D3: Sediment Reuse to Support Restoration Projects
This project reuses local sediment removed through Valley Water’s Stream Maintenance Program, capital projects and other local sources to create and restore tidal marsh, riparian or wetland habitats. Sediment may be reused to support the South Bay Salt Pond Restoration project or other environmental enhancement and restoration projects. Valley Water removes sediment from streams to maintain their capacity to carry floodwaters. To secure environmentally appropriate reuse sites, partnership agreements may be required. This project also funds site improvements necessary to facilitate sediment delivery to the reuse sites.
Beneficial reuse of sediment has become a key component in tidal marsh, riparian or wetland restoration around the bay and throughout the county. As sea levels rise, natural sedimentation and vegetation rates cannot keep up and tidal zones are in danger of being submerged, erasing environmental gains from restoration work. By delivering clean sediment from local creeks that would have naturally flowed into the San Francisco or Monterey Bays, this project accelerates natural marsh-building processes and helps to keep up with sea-level rise. Activities necessary for sediment reuse may include testing, transport, cover material, and site improvements required for access.
Upon completing beneficial reuse efforts with the South Bay Salt Pond Restoration Project at Pond A8, Valley Water explored and identified the Pond A4 Resilient Habitat Restoration Project (Pond A4 Project) along the southern shoreline in Sunnyvale as a new location for sediment reuse. The Pond A4 Project, a Valley Water multi-benefit project that the Valley Water Board of Directors approved in April 2023, is designed to create shallow water habitat for shorebirds and promote flood resilience by beneficially reusing material harvested from local creeks to construct a habitat bench along the southern perimeter of Pond A4. This constructed habitat bench will also provide a great foundation for a potential upland transition zone if and when Pond A4 is restored to tidal action. Construction access improvements are needed to complete this work and are anticipated to be completed in FY27, with sediment delivery beginning in FY28. For more information on the Pond A4 Project, visit https://www.valleywater.org/project-updates/pond-a4-resilient-habitat-restoration-project. Staff is also exploring private partnerships to accelerate the project schedule, reduce costs, and maximize the goal of creating habitat by utilizing not only SMP sediment but also external upland sediment sources.
In the past, because of the higher standards required to meet criteria under the new Quality Assurance Project Plan (QAPP), Valley Water was unable to find enough soil that met the foundation criteria and even less for cover, thus limiting Valley Water’s ability to deposit the soil at Pond A8. SBSPRP, USFWS, and Valley Water are working with the Regional Water Quality Control Board to modify the criteria for reuse material. As a part of that effort, Valley Water continued to test the sediment removed to ensure consistent sediment quality data was available. Valley Water staff met with RWQCB in April 2024 to develop a site-specific QAPP for the Pond A4 Project. RWQCB requested additional studies in order to consider granting a relaxation on the cover thickness requirement (allowing for a thinner cover), which would enable increased reuse of SMP material. Staff is working to complete these studies by FY26, aiming for site-specific QAPP approval, including the thinner cover requirement, by FY27.
On January 24, 2023, the Valley Water Board of Directors (Valley Water Board) held a formal public hearing and approved modifying KPI #1 to “Reuse sediment meeting applicable screening criteria at available Valley Water or partnership project sites to support restoration.” To align with the modification, the Valley Water Board also approved adjusting the project description thus facilitating sediment reuse to support other environmental enhancement and restoration projects beyond the South Bay Salt Pond Restoration Project (SBSPRP). Valley Water had been delivering sediment to Salt Pond A8 of the SBSPRP via an agreement with the U.S. Fish and Wildlife Service (USFWS). In July 2022, Valley Water was informed that Salt Pond A8 had received 100% of the material needed for the ecotone habitat that was designed and permitted as part of SBSPRP. Valley Water had paused sediment delivery to Pond A8 in July 2022. The modification and the adjustments are incorporated into this webpage above (title, description) and in the Environmental & Community Benefits section (KPIs, benefits). For more information and to view the project modification public hearing, visit tinyurl.com/2023Jan24BoardMtg.
August 2025
