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October 10, 2006

Demon drain

Demon drainage project
Devilish fix: We slightly enhanced this aerial photo of the ‘Demon BMP’ by adding a touch of green. (Original photo by Seth Nagy)


Alamance high school uses mascot image in drainage project

Halloween’s edging closer, and an Alamance County school is ready. That is, if the spooky holiday ushers in a rainy season this year.

That’s because at Graham High School, the Trollinger Road home of the “red devils,” North Carolina State University researchers are proving that science can help boost school spirit, while helping keep our drinking water clean.

Here’s how science and spookiness mix.

Graham High officials last year asked Dr. Bill Hunt, of NC State’s College of Agriculture and Life Sciences’ Biological and Agricultural Engineering Department, for an innovative best management practice to catch and clean up petroleum residue, lawn chemicals and soil draining from school property. Hunt turned to designer Ryan Smith.

Smith, a BAE Extension research associate, designed and helped install a bioretention area on the downhill side of one of the school’s parking lots: a water catchment and filtration best management practice.

And keeping GHS’s fiendish mascot in mind, he designed the research and demonstration BMP in the shape of a cartoon-like devil’s head.

The BMP hadn’t filled in sufficiently with vegetation since its spring construction for a definitive photo in late August when N.C. Cooperative Extension personnel overflew the site with a model plane fitted with a small camera. But with a little image enhancement on our part (see slightly retouched photo), you can see Smith’s design concept emerge from the rolling grassy area into which it’s dug.
The BMP works like this: polluted water from the parking lot flows into a central area, the forebay – a pre-filtration holding area – then splits equally into two “eyes” – other holding areas. Water flows around the eyes’ “irises.”

“If it rains a ton, the eyes will cry, the thing fills up and tears come out the tear ducts,” Hunt says. But most importantly, the filtered water then flows to a storm drain, which drains to Haw River, then to Jordan Lake.

The groundbreaking project is the first grassed bioretention area under study in this hemisphere.

“Sometimes landscape aesthetics dictate a grassed area,” Hunt says. Because no study had been done on grassed cells, this and other states had been very reluctant to permit the use of grassed areas, and if they did, didn’t give them the same pollutant removal credit as their tree, shrub or grass mulch counterparts.”

The Graham site also is testing an innovative BMP soil medium. “This is the first time we’ve used a expanded slate in a bioretention area,” he says. “Previously, it had been used just for plants in boxes or garden beds. The slate collects more pollutants than traditional media.

“Early indications show the bioretention areas are both doing a very good job of removing nitrogen (the numbers are out-of-this-world good) and a good job of removing phosphorus,” says Hunt. Both nutrients, used in agriculture and lawn care, can pollute drinking water.

There’s a practical reason for the demonstration and research BMP’s location in Jordan Lake’s upper watershed.

“Water quality regulations are coming soon to Jordan Lake just as they did earlier to the Neuse and Tar-Pamlico river basins,” says Mitch Woodward, a Wake County Cooperative Extension area specialized agriculture agent who spent many hours helping install the BMP.

And, he says, “Nitrogen and phosphorus will both be of interest in the Jordan Lake watershed and this study looks at both of them.”

Research projects such as the “demon” BMP are critical, says Woodward, who like Hunt, is a member of NC Cooperative Extension’s Water Education Network and was active in recent Neuse River basin cleanup research and projects.

“If pollution sources are not managed properly in the Jordan Lake watershed in coming decades,” he says, “the lake won’t support its designated uses as a major regional drinking agent water supply, recreational resource and aquatic habitat.”

That could mean polluted tap water, no jet skis and no fish.

And wouldn’t that be another devil of a fix?

A Piedmont Triad Council of Governments $10,000 grant funded the project’s design work; a 319 grant from the state Department of Natural Resources helped with construction, as did Rett Davis, Alamance County Cooperative Extension director, and cooperators with the Alamance County Schools and the City of Graham.

-A. Latham

Posted by Art at October 10, 2006 11:13 AM