Sediment Deposition Across the Eden Landing Tidal Marsh in San Francisco Bay, CA

Measuring the spatial and temporal patterns of tidal marsh sediment deposition builds our understanding of how physical forcing (tidal flooding and waves) and sediment availability interacts with the marsh. We deployed sediment pad filter traps in twelve shore-normal transects across the Eden Landing Ecological Reserve tidal marshes and restorations in south San Francisco Bay, CA. Sampling was done between October 2023 and January 2025 while a shallow water placement pilot project was occurring adjacent to the reserve. Trap stations were located at increasing distance from the edge of the marsh (channel adjacent: 0.5, 2, 6, 12 meters; bay edge adjacent: 6, 8, 12, 24 meters), and three replicate traps were placed at each station. Filter pads were replaced approximately every month, dried and weighed to determine net sediment deposition flux (grams per square meter per day). In addition to the sediment traps, we established feldspar clay marker horizon plots at each station location to obtain quarterly readings of cumulative surface accretion (millimeters). Distinct seasonal and spatial patterns were observed in marsh sediment deposition.