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Natomas Levee Improvement Project - September 2020


Natomas Levee Project—U.S. Army Corps of Engineers 

Goal:  Complete levee improvements started by SAFCA/State to provide Natomas Basin at least 200-year flood protection

Project Status:  Project is fully authorized by Congress (2014 Water Resources and Reform Development Act).  Appropriations are made on an annual basis

Cost Sharing Partners:  SAFCA (local) and Central Valley Flood Protection Board (State)

Operation and Maintenance Responsibility:  Reclamation District No. 1000

Construction Status:  See Construction Phasing Map

September 2020 Status:

Reach A

   i.      The Corps issued its 95% plans for this reach early in August.  One of the key components of this planning and design process was the analysis of the existing concrete tunnel discharge conduits from Pumping Plant 1A (PP 1A).  The testing and analysis which was performed determined that the 100-year-old plus tunnels are structurally and hydraulically adequate to continue to perform their function, with minor repair. The tunnel outlet will be replaced. The 95% plans were reviewed, and comments are being prepared by the Districts consultants, Mead and Hunt (M&H) as well as the District’s representative to the project, Steve Yaeger.  The focus of the Districts participation in the Project Delivery Team monthly meetings (PDT) has been reaching agreement with the Corps on including construction of a minimum 12 foot wide, all weather toe of levee patrol/ maintenance road in the plans, as well as the details of the cutoff wall closure around the existing PP 1A tunnels.  Right of Way acquisition and relocation by SAFCA is progressing on schedule.  Target date for construction contract award is September 2021.

Reach B

   i.      This construction project contract was awarded in spring, 2020.  Initial clearing and stripping as well as demolition of three houses has commenced.  Cutoff wall construction, construction of the adjacent levee and seepage berm will commence next spring.  Don Caldwell has been representing the District and working with the Corps’ inspectors and resident engineers to provide project support.  The District representative to the project will join Don in participating in the weekly construction coordinating meetings in the spring.  The plans have been completed for the Reach B, I 5 Window closure project.  The bidding on this project is being held, waiting for the result of negotiations with Caltrans on a framework agreement with DWR, SAFCA, and the Corps covering their review and processing of comments on the various NLIP projects where Caltrans permits are required. 

Reach C

   i.      The Reach C project was completed by SAFCA several years ago and the Districts’ role is now providing annual maintenance activities in this reach.

Reach D

   i.      The relocation of the Vestal Drain was completed in early summer 2020, however the project is still in the final acceptance phase.  District staff and consultants maintain constant contact with the Corps’ inspectors and Resident Engineers, lobbying for completion of the Districts’ punch list of deficiencies prior to flood season.  The plans for reconstruction of Pumping Plant 4 have been repackaged into a separate project – having been deleted from the earlier construction project due to delays resulting from PG&E conflicts.  Project construction award is scheduled for end of calendar year 2020.  District consultants M & H and staff have conducted a review and have commented on these plans.

Reach E

   i.      Reach E extends along the Pleasant Grove Creek Canal from Sankey Road north to Howsley Road. 

   ii.      The Corps of Engineers completed the 65% plans in July.   Comments were due by August 28.  The District submitted comments along with SAFCA and State DWR.  The proposed project includes limited areas of a 50-foot-deep cut off wall and levee widening with 3:1 back slope and a landside levee patrol road for the entire length.

   iii.      As part of the project, the existing five drainage culverts through the levee foundation will be replaced with reinforced concrete pipe from beyond the waterside levee toe through the existing levee and the new widened levee section.

   iv.      Current schedule is for contract award in July 2021 with construction complete by November 2022 (two construction seasons).

Reach F

    i.      Reach F is along the Natomas East Main Drain Canal from Sankey Road to Elverta Road.  It is being designed concurrently with Reach G

    ii.      The Corps of Engineers and non-federal sponsors (NFS) held the 10% design review in August.  The Corps preliminary design does not include cut-off walls but does include levee widening—currently on both land and waterside.  NFS are recommending no waterside fill and will have our geotechnical consultant review the design which may suggest some cutoff walls and consistent design with Reach G.

   iii.      Next milestone is 35% plans in January 2021.  Current schedule is for contract award in March 2022.

Reach G

   i.      Reach G is along the Natomas East Main Drain Canal from Elverta Road to south of Elkhorn Blvd.   It is being designed concurrently with Reach F.

   ii.      The Corps of Engineers and NFS held the 10% design review in August.  The Corps preliminary design includes some limited cutoff walls and levee widening with landside slope flattening (3:1) and patrol road the entire length similar to Reach E. 

   iii.      Next milestone is 35% plans in January 2021.  Current schedule is for contract award in March 2022.

Reach H

   i.      The cutoff wall and levee slope flattening are mainly complete and are scheduled to be finalized by November 1, 2020.  Work may continue, subject to weather conditions, on grading of the patrol/ maintenance road and fencing into winter and spring.  District staff and representatives participate in weekly construction meetings and assist SAFCA in their project support role, mainly related to fence relocations.  A major remaining District issue which requires District staff, project representatives, and consultants revolves around the completion of PP8 discharge piping prior to flood season.

Reach I

   i.      Construction of the cutoff wall and levee slope flattening is essentially complete, requiring only repaving and stripping for contract completion.  District staff, consultants, and project representative are winding down their project monitoring and support activities for this construction work.  A separate project to construct a toe of levee patrol/maintenance road and fencing is scheduled for 2022 and design and right of way (ROW) easement acquisition is nearing completion.  District staff, consultants and the project representative continue to support these design and implementation activities.