Conversations About Resilience: Muddy Waters to Resilient Shorelines

Most people give little thought to mud or sand until a boat runs aground in shallow water or erosion exposes a vulnerable shoreline. But San Francisco Bay has been fundamentally shaped by sediment flowing down from streams, rivers, and the Sacramento Delta, nourishing estuary and wetland ecosystems and building Bay shorelines. Too much sediment impedes ship navigation; too little starves wetlands and shorelines of critical habitat and protection from rising sea level.

Our relationship with sediment has been changing since the Gold Rush era when mining along streams and rivers pushed sediment from the foothills to the Bay. The extra sediment clouds up Bay and Delta waters and requires annual dredging to keep the shipping channels open. But now we may be facing a sediment drought, as the last of the mining sediment clears the system and sediment that would normally flow through tributaries is instead trapped behind dams. Climate change could exacerbate the sediment shortage with diminished rainfall and extended droughts. Is it time to rethink our relationship to sediment?

Speakers: Bruce Jaffe, USGS; Brenda Goeden, San Francisco Bay Conservation and Development Commission; Brett Milligan, UC Davis