Measuring the amount of nitrogen released into the Neuse River was the primary issue he wanted to address when Showers, an associate professor in the Marine, Earth and Atmospheric Sciences Department persuaded the General Assembly to create RiverNet in the late 1990s. The system uses bundles of sensors to monitor water quality at seven locations between Raleigh and Kinston. Readings are taken every 15 minutes and sent electronically to NC State each night.
Excessive nitrogen discharges from farm fields and wastewater treatment plants have been blamed for fish kills in rivers and Pamlico Sound, but Showers says his data suggests the El Niño current in the Pacific also plays a key role in the fluctuating nitrogen levels by dictating how much rainfall North Carolina sees in a year. The RiverNet system is now serving as a springboard for other research, including using geographic information systems to predict potential problems from hog farms and conducting a U.S. Environmental Protection Agency-funded study of water quality near the Raleigh wastewater treatment plant. “Water quality is getting better, but it takes time,” he says. “These things operate in hydrologic time frames, not human ones.”
Drs. Greg Cope and Jay Levine measure water quality with more natural sensorsfreshwater mussels that sit on the bottom of streams and act as canaries in an aquatic coal mine. As they constantly filter water to obtain microscopic bits of food, the mollusks also absorb contaminants. Consequently, four-fifths of the 60 species of freshwater mussels in North Carolina have either become extinct in recent years or are headed in that direction, says Cope, an associate professor of toxicology. “They’re some of the most endangered animals on the planet,” says Levine, an associate professor in the College of Veterinary Medicine, who analyzes the mussel equivalent of blood to learn more about their health.
Because of Cope and Levine’s research, the EPA is poised to set tougher limits for the concentrations of ammonia and copper in water. Cope is also studying the trace amounts of pharmaceuticals, such as antidepressants and birth-control pills, that wind up in mussels. “An awful lot of attention is paid to nutrients in the water, but the problem isn’t just nitrogen and phosphorus,” he says. “We don’t know what contaminants are in there or how much is making it into our drinking supplies.”
Sediment is a major problem for aquatic life like mussels, so Dr. Rich McLaughlin is testing methods to stop runoff from construction sites from fouling creeks. Construction sites account for more than 100 tons of runoff per acre each year statewide, he says, which is 20 times the amount from agricultural land. Because collecting data at active sites is challengingbulldozers continually rearrange the scenery and affect experimentsthe associate professor of soil science built the Sediment and Erosion Control Research and Education Facility on Lake Wheeler Road. The jumble of flumes can mimic a summer storm by dumping five cubic feet of water per second into an earthen basin. It’s the only erosion research facility of its kind in the U.S.
Piles of rocks typically used to dam retention ponds on construction sites don’t slow rushing water enough to allow sediment to settle out, McLaughlin says. The basins at his Lake Wheeler Road site test ways to improve settling, from baffles made of coconut fiber to plastic floats that skim water off the top of a retention pond to drain into nearby creeks. He also is looking into the best way to apply polyacrylamide, a grainy additive used in water treatment, to coagulate sediment and speed settling. “Sediment control isn’t a priority for developers because it’s a cost to them,” he says. “We’re trying to find economical ways for them to use technology for improved results.”
Elsewhere on campus, technologies studied by Dr. Bill Hunt, an assistant professor in the Department of Biological and Agricultural Engineering, address stormwater runoff in urban settings, where just one inch of rain on an acre of parking lots, building roofs, and paved streets can send 22,000 gallons of water gushing into streams. Hunt works with developers statewide to find the best way to capture and filter runofffrom “green roofs,” where gardens are planted atop buildings, to bioretention zones, which are specially designed islands in parking lots. NC State research has prompted the state to increase environmental credits to developers. Incorporating such designs lower nitrogen and phosphorus discharges, and using permeable pavement lets water percolate through rather than flow into a storm drain. “Water is a valuable resource,” Hunt says. “We have to treat it as such.”