Projects that involve water or flood management are typically contentious almost anywhere in California. Nevertheless, a plan to widen the Yolo Bypass on its east side, in the lower Elkhorn Basin, is heading smoothly toward construction. It has support from the Yolo County Board of Supervisors and the affected landowners.
The project was conceived about a dozen years ago when flood management agencies saw the need to safely move greater volumes of floodwater through the Sacramento Valley and into the Delta. A wider Yolo Bypass will help do just that–accept more water from the Sacramento River and send it downstream. It will also be good for birds.
In Yolo County, levees completely separate the Bypass from the river except along two low stretches (known as ‘weirs’). When the river runs high, water spills over the weirs into the Bypass. The longer of the two, Fremont Weir, is at the north end of the Yolo Bypass, east of Knights Landing. The other, Sacramento Weir, is on River Road just north of West Sacramento. Operators open it to let river water into the Sacramento Bypass, which feeds the Yolo Bypass. Both bypasses serve as pressure relief valves to keep the river from flooding nearby cities.
The draft EIR for the project offers several alternatives for moving levees. An example option would (a) move the east levee of the Yolo Bypass 1500 feet further east, starting at Interstate 5 and running south to the Sacramento Bypass; (b) move the north levee of the Sacramento Bypass 1500 feet further north; and (c) relocate County Roads 124 and 126 to the new levees. After the levees have been moved, later steps will be to lengthen both weirs, which will meet the original purpose of allowing much more river water into the Yolo Bypass.
The levee setbacks will matter to Yolo Audubon, primarily because they will affect two birding hotspots: the Yolo Bypass along the levee that Road 124 follows, and the Sacramento Bypass levee that Road 126 follows. The permanent wetland visible from Road 124 will become wider and therefore larger. The strip of forest along today’s Road 126 will remain, and another strip will probably be planted next to the new levee.
Two more beneficial changes include nine hundred additional acres of wetlands for waterbirds and waders to forage in when the Yolo Bypass floods; and native grass plantings on the levee slopes, replacing the mostly thorny weeds there now.
The final EIR for the levee setback project is due for release early in 2019. It will identify the preferred design. Construction is expected to start in 2020. You can learn more about the project here.
Michael Perrone, YAS Board