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Tar-Pamlico Nutrient Strategy: Introduction
In the mid-1980's, the Pamlico River estuary saw an increase in problems that pointed to excessive levels of nutrients in the water - harmful algal blooms, low oxygen levels, increased numbers of fish kills, and other symptoms of stress and disease in the aquatic biota. Monitoring during this periodfound chlorophyll levels that exceeded the state water quality standard of 40µg/l, with the highest number of exceedances in the upper part of the estuary. In 1989, the NC Environmental Management Commission (EMC) responded by designating the Tar-Pamlico River Basin as "Nutrient Sensitive Waters", and calling for a strategy to reduce basin nutrient inputs to the estuary.
In late 1989, the EMC approved the first nutirent strategy for the basin, an agreement with the Tar-Pamlico Basin Association, an association of wastewater dischargers in the Pamlico River watershed, to reduce their discharge nutrient loads and fund development of an estuarine model characterizing the relationship between nutrient loading and estuarine water quality. Additionally, it included a novel point-to-nonpoint source trading agreement to allow for cost-effective nutrient reductions. More information on this and subsequent agreement can be found on the Point Source Page.
Modeling of the estuary was completed in 1993 and used to establish nutrient load reductions needed to restore estuarine water quality. Detailed in the 1994 Tar-Pamlico Basinwide Water Quality Plan, the loading goals for point and nonpoint sources were also submitted to EPA as a Total Maximum Daily Load (TMDL). The TMDL calls for a 30% reduction goal for nitrogen loading from 1991 levels and holding phosphorus loading to 1991 levels.
Follow-up action from the EMC in 1994 resulted in nutrient caps reflecting the estuary goals for wastewater discharges in the Association. Additionally, a voluntary NPS reduction strategy that was passed in 1995 was replaced in 2001 with the Tar-Pam Nutrient Strategy that includes mandatory actions by nonpoint sources to meet their load allocations. Accordingly, the strategy has rules addressing agriculture, new development, nutrient management, protection of riparian buffers and wastewater dischargers. It also includes elements allowing for nutrient trading in the form of offsets to reduce loads from point sources and new development.