Adopt an Initial Study/Mitigated Negative Declaration for the Knights Landing Flood Management Project (Sacramento River, Mid-Valley Levee Construction Sites 9, 10, 11 and Widened Parking Area near Wild Irishman Bend) and Mitigation Monitoring and Reporting Plan, as the appropriate level of environmental review in accordance with the California Environmental Quality Act (CEQA); approve the project; direct County staff to file a Notice of Determination with the County Clerk-Recorder and the State Clearinghouse; approve the plans and contract specifications for the project at Sites 9 and 10; and authorize the Director of Public Works to advertise for construction and take other project solicitation related actions. (No general fund impact) (Perez/Sabatini)

1. Adopt an Initial Study/Mitigated Negative Declaration and Mitigation Monitoring and Reporting Plan (Attachment B) as the appropriate level of environmental review in accordance with the California Environmental Quality Act (CEQA);
    
2. Approve the Project;
    
3. Direct the County Administrator's Office to file a Notice of Determination with the County Clerk-Recorder and the State Clearinghouse (Attachment C);
    
4. Adopt the plans (Attachment D) and contract specifications (Attachment E) for the Project at Mid-Valley Sites 9 and 10;
    
5. Authorize the Director of Public Works to sign the Notice to Contractors (Attachment F);
    
6. Authorize the Department of Community Services to advertise for competitive bids once construction authorization is received from the State of California Department of Water Resources;
    
7. Authorize the Director of Public Works to execute a construction contract with the lowest responsive bidder, provided the contract amount does not exceed available funds, or to reject all bids; and
    
8. Authorize the Director of Public Works to approve all construction change orders, provided the contract amount does not exceed available funds for the project.

	Thriving Residents
	Safe Communities
	Flourishing Agriculture

BACKGROUND
The levees surrounding the Knights Landing Basin are part of the federally authorized Sacramento River Flood Control Project (SRFCP).  After the 1986 flood events, the levees were evaluated by the U.S. Army Corps of Engineers (USACE) and they identified three sites (Sites 9, 10, and 11) along the right bank of the Sacramento River needing to be addressed to fix through-seepage.  The initial design of the Project is described in the SRFCP, California, Mid-Valley Area, Phase III, Design Memorandum, dated March 1996, and after the 1997/1998 flood events, subsequent re-analyses were ensued.  Design refinements were made for Sites 9 and 10 to include shallow cutoff walls to address the original concerns of through-seepage and documented in the USACE, Final Design Documentation Report (DDR) dated November 28, 2012.

Construction of the Project is authorized under a Project Cooperation Agreement between the Department of the Army and the State of California, dated April 4, 2000.  A Local Project Cooperation Agreement (Yolo County, 2000) between the State and Yolo County was also executed in 2000 to formally recognize Yolo County as the Local Sponsor responsible for non-Federal costs and perform the necessary Operation and Maintenance, Repair, Replacement and Rehabilitation (OMRR&R) tasks for the portion of work that encompasses the subject Project.

In 2017, the County received a grant from the State Department of Water Resources (DWR) Small Communities Flood Risk Reduction Program (SCFRRP) to complete a feasibility study of structural and non-structural actions that could reduce flood risk to Knights Landing. The County prepared the 2019 Knights Landing Small Community Flood Risk Reduction Feasibility Study, which identified a preferred alternative, for levee remediation, that justified the State's interest in the Mid-Valley Sites 9, 10, and 11 projects. DWR reviewed the Feasibility Study for further implementation and funding.  In 2020, the County received additional grant funding ($15.2 M) from DWR as part of Phase 2 of the SCFRRP, which included funding for a portion of the preferred alternative; specifically, to complete design and environmental documentation and permitting for the Mid-Valley Sites 9, 10, and 11 and construct Sites 9 and 10.

When completed, the Knights Landing Small Community Flood Risk Reduction Program will reduce or prevent flooding to a population of 995, approximately 321 structures and 3,500 acres of prime agricultural lands.

PROJECT LOCATION
The levee improvement project area is located in eastern Yolo County, south of the town of Knights Landing, along the right bank of Sacramento River.  The site boundaries include sections of the Sacramento River Flood Control Project (SRFCP) levees, easements, and right-of-way areas along the County Service Area-6 (CSA-6) maintained levee.  Work on the Sacramento River right bank levee would be conducted at Sites 9, 10, and 11 between levee mile (LM) 2.66 and 5.35. The site boundaries include the levee prism to Yolo County Road (CR) 116B.

• Site 9 starts approximately 1.6 miles southeast of Knights Landing at LM 2.66 and extends 794 feet downstream to LM 2.87.
• Site 10 starts approximately 878 feet downstream of Site 9 at LM 3.0 and extends 878 feet downstream to LM 3.22.
• Site 11 starts approximately 1,200 feet downstream of Site 10 at LM 4.3 and extends 1.05 miles (5,540 feet) downstream to LM 5.35 along CR 116B.

