Tar-Pamlico Basinwide Water
Quality Management Plan
Foreword and Executive Summary
December 1994

 The Tar-Pamlico River system is a major tributary to Pamlico Sound. Together, Pamlico Sound and neighboring Albemarle Sound constitute one of the most productive estuarine systems in the country and are a part of the US Environmental Protection Agency's National Estuary Program.

The Tar-Pamlico Basin encompasses the relatively undeveloped 5440-square mile watershed of the Tar-Pamlico River system and a large part of Pamlico Sound. It extends from the north central Piedmont region of the state to the Atlantic Ocean. It includes portions of 16 counties and has a population of approximately 365,000 people. It also provides habitat for at least nine state or federally listed threatened or endangered freshwater mussel species and includes all or part of three national wildlife refuges.

Despite the rural character of the basin, there are a number of water quality problems that need to be addressed. Almost one third of the freshwater streams in the basin are considered impaired. Major causes are sediment, low pH and fecal coliform bacteria. Several lakes are impaired due to excessive nutrients. In the estuarine waters, over 50,000 acres do not fully support their uses. Problems in the estuary include occurrences of algae blooms, fish kills, toxic dinoflagellates, diseased crabs and fish and closed shellfish waters.

A large portion of the estuarine problems have been linked to an overabundance of nutrients from agricultural and urban runoff, wastewater treatment plant discharges and atmospheric deposition. Nutrients, which occur in fertilizers, human and animal wastes and air pollution, can promote excessive algal growth, called blooms. These blooms, in turn, can deplete the water column of oxygen thereby causing fish kills. In addition, nutrient overenrichment has been linked with the occurrence of blooms of toxic dinoflagellates that have recently been implicated in fish kills.

The nutrient problem in the basin has been known for a number of years and significant actions have been taken to address it. The entire basin was supplementally classified as nutrient sensitive waters (NSW) by the North Carolina Environmental Management Commission in 1989. As a result, nutrient reduction goals were established for wastewater treatment plant discharges, and an innovative nutrient trading approach was developed in an agreement between major dischargers, environmental groups and the state. In addition, Texas Gulf, a company which mines phosphate rock at a site near the southern shore of the Pamlico River has reduced its discharge of phosphorus by 93% since 1988. Despite the fact that the dischargers have been able to meet their nutrient reduction goals through Phase I of this agreement, intensive modeling of the Pamlico River estuary indicates that a significant reduction in nitrogen from both point and nonpoint sources will be needed if water quality standards are to be restored. An interim goal of a 30% reduction in nitrogen loading at Washington has been recommended.

NORTH CAROLINA'S BASINWIDE APPROACH TO WATER QUALITY MANAGEMENT - PURPOSE OF TAR-PAMLICO BASINWIDE PLAN

Basinwide management is a new watershed-based water quality management initiative being implemented by the North Carolina Division of Environmental Management (DEM) which is intended to improve the efficiency, effectiveness and consistency of the state's water quality protection program. The Tar-Pamlico Basinwide Water Quality Management Plan (Tar-Pamlico Plan) is the third in a series of basinwide water quality management plans that will be prepared by DEM for all seventeen of the state's major river basins over the next five years. The plan will be used as a guide by DEM in carrying out its water quality program duties and responsibilities in the Tar-Pamlico River Basin. The schedule for all 17 basins is presented in Chapter 1.

DEM is applying this approach to each of the major river basins in the state as a means of better identifying water quality problems; developing appropriate management strategies; maintaining and protecting water quality and aquatic habitat; assuring equitable distribution of waste assimilative capacity for dischargers; and improving public awareness and involvement in management of the state's surface waters.

A basinwide management plan report is prepared for each basin in order to communicate to policy makers, the regulated community and the general public the state's rationale, approaches and long-term strategies for each basin. The draft plans are circulated for public review and comment and are presented at public meetings in each basin. The plan for a given basin is completed and approved prior to the scheduled date for basinwide permit renewals in that basin. The plans are then to be evaluated, based on follow-up water quality monitoring, and updated at five year intervals. The Tar-Pamlico Basinwide Plan is due for completion in December of 1994 and will be updated in 1999. Basinwide NPDES permitting is scheduled to commence in January 1995.

BASINWIDE GOALS

The primary goals of DEM's basinwide program are to 1) identify and restore full use to impaired waters, 2) identify and protect highly valued resource waters, and 3) manage problem pollutants throughout the basin so as to protect water quality standards while accommodating reasonable economic growth.

