*UPDATE: The U.S. Army Corps of Engineers Sacramento District awarded a construction contract for the Natomas Basin Reach D Highway 99 Project in January 2024, enabling the agency to continue constructing levee improvements. Construction will begin in May and continue through October 2024. Highway 99 will have lane closures near Howsley Road exits (Sutter County) in both directions, affecting traffic conditions. This work is part of the American River Common Features – Natomas Basin project authorized by Congress in 2014.

Our mission is to reinforce 42 miles of levee surrounding the Natomas Basin in partnership with the State of California and the Sacramento Area Flood Control Agency. Further levee improvement details will be announced as we continue our mission of making the Natomas Basin safe from flooding.

Reach A: Sacramento River east levee from the intersection of Garden Highway and Gateway Oaks Drive extending upstream to Farm Road. The length of this reach is approximately 3.5 miles. The general improvements include widening the existing levee a minimum of 15 feet through construction of an adjacent levee, and installation of approximately 2.4 miles of seepage cutoff wall with a maximum depth of approximately 145 feet and flattening the landside levee slope. The Post-Authorization Change Report and Interim Reevaluation Report American River Watershed evaluated the use of a seepage berm in certain areas of this reach. The contract number is W9123821C0034 and was awarded on Sep. 23, 2021, with construction beginning Aug. 2022. For more information on Reach A, please visit the Reach A webpage

Sacramento River east levee from Farm Road upstream (north) to Elverta Road. The length of this reach is approximately 9.7 miles. The general improvements include widening the existing levee by construction of an adjacent levee, installation of approximately 4.3 miles of a seepage cutoff wall that ranges in depth between approximately 40 and 115 feet, and installation of approximately 5.6 miles of seepage berms that range in width from approximately 80 to 300 feet, and flattening the landside levee slope. A portion of the Reach B features were constructed by the Non Federal Sponsors upstream of approximately Powerline Rd, apart from several “windows” within the alignment that were left for the USACE to construct. The USACE Reach B contract spans along Garden Hwy from just downstream of Powerline Road, south to Farm Road and consists of 2.3 miles of adjacent levee construction, an irrigation pipeline relocation, improvements to Pumping Plant #3, and seepage berm construction. The contract number is W9123820C0002 and was awarded on Nov. 14, 2019 for $49,283,799.95.

Reach B I-5 Window: Government Pre-final inspection conducted 1 November 2022. Punch list in process. Final inspection date TBD. N. Bayou Way cannot be re-opened due to overhead communication line remaining about 13 feet above surface. Remaining contract work to be completed following relocation of overhead utilities including finalizing fill at current utility pole location, demolition of detour road, installation of cross gutter, and erosion protection of fill. Contractor plans to demobilize 4 November 2022. Reburial of cultural resources completed. The contract number is W9123821C0015 and was awarded on May 7, 2021 for $4,424,525.

Reach B PP#5: This is a Flood Damage Reduction project located just north of downtown Sacramento located in Reach B. Upgrading of interior drainage pumping plant and relocation of discharge pipes crossing levee. The design is 35% complete and construction is planned for the 2026 construction season.

Reach B Riverside Pumping Plant Relocation: On behalf of the Non Federal Sponsors, the Natomas Central Mutual Water Company (NCMWC) will be replacing the Riverside Pumping Plant and relocating the discharge pipes up and over the levee and above the 200-year flood elevation. This will occur in two phases with the first being the pumping plant replacement which was awarded in the Summer 2022 with construction 100% complete. The second phase is the relocation of the discharge pipes which is scheduled to begin late 2026.

Reach B Elkhorn Pumping Plant Relocation: On behalf of the NFS, the NCMWC will be replacing the Elkhorn Pumping Plant and relocating the discharge pipes up and over the levee and above the 200-year flood elevation. This will occur in two phases with the first being the pumping plant replacement which was awarded in April 2024 with construction beginning in Summer 2024 and lasting two seasons. The second phase is the relocation of the discharge pipes which is scheduled to begin late 2028.

Sacramento River east levee from Elverta Road upstream (north) to Sankey Road at the west end of the south levee of the Natomas Cross Canal. The length of this reach is approximately 5 miles. The general improvements include widening the existing levee by construction of an adjacent levee, installation of approximately 4.6 miles of seepage cutoff wall that ranges in depth between approximately 19 and 65 feet, and installation of approximately 2.7 miles of seepage berms that range in width from between approximately 100 to 500 feet, and flattening the landside levee slope.

Reach C Pritchard Lake Pumping Plant Relocation: On behalf of the Non Federal Sponsors, the Natomas Central Mutual Water Company replaced the Pritchard Lake Pumping Plant in 2015, except for the installation of one of the three new pumps. The installation of the last pump and the relocation of the discharge pipes up and over the levee and above the 200-year flood elevation will occur during the second phase of construction and is scheduled for Spring 2027. 

Natomas Cross Canal south levee from Sankey Road upstream (northeast) to Howsley Road at the PGCC. The length of this reach is approximately 5.5 miles. The general improvements include widening the existing levee by fix in-place construction, and installation of a seepage cutoff wall that ranges in depth between approximately 60 and 75 feet, and flattening the landside levee slope. The construction contract is W9123818C0014 and was awarded on May 10, 2018 for $24.2K. Construction began Aug. 13, 2018 with physical construction completion on Nov. 22, 2021.

