How the Sacramento Weir works

The Sacramento Weir is the only manually operated weir on the Sacramento River system.

While the system’s five other weirs overflow automatically once the river reaches a certain elevation, the 1,920-foot-long Sacramento Weir consists of 48 gates that must be opened with a long hooked pole. The gates are opened when the river level at the I Street Bridge reaches 29.87 feet. The weir, built in 1916, was last opened in December 2005.

How it works:

 

The gates

▪ Each gate consists of 38 hinged wooden planks

▪ 1,500 cubic feet of water per second can move through each gate

Source: California Department of Water Resources

This story was originally published January 9, 2017 at 12:14 PM with the headline "How the Sacramento Weir works."