A new report from an advisory committee of scientific experts recommends the Chesapeake Bay Program’s Watershed Model be adjusted to better account for the influence of stream corridors and tree canopy on pollution from urban areas.
In the report, experts from the Bay Program’s Scientific and Technical Advisory Committee (STAC) suggest accounting for the effects of stream corridors and urban trees to improve the model’s accuracy and allow managers to better target pollution-reducing best management practices.
Trees and stream corridors interact with nutrient and sediment pollution in ways that are unique compared to other urban land covers, the study suggests. The erosion of stream channels can significantly increase the amount of sediment pollution associated with an urban area, while trees can help reduce the volume of polluted runoff.
The Watershed Model is used by Bay Program partners and stakeholders to estimate the amount of nutrients and sediment reaching the Bay. The model currently includes three urban land use categories: impervious (paved) surfaces like buildings, roads or parking lots; pervious (porous) surfaces like lawns or landscaping; and construction sites.