These days, with so many roads, parking lots and rooftops, a lot of rain water never soaks into the ground, but instead collects on the landscape and flows into the nearest storm drain. Storm drains often carry the untreated stormwater directly to nearby rivers, creeks, lakes, and wetlands. Increased runoff, resulting from the increase in paved areas and other impervious surfaces, causes streams to become "flashier", which means that water levels rise precipitously after rain storms. An increase in flashiness degrades water quality and habitat due to river channel scouring, streambank erosion, sedimentation and other detriments. Unnaturally flashy streams are more likely to injure or kill fish, aquatic insects, and other aquatic life, while also leading to more flash flooding. Furthermore, stormwater runoff washes pollutants from the landscape into our rivers and creeks, including accumulated dirt, leaked automotive fluids (e.g., oil, antifreeze), excess fertilizers, and animal wastes. These contaminants that accumulate in our urban, residential, and agricultural areas and are washed into surface waters from rain or snowmelt are referred to as “nonpoint source pollution." By reducing the amount of rain rushing into our stormwater system with rain gardens, rain barrels, pervious pavement, and other "best management practices", we can collectively reduce flooding and negative impacts to our rivers and creeks.
A rain garden consist of a shallow depression with soils, mulch, and plants designed to soak up excessive rain water and filter out any pollutants picked up from the landscape. They are constructed adjacent to impervious areas, such as a parking lots or driveways, in order to capture and treat stormwater runoff. By increasing infiltration of stormwater, rain gardens recharge important groundwater stores and reduce the negative impacts of unnaturally high volumes of water flowing into nearby surface waters. The plants and soils also function to filter contaminants caught up in the stormwater runoff. Rain gardens come in an endless variety of shapes and sizes, built to accommodate the volume of runoff in the space available.
In 2013, Harpeth Conservancy worked together with the Tennessee Environmental Council, the City of Brentwood, YMCA, and other partners to construct a 4000' rain garden at the YMCA on Concord Avenue in Brentwood. Site assessments were performed, including infiltration tests, soil characterizations, elevation measurements, drainage area maps, and stormwater runoff calculations. Materials were ordered including 4 tons of river rock, 20 cubic yards of sand, 20 cubic yards of topsoil and 40 cubic yards of mulch. About 64 cubic yards of soil were hauled from the site and Moody's Gradeworks donated 2 days of work to help prepare the site. A forebay was built to help slow down the runoff from adjacent parking lots. Nashville Natives provided 320 native plants and Gobbell Hays Partners spent a day planting 320 native plants provided by Nashville Natives. This project, completed in just 5 days, now protects the Little Harpeth River from the hot, polluted runoff from the YMCA parking lots and driveways. It is a great example of effective collaboration, which could not have been done without the generous support of the Dan and Margaret Maddox Charitable Fund as part of the Fish Habitat Restoration Initiative. Learn More About Brentwood YMCA's Rain Garden
Rain barrels are typically large (50+ gallons) new or repurposed barrels that are modified to receive water draining from rooftops and distribute water for irrigation via gravity. Modifications usually consist of creating a hole on top of the barrel to receive water from a downspout and attaching a spigot toward the bottom for attaching a hose. Constructing rain gardens, installing rain barrels, or using other best management practices on your property will help protect and restore the rivers, creeks, lakes, and wetlands in your area
REMEMBER: by constructing a Rain Garden or installing Rain Barrels on your property, you can be a part of the solution!