The alternative materials the Allies used to disguise aircraft runways in World War II may provide city planners and engineers the means to improve the water quality of the Neuse River.
Whereas the Allies were using materials other than asphalt and concrete to handle airplanes taking off and landing, engineers will be testing them in Kinston to combat stormwater pollution.
Kinston installed an alternative-paving site earlier this summer, which will serve as a demonstration parking lot that engineers, architects, planners, contractors and the general public can visit. They will be able to see whether the pavements carry the load (don’t crack due to weight of tires) and remain permeable – that which allows water to soak in, not run off.
Traditional pavement consists of asphalt or concrete. Each is very impervious, producing lots of runoff when it rains. Alternative pavement, while not quite as strong, allows some rainfall to pass through the surface into the ground, sending it along a more "filtered" route to the Neuse River.
Not all pavement areas need to be as strong as asphalt or concrete. Alternative pavement materials include concrete blocks with open holes, plastic matrixes filled with washed stone and hard plastic materials filled with soil. Water is allowed to filter through the ground with these materials, reducing runoff. By reducing stormwater runoff, streams experience less erosion and less pollutants enter our waters.
"Most developers have not considered using this type of pavement because they have yet to see it work in real-world conditions," says Bill Hunt, Neuse Education Team Extension specialist. " This research and demonstration site will provide those conditions."
Controlled drainage has a new classroom in the Neuse River Basin. In conjunction with the Neuse Crop Management project, a controlled drainage
demonstration site was installed on Dean Gurley’s Wayne County farm earlier this summer. It is the first of a series of BMPs aimed at educating Neuse
River Basin growers about ways they can comply with the state-mandated Neuse agricultural rule.
"We are very grateful for Dean's cooperation," says Deanna Osmond, Neuse
Education Team member and lead project manager for the Neuse Crop Management
Project. "Without cooperators like Dean, none of our work would be possible."
"Demonstration and in-field training are tried and true methods when it comes to working with agricultural issues," says Dr. Jon Ort, Director of the North Carolina Cooperative Extension Service. "The Neuse Crop Management Project provides the people and the dollars to deliver a more effective education and outreach program for our farmers."
Gurly grows cotton and realizes the potential of the Neuse Crop Management Project. "Water quality is very important," says Gurly. "Yes, we want to maximize our yields, but we also need to be aware of how we use the land and not take it for granted. I hope to learn a lot from this project."
According to Wayne County Extension Director Bob Pleasants, an August tour of Dean’s farm and the controlled drainage structure is on tap.
Why it's important . . .
The concept is simple. By reducing the amount of water leaving a field, farmers reduce the amount of nitrogen that leaves as well. Controlled drainage is accomplished when water control structures (like the one pictured) are put in drainage ditches. The control structure works like a faucet. Boards are put in the structure to regulate water flow, creating a mini dam. During the summer, when fish kills are known to be high, controlled drainage keeps the water in the field and reduces nutrients leaving agricultural fields.
Field studies show that controlled drainage reduces the annual total nitrogen existing in drainage water at the field edge by 9 pounds per acre per year – 45 percent on average. It works in three ways. First, controlled drainage reduces the volume of water leaving a field by 20 - 30 percent on average. (During dry years, controlled drainage may completely eliminate flow.) Second, controlled drainage sets the stage for better dentrification within the soil. Thirdly, better yields means more nitrogen is used by the crop.
How it works . . .
Boards are put in during the winter to promote denitrification and reduce flow. They are pulled out in the spring to lower the water table so farmers can get in to plant. In the summer, boards are placed back in to keep the water table up for summer crop growth.
According to Robert Evans, Extension specialist at North Carolina State
University, "some studies have shown that nitrate-nitrogen concentrations
have been 10 – 20 percent lower in outflow when compared with uncontrolled systems."
Along with the water quality benefits of controlled drainage, the farmer wins as well. Under controlled drainage corn and soybean increases of 10 percent have been measured, with some farmers reporting even larger increases.
Roughly 450,000 acres of cropland in the Neuse River Basin have the potential for controlled drainage. Farmers wanting to use this best management practice on their farm can obtain 75 percent cost share assistance provided they agree to follow Natural Resources Conservation Service management standards for the next 10 years.
Editor’s Note: The Neuse Crop Management Project was launched earlier this year as a way to educate farmers in the Neuse River Basin about nitrogen and herbicide management. It focuses on helping farmers reduce cost and decrease the nitrogen reaching the Neuse River. It will be a regular feature in the NeuseLetter. Readers who are interested in visiting the controlled drainage site featured in this article should contact Bob Pleasants at 919.731.1520.
Over the past few years, several projects in Eastern North Carolina have been installed that demonstrate effective means of reducing the effects of stormwater runoff. The Neuse Education Team has cooperated with several towns and communities to implement stormwater best management practices.
On Friday, October 8th, a tour beginning in Goldsboro (at the Wayne County Extension Center) will visit several of these innovative sites. Stops will include a wet detention basin in Smithfield, a proprietary sand filter in Wilson, a rain garden and alternative pavement parking lot in Kinston, and a stormwater wetland in Craven County’s River Bend community. These stops represent a good cross-section of BMPs useful in Eastern North Carolina.
The filter installed in Wilson was completed in cooperation with the City of Wilson, CVS Pharmacy, and Green Engineering. Master Gardeners and Wilson County Extension are monitoring the sand filter’s effectiveness.
In Kinston, both the city engineering and the parks and recreation departments joined with the Neuse Education Team in installing two very innovative practices: a rain garden and a porous pavement parking lot. Civil engineering students designed the parking lot and runoff reduction is being measured from this site.
The Division of Water Resources provided funding to the Town of River
Bend to construct an in-line constructed wetland. It was designed by members of the Neuse Education Team and installed under the guidance of River Bend.
The October 8th tour will highlight the work of these effective partnerships. Engineers, planners, landscape architects and others who attend the $15.00 tour will see first-hand the most innovative stormwater practices used in the eastern Neuse Basin.
For more information, please contact Joni Tanner at 919-513-6178