Though rainwater and sediment serve as the main conduits for many of the particles released from agricultural sites, this runoff deserves to be treated as a separate issue from sedimentation because of the unique contaminants involved and because of the complex legal system that governs agricultural practices in North Carolina. Runoff from agricultural sites may contain not only particles normally involved with sedimentation but also nutrients such as nitrates and phosphates, as well as fecal matter and the heavy metal arsenic. Fortunately, the current legal system of agricultural regulation is well-established and precedented. Though agriculture and related industries are not bound by the Sedimentation Pollution Control Act of 1973, there are numerous federal and state laws involved with agricultural management, including the Clean Water Responsibility and Environmentally Sound Policy Act of 1997, and the North Carolina Clean Water Act of 1999. These laws outline numerous policies of management and include effective enforcement procedures.
Therefore, our first recommendation is not a reform of the current system but a call to review and fortify it. The fact that the Catawba River still experiences issues due to agricultural contaminants shows that, though current regulations are extensive, enforcement does not address every case. The Division of Environmental Management should expand its efforts ensure that every source of contamination is controlled. In addition to this, live stock waste removal and containment must be carefully assessed. The arsenic in litter from poultry, swine, and turkey farms has been shown to leak into surface water under current regulation techniques.
Second, we recommend that new irrigation techniques for nurseries and field crops be developed and implemented. Some current techniques, such as overhead watering, are both inefficient (only 50-70%) and relatively ineffective. Drip irrigation allows for significantly higher inefficiency (up to 100%) while also ensuring that water and fertilizers more easily and effectively reach their targets; this leads to reduced water use, which helps prevent erosion and sedimentation, and also to reduced fertilizer use. Additionally we champion the use and research of slow release fertilizers, which reduce the amount of fertilizer necessary to use and in turn reduces excession introduction of nutrients to soil and water. These changes in technique, as well as the reinforcement of current regulatory processes, will provide a stronger network of control for contaminants from agricultural runoff.
Shah, Sanjay B., Grabow, Garry L., Dean L. Hesterberg, Rodney L. Huffman, Kim J. Hutchison, David H. Hardy, and James Parsons. “Leaching Potential of Arsenic and Other Pollutants from Turkey Litter Stockpiled on Bare Soil.” Ed. Sanjay B. Shah. Southern Animal Manure and Waste Management Quarterly (15 Sept. 2006): 1-2. Print.