Breeching levees may be a good thing.
By Rachel Dovey
They’re no stranger to wildfires and drought, but the cities around the San Francisco Bay haven’t been hit with a climate change-fueled disaster on par with Hurricanes Sandy or Harvey—yet. Still, sea-level rise won’t spare the metros. Even if they escape the drowning predicted by certain apocalyptic maps, Bay Area residents rely on freeways and rail lines built on soft, low-lying bay fill—areas particularly vulnerable to flooding and erosion. And the region’s tidal marshes and mudflats, which should act as natural barriers, are slowly losing sediment owing to poorly engineered dams.
“Unlike New York City, the Bay Area has all these slower and more invisible problems related to climate change,” says Gena Wirth, ASLA, the design principal at SCAPE Landscape Architecture.
The Resilient by Design Bay Area Challenge is bringing some of those unseen issues to light. Last year, judges selected 10 winning teams (SCAPE is the leader of one) made up of ecologists, designers, and landscape architects to imagine infrastructure that works with the region’s shifting landscape rather than against it. The challenge, which is funded by the Rockefeller Foundation, among others, is modeled on New York’s post-Sandy Rebuild by Design contest, with one key difference: This one is proactive, not reactive. Instead of waiting for federal funds to come in after a disaster, Bay Area leaders want to chart a more sustainable course now. The teams led by landscape architects take a particularly whole-systems approach, peering beneath the streets and beyond the shorelines to brainstorm innovative solutions to those slower-moving but no less pressing problems.
The Public Sediment team, led by SCAPE, wants to start with tidal buffer zones.
“Sediment is really the building block of resilience in the bay,” Wirth says.
Using Alameda Creek, south of Oakland on the bay’s east side near Union City, as a pilot, the team proposes strategically breaching certain levees to let trapped sediment out, ultimately creating a stronger network of marshes and mudflats that will cushion the cities from strong waves and drastic tides.
Another unseen problem: overdevelopment on the cities’ low-lying bay fill, which is vulnerable to seismic activity as well as sea-level rise. When the Big One hits (as it inevitably will), heavily trafficked thruways like Highway 37 could very well crumble into the marshes that surround them. Common Ground, a team led by TLS Landscape Architecture, suggests planning and funding transportation infrastructure on the region’s more stable high ground going forward, and taking greater advantage of water-based transportation routes linked by ferries.
The BionicTeam, led by Bionic, looks at the fact that many of those waterside lowlands also house the region’s lowest-income residents. The team overlaid a number of existing data sets to create a scale for policy makers, showing each area’s “composite vulnerability” and identifying spots where the response to sea-level rise should be fast-tracked.
And the Field Operations Team, led by James Corner Field Operations, takes an all-of-the-above approach to a whole host of interrelated problems—housing costs, transportation, shrinking wetlands—with a design scheme that emphasizes elements such as “edges” (i.e., better-designed waterfronts) and intertidal “sponges” for stormwater absorption.
Ultimately, the proposals reiterate one consistent message: The water that gives the Bay Area its name needs to be front and center in planning decisions going forward.
“Native American peoples knew how to live flexibly within the shore as a zone,” the Common Ground research report states. “[W]e will similarly need to alter our lives and create adaptations to become more comfortable with the dynamic bay.”