PUBLIC WORKSHOPS

Two public workshops were held in the Tar-Pamlico Basin to familiarize stakeholders with the basinwide approach and to solicit their comments on improving water quality protection in the basin. These workshops were held on February 28, 1994 in Greenville, and March 18, 1994 in Louisburg. The workshops were sponsored by North Carolina Cooperative Extension Service (CES), DEM and the North Carolina League of Municipalities. Priority issues compiled by the CES facilitators included:

• increase public education and participation by stakeholders

• improve nonpoint source pollution control

• identify and target problem areas/resources in the river basin

• consider land use planning and property rights

• improve water quality data

• improve funding and enforcement of regulations

• consider cost-benefit relationships

DEM is doing its best to address these issues through its basinwide approach and has considered these and other issues identified by workshop participants in developing its basin plan. A more complete summary of the workshops is provided in Appendix V.

The Tar-Pamlico River Basin stretches 180 miles from its headwaters in the north central Piedmont portion of North Carolina to the Atlantic Ocean (Figure 1). The basin, encompassing 5440 square miles, is the fourth largest river basin in North Carolina and is one of only four of the 17 major river basins in North Carolina whose boundaries are located entirely within the state. There are 2,355 miles of freshwater streams in the basin, 634,400 acres classified as salt waters and thousands of acres of impoundments including Lake Mattamuskeet, the largest natural lake in the state. Part or all of three national wildlife refuges are located in the basin (Lake Mattamuskeet, Swanquarter and Pocosin Lakes National Wildlife Refuges).

The Tar-Pamlico River basin originates in Person and Granville Counties west of Interstate 85. The upper portion of the river from its headwaters downstream to US Highway 17 in the Town of Washington is called the Tar River. From Washington to Pamlico Sound it is called the Pamlico River. Major tributaries include Swift Creek, Fishing Creek, Cokey Swamp, Tranters Creek and the Pungo River. Most of the Tar River is fresh and free-flowing. Tidal influence begins near Greenville. The Pamlico River is entirely estuarine.

The population of the basin, based on 1990 census data, is approximately 365,000. The basin encompasses all or part of the following 16 counties: Beaufort, Dare, Edgecombe, Franklin, Granville, Halifax, Hyde, Martin, Nash, Pamlico (<5%), Person, Pitt, Vance, Warren, Washington and Wilson. Municipalities with a population of 5,000 or more include Washington, Rocky Mount, Tarboro, Oxford, Greenville and Henderson. The overall population density of the basin is 80 persons per square mile versus a state average of 127 persons per square mile. The percent population growth over the past ten years (1980 to 1990) was 7.9 % versus a statewide percentage increase of 13.1%. However, cities such as Greenville and Rocky Mount have experienced 10-year percentage increases in population of 26% and 18%, respectively.

Average rainfall in the basin ranges from less than 44 inches per year in the Piedmont area to more than 50 inches per year near Pamlico Sound. The average July temperature is just under 80°F while the average January temperature ranges from 46°F near Pamlico Sound to 42°F in the upper basin. The evapotranspiration rate for the basin is about 40 inches per year.

Land cover, based on 1987 Landsat satellite imagery, is dominated by agriculture (33.6%) and forests (29.6%) which jointly comprise a little less than two thirds of the land/water surface area in the entire basin. Open water (19.7%) and wetlands (11.4%) comprise slightly less than one third of the total area. The remaining land is made up of scrub growth (3.4%), urban area (1.8%) and barren land.

The upper one-fifth of the basin, or that area generally encompassed by Franklin, Warren, Vance, Granville and Person Counties, is located in the Piedmont physiographic region. That portion of the basin east of this area is located in the Coastal Plain region. The Piedmont is typified by highly-erodible clay soils; rolling topography with broad ridges and sharply indented stream valleys; and low gradient streams composed of a series of sluggish pools separated by riffles and occasional small rapids. Stream floodplains are relatively narrow and mostly forested. There are no natural lakes in the Piedmont region. Soils in the region are underlain by a fractured rock formation with little water storage capacity which offers only a limited supply of groundwater.

Figure 1 General Map of the Tar-Pamlico River Basin

The Coastal Plain is characterized by flat terrain, "blackwater streams," low-lying swamplands and productive estuarine areas. Streams, including the mainstem of the Tar, are meandering and slow-moving with low banks. They are often lined by extensive swamps, bottomland hardwood forests or marshes. This is particularly true in the lower half of this region (sometimes referred to as the outer Coastal Plain). Streams flowing through swampland areas are naturally discolored by tannic acid from decomposing plant material and become tea-colored, hence the name "blackwater." The Coastal Plain is underlain by deep sands and groundwater is abundant. In light of the increased abundance of groundwater, permeable soils, and flat terrain, there are few surface water impoundments.

Forestry and agriculture are the primary land use activities in the Coastal Plain along with the Texas Gulf phosphate mining operation in Beaufort County.

