To mitigate local flooding, this D.C. neighborhood looks beyond its borders
- Use cases
Ivy City is adopting a catchment-based approach to solving urban hydrologic problems.
Ivy City has struggled with challenges of community vulnerability to climate hazards for decades. As the climate shifts, the Washington D.C. neighborhood now faces growing exposure to flash flooding. The city has answered the call to prevent future flooding in one of the most underserved areas of the nation’s capital.
The problem is severe and complex. In the most recent extreme rainfall event, Ivy City saw devastation from up to three feet of flooding caused by a combination of overland flow and storm sewer surcharge. Simon Kates, AICP, WEDG, Senior Project Manager at Ramboll is leading the effort, and brings over a decade of experience in urban resilience planning for public and private stakeholders across the country. He recognizes that much of the floodwaters were generated by rainfall occurring outside the neighborhood. Water doesn’t care about administrative boundaries.
"Being able to see these catchments and flow analyses help us understand which streets we need to focus on for blue-green infrastructure".
Simon Kates, Ramboll
Simon used Scalgo Live to delineate the watersheds draining towards Ivy City.
“Ivy City sits in a valley,” Simon explains, "so we cannot look at the neighborhood alone – water doesn’t care about that arbitrary line on a map. It’s going to go where it wants to go and a lot of the water comes from upstream.”
Rather than focusing solely on conditions within the study area, the Ramboll team is using a catchment-based approach that accounts for flows from beyond the project boundaries to holistically address community vulnerabilities.
“Scalgo Live is incredibly helpful for identifying flow paths and catchment areas,” Simon says. “If we're trying to solve overland flow, we can very easily see with the catchment analysis where we need to look and how far out we need to extend our assessment.”
Sub-watershed areas contributing surface runoff to Ivy City exported from Scalgo Live.
"Scalgo Live is incredibly helpful for identifying flow paths and catchment areas".
Simon Kates, Ramboll
Simon combined the flow accumulation analysis from Scalgo Live with the city’s sewer model to build a comprehensive picture of water movement above and below ground. These insights have laid the groundwork for the development of an integrated plan combining modern blue-green infrastructure with traditional subsurface infrastructure. The plan will reduce flooding and minimize pressure on the stormwater system while improving public spaces in alignment with community health and equity goals.
Blue-Green Infrastructure Map produced by Ramboll for the Ivy City Climate Resilience Strategy.
“Being able to see these catchments and flow analyses help us understand which streets we need to focus on for blue-green infrastructure,” Simon explains.
Scalgo Live enabled the team to easily assess both site-scale and catchment-scale conditions, quickly account for off-site drainage, and identify priority streets for blue-green infrastructure. Simon used Scalgo Live to guide Ramboll design decisions in conjunction with detailed hydrological analysis and community feedback. Simon emphasizes that the methodology behind the Ivy City Climate Resilience Strategy goes beyond effective data visualization, offering a fundamental rethinking of how to approach urban resilience. The Ivy City Climate Resilience Strategy is available for public comment until January 19th, 2026.