Reach D, Pumping Plant #4: Flood Damage Reduction project in the northwest corner of Natomas Basin adjacent to the Natomas Cross Canal. Work involves demolition and rebuild of the pumping plant including elevation of three stormwater pipes 10 feet to design water surface elevation, and a new electrical station and pumping plant. Work includes the demolition and replacement of Pumping Plant 4 including elevation of three stormwater pipes 10 feet to design water surface elevation, and a new electrical station and pumping plant. The construction contract is W9123821C0012 and was awarded on Feb. 11, 2021, for $7.6K. Construction began on May 18, 2021, with physical construction completion anticipated for Fall of 2024.

Reach D, HWY99:  Reach D levee improvements were completed by the Non Federal Sponsors in 2010 with the exception of an approximately 690-foot section (window) of the levee where the Highway 99 bridge crosses over the top of levee. Since the top of levee serves as the northbound and southbound lanes of Hwy 99, traffic control and highway lane closures will be required to complete the construction of the cutoff wall. The Hwy 99 project includes a 750-foot-long cutoff wall which will overlap and close the gap between the cutoff walls constructed by the NFS. The construction contract is W9123824C0007 and was awarded on January 17, 2024, for $9.1M. Construction begins in June 2024, with physical construction completion anticipated for Fall of 2025.

Pleasant Grove Creek Canal west levee from Howsley Road upstream (south) to Sankey Road. The length of this reach is approximately 3.4 miles. The general improvements include widening the existing levee by fix in-place construction, installing an adjacent levee, installation of a seepage cutoff wall that ranges in depth between approximately 38 and 50 feet, flattening the landside levee slope and replacement of (5) underdrain culverts and gatewells. The contract number is W9123823C0008 and was awarded on April 10, 2023, and construction began June 2023. Natomas Levee Road is currently closed from Sankey Road heading north to Howsley Road due to construction of the Reach E project improvements.

The Natomas East Main Drainage Canal west levee from Sankey Road downstream (south) to Elverta Road.  The length of this reach is approximately 4.7 miles. The general improvements include widening the existing levee by fix in-place construction, levee widening, flattening the landside levee slope and installation of a patrol road. The design is 100% complete and construction is planned for the 2027/2029 construction season.

The Natomas East Main Drainage Canal west levee from Elverta Road downstream (south) to the drainage pumping station just upstream of Dry Creek.  The length of the reach is approximately 3.6 miles. The general improvements include improving the levee by fix in-place construction, and installation of a seepage cutoff wall with a depth of approximately 40 feet near Pump Station No. 6, levee widening, flattening the landside levee slope and installation of a patrol road. The design is 100% complete and construction is planned for the 2027/2029 construction season.

The Natomas East Main Drainage Canal west levee requires cutoff wall improvements from the pumping station just upstream of Dry Creek downstream (south) to Arden-Garden Connector Bridge. The length of this reach is approximately 4.0 miles. The general improvements include improving the existing levee by fix in-place construction, and installation of a seepage cutoff wall with a depth of approximately 30-70 feet and flattening the landside levee slope. There are two pumping stations which will require the discharge pipes to be raised and installation of a landside maintenance road.  The design was done by AE firm Wood Rodgers.  The construction contract W9123819C0006 was awarded on Jan 23, 2019 for $41.2M.  Construction began May 2019, with physical construction expected to be complete Spring 2024.

The Reach I project was planned to be constructed during two contracts of work.

Contract 1 - The Natomas Basin Reach I Contract is located on the reach of Natomas levee adjacent to the American River in Sacramento, CA. Reach I Contract 1 includes installation of approximately two miles of cement-bentonite cutoff walls between Gateway Oaks Boulevard and Northgate Boulevard, mostly centered on Garden Highway. The cutoff walls will have an average depth of 45 feet. Excavation spoils will be hauled to a site identified herein to be spread and compacted. A landside drainage blanket will be installed on the levee slope underneath Interstate 5. Relocation and/or removal of waterlines, sanitary force mains, and other utilities are included in the contract.  Multiple lane closures, road closures, and bicycle trail closures are also included. The construction contract W9123818C0022 was awarded on July 30, 2018 for $23.6M. Construction began Oct 2018, with physical construction completing on Nov. 4, 2020. Final Payment is currently set for September 2023.

Contract 2 - The American River north levee from Northgate Boulevard downstream (west) to Interstate Highway 5. The length of this reach is approximately 1.8 miles. The general improvements include improving the levee by fix in-place construction, and installation of a seepage cutoff wall with a depth of approximately 37 feet, flattening the landside levee slope and installation of a patrol road. The Reach I project was planned to be constructed during two phases of work (contracts). Reach I Contract 1 included installation of the cutoff wall and was completed by USACE in Nov. 4, 2020. Reach I Contract 2 is in the final design phase and includes the landside improvements. Construction for Reach I Contract 2 is planned for the 2025 construction season.

Overall Natomas Mitigation includes creation of Woodland Mitigation in various sites including Novak and the Woodland Corridor, 80 acres of Giant Garter Snake Habitat and improvements to the West Drain to enhance connectivity between Giant Garter Snake habitats. The Natomas Basin is a unique ecological system separated from other systems by a circular levee system. A Biological Assessment was performed which accurately described the mitigation measures. As a result of this coordination the BO’s received for the previous four phases have obtained mitigation measures similar to what was proposed in the BA. Project mitigation needs have been coordinated with U.S. Fish and Wildlife Service, National Marine Fisheries Service , and the California Department of Fish and Game.