Communicating flood risk and adaptation options from fluvial and sea level rise in the Sacramento-San Joaquin Delta

Abstract:

The Delta Stewardship Council, with the assistance of partner agencies and consultant AECOM, has been developing a climate change vulnerability assessment and adaptation strategy for the Sacramento-San Joaquin Delta (Delta) also known as Delta Adapts. One vulnerability identified as critical is the prospect of increased flood risk due to higher riverine inflows and sea level rise. Unfortunately, it is difficult to model the influence of climate change on the Delta’s flood risk because of its unique geometry, tidal and riverine influences. The combined effects of projected fluvial inflows and sea level rise on planning scenarios in the Delta requires making choices across multiple dimensions of uncertainty. In order to address this difficulty, researchers used a novel approach employing Bayesian methods with a decision-scaling framework. This allowed the team to simulate millions of potential future conditions to stress test the existing system of levees and channels. The resulting analysis was used to develop flood maps that show existing and future projected flood risk throughout the Delta in terms of likelihood of flooding over 10-years. Flood maps will be used in a wide array of public outreach and education settings as well as policy and investment decision making. Ultimately, the results will be used to inform future climate change adaptation decisions, investments, and policies.