ASCE OC EWRI Presents Multi-Benefit Adaptation to CA's Ultrahazardous Flood Risk

Presentation Topic:

California’s coastal economic and population growth over the 20th century, from San Francisco down to San Diego, required the taming of deadly and destructive flash floods that brought mud and debris out of fire-scarred coastal mountains during Winter storms—what’s been called ultrahazardous flooding. That technical feat was achieved using hardened channels that were designed to quickly sweep flood waters to the coast, often under supercritical flow regimes. And from a flood protection perspective, the designs have proven to be very effective. However, California is now paying enormous costs linked to the adverse side effects of these designs: disrupted sediment fluxes that are costly to manage, poor surface water quality that requires extensive monitoring and source control measures, minimal riparian habitat and degraded ecosystems, poor stormwater capture efficiencies that increases reliance on costly imported water, high albedo that amplifies heat stress, and limited public access to parks and green…