PROJECT DETAILS
The Project would include constructing slurry cutoff walls in the existing Sacramento River right bank levee at Sites 9 and 10 to address through-seepage. Site 11 would include constructing a combination berm to address through- and underseepage. In addition, easements for a maintenance road would be obtained where feasible and necessary at the landside levee toe; however, the maintenance road would not be constructed as part of the Proposed Project.

Remediation work at Sites 9 and 10 would consist of installing a soil/bentonite cutoff wall of various lengths and depths.  The work would involve (1) degrading the existing top of the levee to create a level working surface of sufficient width to install the cutoff wall; (2) excavating a trench down through the crown of the levee; (3) mixing water and bentonite slurry material using an excavator in a lined pond or mixing box; (4) rebuilding the levee, including a clay cap over the cutoff wall; and (5) adding an aggregate base surface course on top of the levee to provide an all-weather road for levee maintenance.  At Site 9, the proposed depth of the cutoff wall below the levee crest is approximately 29 feet.  The length of the cutoff wall would be 794 linear feet, matching what was shown in the 2012 USACE plans, plus a 40-foot-long lead in trench on each end of the wall.  At Site 10, the proposed depth of the cutoff wall below the levee crest is approximately 25 feet. The length of the cutoff wall would be 878 linear feet, matching what was shown in the 2012 plans, plus a 37-foot-long lead in trench on each end of the wall.

Remediation work at Site 11 would consist of installing a drained seepage-stability berm.  The work would involve (1) constructing a drained seepage-stability berm on the landside toe of the levee; (2) relocating drainage ditches; and (3) reseeding the berm with native vegetation to reduce erosion.  At Site 11, an 80-foot-wide, maximum width, drained seepage-stability berm would be constructed on the landside of the levee continuing north from the intersection of CR 16 and CR 116B approximately 5,600 feet to the north end of Site 11.  The seepage-stability berm consists of a 2-foot-thick layer of drainage rock below a 3-foot layer of earthen material.  The thickness of the berm would be 5 feet at the landside levee slope and decrease to 3 feet at the landside toe of the berm.  The seepage-stability berm at Site 11 would require relocating the existing irrigation ditches that are located at the toe of the levee; relocation of piping for two pump stations located within the footprint of the seepage-stability berm; and installation of relief wells around a tesla tower located within the seepage berm alignment.  There are a number of electrical poles that would need to be relocated to the maintenance road/utility corridor.

As part of the Project, at Site 11, the County may acquire a 15-foot-wide maintenance/utility easement along the landside toe of the seepage-stability berm.  This maintenance road would be used for future operations and maintenance activities.  The CSA-6 would acquire the 15-foot-wide easement along the remaining Sacramento River right bank after all improvements along the Knights Landing Levee System have been constructed.

At the Mid-Valley Site 11, the levee crown would be expanded 10 feet to provide off-road parking for people accessing the river, eliminate an existing safety hazard caused by road blockages, prevent damages to the waterside levee slope, and accommodate an existing recreational use.

The project plans and contract specifications included in Attachments D and E are for the levee improvement work at Sites 9 and 10 only.  A request for authorization to proceed with construction for sites 9 and 10 was submitted to DWR on September 1, 2021.  The Project is programmed for DWR reimbursement for up to 90% of the final cost; with Yolo County’s contribution of construction funds, the County will not need to request the full amount programmed.  Staff has been informed that the reimbursement would be distributed no later than June 1, 2023.  County staff recommends proceeding with the project in order to preserve State funding.  Assuming that the project is approved, and project permits and approvals are obtained, construction is anticipated to start in the Spring of 2022 and last for approximately 5 months. Construction of Site 11 has not yet been established; however, it is anticipated to consist of a similar schedule as for Sites 9 and 10 and last approximately 5 months.

ENVIRONMENTAL REVIEW
The County has principal responsibility for carrying out the Project and is, therefore, the CEQA lead agency for the IS/MND. The County has an agreement with DWR for Project funding; therefore, DWR is a responsible agency pursuant to CEQA.  The County prepared the IS/MND to evaluate the expected environmental effects of the entire Project, and has incorporated mitigation measures to reduce or eliminate any potentially significant project-related impacts.  The IS/MND was submitted to the Yolo County Clerk Recorder's Office and the State Clearinghouse and circulated for public review and comment from December 3, 2021, through January 4, 2022.  A total of four comments were received during the review period.  Responses to those comments are included in the attached Final lS/MND (Attachment B).

County staff is currently in the process of obtaining coverage under the Yolo Habitat Conservation Plan/National Community Conservation Plan (HCP/NCCP) for potential impacts on covered species and land cover, as well as securing other state and federal permits. 

Staff from the County Administrator's Office has collaborated with staff from the Department of Community Services and the Office of County Counsel, as well as the State Department of Water Resources, Central Valley Flood Protection Board, U.S. Army Corps of Engineers, Sacramento District, Yocha Dehe Wintun Nation, and the Yolo Habitat Conservancy.