MGE, as a joint venture partner with Wood Rodgers in Pacific Civil & Structural Consultants LLC (PCSC), prepared the plans, specifications, Design Documentation Report (DDR), construction estimate, and related bid documents to complete a floodwall segment that was skipped in a prior slurry wall project due to the presence of two 60 inch sewer force mains. The purpose of the American River Common Features project is to remediate historic levee seepage along the American River. Since constructing a cutoff wall around the existing sewer lines using conventional slurry wall construction methods was determined not to be feasible, MGE designed the closure wall utilizing jet grout construction. The project plans provided for installation of a jet grout cutoff wall along the levee centerline, adjacent to the CSU Sacramento campus. The 154 foot closure was designed to have a constant depth of 57 feet, completely surround the existing sewer lines, and overlap the ends of the existing slurry cutoff wall by 12 feet at each end, providing an effective seal. The project included structural analysis of the existing force mains to ensure the jet grout pressure would not deform, displace or damage the active sewer force mains.

Key Facts:
Construction is expected to be completed in 2013.
Estimated construction cost: $2.5 Million.

Key Staff:
Project Manager: Bob Sennett
Civil Lead: Steve Hawkins

Sacramento District US Army Corps of Engineers