Limit Impervious Surfaces
Impervious surfaces are mainly constructed surfaces-rooftops, sidewalks, driveways, roads-covered by impenetrable materials such as concrete, blacktop, and mortared brick or stone. But urban and suburban soils, which are often compacted by intense foot traffic or construction equipment, are also highly impermeable. As urbanization increases, so does the amount of impervious surface. Studies have shown that the pervasiveness of impervious cover is directly related to the poor quality of many urban watersheds.
Because they prevent precipitation from seeping down into the soil, impervious surfaces are a primary cause of stormwater runoff. Torrents of destructive runoff are generated as rainfall strikes rooftops and pours into gutters and downspouts, picking up volume, speed, and pollutants as it rushes over paved surfaces and into storm drains.
What To Do:
Following are some of the ways you can reduce impervious surfaces to enable water to seep into the ground.
- Two ribbons of pavement with a low groundcover in between is a more porous alternative to a solid driveway of concrete or blacktop.
- Use stepping stones surrounded by creeping groundcovers instead of continuous impermeable pathways.
- Opt for “dry laid” instead of “wet laid” or mortared patios and walkways. Set in stone dust or sand, these allow some stormwater to infiltrate into the soil, unlike the impervious cement products typically used as mortar.
- Green spaces between patios, pathways, and other impermeable spaces can help prevent stormwater from accumulating and running off your property. Plant a rain garden to capture stormwater runoff from your roof.
- Restore the structure of any compacted soil on your property, and take steps to prevent soil compaction elsewhere in your landscape.
- Various types of permeable paving, such as concrete products with a porous structure that allows water to pass directly through, can be expensive but are worth considering.
- Some green roof systems can help manage stormwater and are worth considering if you're in the market for a new roof.
