Turning Stormwater Problems Into Water Supply Assets

The EPA (Environmental Protection Agency), is testing a variety of different permeable pavement materials and rain gardens in the parking lot at the agency’s Edison, N.J. facility. Green infrastructure applications and approaches can reduce, capture, and treat storm water runoff at its source before it can reach the sewer system. Site-specific practices, such as green roofs, downspout disconnections (downspouts on many homes are connected directly the sewer system — I passed smooth out when I first heard about that little modern convenience!), rain harvesting/gardens, planter boxes, and permeable pavement are designed to mimic natural hydro logic functions and decrease the amount of impervious area and storm water runoff from individual sites. These applications and approaches can keep storm water out of the sewer system to reduce overflows and to reduce the amount of untreated storm water discharging to surface waters.

A raingarden is an approach to rainwater harvesting that can prevent flooding and erosion and turn storm water problems into water supply assets by slowing run-off and allowing it to soak into the ground. Akin to the vegetated roadside swales, now promoted as “bioswales”, which remain the conventional drainage system in many parts of the world from long before extensive networks of cement sewers became the conventional engineering practice here in the USA and other countries.

Flow monitoring done in the years after Dick Brinker, a developer building a new housing subdivision first had the idea to replace the traditional best management practices (BMP) pond with a bioretention area showed that the rain gardens have resulted in a 75–80% reduction in storm water runoff during a regular rainfall event. Rain gardens may be located near a drainpipe from a building’s roof (with or without rain barrels). They allow a household or building to deal with excessive rainwater runoff without burdening the public storm water systems.

In developed areas, the natural depressions are filled in. The surface of the ground is leveled or paved, and water is directed into storm drains. Storm water runoff increases urban flooding and erodes the banks of rivers and streams. Urban runoff water is warmer than the groundwater that normally feeds a stream, which upsets the delicate system. Warmer water cannot hold as much dissolved oxygen and many fish and other creatures in streams are unable to live in an environment with fluctuating temperatures. Also along with trash, a wide variety of pollutants spill or settle on land surfaces between rain events. The initial rinse from each runoff event can wash this accumulation directly into streams and rivers and eventually into the oceans.

Rain gardens are beneficial for many reasons: improve water quality by filtering run-off, provide localized flood control, aesthetically pleasing, and provide interesting planting opportunities. They also encourage wildlife and biodiversity, tie together buildings and their surrounding environments in attractive and environmentally advantageous ways, and provide significant partial solutions to important environmental problems that affect us all.

Raingardens are not ponds, they are artificial depressions in the landscape that collects and stores storm water runoff. Thereby allowing the runoff from impervious urban areas like roofs, driveways, walkways, and compacted lawn areas the opportunity to be absorbed, ground filtered and returned to the water table. They are usually planted with native vegetation that is hardy and attractive. Plants in a raingarden can give color to the landscape at all times of the year. Raingardens can be designed for an individual yard or a neighborhood. They provide an urban habitat for many animals including native butterflies, birds, and beneficial insects. The water will infiltrate the ground within a day or two, an advantage in not allowing mosquitoes to breed.

Native plants are recommended for rain gardens because they generally don’t require fertilizer and are more tolerant of one’s local climate, soil, and water conditions. The plants should be a selection of wetland edge vegetation, such as wildflowers, sedges (any of numerous grasslike plants), rushes, ferns, shrubs and small trees which take up excess water flowing into the rain garden. Water filters through soil layers before entering the groundwater system. Root systems enhance infiltration, moisture redistribution, and diverse microbial populations involved in biofiltration. Also, through the process of transpiration, rain garden plants return water vapor into the atmosphere.

Raingardens run the gamut from extravagant to simplistic. They can be easy and affordable for all, from homeowners with little land to business’, towns, cities, and governments. You can let your imagination run wild with a myriad of possibilities that can be used to capture, channel, divert, and make the most of the natural rain and snow that falls on a property.

Beautiful and so environmentally conscientious Mother Nature smiles….

…… as the green future unfolds.