1930s. The weir is opened and closed based on a set of rules issued by the U.S. Army Corp of Engineers (to avoid instances like what happened in 1922 when a city engineer opened part of the weir without telling anyone and drowned $900 worth of livestock).
The weir about 100 years old.