This data release provides bathymetric change grids of four geographic areas of San Francisco Bay, California, comparing digital elevation models (DEMs) created from bathymetric data collected in the 1970s and 1980s with DEMs created from bathymetric data collected in the 2010s and 2020. These types of change analyses can provide information on the quantities and patterns of erosion and deposition in San Francisco Bay over the 9 to 47 years between surveys, and they reveals that the bay floor lost about 34 million cubic meters of sediment between the intervening time period. Results from this study can be used to assess how San Francisco Bay has responded to changes in the system such as sea-level rise and variation in sediment supply from the Sacramento-San Joaquin Delta and local tributaries, and supports the creation of a new, system-wide sediment budget. These bathymetric change grids can also provide data to ecosystem managers about the quantities and patterns of sediment volume change in San Francisco Bay to assist in decision-making for a variety of sediment-related issues, including restoration of tidal marshes, exposure of legacy contaminated sediment, and strategies for the beneficial use of dredged sediment.
Bathymetric change analyses document historical patterns of sediment deposition and erosion, providing valuable insight into the sediment dynamics of coastal systems, including pathways of sediment and sediment-bound contaminants. In 2014 and 2015, the Office for Coastal Management, in partnership with the National Oceanic and Atmospheric Administration (NOAA) Office of Coastal Management, provided funding for new bathymetric surveys of large portions of San Francisco Bay. A total of 93 bathymetric surveys were conducted during this 2-year period, using a combination of interferometric sidescan and multibeam sonar systems. These data, along with recent NOAA, U.S. Geological Survey (USGS), U.S. Army Corps of Engineers, and private contractor surveys collected from 1999 to 2020 (hereinafter referred to as 2010s), were used to create the most comprehensive bathymetric digital elevation models (DEMs) of San Francisco Bay since the 1980s. Comparing DEMs created from these 2010s surveys with USGS DEMs created from NOAA’s 1971–1990 (hereinafter referred to as 1980s) surveys provides information on the quantities and patterns of erosion and deposition in San Francisco Bay during the 9 to 47 years between surveys. This analysis reveals that in the areas surveyed in both the 1980s and 2010s, the bay floor lost about 34 million cubic meters of sediment since the 1980s. Results from this study can be used to assess how San Francisco Bay has responded to changes in the system, such as sea-level rise and variation in sediment supply from the Sacramento-San Joaquin Delta and local tributaries, and supports the creation of a new, system-wide sediment budget. This report provides data on the quantities and patterns of sediment volume change in San Francisco Bay for ecosystem managers that are pertinent to various sediment-related issues, including restoration of tidal marshes, exposure of legacy contaminated sediment, and strategies for the beneficial use of dredged sediment.
The U.S. Geological Survey, Western Ecological Research Center collected sediment and accretion data at a wave-exposed tidal salt marsh in South San Francisco Bay, California. Sediment traps and feldspar marker horizons (MH) were deployed along transects of increasing distance from the sediment source, at primary, secondary and tertiary marsh channels/bay. Data were collected bi-monthly over two month periods in summer 2021 and winter 2021/2022. Included here are trap and MH plot locations, calculated sediment fluxes at each station by deployment period, annual accretion rates, and covariates associated with sediment deposition and accretion including vegetation structure and elevation. This project aimed to assess the temporal and spatial patterns in sediment deposition in order to better understand sediment delivery and marsh resilience to sea-level rise.
Sediment samples were collected on and adjacent to the Whale’s Tail South marsh. Short push-cores of bed sediment were collected in South San Francisco Bay adjacent to Whales Tail South marsh on five days from June through August 2021 and 3 days from November 2021 to January 2022. Additional samples were taken from ceramic tiles placed on the marsh to measure sediment deposition and from rip-up clasts deposited on the marsh edge. Samples were analyzed for sediment properties including bulk density, particle size distribution, and percent carbon. These data were collected as part of a collaborative study with the USGS Western Ecological Research Center to quantify sediment fluxes, deposition on the marsh, and changes in marsh morphology at Whale's Tail marsh in southern San Francisco Bay.
In 2024, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is entering its 32nd year of collecting data and communicating information to support water quality management decisions. This Detailed Workplan and Budget describes the activities that will be completed in 2024, the proposed funding levels, and the deliverables for each task.
The planned revenue from RMP fees for 2024 is $4,156k, with additional supplemental fees of $339k from municipal wastewater and $100k from municipal stormwater bringing the total revenue to $4,596k. The expected revenue is $5,216k as shown in Table 1 and Figures 1-2, which is reduced by $200k to account for the lower volume of dredged sediment being disposed of in the Bay, per the Long-Term Management Strategy (LTMS) plan. The $200k figure is a placeholder and the dredger contribution will be updated when we receive the final in-Bay dredge disposal volumes for calendar year 2023 (typically in March of the following year). The majority of the expenses in 2024 (71%) will be for Status and Trends monitoring and special studies (Tasks 6-7). The cost for running the RMP (Tasks 1-5) is $115k higher in 2024 than 2023 and funding allocations have been shifted slightly within each subtask.
The U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center collected hydrodynamic and suspended sediment flocculation data at channel and shallow water sites in south San Francisco Bay in July 2020. The data were used to determine water column stratification, turbulence profiles, and floc size evolution. The goal of this project was to bound the controls on floc size and floc settling velocity to improve estimates of sediment fluxes and consider error in numerical models of sediment transport in San Francisco Bay. This data release includes hydrodynamic, sediment concentration, and particle size timeseries during July 2020, as well as sediment bed properties, water column particle size distributions, and CTD profiles collected on four days in July 2020 at both sites. Details on station location, instrumentation, and measured variables are included on pages for each data type. These data were collected as part of a collaborative project with the USGS California Water Science Center. Funding was provided by the San Francisco Estuary Institute.
This data release provides bathymetric change grids of four geographic areas of San Francisco Bay, California, comparing digital elevation models (DEMs) created from bathymetric data collected in the 1970s and 1980s with DEMs created from bathymetric data collected in the 2010s and 2020. These types of change analyses can provide information on the quantities and patterns of erosion and deposition in San Francisco Bay over the 9 to 47 years between surveys, and they reveals that the bay floor lost about 34 million cubic meters of sediment between the intervening time period. Results from this study can be used to assess how San Francisco Bay has responded to changes in the system such as sea-level rise and variation in sediment supply from the Sacramento-San Joaquin Delta and local tributaries, and supports the creation of a new, system-wide sediment budget. These bathymetric change grids can also provide data to ecosystem managers about the quantities and patterns of sediment volume change in San Francisco Bay to assist in decision-making for a variety of sediment-related issues, including restoration of tidal marshes, exposure of legacy contaminated sediment, and strategies for the beneficial use of dredged sediment.
The U.S. Geological Survey Pacific Coastal and Marine Science Center collected hydrodynamic and sediment-transport data at shallow water sites in South San Francisco Bay and in the Whale's Tail South marsh in Eden Landing Ecological Reserve in Alameda County, CA in 2021 and 2022. This data release includes hydrodynamic and sediment transport time-series data spanning from June 2021 to January 2022, as well as sediment bed properties and water column suspended-sediment concentrations Details on station location, instrumentation, and measured variables are included in sections for each data type. The data were collected to determine sediment supply and sediment delivery to marshes, both in the bay and in tidal creeks as well as across the bay-marsh interface during varying tidal and wave conditions. The goal of the project was to more accurately predict the fate of marshes and to optimize management actions. They were collected as part of a collaborative study with the USGS Western Ecological Research Center. These data are intended for science researchers, students, policy makers, and the general public.
