Grimes Floodplain Restoration and Levee Resiliency Project

Grimes Floodplain Restoration and Levee Resiliency Project

Notice of Intent to Adopt a Mitigated Negative Declaration


The Sacramento River West Side Levee District (SRWSLD), acting as the California Environmental Quality Act (CEQA) lead agency, has made available for public review and comment an Initial Study and proposed Mitigated Negative Declaration (IS/MND) for the Grimes Floodplain Restoration and Levee Resiliency Project (proposed project).


Project Description: SRWSLD, with funding from the California Department of Water Resources (DWR), is proposing this project, which would consist of constructing a 1.8-mile-long slurry cutoff wall in the existing Sacramento River West Bank Levee System (SRWBLS), encroachment remediation, waterside hardening, establishment of an operations and maintenance area, and restoration of approximately 11 acres of floodplain for salmonids. DWR investigations have determined that the section of the SRWBLS north and south of, and directly adjacent to, the town of Grimes in Colusa County is vulnerable to seepage. Currently, Grimes is not mapped within a Federal Emergency Management Agency (FEMA) special flood hazard area; however, FEMA has initiated a remapping process for Colusa County. Initial results indicate that without remediation of the Sacramento River levees, FEMA will model the area assuming no levees are present. The goal of the proposed project is to increase flood resiliency a 100-year level of flood protection to the town of Grimes in a manner consistent with the 2012 Central Valley Flood Protection Plan and its 2017 update, including investments in multi-benefit flood projects (e.g., improvement of salmonid habitat). The construction phase will begin once the SRWSLD secures a State or Federal implementation grant. Construction is anticipated to begin no earlier than 2024.


Public Review Period: The proposed project’s IS/MND is available for review from August 30, 2022, to September 28, 2022, and may be downloaded here Grimes_ISMNDwAppendices or viewed at the following locations:

  • SRWSLD: 975 Wilson Bend Road, Grimes, CA 95950
  • Grimes Library: 240 Main Street, Grimes, CA 95950


Lead Agency Contact: Questions, comments, or requests for digital or physical copies may be directed to Ms. Meegan Nagy by email at; or in writing care of Sacramento River West Side Levee District, PO Box 50, Grimes, CA 95950; or by telephone at (530) 437-2221.

Knights Landing Ridge Cut Erosion Repair Project


DATE: December 07, 2021
TO: Responsible Agencies, Interested Parties, and Organizations
SUBJECT: Knights Landing Ridge Cut Erosion Repair Project
The Knights Landing Ridge Drainage District (KLRDD) is the California Environmental Quality Act (CEQA) Lead Agency for the proposed Knights Landing Ridge Cut Erosion Repair Project (Proposed Project). KLRDD has directed the preparation of an Initial Study/Mitigated Negative Declaration (IS/MND) for the Project in compliance with CEQA.
Project Location: 6.25 miles along both banks of the Knights Landing Ridge Cut canal levee just south of Knights Landing in Yolo County, California.
Project Description: The Project is the repair of eroded areas on the waterside of levees of the 6.25-mile-long Knights Landing Ridge Cut (KLRC), a human-made leveed drainage channel, using rock slope protection, and vegetation in some areas, similar to the approach approved by the United States Army Corps of Engineers (USACE) in their Sacramento River Bank Protection Plan Environmental Impact Statement (EIS)/Environmental Impact Report (EIR). The Project objective is to arrest or avoid streambank erosion that threatens the integrity of the Sacramento River Flood Control Project levee system. Hydraulic excavators would be utilized at repair locations to remove and reshape existing soil and to place rock and other materials hauled in from commercial sources by truck. Some in-water work would occur, including installing up to 1-ton rock slope protection (RSP) below the water line using land-based methods and equipment, and possible installation of silt curtains within the canal using a small boat. Excavated materials would be incorporated into the work. Limited excavation or cutting into the landward side of levees would occur. Rock fill materials would be brought in utilizing trucks on existing roads. Any material staging would occur in the immediate vicinity of the work on the levee, on the levee toe roads, or within the designated 2.5-acre staging area at the base of the east levee. Solid waste generated by the Project would include limited quantities of removed vegetation that would be disposed of at the nearest solid waste disposal facility. Access routes to the Project location would be via State Route 113 to the northern end, or via County Road 16 and CR 17 near the southern end. Vehicles would then use the existing dirt and gravel levee toe roads and the gravel road on the levee crown. Repairs will be implemented in phases over the next 10 years as erosion areas are identified and funding becomes available.
Potentially Significant Environmental Impacts: Potentially significant impacts to biological resources, cultural resources, geology and soils, hazards/hazardous materials, hydrology and water quality, land use and planning, transportation, and tribal cultural resources were identified in the Initial Study. All impacts would be reduced to a less than significant level with the implementation of identified mitigation measures.
Draft IS/MND Document Review and Availability: The public review and comment period for the Draft IS/MND will extend for 45 days starting December 7, 2021 and ending January 6, 2022. Due to the COVID-19 pandemic, printed hard copies will not be available to the public. However, the Draft IS/MND can be viewed and/or downloaded here:
Requests for confidential reports held in Appendix C can be submitted to
Questions: Comments and/or questions regarding the IS/MND may be directed to:
Meegan Nagy, PE, Deputy Manager
Knights Landing Ridge Drainage District
P.O. Box 50
Grimes, CA 95950




