Those noticing the construction equipment at work in front of Mount Airy Middle School are seeing the beginning of what local officials hope will be an elegant, educational, and more natural alternative for storm water filtering.
These constructed features at the Mount Airy Middle School and Rowe Environmental Park are known as structural storm water best management practices (BMP’s), or specifically as bio-retention cells areas.
Information supplied by the school district indicated as communities in North Carolina develop, more and more land is converted into impermeable surfaces which do not allow water to infiltrate. These surfaces include driveways, parking lots, homes, offices, schools, highways, and paved walkways.
The increased volume of unfiltered storm water may cause problems such as flooding, less ground water, increased erosion and sedimentation in streams and rivers as well as chemicals and heavy metals reaching waterways.
Nutrients such as nitrogen and phosphorus may also be carried by unfiltered storm water to waterways, potentially harming plants and animals living in streams, and lakes.
The projects will first direct storm water into bowl shaped cells through pipes, swales (ditches which may be mowed) and curb openings. The cell temporarily holds the water allowing it to slowly percolate through engineered soil media, filtering the storm water. The treated storm water infiltrates into the groundwater or is slowly released into a waterway via under drains and pipes. Plans for the MAMS area call for specially suited plants to uptake pollutants as a natural wetland area is established.
The school can use these BMP’s as outdoor classrooms and hands-on labs to learn about subjects such as the hydrologic (water) cycle, horticulture and native plant identification, ecology, physical, chemical, and biological processes, and environmental science.
City engineer Jeff Boyles said estimates for the project say it could be finished as early as next month. He explained the BMPs are part of larger projects locally which include the Greenway and Ararat River restoration.
“The city school system has really has embraced the project,” said Boyles. “The issue (storm water management) is not new to North Carolina but it is new to Mount Airy. It’s more of a natural process for water filtration.” He explained the BMPs basically picked up where projects had stopped at Tharrington Primary School.
He said in the 1990s a flood prevention project using interlocking blocks which allowed vegetation to grow through them preceded constructing the Greenway, from Riverside Park almost to the Highway 52 bypass. Improvement efforts will continue from MAMS to where the Ararat joins Lovill’s Creek and go from there as erosion to the sides of the creek and further creek restoration continue.
“This will complete the river restoration project which will end in the vicinity of Big Lots and the water treatment plant, asthe Greenways are tied together “said Boyles. “It’s good for everyone involved because we have learned the quantity as well as the quality of storm water affects people downstream.” He explained the filtering process at the MAMS project will mean the area will not always be filled with water.
The BMP sites, in addition to being a teaching tool in the middle school STEAM curriculum, can also be an aesthetically pleasing way to address water run-off issues. The plants provide food and shelter for many birds, butterflies and beneficial insects, such as dragonflies which eat mosquitoe), said Parks and Recreation Director Catrina Alexander “Instead of a ditch and grate approach, a combination of shrubs, grasses and flowering perennials incorporate color in the spring and summer and patterned grasses in the fall and winter. All the while, slowing the water down and allowing for more optimal absorption. BMP’s of this nature are usually found near parking lots in low lying areas where drainage speeds are escalated due to the addition of impervious surfaces.”
David Broyles may be reached at 336-719-1952 or on twitter@MtAiryNewsDave.