Watershed Steward Recommendations for Residential Stormwater Runoff Problems
Watershed Steward assessment requests are increasingly listing ‘flooding’, ‘saturated lawns’ or general ‘water issues’ as the problem homeowners would like help solving. Some of the problems can be daunting and out of our realm of expertise – that’s when our Consortium Members¹ are called in. However, while we’re on site, it’s important that Stewards be prepared with basic information to provide some level of guidance and general best-practice advice to these homeowners. Many residents are simply interested in just getting the stormwater off their property – we know that’s not the solution, but not everyone may know this. With some education we can help them to slow down, spread out, capture and filter runoff before sending it to our waterways.
The health of the Chesapeake Bay report² was released in January 2019; the Bay was downgraded from a C- to a D+. Stormwater pollution (containing increased amounts of sediment, nitrogen and phosphorous) was listed as the main contributing factor. This is significant because the health of the Bay had been improving, albeit ever so slightly. Runoff continues to be the one contributor to the degradation of our waterways that is not slowing down – it is increasing. Plants, specifically native plants, are included in all stormwater best-management practices (bmps) that are recommended by the Watershed Stewards Academy and other stormwater management organizations.
Some basic advice to give homeowners:
Disconnect Downspouts: direct them away from the home onto a vegetated area or rain garden. Use a splash block or fist-sized rocks to spread out the water and to dissipate energy. Do not direct them to impervious areas such as driveways, sidewalk or the street where they go directly into a storm drain without any treatment (cooling, slowing down, filtering).
Capture the Water: Install a rain barrel or cistern to capture the rain. A 55-gallon rain barrel will capture the first flush of rain which is the most polluted. Drain the barrel to your tall fescue lawn, rain garden, or native plant area; plants prefer rain water that is softer and free of chlorine and other chemicals. Do not water your vegetable garden with roof runoff.
Install a Rain Garden: Rain gardens can be powerful and attractive solutions. Siting is the most important rain garden consideration. Don’t site: Within 10 feet of a building, over a septic drain field, near the edge of a steep slope, into low spots that don’t drain well. Seek professional advice for best siting and size.
Plant Groundcovers: On thinly vegetated areas, slopes or under trees, groundcovers can be very effective at preventing erosion and slowing down runoff.
Conservation Landscaping: Reduce your lawn and impervious surfaces; add native plants that are adapted to our local climate. Native plants are low-maintenance, they have deeper roots than lawn and will help prevent erosion, soak up and filter runoff while adding value to your property. Mature trees intercept rainwater which slows it down; much of it stays on the leaves to be transpired. They also sequester carbon, clean the air, cool the planet and provide much-needed habitat for birds.
Steep Slope: Consider terracing. Keep each terraced area flat and plant densely. This solution often requires professional advice or an engineered design.
Swale: A swale is a shallow, broad depression in a landscape that follows the contour of the land and can be very effective at capturing and filtering water. A swale can be created if a natural one doesn’t exist.
Install a Bioretention Basin: Sited underground with the ability to capture large amounts of water these basins are best designed by professionals who will size them and insure they function as designed.
Regulatory Jurisdictions: Be aware of local covenants, right-of-way/easements, critical areas, and grading permit requirements before taking on a serious stormwater runoff or drainage project. Visit the Watershed Stewards Academy site for a list of landscaping professionals familiar with these problems.
Native Plants for Wet Areas
Trees: River Birch (Betula nigra), Atlantic White Cedar, (Chamaecyparis thyoides),
Bald Cypress (Taxodium distichum), Willow Oak (Quercus phellos)
Shrubs: Button Bush (Cephalanthus occidentalis), Winterberry (Ilex verticillata),
Highbush Blueberry (Vaccinium corymbosum), Sweet Pepperbush (Clethra alnifolia)
Herbaceous Plants: Rose Mallow (Hibiscus moscheutos), Turtlehead (Chelone glabra),
Blueflag (Iris versicolor), Marsh Marigold (Caltha palustis), Monkeyflower (Mimulus ringens)
~ Alison Milligan – MG/MN 2013
Master Watershed Steward Class 7