When we cover the earth with roads, sidewalks, buildings, and parking lots, the rain that used to fall and be absorbed by the soil instead runs quickly off of these impervious surfaces and in fast succession moves from gutters, down storm drains, and into creeks. After a thunderstorm or other intense rainfall event, you can easily observe the quick rise of a stream, the overflow of stormdrains, and sometimes the flooding of streets. All of this water used to slowly soak into the ground over a large area before we covered so much of the sponge-like earth with pavement and other non-permeable surfaces. Now the increased volume of water that runs off impervious surfaces contributes to flooding, erosion, property damage, and carries a large flush of pollutants into streams. By trading impervious with pervious or permeable surfaces, we can allow rain to slowly soak into the earth like it used to, thereby reducing runoff, allowing groundwater supplies to recharge, and improving water quality by reducing the volume of pollutants carried to streams.
There are many ways to take action to improve your property to reduce impervious surfaces and allow rainwater to soak into the ground.
Pledge to help reduce your impervious surface footprint by allowing stormwater to soak into the ground on your property, or by working to encourage the use of pervious surfaces in your community.
There are many choices when installing pervious surfaces. The cost, utility, and pervious ability of these materials varies. These permeable surfaces offer many benefits including reducing the volume of stormwater runoff and effectively trapping suspended solids and filtering pollutants from stormwater runoff.
The goal in using pervious or porous pavement is to limit runoff at the source, reduce downstream erosion, and improve water quality by filtering pollutants. With both pervious and porous pavers, this is partially achieved within the paver itself as water moves through the paver. With permeable pavers, water is circumvented around the paver, and the filtering process begins between the pavers in the void space filled with gravel or other materials. All of these types of pavement require a similar compacted stone aggregate layering process beneath the surface to accept the stormwater and create a “reservoir” through which the water percolates.. In this way, your pavement choice helps keep our streams cleaner. That is Stream Smart!
Learn more about alternatives to impervious pavement.