ICPRB recently updated an interactive map, Susceptibility to Runoff Impacts in the Potomac Basin, to help developers, zoning agencies, and other land use decision-makers identify areas most vulnerable to the impacts of stormwater runoff.

Impervious surfaces (parking lots, roads, sidewalks, etc.) prevent rain from slowly seeping into the ground. Instead, water runs swiftly off the land and directly into nearby streams. This increases the likelihood of flooding, damages the physical structure of the stream leading to erosion and excess sediment in the water, and carries trash and chemicals to our waterways.

Some areas are more vulnerable to these impacts than others based on landscape factors such as soil characteristics and slope. The interactive map includes a new color-coded “susceptibility index” of areas that may be most impacted by runoff. Those who make decisions on land use in the basin can use the information as a factor in siting new development, anticipating the effects of planned development and/or identifying areas where mitigation efforts may prove useful.

The map was published as part of the implementation of the Potomac Basin Comprehensive Water Resources Plan. The science behind the map is documented in a peer-reviewed paper written by ICPRB staff and published in the Journal of the American Water Resources Association.