Sacramento River West Bank Seepage Mitigation Project

Sacramento West Side levee finishes ‘seepage project’


The Sacramento River West Side Levee District (SRWSLD), acting as the California Environmental Quality Act (CEQA) lead agency and project proponent, has reviewed the proposed project described below to determine whether substantial evidence supports a finding that project implementation could have a significant effect on the environment. “Significant effect on the environment” means a substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land use, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic significance.

Name of Project: Sacramento River West Bank Seepage Mitigation Project, Levee Miles 3.41 to 6.45

Project Location: The proposed project is located along the landside toe of the Sacramento River west levee between levee miles 3.41 and 6.45, approximately 3 miles north of the community of Knights Landing in Yolo County, California. The right (west) bank of the Sacramento River in the project area is a Sacramento River Flood Control Project (SRFCP) levee. The entirety of the project area is on the landside of the levee.

Project Description: SRWSLD is proposing the Sacramento River West Bank Seepage Mitigation Project, Levee Miles 3.41 to 6.45 (proposed project) to construct approximately 3.25 miles of permanent drained seepage berm over several construction seasons along the landside toe of the Sacramento River west levee. The proposed project would be constructed in response to seepage that occurs periodically along the levee toe during high water events in the Sacramento River, as well as to prevent future seepage problems along the levee. The seepage berm would provide additional weight needed at locations where seepage has historically been observed. The additional weight and internal rock drainage layer would help to counteract and contain upward seepage forces from under-seepage during high water events.

If left unaddressed, seepage can lead to erosion of the landside levee toe and possibly levee failure. Drained seepage berms are landside earthen embankment structures that resist accumulated water pressure and safely release seeping water at the landside toe of the berm through an internal rock drainage layer.

The first 1.3 miles of berm would be constructed in 2018, with additional sections being constructed over the next 5-7 years as additional funding becomes available. Berm construction would occur between April 15 and November 1 in any given year, with the actual duration dependent on the length of berm to be constructed in each individual construction year. No known hazardous waste sites exist in the project area.

Cecil Lake Levee Maintenance




The Sacramento River West Side Levee District has completed the levee widening of 500 feet of the Sacramento River West Side Levee near Cecil Lake. The work was completed to combat seepage during flood events. The budget for the project is approximately $200,000. The project included constructing ramps up and down the levee, a water side levee toe road and widening the levee by approximately 8 feet. After the construction was completed, the levee top road was re-graveled. The Reclamation District No. 108 crew completed the maintenance on time and within budget. The photographs below show the site before the project and through construction.

 Before Project Filling Trucks
 Before Construction  Loading Trucks
 1  2
Building Ramps Levee Toe Road
3 4
Widening the Levee Widening the Levee Continued



Reclamation District No. 108 has invested heavily into recycling infrastructure over the years. The unique topographic features of the district, mainly being completely surrounded by flood protection levee’s, allows all the irrigation drain water to be captured and can be either pumped back into the river or recycled within the district. The disadvantage of recycling is the accumulation of salts, which is why in normal years much of the water is pumped back into the river. However, in dry years recycling water is a priority and allows the district to fully farm with just a 75% supply. It is estimated that the district can recycle well over 50,000 AF of water in a normal year. In a drought year such as 2014, the amount of recycling can be significantly increased by reducing the water quality standards within the district.

The recycling facilities in RD 108 include:

Riggs Ranch Pumping Plant

Riggs Ranch Pumping Plant

Lateral 8 Check Pumping Plant

Lateral 8 Check Pumping Plant

Lateral 8 Pumping Plant

Lateral 8 Pumping Plant

Sycamore Slough Pumping Plant

Sycamore Slough Pumping Plant

Sycamore Slough Solar Project

solarIn 2009 Reclamation District No. 108 completed construction of a 386KW DC solar generation facility that produces enough energy to power 110 California homes.

