Salt marshes, critical buffers against coastal erosion, rely on a net gain of sediment to maintain their elevation and resilience as sea levels rise. A new study examines how two different sediment delivery routes—wave-battered marsh edges and meandering tidal creeks—combine to shape the future of these vital ecosystems. Focusing on Whales Tail Marsh in South San Francisco Bay, which features both an eroding bay-facing edge and a major tidal creek, researchers deployed net-deposition tiles and oceanographic sensors to track when, where, and how sediment moved into and through the marsh.