This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Urban flooding causes significant social, environmental and economic losses every year. In Baltimore, those losses have increased in frequency and intensity since flooding records began in 1748 and are expected to continue doing so as the climate changes.
Traditional flood prevention approaches, which use concrete and other impervious surfaces to direct flow, often fail in urban settings because they impede rainwater infiltration. A team led by Penn State researchers worked to design mitigation techniques with those who know the city best—people who live in Baltimore. The team found that the collaboratively designed mitigation techniques, including planting rain gardens and cleaning storm inlets, could reduce flood depths by up to 55% in some locations.
The team published their findings in Sustainable Cities and Society. "This study presents a co-designed urban flood modeling framework in which community and technical experts directly inform flood model development and adaptation design through long-term and iterative engagement," said Ava Spangler, a graduate student in the Department of Geosciences at Penn State and lead author of the paper. This project is part of the larger Urban Integrated Field Program investigating climate hazards in American cities with the goal of bringing together interdisciplinary teams to work on science that is relevant to the communities.
Each team brings together scientists from multiple disciplines like hydrology, ecology and landscape architecture with city planners and community members to best understand and address local climate hazards and impacts. The urban flood modeling framework described in this paper focused on pluvial flooding—flooding caused by rainfall rather than river overflow or high tides from storms. Not only is it an understudied flood type, the researchers said, it was also a main concern expressed by the community members in Baltimore during workshops the team organized in the city.
Over three years, the researchers learned about the community's concerns, as well as what types of mitigation techniques might be most feasible for residents. That information informed their model, which also needed to accurately account for the complexities of the terrain and of the flooding type. "It's challenging to model this kind of flooding partly because we have to deal with complex urban micro-topography," Spangler said.
"Remotely sensed elevation data captures big hills and valleys pretty easily, but struggles to capture very small topography, like the difference between a curb and the road. It's only about 6 inches (15 centimeters), but that kind of topography makes a big difference in where the water flows." Not only does urban topography make it hard to build a flood model, but pluvial flooding itself is challenging to capture because it is harder to predict and can occur very suddenly. "Observations are one of the biggest limitations to building these types of models because floods come and go very quickly, and they can be hard to measure with tools like satellites," said Antonia Hadjimichael, assistant professor of geosciences and co-author on the paper.
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