The Tar-Pamlico River Basin provides habitat for at least nine state and/or federally listed, threatened and endangered freshwater mussels. Factors in their continued survival would appear to be the minimal amount of urban development that has occurred in these subbasins and the limited number and size of wastewater treatment plants. The Swift Creek subbasin, in particular, has been singled out as having unique and special values as habitat for threatened and endangered species and for its zoogeographic importance. Based on these values, a 1993 report published by the NC Wildlife Resources Commission identified Swift Creek as possibly one of the most valuable freshwater stream ecosystems remaining along the Atlantic Seaboard.

This summary is based on data collected by the Environmental Sciences Branch of DEM's Water Quality Section including consideration of information reported by researchers and other agencies within the Tar-Pamlico River Basin. Water quality monitoring programs include: benthic macroinvertebrate (benthos) monitoring (94 sites), phytoplankton monitoring, aquatic toxicity monitoring, fish community (19 sites) and tissue monitoring (46 sites), special chemical/physical water quality investigations, lake assessments (4 sites), sediment oxygen demand monitoring and ambient water quality monitoring (31 sites - see Appendix for location map and list of sites). A full compilation of this data and descriptions of the monitoring programs is presented in the Basinwide Assessment Report Support Document for the Tar-Pamlico River Basin (Final Draft) prepared by the DEM in November 1993.

The entire Tar-Pamlico River basin was designated as Nutrient Sensitive Waters (NSW) in 1989 in response to the problems associated with nutrient loading (from both point and nonpoint sources) and the resulting eutrophication and algal blooms in the Pamlico River estuary.

Water quality conditions in the upper Tar River are rated Good/Fair near the Town of Tar River and Good at Louisburg, based on the most recent benthos data. These data indicate a slight decline in water quality at the Tar River location (1984 vs 1992 data) and improvement at the Louisburg location (1983 and 1986 vs 1992 data). Most tributary sites were found to have Good/Fair water quality using benthos data. Evaluation of water quality at the Tar River site can also be affected by low flow drought periods. Fish community analysis found the upper Tar River to have Good-Excellent water quality and tributary sites to have Good water quality. Phytoplankton data have indicated eutrophic conditions in Lake Devin, Lake Royale and Hart Pond.

Good water quality conditions have been consistently recorded from several benthos locations and one fish sampling site on Swift Creek. Benthos data from near Hilliardston in 1992, indicated a Good rating. An upstream site on Sandy Creek also had Good/Fair water quality. Swift Creek supports one of the only viable populations of the Tar River spiny mussel (Elliptio (Canthyria) steinstansana) in the world, a federally endangered species. It also supports the best populations in North Carolina of five other mussel species listed by the state as threatened.

The division between the Piedmont and the Coastal Plain is generally accepted as the fall line, which occurs near Rocky Mount in the Tar River basin. Below the fall line, the river has a flatter, sand/silt substrate with numerous swamps along its borders. Benthos data from the Tar River near Rocky Mount indicate generally Good/Fair water quality, with no long term changes. Benthos data from stations sampled in 1992 above and below the Rocky Mount WWTP noted no impact, while prior studies have noted a slight impact.

Fishing Creek is a major tributary whose confluence with the Tar River is above Tarboro, North Carolina. Benthos data from 1992 indicated Fair water quality at an upstream site on Fishing Creek, but Good bioclassifications at all other Fishing Creek sites. These data primarily reflect the effects of nonpoint sources of water pollution in this watershed. Little Fishing Creek was rated Good/Fair, while Shocco Creek, a tributary of Fishing Creek, received a Fair bioclassification. Fisheries data also gave a fair rating to Shocco Creek, and gave a Fair-Good rating to Rocky Swamp. Fisheries sampling of Fishing Creek gave NCIBI scores in the Good-Excellent range, while Little Fishing Creek scored in the Good range.

The next downstream mainstem ambient monitoring location is the Tar River at Tarboro. Benthos data from this location have consistently produced a Good bioclassification. The river at this point also supports populations of other threatened or endangered mussel species including Elliptio (C.) steinstansana. A benthos sample was collected at NC 42 below Tarboro in 1992, that indicated an Excellent bioclassification.

Biological information from the ambient location on Conetoe Creek near Bethel has indicated consistently Fair water quality during the period of record (1985 to 1992). Town Creek and Otter Creek resulted in Good ratings using the fisheries data.

The only ambient monitoring station on the lower Tar River is the station at Grimesland. Benthos data from this location have indicated Fair to Good/Fair water quality conditions for the period of record. The Tar River at Grimesland is located below the Greenville area and is influenced by urban runoff and numerous small dischargers. The lowest median dissolved oxygen values for the Tar River and the highest median levels of nitrate/nitrite-nitrogen are found at this ambient station. This station supports sparse populations of freshwater algae which are subject to washout following spate events.

