Question: For my new home, what are some stormwater management practices to protect my yard and for water conservation so that water can be retained and used onsite?
Thank you for asking about stormwater Best Management Practices (BMPs) to use on your property in a sustainable and environmentally friendly way!
Preconstruction Considerations
The best time to design home landscape for water conservation and yard protection is early in the construction of your home. The goal is to limit disturbance to your natural surroundings and maintain the natural flow and percolation of water as closely as possible.
There are many practices that will help contribute to this overall goal, ranging from minimal work to those requiring more effort. These practices include ways to reduce or eliminate runoff by:
- increasing infiltration
- water capture
- onsite water use, and
- evapotranspiration (water lost from wet soil and plant surfaces plus water lost as it travels through and exits plant tissues, usually through leaves and stems).
A good resource for stormwater BMPs is Virginia Tech’s Virginia Stormwater BMP Clearinghouse providing a variety of recommendations, with some applicable to a new home site.. For concise information specific to residential sites, review Green Infrastructure for Single Family Residences City of Atlanta Stormwater Guidelines
The following BMPs offer many options for the homeowner for stormwater management. They can be used separately or can be combined to design a very effective, robust and sustainable landscape design. For example, a rain barrel overflow discharge can be directed to a drywell and sustainably managed when water is not needed for the garden.
1. Conservation of Open Spaces and Limiting Land Disturbance
a. Use temporary fencing or other means to restrict construction vehicles and equipment to the area immediately around the house. This allows you to leave as many areas as possible undisturbed and avoids unnecessary compaction of the soil decreasing runoff’s ability to infiltrate the soil.
b. Preserve as much forest and meadow as possible. They are particularly good at conserving water and reducing surface water runoff by maximizing infiltration to groundwater and promoting evapotranspiration. Areas that are downhill from your site can help control the movement of sediment during and after construction by reducing runoff and transport of sediment off your site.
2. Rooftop Disconnection
a. Use downspouts from your new roof to capture water for reuse, allowing it to infiltrate the soil, evaporate or be stored in rain barrels or cisterns. Don’t let water flow directly to a stormwater sewer or flow into the gutter along your street.
i. Downspouts should empty onto a vegetated area where the water generally flows away from the foundation of the house and is directed to areas that can utilize and filter the water. Lot size and slope need to be considered so that water flow does not adversely impact neighboring properties or structures.
b. Rain barrels can hold fifty gallons or more of water for reuse on your landscape. Drawing water from them involves placing barrels uphill to make use of gravity via a hose or watering by hand. Large storm events quickly fill typical rain barrels.
c. Cisterns catch and hold a few thousand gallons for landscape irrigation or in-house use. Cisterns are usually equipped with an electric pump to dispense water.
i. For indoor use, the water system must meet certain local health department requirements to ensure that rainwater is not mixed with drinking water. This is a great way to reduce use of potable water for non-potable uses like flushing a toilet.
d. Rain gardens can be constructed to collect rainfall and manage stormwater. Designed to hold water for less than 48 hours, a rain garden contains plants that tolerate short wet periods and long dry periods. To function properly, these gardens must include the right plants and be constructed properly.
e. Dry wells are gravel-filled underground structures that collect, store, and infiltrate stormwater, allowing water to percolate slowly downward into the subsoil. They are typically covered by a few feet of soil, not visible from the surface and lend themselves to many types of landscaping.
f. Vegetated filter strips are areas of land where the soil has been significantly enriched with compost and other amendments to improve its ability to absorb water. The stormwater flows over the surface where it is absorbed quickly by the soil and infiltrates into the subsurface.
g. Stormwater planters are generally above-ground planters that collect, hold, evaporate, and discharge stormwater, as needed.
i. In smaller storm events, the planter can hold and evaporate all of the water collected. For larger storms, excess water can discharge to the surface.
3. Permeable Pavements
a. Permeable pavements provide many alternatives to replace typical impermeable paving materials, such as concrete slabs and asphalt. Rainfall collects quickly on these hardscape surfaces and rapid runoff results.
i. Using permeable materials, like pervious concrete, porous asphalt, and an assortment of pavers reduces rapid runoff of rainwater by allowing it to infiltrate into the material below where it can be stored, recharge groundwater, and discharge at a much slower rate to the surface. There are a wide variety of pavers available with many choices of shape, color, texture, interlocking or not, etc.
b. To be successful, the design for permeable pavement must consider your situation including soil type, size of area to be paved, off-site water sources, structural loads and the purpose of the pavement (driveway, sidewalk, etc.). It also relies on a drain layer under the pavement to accept the stormwater and possibly an underdrain.
c. In localities where there is a stormwater utility fee charged based on impermeable surfaces, employing permeable pavements can greatly reduce the fees you pay.
These options allow for capture of rainfall and reuse on site to maintain your landscape plants or gardens and allow excess water to recharge the aquifer beneath your property. The runoff that does leave your property should be of high quality with the flow rate considerably less than without this sustainable effort.
References
Photo Credit: Rain Garden Fact Sheet, USDA Natural Resources Conservation Service
“Green Infrastructure for Single Family Residences: City of Atlanta Stormwater Guidelines,” City of Atlanta GA, Department of Watershed Management, Nov. 2021.
“Permeable Pavement,” Virginia DEQ Stormwater Design Specification, No. 7, Version 2.0, 1 Jan. 2013.
“Rain Garden Fact Sheet,” United States Department of Agriculture, Natural Resources Conservation Service.
“Rooftop (Impervious Surface) Disconnection,” Virginia DEQ Stormwater Design Specification, No. 1, Version 2.0, 1 Jul. 2013.
“Sheet Flow to a Vegetated Filter Strip or Conserved Open Space,” Virginia DEQ Stormwater Design Specification, No. 2, Version 2.0, 1 Jan. 2013.
“BMPs,” Virginia Stormwater BMP Clearinghouse, Virginia DEQ, Virginia Water Resources Research Center, Virginia Tech, updated 2013.
