The Rivers Erosion Site Project SAA #1600-2014-0084-R2

The Rivers Erosion Site Project SAA #1600-2014-0084-R2

The California Department of Fish and Wildlife is executing Lake or Streambed Alteration Agreement number 1600-2014-0084-R2 pursuant to Section 1602 of the Fish and Game Code to the project applicant, West Sacramento Area Flood Control Agency. The proposed project consist of repairing an erosion site through the installation of a ScourStop channel at the top of an erosion scarp, placing vegetated mechanically stabilized earth (VMSE) along the erosion site, and construction a longitudinal stone toe at the base of the site. TheScourStop channel would be placed above the top of the erosion site and down the face of the VMSE to the top of the stone toe to control the discharge point of the concrete swale. Placement of the VMSE would restore the slope of the bank to match the contours upstream and downstream of the erosion site, as well as help retain soil placed as part of the project. The longitudinal stone toe would prevent erosion from fluvial forces, boat wake, and discharged flows from the scour stop channel, and provide platform to anchor in stream woody material. These repairs would address the existing erosion problems, enhance fish habitat values, and prevent future erosion from encroaching on the levee, the levee maintenance road, and the adjacent recreation features. The proposed erosion site repairs would require the excavation of the existing unvegetated bank in order to construction the VMSE benches. The excavated VMSE benches would be approximately 1-foot high, and the overall benched riverbank would have a slope of approximately 2.25:1.0, and would be approximately 65 linear feet at their widest point at the base of the bank. Rock slope protection would be placed along approximately 65 linear feet of the bank and along the upstream and downstream edges of the VMSE benches to help delay erosion. The riprap toe would extend approximately 22-feet up the bank and would approximately 2-feet thing with a 2:1 slope between elevations of +10 feet and +13-feet to create a buttress below the benches, and slope of 10:1 between elevations +8.8 and +10-feet to create a shallow rock bench. The VMSE benches would then be constructed by placing clean soil fill and VMSE soil wraps along the excavated benches, allowing the site to match the upstream and downstream contours of the bank. Final compacted fill limits would be approximately 1-foot high and 2-feet deep for areas upstream and downstream of the ScourStop channel. Final compacted fill lifts for the area beneath the ScourStop channel would be approximately 0.5-foot high and 1-foot high. Permanent Impacts associated with the installation of the VMSE will include 0.03-acre of stone fill, and 0.04-acre of soil fill; temporary impacts will total 0.01-acre. Additional project activities include the annual maintenance associated with ensuring successful implantation of the VMSE. The proposed project would use a dump truck, a front-end loader, a track-hoe excavator, a bulldozer, and a compactor.

West Sacramento

Yolo