The negative impacts of urban runoff – primarily flooding, water pollution, and reduced groundwater supplies – threaten the health and water supplies of our communities. Stricter regulations are forcing communities to rethink their stormwater options. Newer more economical ways to meet these regulations use systems that echo nature’s way of handling runoff water.
Stormwater runoff is part of natural drainage processes that occur when it rains. In developed areas, rain is not able to drain properly; the drainage routes that rainwater would normally take are blocked or covered over.
Covering over land, i.e., developing it, interferes with that natural drainage process through:
- The loss of undeveloped natural areas that absorb runoff;
- The expansion of impervious surfaces that prevent natural infiltration of runoff; and
- Impacts associated with construction and post-construction activity such as greater traffic that increase water pollution.
Opportunities exist to control the impacts of urban runoff if communities:
- Protect sensitive sites and valuable natural areas,
- Minimize imperviousness and maximize permeability, and
- To the maximum extent possible, handle runoff on site, through holding ponds, natural drainage systems, and other low-cost strategies.