Los Angeles Flooding Risks Vary by Geography and Demographics

Floods are a major cause of property damage in Los Angeles and can be deadly. A recent study focuses on how these risks vary by geography and demographics, including race, income, and education level.

A team of scientists from the University of California, Irvine, developed a new mapping methodology that intersects flood hazards from rainfall, river runoff and storm tides with measures of vulnerability including age, gender, socioeconomic status and racial or ethnic identity to identify high-risk areas of the city. Their work lays the foundation for more holistic regional planning that includes flood risk management as part of broader efforts to address climate change.

Compared to traditional coastal areas, more of the county is at risk of flooding during a so-called 100-year event. The analysis identifies areas that could be vulnerable to flooding from the Venice Canals, coastal Long Beach and a large swath of Santa Clarita to an area east of Los Angeles River near Chinatown. The researchers also report that people living in lower income neighborhoods are more likely to be exposed to waist-high water levels during such an event. They are 79% more likely to experience deep flooding than white Angelenos and 17% more than Latinos.

The research builds upon previous flood studies, including one that focused on the impact of back-to-back Pacific storms that caused 115 deaths and swept away homes in 1938. In addition, the team surveyed residents about their experiences with flooding. They found that a majority of respondents experienced floods at least once in their lifetime and most said they had not been prepared for them. They were also concerned about the impact of a flood on their property and community, such as the loss of power, transportation and access to services.

A key finding was that the public wants to do more to protect themselves from flooding risks, such as by lowering insurance rates and building resilient communities. This includes implementing green infrastructure, which gathers and removes rainwater at its source, rather than grey infrastructure like concrete or steel structures, which can control flooding Los Angeles flooding risks but are costly to construct and require regular maintenance.

But achieving these goals will require more than just investing in infrastructure projects. The authors suggest that a more holistic approach is needed, one that incorporates the needs and preferences of all types of communities. The authors recommend that a multi-disciplinary group be created to develop strategies for managing flooding risks. This group should include researchers, planners and designers, business leaders and community representatives. A community-based participatory process should be incorporated as well, to ensure that the interests of all residents are taken into account. The authors point out that this approach would be less politically contentious than the “dual-strategy” approach that many have used in the past — a strategy of investing in both infrastructure and resilience measures. It is also an approach that could be replicated in other cities facing similar problems of urban flooding.