Benthos data from Chicod Creek, a tributary on the west side of the Tar River above Washington, have indicated Fair water quality. Fisheries data from the Chicod Creek watershed also noted Fair ratings. The lower ambient station on Chicod Creek has the lowest DO values and the highest Total Phosphorus values of all Tar-Pamlico tributary stations. There is a relatively large concentration of animal operations in this areas. Grindle Creek was rated Fair using benthos, and Good from fisheries data.

Data have been collected from the ambient location on Tranters Creek near Washington. Bioclassifications from this station have been in the Fair to Poor range. Data are difficult to interpret because of the possible influence of saline water. Several euryhaline benthic taxa are often collected at this location.

Very few biological investigations have been conducted on the tributary streams of the Pamlico River, due to the swampy nature of the streams. The only fisheries data are from Horse Creek, which had a Fair-Good rating. Some benthos data have been collected from estuarine sites, but no water quality ratings are associated with these data. Lakes data note that Pungo Lake is a dystrophic lake. Lake Mattamuskeet, the largest natural lake in North Carolina, is classified as fully supporting its designated uses.

The estuarine portion of the basin has been the focus of a variety of research efforts since the early 1970's, and especially since 1988 in conjunction with the Albemarle-Pamlico Estuary Study (APES). The APES program is one of the US Environmental Protection Agency's nationwide estuary programs, and it has generated a number of research projects. Highlights of some of that research can be found in the Phytoplankton and Water Quality part of Chapter 4 of this report. Much of this research has been aimed at describing nutrient and phytoplankton interactions, documenting water column stratification and occurrences of hypoxia and anoxia, determining the distribution and behavior of a toxic dinoflagellate (to be named Pfiesteria piscimorte), and investigating nitrogen and phosphorus cycling.

Numerous phytoplankton samples have been collected by DEM from the Pamlico River and Pamlico Sound. Where the Pamlico River typically becomes brackish near Washington, phytoplankton populations were comprised of a diversity of algal classes. This station supports both fresh and brackish water species of algae since the fresh-brackish water interface migrates depending on flow and winds. Downstream, phytoplankton communities at mainstem stations were comprised of typical estuarine phytoplanktors including bacillariophytes, dinoflagellates and cryptophytes. Small filamentous cyanophytes and bacillariophytes were also common by density estimates. Mainstem stations often exhibited algae blooms during the summer. In addition, these stations exhibited winter blooms of cool weather dinoflagellates, Heterocapsa triquetra and Prorocentrum minimum. These dinoflagellate blooms cause little concern during winter months because sufficient oxygen is present in the water column even with high levels of algal respiration. Data from phytoplankton samples are almost always below bloom thresholds from the ambient station in the lower Pamlico River estuary. Ambient water quality data show low nutrient values for this area.

WATER QUALITY USE-SUPPORT RATINGS / CAUSES AND SOURCES OF POLLUTION

Another important method for assessing surface water quality is to determine whether the quality is sufficient to support the uses for which the waterbody has been classified by the state. The word uses, depending on the classification of the waters, refers to activities such as swimming, fishing, water supply and shellfishing. DEM has collected extensive chemical and biological water quality monitoring data throughout the Tar-Pamlico basin as summarized above. All data for a particular stream segment have been assessed to determine the overall use support rating; that is, whether the waters are fully supporting, partially supporting or not supporting their uses. A fourth rating, support-threatened, applies where all uses are currently being supported but that water quality conditions are marginal. Streams referred to as impaired are those rated as either partially supporting or not supporting. Use support ratings in the Tar-Pamlico basin, described more fully in Chapter 4, are summarized below for freshwater streams, saltwaters (estuarine areas) and lakes.

Freshwater Streams and Rivers

Of the 2355 miles of freshwater streams and rivers in the Tar-Pamlico basin, use support ratings were determined for 89% or 2088 miles with the following breakdown: 21% were rated fully supporting, 43% support-threatened (for a total of 64% of freshwaters currently supporting uses), 20% partially supporting, five percent not supporting and 11% nonevaluated. In general, subbasins 01, 02, 03, 04, 06 and 07 had a majority of their streams which were either supporting or support-threatened, while subbasins 05 and 08 had a larger percentage of streams which were considered impaired (partially supporting or not supporting their uses).

Probable causes and sources of freshwater impairment were determined for about 87% of the impaired streams. Sediment was the most widespread cause of impairment, followed by low pH and fecal coliform bacteria.

Information on sources of impairment indicated that 520 stream miles (or 92% of stream impaired stream miles) were impaired by nonpoint sources, and 43.5 stream miles (or 8% of impaired stream miles) were impaired by point sources. Agriculture was the most widespread nonpoint source, followed by hydrologic/habitat modification (e.g., stream channelization, drainage ditching, wetlands drainage, etc.), and unknown sources (e.g., general erosion). Forestry and urban activities also contributed substantially to the nonpoint source pollution in this basin. Subbasins 04 and 05 had the highest number of streams thought to be impaired by agriculture and subbasin 05 had the highest number attributed to hydrologic modification.

