By Elaine Mills, Extension Master Gardener
This is the first of a three-part series on stormwater management solutions. In part 1, Extension Master Gardeners living in Alexandria share their experiences dealing with stormwater and the solutions they found for their own gardens. In parts 2 and 3 we will address the situation and solutions in Arlington.
Over the past few years, local residents have faced increasing problems with damaging downpours, flooding, and lingering wet spots on their properties. This is not surprising as the National Oceanographic and Atmospheric Administration (NOAA) has recorded a 27 percent increase in extreme precipitation events in Virginia and the Southeast region between 1958 and 2016. The rise in precipitation intensity is attributed to the higher air temperatures resulting from global warming; warmer air is capable of holding more moisture.
Local jurisdictions are responding to the challenges of stormwater management by developing programs of adjusted utility fees and credits. In the City of Alexandria, the Stormwater Utility Fee was adopted as part of a larger Eco-City Clean Waterways initiative to provide a dedicated funding source for existing management services as well as for new capital projects to reduce sediment and nutrient pollution. An updated Stormwater Utility Fee Credit Manual approved by the City Council outlines a menu of credits to reduce the fee for eligible households.
Several Extension Master Gardeners living in Alexandria detail below some of the ways they implemented sustainable practices for dealing with stormwater issues on their properties.
Capturing rainwater for re-use
Kathryn, who lives not far from the George Washington Masonic National Memorial, is responding to increased precipitation by using multiple strategies to capture and retain rainwater on her property for use in watering her indoor and outdoor plants. Her collection systems are so successful that she only makes use of City water for these purposes during periods of drought.
- Water from two roofs of her house is diverted from a front downspout to a 54-gallon rain barrel located beneath her porch. This container has a retrofitted pump and insulated piping that allows water to run to an extendable indoor hose for weekly watering of her porch plants except in very cold weather. Any overflow from rainfall is diverted back to the sewer system.
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- Rain from another downspout is collected in a 55-gallon rain barrel and is gravity fed through a hose for watering plants in her side yard. The native plantings there were installed through a City program and include tall, showy-blooming Maryland senna and Joe-pye-weed; mid-height garden phlox and great blue lobelia; lower-growing Indian pink, Christmas fern, and larkspur coreopsis; and two vines, trumpet honeysuckle and leatherflower.
- A 214-gallon cistern collects water from downspouts at the back of the house and has an on-off switch for a pump which directs water beneath a patio to a hose for watering patio plants and beds in the backyard as well as topping up a pond.
Turning a soggy backyard into a usable space
Cindy, an Alexandria resident in a neighborhood bounded by Quaker Lane and Russell Road, researched various options for dealing with stormwater issues when her backyard remained very wet every time it rained. By demonstrating compliance with several regulation-approved methods of management, she was able to reduce her City utility fee by 50 percent.
- She regraded her lawn area to slope away from the house by using a sod cutter to pull back the existing grass and then spreading a compost/soil mixture to level it and redirect the flow of water.
- She then planted the beds bordering the perimeter fence with native plants that are well-suited for moist-to-wet conditions, such as fringetree, sweetbay magnolia, buttonbush, winterberry holly, and hibiscus.
- The worst ponding in a corner of the yard was remedied by installing drainage pipes, a permeable path, and three small below-ground catch basins. Her family can now enjoy outdoor seating on flagstone hardscape over what was formerly soggy ground.
Reducing runoff and retaining water
Scarlett, another Alexandria resident, built a new home near the Masonic Temple. After construction, she noted tremendous runoff over the bare ground. Over a period of several years, she has arrived at several approaches that enable her to retain most stormwater on her property.
- The first step in controlling the most obvious flow of water was to direct runoff from two downspouts into channels that connect in a single dry streambed of leftover flat rocks leading to an alley. Moss built up there, but it didn’t alleviate the problem. The addition of river stones from a free source in a structured bed over several inches of soil now slows the water and allows it to absorb.
- She decided to retain some of her lawn (originally 700 square feet) but reduced it over time, using newspaper and arborists’ wood chips to kill the grass that had already been languishing from the effects of drought and cold.
- A pipe leading from the garage roof runs under the grass to irrigate a shrub border on the perimeter of the property. A wide wood-chip path provides easy access to both this area and to new curved planting beds bordering the lawn. Throughout the garden, edibles, such as beans, okra, basil, eggplant, and tomatoes are interspersed with ornamentals. Native species include flowering dogwood, sweetbay magnolia, witch hazel, red twig dogwood, ninebark, New Jersey tea, sweet pepperbush, meadowsweet, anise hyssop, coreopsis, and green-and-gold.
- Hardscape on the property consists of permeable driveways, as well as a patio and brick walkways that were installed onto tamped-down polymeric sand that is known for suppressing the growth of weeds in paver joints.
Return next week to learn about the Stormwater Utility Fee which will be taking effect in Arlington County in 2024 and stormwater management solutions devised by Extension Master Gardeners in the county.