Point Source Agreements
Phase 1 of the Tar-Pamlico nutrient strategy, from 1990-1994, focused on wastewater treatment plants and industry - "point source" discharges of water, since they were better understood than runoff sources ("nonpoint" sources), easier to control, and made significant nutrient contributions to the river. The Tar-Pamlico Basin Association, a coalition representing the largest wastewater dischargers in the basin, agreed to either reduce their nutrient loading to the estuary or, if they exceeded an annual collective loading cap, to fund agricultural Best Management Practices (BMPs) through the state’s existing Agriculture Cost Share Program. The agreement, therefore, allowed Association dischargers to find more cost-effective ways to collectively meet their loading cap-payments for agricultural BMPs that are documented to be more cost-effective than retrofits or treatment modifications during expansion. Provisions of the agreement also called for the association to support increased water quality monitoring and development of an estuarine model.
Phase 1 Accomplishments: The Phase 1 agreement yielded progress in several respects: Every year, the Association kept nutrient loading beneath an annually decreasing cap, reducing overall nitrogen and phosphorus loads by about 20% despite growth as reflected in a flow increase of about 7%. They did so largely by improving treatment. The Association began funding agricultural BMPs, in large part through a federal EPA grant. They banked credit from this toward future cap exceedances. In Phase 1, fourteen dischargers equaling about 90% of all point source flows to the river joined the Association. Monitoring and modeling during this Phase supported improved understanding of the estuary.
The Tar-Pamlico Phase 2 point source agreement covered a period from 1995 to 2004. An estuarine model developed during Phase 1 was used to identify required nutrient reductions and establish a TMDL the details nutrient load reductions needed to restore estuarine uses. Described in the 1994 Basinwide Water Quality Plan, the TMDL calls for a 30% reduction goal for nitrogen loading from 1991 levels and holding phosphorus loading to 1991 levels. These reductions were then used to create nitrogen and phosphorus loading caps for both point and non-point sources.
Phase 2 Accomplishments: The Association stayed beneath both nitrogen and phosphorus caps throughout Phase 2, steadily reducing its loading of both nutrients despite steady increases in flow. In addition, the Association contributed funds and acquired grant funding for agricultural BMP implementation. The combined total of their contributions was $850,000 that funded nutrient-reducing BMPs like nutrient management plans, waste lagoon closures, cover crops, and water control structures.
The EMC approved Phase 3, the current phase of the Strategy, in 2005 and it continues through the end of 2014. The Phase 3 agreement updates TPBA membership and related nutrient caps to encompass 98% of permitted discharge flows to the basin. It maintains the nutrient reductions called for in Phase 2 (30% TN reduction and no increase in TP loads from 1991 levels).
Phase 3 accomplishments: Monitoring by the Association have shown their TP and TN loads to be in compliance with the required nutirent reductions. More information on nutrient loads from point sources can be found on the tracking progress page.