Placards posted in the Tijuana River Valley at the U.S.-Mexico border near San Diego warn of the hazards of flooding. A risk management project developed by UCI civil engineers and social scientists demonstrated the efficacy of a new collaborative flood modeling approach in addressing the threat of rising waters. Steve Zylius / UCI

Irvine, Calif., Jan. 21, 2020 – Community collaboration and high-resolution maps are key to effective flood risk management, according to civil engineers and social scientists at the University of California, Irvine and other institutions.

In a study published recently in the American Geophysical Union journal Earth’s Future, the researchers report on a successful new process called “collaborative flood modeling” for addressing the increasing threat of rising waters brought on by climate change, aging infrastructure and rapid urban development.

“The impacts of flooding continue to escalate in the U.S. and around the world, and the main culprit is urban growth in harm’s way, with communities underprepared to deal with extreme events that are getting more intense in a warming climate,” said lead author Brett Sanders, UCI professor of civil & environmental engineering. “Our approach rests on making modern flood simulation technologies accessible and useful to everyone within at-risk communities.”

UCI researchers put the method into practice during the Flood-Resilient Infrastructure & Sustainable Environments project, a five-year effort funded by the National Science Foundation. Beginning in 2013, FloodRISE teams worked in two Southern California coastal areas at risk of flooding – Newport Bay and the Tijuana River Valley – gathering data, conducting surveys and holding face-to-face meetings with residents.

The technique showed considerable traction in the two regions. For example, following focus group meetings, Newport Beach managers asked FloodRISE engineers for flood elevation datasets to integrate into the geographic information systems used by the planning department.

And after joint sessions in the Tijuana River Valley, San Diego County officials called for additional flood hazard modeling related to proposed dredging, and Tijuana River National Estuarine Research Reserve authorities requested flood hazard information related to a planned road realignment and marsh restoration project.

Collaborative flood modeling combines the experiences and concerns of residents, landowners, government officials and business leaders with the knowledge and technological capabilities of academic researchers to foster a shared understanding of flood risk. A crucial element of any such effort is the iterative development of high-resolution flood maps, or visualizations, based on hydrologic models and the insights of people who have lived through past floods.

“When we integrate what people in vulnerable communities have learned with the expertise of civil engineers and social scientists, we create more accurate and more functional flood maps customized for the specific needs of a community. This takes us away from the one-size-fits-all approach to flood mapping that’s widely in use today,” said Richard Matthew, UCI professor of urban planning & public policy and faculty director of the campus’s Blum Center for Poverty Alleviation. “We also found that residents gain a much deeper and more shared awareness of flooding through these highly detailed maps. This is critical for stimulating productive dialogue and deliberation about how to manage risks.”

According to Sanders, collaborative flood modeling exercises such as those conducted through FloodRISE open flood-related decision-making to diverse groups of constituents, giving them helpful insights into the spatial extent, intensity, timing, chance and consequences of flooding.

The approach is designed to complement the flood insurance program administered by the Federal Emergency Management Agency so that a wide range of planning, land use and behavioral choices can be informed by the best available science in the form of intuitive and accurate flood simulations.

“We have tried to focus on eliminating much of the technical terminology from our discussions with community members,” Sanders said. “We advocate a bottom-up alternative to what has become a top-down process of flood hazard mapping filled with technical jargon that’s short-circuiting important contemplation and dialogue about flooding.”

The novel process has been well-received. “Existing maps that depict flood risks are difficult to interpret, with cryptic classifications such as ‘Zone X’ and ‘Zone VE,’” he said. “We found that communities were eager to have access to this more intuitive and useful information and were quick to adopt it, especially for planning and land management purposes.”

Added Matthew: “Our next step is to combine these powerful visualization tools with socioeconomic data to anticipate how different types of severe flooding are likely to affect poor communities in California and then co-develop with them risk management strategies. This is critical if we want to try to avoid the enormous and long-term devastation we’ve seen when large flood events affect poorer communities on the East Coast.”

UCI faculty participating in the FloodRISE project included Professor Victoria Basolo, Professor David Feldman and Associate Professor Doug Houston from the Department of Urban Planning & Public Policy and Amir AghaKouchak, professor of civil & environmental engineering. Abigail Reyes, director of community resilience projects in the Office of Sustainability, provided leadership on community engagement.

About the University of California, Irvine: Founded in 1965, UCI is the youngest member of the prestigious Association of American Universities. The campus has produced three Nobel laureates and is known for its academic achievement, premier research, innovation and anteater mascot. Led by Chancellor Howard Gillman, UCI has more than 36,000 students and offers 222 degree programs. It’s located in one of the world’s safest and most economically vibrant communities and is Orange County’s second-largest employer, contributing $5 billion annually to the local economy. For more on UCI, visit

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