Identifying Pollution Sources for Management Prioritization in the Albemarle-Pamlico Watersheds

Abstract

The Albemarle-Chowan, Roanoke, and Tar-Pamlico watersheds have displayed degradation in water quality in recent history. To address concerns about the effects of poor water quality, the North Carolina Chapter of The Nature Conservancy (TNC) is interested in identifying where nutrients are concentrated across the landscape, and identifying the best management practices (BMP’s) available to address pollutants. To find where pollutant levels are highest, we used InVEST and SPARROW models, and converted raw outputs into hot spots, providing a smaller region for The Nature Conservancy to focus management actions. Within the agriculturally dominated hot spots, we identified 4 best management practices, riparian buffers, cover crops, ditch retention structures, and peatland restoration, as implementation options available to TNC. Scenarios run within InVEST models for each best management practice quantified the scope of action needed and estimated the reduction in nutrient concentrations from implementation. The results of these scenarios showed that TNC will have to address tradeoffs between efficiency and overall impact from best management practices. For example, cover crops were found to be the least efficient at removing nitrogen per acre, but due to the large amount of land available to plant cover crops on, this BMP has the largest potential for reducing nitrogen overall. To aid TNC in finding landowners to approach about using BMP’s, we ran a parcel prioritization, and identified landowners with large parcels containing large amounts of agriculture, peatland, and close to land that is already protected. The results of these analyses will help inform TNC staff as they take steps to improve water quality in the Albemarle-Pamlico region.