Salt (Estuarine) Waters

Use support determinations were made for all 634,400 acres of saltwater in the Tar-Pamlico Basin which includes 120,000 acres in the Pamlico River (subbasin 03-03-06) and 514,400 acres in Pamlico Sound and its tributaries (03-03-07). Use support data for all saltwaters are presented in Table 4.7. Data are presented for each of 12 shellfish management areas used by the NC Division of Environmental Health's Shellfish Sanitation Branch (Figure 4.27). In evaluating all 634,400 saltwaters in the basin, approximately eighty-four percent of the saltwaters were rated as fully supporting, 7.1 percent were rated support- threatened and 8.6 percent were rated partially supporting. However, all of the support-threatened and most of the partially supporting waters are located in the Pamlico River. Therefore, while 99.5% of the waters in Pamlico Sound are considered supporting (with only 0.5% partially supporting), just 19% of the Pamlico River's saltwaters are fully supporting with 38% being fully supporting but threatened and 43% being partially supporting.

Chlorophyll a was the most widespread probable cause of impairment followed by low dissolved oxygen, and fecal coliform bacteria. Elevated levels of Chlorophyll a and fecal coliform bacteria are both indicators of water quality degradation, with the first related to nutrient overenrichment and the second to elevated bacterial levels that require the closure of shellfishing areas. The majority of partially supporting waters were in the upper part of the Pamlico River estuary where these waters were mainly impacted by nutrient overenrichment

Nonpoint source pollution is estimated to be the primary pollution source in 85% of the impaired waters, while point source impacts were identified in 15%. Waters were impacted primarily by multiple nonpoint sources including agriculture, urban runoff, septic tanks and marinas.

Lakes

Due to a combination of hydraulic conditions and nutrient inputs from upstream, the estuary from Washington downstream to the Pungo River is experiencing degradation from excessive nutrient loadings, especially nitrogen. Algal blooms are common in the middle reaches of the estuary, and winter blooms regularly occur. Lack of dissolved oxygen near the bottom of the sound has been responsible for the die-off of bottom dwelling (benthic) organisms. This condition occurs during periods of water layer stratification (no mixing of waters between the top and bottom layers) and warm temperatures. To address this problem, and based on the results of extensive computer modeling of nutrient loadings and their impacts on the estuary, an interim of reduction goal of 30% for total nitrogen (TN) and maintenance of existing total phosphorus (TP) loading at Washington are recommended for the Tar-Pamlico River Basin. With a 30% overall reduction in nitrogen loading, the targeted annual nitrogen loading at Washington would be 1,361,000 kg/yr. The annual TN reduction goal from all sources, at Washington, is 583,000 kg/yr (1,800,000 kg/yr - 1,361,000 kg/yr = 583,000 kg/yr). The targeted annual loading of phosphorus would be maintained at 180,000 kg/yr at Washington.

Nonpoint source nutrient reductions needed to achieve nutrient reduction goals.
The nutrient loading described in Chapter 3, based on the export coefficient model, indicates that point sources contribute only 5% of the total nitrogen in the entire basin and approximately 8% of the total nitrogen in the basin upstream from the estuary (subbasins 01 through 06). Nonpoint sources therefore account for 92% of the TN loading from subbasins 01 through 06. Based on the overall annual TN reduction goal of 583,000 kg/yr at Washington from all sources, annual point and nonpoint source reduction goals at Washington are as follows:

Therefore, in order to meet the nitrogen loading targets, nonpoint source controls will need to be implemented along with continued efforts by point sources dischargers to reduce their nutrient loadings.

Recommendations established for point and nonpoint sources under Phase II of the NSW strategy with the Tar-Pamlico Basin Association.
The Division has negotiated a Phase II NSW Agreement which outlines loading targets for both point and nonpoint nutrient sources. Parties to the agreement include the Association, DEM and the NC Division of Soil and Water Conservation. It also outlines other actions Association dischargers have agreed to take to reduce nutrient loading in the basin. The fact that the majority of the nutrient loading in the basin is from nonpoint sources has been addressed in the Agreement. The Agreement contains a commitment by the Division of Environmental Management to convene and coordinate meetings with appropriate groups and agencies to establish a coordinated and focused plan to achieve the required nonpoint source nutrient reductions. This additional strategy that will provide further details of how such reductions are to achieved by nonpoint sources and the accounting of such actions is to be established by September, 1995.

