The San José-Santa Clara Regional Wastewater Facility (RWF) owns and operates two gate structures providing essential flow control between the adjacent Pond A18 and the Artesian Slough and San Francisco Bay, which are located on the levee forming the southwest side of the pond.  The South Gate Structure is one of the two gate structures. Flow through the gate structure forces turbulent eddies to cause significant erosion to the levee embankment adjacent to the South Gate Structure. 

Cal Engineering & Geology (CE&G) was first tasked with conducting a condition assessment of the distressed structure. This included site observations and a review of design documents.  The assessment revealed structural deficiencies that were rapidly being exacerbated by the erosion of the levee.  CE&G next conducted a geotechnical investigation. An assessment of the soil conditions and evaluation of the cause of the damage led CE&G to develop a design concept that included the construction of sheet pile walls with walers to provide the necessary protection for the levees from future erosion.  Our services included structural design for repairs, and preparation of plans, specifications, and estimates for repair.  The repair design included the installation of sheet piles, tie rod anchors and walers, as well as earthwork to restore and protect the portion of the levee subjected to severe erosion.  In addition, CE&G has been responsible for conducting periodic monitoring of the condition of the repairs.

Project elements include:

  • Condition assessment of the distressed South Gate Structure
  • Geo-structural design for sheet pile walls to provide the necessary erosion protection for the levee