How Hurricane Ida Sparked a Major Watershed Investigation
After a two-year investigation of worsening flooding, the Brandywine Conservancy and its partners have released the final report of the Brandywine Flood Study.
Launched after Hurricane Ida caused nearly $45 million in damage to private property and public infrastructure in southeastern Pennsylvania and northern Delaware, the study examined the impacts of intense storms and flooding along the Brandywine Creek and its tributaries. The Federal Emergency Management Agency, the Pennsylvania Emergency Management Agency, and Chester and Delaware counties in Pennsylvania funded the project, which included community outreach, data collection, modeling, and analyses.
The report provides a comprehensive assessment of historical, current, and future flooding scenarios through modeling, and it offers a suite of strategies and actions to address longstanding flooding throughout the watershed.
Among the findings were that while two-thirds of surveyed stakeholders reported experiencing financial losses due to flooding and 95% said they are worried about future flooding, only 28% reported having flood insurance.
Climate Change and Urban Development Drive Rising Flood Risks
Melinda Daniels, Ph.D., one of the authors of the report and a senior research scientist at Stroud Water Research Center, said, “Flood severity is increasing in southeastern Chester County as well as elsewhere on the East Coast. Data from NOAA and the Northeast Regional Climate Center show clearly that over the last several decades, precipitation intensity (the amount of rain from one storm) has increased across the mid-Atlantic and northeastern United States.”
During the same time, cities and suburbs have expanded significantly, replacing natural land covers such as forest with residential, commercial, and transportation infrastructure. These changes produce more runoff during storms.
Daniels added, “The combination of more intense rainfall and more intense runoff production from development have combined to increase the magnitude and risk of severe flooding.”
Top Recommendations From the Brandywine Flood Mitigation Report
Some of the recommendations from the report include adding more support for emergency services, installing green infrastructure, and preserving open space in flood-prone areas. Although none of the proposed solutions will alter decades of forest loss, development, and weather intensification, they can help reduce the impacts of flooding.
Daniels and Stroud Center Executive Director David Arscott, Ph.D., began working on the project in 2023 with the Chester County Water Resources Authority, Brandywine Conservancy, and University of Delaware Water Resources Center.
Daniels said, “Achieving full implementation of this study’s potential will require coordinated engagement from individuals, municipalities, and organizations throughout the watershed as well as support from state and federal flood mitigation resources.”
Dive Deeper
- Read the Brandywine Flood Study report.
- Flooding isn’t just an urban problem. Watch a webinar on restoring and protecting water quality and mitigating flooding in rural landscapes.
- Support our work.
