The Mid-Valley Project is part of the Knights Landing Ridge Drainage District. The project proposes to repair levees at 13 sites northwest of the City of Sacramento which have required flood fighting or experienced seepage and boils during previous flood events. These levees are integral to the system-wide performance of the Sacramento River Flood Control Project and provide direct flood protection to the towns of Knights Landing, Verona and Nicholas, indirect flood protection to the Cities of Sacramento and West Sacramento, while also protecting 93,000 acres of farmland and associated infrastructure that support the Sacramento Valley’s capacity as one of the most productive agricultural regions in the world. The repair of levees in Area 3 will nearly triple the level of flood protection afforded the town of Knights Landing and the adjacent agricultural areas.
Area 3 levee reconstruction involves 3.4 miles of levee repair along the Knights Landing Ridge Cut and 1.3 miles of levee repair along the west bank of the Sacramento River.
The U.S. Army Corps of Engineer initiated a system-wide evaluation of levees comprising the Sacramento River Flood Control Project which exhibited poor performance, including seepage and boils, or required flood fighting during the 1986 flood. In the Mid-Valley portion of the project, the Corps identified 30 deficient sites with a total required repair length of approximately 20 miles within the 240 miles of levees evaluated. These 30 sites have been grouped into 4 areas based on the benefits they provide. The repair of 17 sites located within Area 1 was completed in 1998. The remaining 13 sites in three areas across Yolo and Sutter County are still in need of repair. These repairs include seepage and stability berms, levee crown restoration, slurry cutoff walls interior drains and encroachment relocations.
Despite the subsequent poor performance of these levees in the 1995 and 1997 flood events, the remaining three areas of the Mid-Valley Project in Yolo and Sutter Counties has never been completed. Most recently, the U.S. Army Corps of Engineer released a Draft Engineering Documentation Report in June 2009 to update the project design, associated total project cost estimate and the economic analysis for the remaining three areas. The repairs are necessary to simply restore the levees to their designed level of flood protection as originally authorized by Congress in the Flood Control Act of 1917.