Freetown Farm Pluvial Flooding Mapping and Remediation

Coastal Resources, Inc. (CRI) has joined with a GIS partner firm in providing pro bono services to the Community Ecology Institute (CEI) in support of their efforts to alleviate nuisance flooding and provide stormwater treatment at the Freetown Farm.   Freetown Farm is a property that was historically farmed by freed slaves. It is currently a 6.5-acre organic farm and will be a part of one of the inaugural “Walkable Watersheds” in Maryland, an initiative supported by the National Fish and Wildlife Foundation that will address stormwater management issues while simultaneously addressing community needs, neighborhood connectivity, and quality of life goals. Current untreated stormwater runoff from adjacent properties causes flooding on the Freetown Farm as well as on other neighboring properties.  The project aims to alleviate flooding, provide effective treatment of stormwater to protect the health of the Middle Patuxent River, and model how communities can address stormwater issues in a “socio-ecologically beneficial manner”.

The team worked together to map existing flow conditions and then model potential future conditions in PCSWMM.  PCSWMM is an interface with the EPA SWMM freeware. PCSWMM allows georeferencing of data to produce maps of flooded areas. A terrain from LiDAR imaging is brought into the software to allow the program to show the sheet flow, drainageway flow, or pipe overflow flooding over the landscape. Infiltration and storage practices can be placed within the watersheds to simulate relative alleviation of flooding with each of the various stormwater treatments. This allows PCSWMM to be used as a planning tool, pinpointing the most effective practices shown to reduce flooding, which can then be implemented in the landscape.

After CRI’s partner firm gathered information on existing stormwater and sheet flow and input it into GIS, CRI uploaded the data into PCSWMM and entered in the hydrologic and hydraulic information to run the model. Various conceptual best management practices (BMPs) were inserted into the model to evaluate which combination of treatments would achieve the desired flooding reduction on the farm property. The concept BMPs found to be most effective were then developed into a BMP plan and presented to the CEI to be implemented by CEI using grant funding.


Howard County, MD


Community Ecology Institute

Key Services:

  • Pluvial Mapping
  • Concept Designs