Water Resources Research Act Program

Details for Project ID 2014NC190B

Land Application of Aquaculture Effluents to Prevent Surface Water Eutrophication and Promote Groundwater Re-Infiltration in Coastal North Carolina

Institute: North Carolina
Year Established: 2014 Start Date: 2014-07-01 End Date: 2015-06-30
Total Federal Funds: $13,500 Total Non-Federal Funds: Not available

Principal Investigators: Harry Daniels, Dennis Hazel

Abstract: Pond production of fish is a highly water-intensive operation, and the aquaculture industry in NC and the US is facing increasing scrutiny from water quality regulators about the discharge of effluents from production ponds into receiving streams. This project combines the resource needs and unique attributes of two important agriculture and natural resources fields - aquaculture and woody biomass production. Aquaculture, now a billion-dollar industry in the United States, is growing annually by 12% and is the fastest growing agribusiness in NC with an annual economic impact of over $250 million. The majority of aquaculture production is centered in economically challenged rural and coastal counties where fish farms have served as alternatives to traditional row crop farming and commercial fisheries. More than 90% of the fish production is done in the coastal portion of the state in large (3-10 acres), shallow (4-ft average depth), earthen ponds. Water to fill the ponds is pumped from groundwater aquifers.Current production practices require annual pond draining to harvest and move fish and to avoid infestations by the parasitic yellow or white grub (Daniels 2005). These practices create large volumes of effluent from April to October and have led to complaints from the general public about stream eutrophication and habitat degradation. Effluents released from the North Carolina fish farms are slow-moving and drain into wide, shallow coastal creeks that empty into waters such as the Pamlico Sound – part of the nutrient sensitive Tar-Pamlico River Basin (sub basin No. 7). In North Carolina, these streams are classified as zero-flow waters, which severely restricts their use for receiving effluents. The Albemarle sound system and the Cape Fear River are also potentially impacted. Although many studies have shown that the nutrient content of the effluents is low relative to other animal production systems, the high volume of water presents an engineering challenge that overwhelms surface water systems as well as traditional land application to row crops. Based on preliminary studies at the Tidewater Research Station, we have developed a fish-watertree system that has the potential to absorb the pond effluents and divert this wastewater to woody biomass production for carbon storage (managed forest plantations), sustainable wood products, or sustainable bioenergy such as wood pellets, a fast-growing renewable energy market in coastal North Carolina. This system re-infiltrates pond water back to groundwater systems allowing for groundwater recharge. Ideally, these systems could be designed to land-apply pond effluents on managed forest systems up-gradient of source wells to better manage groundwater resources and limit surface water impact. This proposal requests funds to advance preliminary field studies to determine how managed forest systems can be used to accommodate pond effluent volumes and best management strategies to optimize this particular land application system. The scope of the proposal work addresses statement needs of both NC Sea Grant and WRRI, specifically to prevent surface water eutrophication in coastal North Carolina. Providing a cyclical system for groundwater resource use by aquaculture operators will better manage groundwater resources in coastal North Carolina.