Priority management areas for nonpoint source nutrient reductions are recommended.
Agencies other than DEM have jurisdiction over many of the nonpoint source programs. In order to provide guidance in prioritizing areas in need of BMPs, a list of streams with high areal loadings is given here. This list should also be used by DEM to prioritize waterbodies for 319 project moneys as they become available to the state. This prioritized list is as follows: Swift Creek, Conetoe Creek, Cokey Swamp Creek, Tranters Creek and the Tar River Estuary

Nutrient management plans are recommended for agricultural lands.
In addition to the strategies listed above, the mass balance model described in chapter 3 indicated that on average, 40% of the nitrogen applied as fertilizer is lost to the environment. Research should be done to see if this number can be reduced. Information assimilated through the Chesapeake Bay program indicates that nutrient management is one of the least costly methods to reduce nutrient loading and, when combined with other BMP practices, is very effective at reducing nutrients.

A nonpoint source BMP database needs to be developed.
During the next five years, DEM should continue to work with the nonpoint source agencies to develop a good database on the type, location and effectiveness of BMPs.

Voluntary implementation of nutrient BMPs is preferred over mandatory controls.
To make this happen, there needs to be a concerted effort to educate the nonpoint source contributors on the importance of reducing nutrient loading, to encourage further voluntary participation in the BMP programs, and to provide them with cost-effective options. Education may be conducted through the NC Cooperative Extension Service, Soil and Water Conservation Districts, Farm Bureau, NC Department of Agriculture and others. Cost share opportunities are offered through the USDA Agricultural Stabilization and Conservation Service and the NC Agricultural Cost Share Program. DEM will need assess the need for mandatory nonpoint source control measures during updating of the basin plan in 1999.

Development of cost effective measures and new technologies needs support.
DEM should also work with the appropriate agricultural agencies to obtain better information on best management practice (BMP) cost/effectiveness to supplement research such as that being done by Research Triangle Institute. A portion of federal 319 nonpoint source funds and cost share moneys should be used to perform site specific monitoring before and after BMPs are implemented. These studies will provide data specific to the North Carolina coastal plain to help develop cost effective nutrient management strategies.

Performance monitoring is needed to evaluate the effectiveness of recommended nutrient reduction strategies.
An instream monitoring plan should be developed during the next year which will allow DEM to evaluate these recommended management strategies. As part of this monitoring network, a USGS gaging station should be located between Grimesland and Tarboro, and monthly ambient data including the nutrient series should be measured there. This will give the Division accurate loading estimates at Greenville. The Division should also consider setting up gages to obtain better flow information in the estuary as this will allow the model hydrodynamics to be recalibrated so the model can be used to evaluate nutrient control strategies in the lower portion of the basin. In addition, extensive monitoring should continue throughout the estuary.

Maintaining adequate dissolved oxygen in surface waters is critical to the survival of aquatic life in the Tar-Pamlico Basin. Over the past twenty years, tremendous progress has been made in reducing the amount of oxygen-consuming wastes discharged into surface waters from wastewater treatment plants (WWTPs). While the total daily effluent flow from these facilities has increased by 67% over the past 20 years, the actual daily loading of oxygen-consuming wastes has decreased by 63%. Despite these overall improvements, point source control strategies are being recommended for several areas of the basin in order to prevent violations of dissolved oxygen standards in the receiving waters associated with new or expanding WWTPs.

Fishing Creek and its tributaries in and around Oxford
Although few DO violations have been observed by the City in recent years, the City of Oxford's existing NPDES permit limits were based on the Division's old empirical model, and the new model indicates that more stringent limits are needed to protect water quality during critical low flow conditions. If the City expands or modifies its treatment plant, more stringent limits would be recommended for the facility. Any proposed and expanding dischargers in the basin should examine the feasibility of connecting to Oxford before they receive a permit.

Tar River mainstem between Rocky Mount and Greenville
Substandard DO concentrations have been measured in the Tar River between Rocky Mount and Greenville. In order to evaluate the effects of point source dischargers on the instream dissolved oxygen concentration in the freshwater portion of the river, a QUAL2E model was developed from Rocky Mount to Greenville, a distance of approximately 60 miles. Two major NPDES dischargers, Rocky Mount and Tarboro, were included in the model. In light of the modeling results, it is recommended that Rocky Mount receive advanced tertiary limits (5 mg/l BOD5, 2 mg/l ammonia, 6 mg/l DO) for its expansion request to 21 MGD. These stringent limits are necessary to protect the Tar River mainstem below the City's discharge.

For other dischargers in this segment of the river, since the Tar River has already been overallocated, and DO violations have been observed, no new or expanded discharge should receive limits less stringent than 15 mg/l BOD5, 4 mg/l ammonia, and 5 mg/l DO.

