According to the Chesapeake Bay Program, increased development across the Potomac Watershed has made stormwater runoff the fastest growing source of pollution to the Chesapeake Bay. The non-permeable asphalt that covers our roads and parking lots coupled with the roofs of densely packed buildings in Fairfax County, force rain water and any litter or chemicals into stormwater drains which have outfalls into our streams. The faster flow of water caused by the impervious surfaces also is a major source of erosion.
Here are some suggestions from Recycle Works for individual homeowners to try to reduce the polluted run-off that ends up in our streams and the erosion that this water flow causes:
Replace solid driveways with porous alternatives. Replace solid concrete and asphalt driveways, with pavers, cobblestones, brick and turf stone, all of which will slow down the flow of water and allow it to settle into the ground. Another alternative is using impervious paths for the car tires with green plant material in between. Solid concrete can also be broken-up with decorative and functional paver inlays.
Porous paving or pervious pavement. Pervious pavement is a cement-based concrete product that has a porous structure allowing rainwater to pass directly through the pavement and into the soil at the rate of 8 to 12 gallons per minute, per square foot. This is achieved without compromising the strength, durability, or integrity of the concrete structure itself.
Use dry laid patios and walk ways instead of wet laid. Wet laid patios are set in concrete, which does not allow for any stormwater to be absorbed in that area. In contrast, dry laid patios are set in stone dust, which slows the velocity of sheet flow and allows for some absorption of storm water in that area. An additional benefit for regions that receive freezing temperatures is that dry laid patios will not crack like wet laid surfaces.
Interrupt walkways. Small planting beds and creeping groundcovers, such as thyme, can be incorporated into the edges of walkways and patios. These planted areas will help to slow storm water flow and create a more aesthetic space.
Rain Barrels. Placing rain barrels at the end of downspouts enables collection of run-off water impermeable roofs that can then be used for watering gardens. Note: Due to possible leaching from roof shingles, rain barrel water is not recommended for vegetable gardens.
Decking materials. Treated wood, commonly used for decking, can be replaced with several alternatives. The first, and best alternative, is salvaged lumber. Salvaged lumber has been harvested from previously existing sites and is in good condition. Salvaged lumber can be attained in bulk from salvage shops.
A second alternative to using treated wood is lumber certificated sustainable by the Forest Stewardship Council (FSC). The Council utilizes region-specific forest-management standards to judge if a particular forest operations is in conformance with FSC standards. A certificate is issued, enabling the landowner to bring product to market as “certified wood,” and to use the FSC trademark logo. This process is at the landowner’s request.
A third option is plastic wood or products such as TREX, which is made from reclaimed plastics and woodwaste. Advantages of plastic wood include thatit will not rot, does not need to be sealed, is resistant to moisture, bacteria growth and graffiti, and cleans up with soap and water. Guide to Plastic Lumber.
Vegetated steps. Utilize groundcovers and moss as the landing surface cover onsteps that are located in low-traveled areas. A solid riser will still be needed to retain the integrity of the step.
Recycled concrete. Use concrete from demolished walkways and driveways to build retaining walls and patios.
Green retaining walls. Build small out-pockets and planters on the sides of retaining walls. Planting these planters with visually interesting material and vines will also help to absorb water and reduce run-off.