This is the second part in a series about how a Bel Air community tackled the problem of polluted runoff together. Click here to read part one.
We applied for and received a grant from the Chesapeake Bay Trust to assist in the purchase of native vegetation, and Christ Our King's administration provided significant donations of time, money, and supplies. As rain gardens provide beautiful, effective ways to mitigate polluted stormwater, our team designed and installed two rain gardens that converted 1,200 square feet of turf grass to beds of sand/soil mixture growing 16 species of native shrubs and perennials.
During a rain event, water temporarily collects on the garden surface, then soaks into the soil, removing pollutants and preventing erosion as it does. Native plants in the garden require little maintenance, provide habitat for local wildlife, and prevent toxins from reaching groundwater. Our rain gardens capture runoff from 4,000 square feet of roof and treat more than 2,300 gallons of polluted runoff during a one-inch rain event. That's more than eight tons of water! The water in the rain gardens infiltrates within 24 hours and alleviates flooding in the stormwater management pond.
In addition, gutters around the parish house roof funnel collect 1,500 gallons of clean rainwater into a rain harvesting cistern for landscape maintenance. These cisterns help water nine vegetable garden beds that support families in the congregation. Catching rainwater this way protects the rain gardens during extreme storms.
Moreover, this water keeps the landscaping and gardens productive and reduces the Parish's need for municipal water. When a rains storm occurs, the first quarter of an inch of water collects the highest concentration of bacteria and debris from the roof. This "first flush" of polluted water enters the gutter system, where a diverter and filter system directs it to the rain gardens, helping to keep the cistern clean, and lessening maintenance demands.
This coordinated series of best management practices has alleviated the flooding and erosion issues on the property associated with polluted stormwater runoff. Together, they provide a wildlife corridor for local pollinators like bees, butterflies, and birds. Hummingbirds have been visiting the gardens' bee balm and cardinal flower for nectar, and many bee species buzz around the black-eyed susans and mistflower for pollen. The Sunday school classes and the youth group created interpretive signage to educate visitors about how the rain gardens and cistern are helping to alleviate polluted runoff. The youngest volunteers even converted parts of scrap wooden pallets into garden markers.
And what happened to the sand bags?
We used their contents to make up the soil mix for the rain gardens. Christ Our King Presbyterian may be only one church, but our project has greatly benefited our common property as well as Bynum and Winters Runs. We hope our experience will inspire and inform other churches to take on similar projects for the benefit of God's Creation.
--Julia Poust, Chesapeake Conservation Corps Volunteer
Chesapeake Bay Foundation