Energy is a significant operating expense for RD 108.  Water and recycled water enters and leaves the District through the pumping facilities along the Sacramento River.  The District is very efficient in its water use and operates an extensive water recycling system that encompasses four pumping plants that recycle approximately 50,000 acre-feet annually with Sycamore Slough being the largest.  Water draining from the fields is captured in the system and reapplied to the fields for irrigation.

The solar generation facility sits on seven acres adjacent to the Sycamore Slough Pump Station.  The panels operate on a dual axis tracking system to follow the sun as it moves throughout the day to optimize energy production.  The tracking system is also designed to meet minimum flood requirements by raising the solar panels 15 feet in the event of a flood.

Energy SavingsSolar_2

The potential for cost savings first attracted the District to the solar project.  As energy prices continue to rise, the solar facility provides affordable renewable energy for today and years to come.  The money savings are passed along to the farmers in the District.

The project is part of a net energy metering program that allows the District to balance energy production and usage on an annual basis.  PG&E calculates the amount of energy the District consumed and credits the District with the total amount of energy produced at the solar facility.  At the end of the year, the District will only pay the difference from the amount of energy used and amount of energy produced.

The total project cost was $3.4 million, not including a $1.5 million rebate the District received for PG&E.  The exact cost savings from the project will fluctuate with PG&E’s changing rates, but the District calculated that when the PG&E rates increase by 2.5 percent annually, the project will result in a 10 percent savings.

Clean Energy

The solar generation facility produces clean renewable energy that reduces impacts to the environment.  The solar facility continues the Reclamation District No. 108 commitment to serve its water users in a reliable, economic and environmentally sound manner.

Long Crested Weir

Long Crested Weir 3Distribution canals in the Eastern area of the District are concrete lined with low volumes and high velocities, making them difficult to manage with flash board check structures.  Prior to the project, approximately 10 cubic-feet per second of additional flow was required throughout the irrigation season in order to ensurer sufficient flows were delivered to the farm turnout.

Previously, an adjustable flash board structure was located slightly downstream of each farm turnout.  In order to maintain a stable canal water surface elevation, every time the flow in the canal was Long Crested Weir 2changed, boards were added or removed.  The benefit to installing Long Crested Weirs in place of adjustable flash board structures is that for cost fluctuations in canal flow rate, the change in water surface elevation at the turnout remains nearly constant.  This provides a constant flow to the irrigated field.  It also substantially reduces labor and the chance of human error.

The same characteristic of the Long Crested Weir that makes it useful in canals for water level control eliminates the weir as a measurement device.  Therefore, the District was required to add measurement methods at key locations throughout the conveyance system.

Long Crested Weir 1

Fishscreen Program

Reclamation District No. 108 diverts irrigation water from the Sacramento River.  In order to protect the fish populations in the Sacramento River, RD 108 was one of the first irrigation districts to invest and install a fish screen on its primary river diversions.

Wilkins Slough Pumping Plant and Fish Screen

The Wilkins Slough Positive Barrier Fish Screen culminates nearly 8 years of planning, agency coordination, testing alternative barriers, feasibility study, design and construction.  The Wilkins Slough Positive Barrier Fish Screen was put into operation in March 1999 at the start of the irrigation season.

The objectives of the project were to make the Wilkins Slough Diversion “fish friendly,” minimize the impact of water diversions on winter-run chinook salmon and meet current resource agency criteria for fish protection facilities.  A critical goal that was successfully met was to construct the fish screen structure without interrupting irrigation water deliveries or interfering with fish migrations in the Sacramento River.

Wilkins Slough Positive Barrier Fish Screen is one of the largest fish screening facilities in the Sacramento River Basin.  The facility has a design flow capacity of 700 cubic feet per second but can accommodate flows up to 830 cubic feet per second.  The structure is positioned along the right bank of the Sacramento River in front of the Wilkins Slough forebay.  The screens are continuously cleaned by a single-arm mechanical brush mechanism that sweeps across the entire screen surface every 5 minutes.

Emery Poundstone Pumping Plantpoundstone_pp

Reclamation District No. 108 consolidated three of its river diversion pumping plants into a single facility with a state-of-the-art fish screen.  The initial project investigation confirmed that it would be less costly to build a new combined pumping plant with a fish screen than to install separate fish screens on each of the three existing pumping plants.  Further, it was determined that combining the three pumping plants would result in a lower water diversion requirement, thereby lessening the effects on protected fish species.