Tranters Creek and several of its tributaries
The Town of Robersonville and Eagle Snacks Company discharge into Flat Swamp which drains into Tranters Creek. A QUAL2E model was calibrated for this section of stream which indicated that assimilative capacity is limited. Each of the above dischargers was assigned advanced tertiary limits based on the modeling analysis. In addition to the modeling results, substandard DO concentrations have been observed at an ambient site in Tranters Creek. Due to the limited assimilative capacity, it is recommended that no new dischargers should be allowed into Flat Swamp and the upper portion of Tranters Creek (to Turkey Swamp Creek).

Kennedy Creek at Washington
Dissolved oxygen standard violations have occurred in Kennedy Creek. The City of Washington discharges into the creek. Due to poor natural flow, the effluent remains in the creek contributing to the water quality standard violations. The City of Washington has not been allowed to expand its discharge and is in the process of planning the removal of its discharge from the creek. If the City does not relocate, no flow expansion will be permitted and limits of 5 mg/l BOD5 and 2 mg/l NH3 will be included in its NPDES permit. No new discharges shall be allowed to Kennedy Creek.

Outstanding Resource Waters (ORW) at Swanquarter National Wildlife Refuge - The Swanquarter Bay and Juniper Bay area have been designated as outstanding resource waters (ORW). No new or expanded NPDES discharges are allowed in this area.

Discharges to Swamp Waters - Many of the streams in the Tar-Pamlico River Basin are classified as swamp waters. DEM does not have a good tool to evaluate the ability of these streams to assimilate oxygen-consuming wastes as our desktop dissolved oxygen model assumes a steady-state, one-dimensional flow, and these conditions may not exist in a swamp water. In addition, data analysis on the previously-studied Lumber River basin indicated that critical flow conditions in a swamp system do not necessarily occur during low flow conditions. Inadequate flow and water quality data prevent verification of the relationship between flow and dissolved oxygen in many of the tributaries which are classified as swamp waters. Given the difficulty of determing the assimilative capacity of swamp waters, DEM has identified the need to develop a better tool to evaluate the ability of a swamp system to assimilate waste flow. Since the large influx of flow from a pipe may have a larger impact on these systems than actual treatment levels, DEM will be investigating the potential for innovative outfall designs which will allow a slower release of effluent to the system. Until these studies are completed, new discharges will not be permitted at limits greater than 15 mg/l BOD5 and 4 mg/l NH3-N (NH3-N may be lower if dilution is low). More stringent limits may be given if, in the opinion of the Director, they are needed to protect water quality standards. For existing non-expanding facilities, existing limits will be recommended unless site specific information is available which indicates more stringent limits are needed. For expanding facilities, it will be recommended that existing loading (mass basis) be maintained although flow increases may be allowed.

C. Shellfish Water Closures due to fecal coliform bacteria

Approximately 10,000 acres of shellfish waters in the Tar-Pamlico River Basin have been closed to harvesting by the NC Division of Environmental Health's Sanitation Branch due to elevated levels of bacteria. Nonpoint source pollution is reported to be the pollution source for 85% of the impaired estuarine waters with point sources accounting for the remaining 15%. Probable sources of the fecal coliform contamination include urban runoff, septic tanks, agriculture, marinas, commercial forestry and wastewater treatment plants.

Sediment is the most widespread cause of water quality use support impairment in the Tar-Pamlico River Basin. Significant sources include agricultural activities, road construction, urban development, timber harvesting and mining. There are 19 programs administered by various local, state and federal agencies which have been developed to control sediment from these activities (Table 6.3 of Chapter 6). Without these programs, sediment-related water quality impacts would undoubtedly be much worse. However, despite the combined efforts of all of the above programs there were still 387 miles of streams in the Tar-Pamlico Basin estimated to be impaired by sediment, thus pointing to the need for continued overall improvements in erosion and sediment control. Most of the programs referenced above and listed in Chapter 6 are the responsibility of agencies other than DEM. DEM is using the basinwide approach to draw attention to this issue to work more closely with the responsible agencies to find ways of improving erosion and sediment control.

Recommendations for Improving Erosion and Sediment Control

A small dinoflagellate that commonly occurs in the Tar-Pamlico River estuary has proven to be toxic and may account for many previously unexplained fish kills. The dinoflagellate, to be named Pfiesteria piscimortuis, represents a new family, genus and species. Although present since phytoplankton monitoring by DEM began in the Pamlico estuary in 1984, it was not recognized as a toxic species since it often comprises a small percentage of the algal biomass and is generally found with several other species of dinoflagellates. In addition, many fish kills occurred in conjunction with salt wedges and resultant hypoxia making it difficult to determine the causative agent of the kills. This organism is apparently not always toxic as it has also been found in high numbers without causing fish kills, but recent unpublished data has implicated it in nearly 50% of fish kills in the estuary. It is stimulated by substances excreted by fish, feeds on fish flesh and encysts in the sediments

