The Bay Cushion

The shape of the Bay bottom impacts the height and severity of tidal inundation. Deeper bays with harder and higher edges amplify the 12-hour tidal wave, leading to higher high tides. Shallow-edged bays dissipate the tidal force, acting as an energy sink. This effect can be local or regional. In San Francisco bay, the long, convergent southern arm becomes more reflective when deepened and hardened, creating a regional impact on tidal levels across the rest of the Central and North Bay. Scientific modeling has shown that restoration of South Bay tidal baylands would mitigate tidal range extremes throughout the entire Bay in an era of sea level rise (up to 10 cm in the South Bay), as compared to a hard-edged scenario.

South Bay Salt Pond restoration projects act as a BAY CUSHION to reduce the effects of sea level rise, around the ENTIRE BAY. However, our restoration goals may not be achievable with sea level rise and low sediment supply.

Our BAY CUSHION proposal acknowledges this risk, and proposes different spatial alternatives for tidal bayland creation that require less sediment input for long term survival including: a double ring fed by tributaries and mudflat feeding, a fat inner ring fed by construction fill from the landward side, and a migration alternative where certain urbanized light industrial areas retreat over time—making room for tidal dissipation space. We will model and study new forms of BAY CUSHIONS for human benefits (like flood risk reduction), but also for sandpipers, leopard sharks, steelhead, and marsh mice.

This low-sediment supply study acts as an equally critical overlay for the ongoing adaptive management plan, promoting public access, sensing, and engagement. We aim to MAKE SEDIMENT PUBLIC in the South Bay, and create a sediment reserve that links ecosystem and human benefits, such as flood risk reduction and tidal energy dissipation. We propose viewing towers, outdoor mud rooms, and sensing stations that extend out from the existing Bay Trail—inviting people to actively use the resources of the BAY CUSHION. These spaces will tie back to existing flood prone neighborhoods like Alviso, providing stewardship tools for the long-term monitoring of sea level rise, groundwater, and water quality, enabling urban adaptive management decisions of the future.

Concept

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The Bay Cushion

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The Bay Cushion

Public Sediment is a multidisciplinary design team that views sediment as a core building block of resilience in San Francisco Bay. The team is led by SCAPE Landscape Architecture with Arcadis, the Dredge Research Collaborative, TS Studio, the UC Davis Department of Human Ecology and Design, the UC Davis Center for Watershed Sciences, and the Buoyant Ecologies Lab.

Our team believes in ecological infrastructure and its protective value. Yet the Bay area’s ecological infrastructure- its marshes, mudflats, and coastal edges- are at risk. The slow and methodical subsidence of the Bay’s...

Public Sediment is a multidisciplinary design team that views sediment as a core building block of resilience in San Francisco Bay. The team is led by SCAPE Landscape Architecture with Arcadis, the Dredge Research Collaborative, TS Studio, the UC Davis Department of Human Ecology and Design, the UC Davis Center for Watershed Sciences, and the Buoyant Ecologies Lab.

Our team believes in ecological infrastructure and its protective value. Yet the Bay area’s ecological infrastructure- its marshes, mudflats, and coastal edges- are at risk. The slow and methodical subsidence of the Bay’s tidal wetlands is a catastrophe of tremendous proportion not just for ecosystems, but for communities. Combined with sea level rise, this subsidence exposes hundreds of thousands of residents and the region’s critical drinking water, energy, and transportation infrastructure to tremendous risk. To creatively adapt to this challenge, our team proposes to focus on sediment, the building block of resilience in the Bay. In short, we propose to design with mud.

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