Research funded by the Albemarle Pamlico Estuarine Study has revealed relatively few toxicity-related water quality problems in the Tar-Pamlico basin. There are a number of toxic sediment hotspots in the Pamlico River estuary, most notably in and around Kennedy Creek. Much of the toxic sediment problem in Kennedy Creek is attributed to discharges that have been removed from creek. Fish tissue data collected by DEM from Pungo Lake and lower Tranters Lake have revealed elevated mercury levels. DEM's Environmental Sciences Branch is conducting a major study throughout much of the state's Coastal Plain to identify the extent of elevated mercury levels in fish tissues.

The general strategy for addressing toxic substances in the Tar-Pamlico Basin and elsewhere across the state involves a combination of prevention, detection and control. Clean up of past abuses is in many cases prohibitively expensive so an effective proactive approach is mandatory. The basin plan describes several point and nonpoint source programs aimed at preventing toxicity problems in surface waters. These include establishment of NPDES permit limits and pretreatment programs for dischargers, requiring of NPDES permits for urban and industrial runoff, in certain circumstances, and implementing nonpoint source control programs such as the NC Pesticide Law.

In addition to the recommendations presented above under Major Issues, the following topics have been identified as priorities to be addressed during the upcoming basin cycle. A number of them have been identified through public comment on the plan.

A. Increasing Public Participation and Stakeholder Involvement in the Basinwide Planning Process

Protection and enhancement of water quality is a shared need and a responsibility of all those who work, reside or recreate in the basin. Communication of ideas, conducting research, sharing information, solving problems cost-effectively with minimal regulation, and balancing the needs of various stakeholder groups are all necessary for long-term success. Basinwide planning can assist in meeting these needs but the planning process and products will need to be improved. Below are several recommended improvements to be undertaken during the next basinwide planning cycle for the Tar-Pamlico basin.

• More clearly define the role for citizen participation in basinwide planning

• Ensure active interaction between DEM staff and proposed regional volunteer implementation groups being considered for establishment for this and the other river basins in the Albemarle-Pamlico Estuarine Program area (see item E, below)

• Increase state staff involved in public outreach so as to provide better opportunities for communication between stakeholders and the state

• Produce more user-friendly basin plans and associated reports in order to enhance public interest and understanding in water quality protection.

B. Integration of Water Resources Planning with Water Quality Protection

Population increases and expanding industrial needs will place greater demands on the basin's limited surface water supplies. Reduced instream flows can adversely affect both aquatic habitat and waste assimilative capacity for municipal and industrial dischargers. At the present time, surface water supply needs in the basin are being met, but without adequate planning, towns, agriculture and industry could be faced with crippling water shortages. Consequently, conservation and reuse of water will need to be a priority for all water users in the basin. In this regard, it is recommended that future updates of the Tar-Pamlico basin plan be developed in consonance with long-range water supply planning needs. DEM will rely heavily on input from the NC Division of Water Resources (DWR), as well as from the US Geological Survey and other appropriate sources. DWR is responsible for administering several water supply statutes including the Water Supply Planning law (G.S. 143-355 (l) and (m)), the Registration of Water Withdrawals and Transfers law (G.S. 143-215.22H), the Regulation of Surface Water Transfers Act (G.S. 143-215.221 et seq.) and the Capacity Use Act (G.S. 143-215.11 et seq.). Local water supply plans under the Water Supply Planning Law are to be approved and submitted to DWR by January 1, 1995.

C. Discussion of Groundwater and Wetlands as they Relate to Water Quality

There are currently programs in place aimed at protecting ground water quality and preserving wetlands. However, the link between protection of these resources and surface water quality needs to explored and strengthened in future updates of the plan.

D. Costs Associated with Water Pollution and Control Measures

One of the potential benefits of the basinwide planning process is to utilize predictive modeling and other tools to show the consequences of growth and development activities on water quality, and to develop long-range protection strategies that allow for sustained growth. With sufficient lead time and involvement in the planning process, local governments, industry and others can plan their activities to work in consonance with these strategies.

This first plan for the Tar-Pamlico basin has begun this process through the nutrient modeling effort and identification of the need to reduce nitrogen loading from all sources upstream from the estuary. It has also begun to address the costs of pollution control through the nutrient trading agreements (Phases I and II) and discussion of costs for implementation of various agricultural best management practices. Future updates to the plan will be strengthened by inclusion of social costs of pollution (fish kills, higher water treatment costs, diminished recreational value, etc.) and a comprehensive discussion of other pollution control costs for both point and nonpoint sources of pollution.

E. APES CCMP and the Tar-Pamlico Basin Plan.