Basinwide Assessment Report: Cape Fear River Basin, June 1999
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Environmental Sciences Branch BASINWIDE ASSESSMENT REPORT CAPE FEAR RIVER BASIN June 1999 NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES Division of Water Quality Water Quality Section D E N R Erratum (June 27, 2000): Because benthos swamp and estuarine criteria are not finalized, all previously rated samples are now “Not Rated”. The correct ratings listed in Appendix B2 should be followed when the text and the listing in Appendix B2 differ. If you have questions, please contact Trish MacPherson at (919)733-6946 or electronically at: [email protected]. Appendices L2 and T and the ambient monitoring chemical data sheets are not included in this electronic version of the report. If you desire these pages, please contact Trish MacPherson at (919)733-6946 or electronically at: [email protected]. EXECUTIVE SUMMARY This document, prepared by the Environmental Sciences Branch, presents a water quality assessment of work conducted by the NC Division of Water Quality, Water Quality Section in the Cape Fear River Basin, and information reported by outside researchers and other agencies. Program areas covered within this report include: benthic macroinvertebrate monitoring, fish population and tissue monitoring, lakes assessment (including phytoplankton monitoring), aquatic toxicity monitoring, and ambient water quality monitoring (covering the period 1993- 1997). In general, the document is structured such that each subbasin is physically described and an overview of water quality is given at the beginning of each subbasin section. This is followed by program area discussions within each subbasin. Specific data and descriptions of information covered by these summaries can be found in the individual subbasin sections and the appendices of this report. General water quality conditions are presented here in an upstream to downstream format. A map showing all 24 Cape Fear River subbasins is presented at the beginning of this report and a map of each subbasin showing basin sampling sites precedes each subbasin section. The Cape Fear River subbasins are described by six digit subbasin codes (030601-030624), but are often referred to by their last two digits (e.g. subbasin 16). The Cape Fear River Basin is the largest river basin in the state and covers an area of 9,149 square miles in twenty four counties. There are an estimated 6,300 miles of streams and rivers in the basin. None of these are found in the mountains, but are confined to the Piedmont, Sandhills and Coastal Plain ecoregions. The Cape Fear River is formed by the confluence of the Deep and Haw Rivers at the Chatham/Lee County line. B. Everett Jordan Reservoir is the largest impoundment in the basin. Several large tributaries join the river as it flows to the Atlantic Ocean at Cape Fear near Southport: Upper and (Lower) Little Rivers, Rockfish Creek, Black River, South River and the Northeast Cape Fear River. The basin is characterized by highly urban and industrialized areas around Greensboro, High Point, Burlington, Chapel Hill and Durham in the upper part of the watershed and around Fayetteville and Wilmington in the middle and lower part. Fort Bragg Military Reservation occupies a large area in the middle of the basin. As might be expected in such a populous area, water quality in the basin has been affected by the impacts of numerous dischargers and nonpoint source runoff. Haw River Drainage (Subbasins 1-4) The Haw River originates in the piedmont ecoregion near Oak Ridge in Guilford County and drains 1,526 square miles. The river falls from about 1,000 feet above sea level to an elevation of 158 feet at its confluence with the Deep River. The watershed topography is generally rolling hills. The textile industry has historically been a principal industry in the area, but the industrial base has expanded, and agriculture is also important in the watershed. The most upstream tributaries of the Haw River are Troublesome and Little Troublesome Creeks. The combination of agricultural land use and highly erodable soils produces widespread nonpoint source problems in both the upper Haw River and Troublesome Creek watersheds. Benthic macroinvertebrate surveys in 1998 produced Fair and Good-Fair bioclassifications at 2 three upstream Haw River sites, while a decline from Good-Fair was observed for the Haw River near Altamahaw. These ratings may be influenced by low flows in this part of the river, especially in 1998. Troublesome Creek received a Good-Fair benthos bioclassification, but a fish survey produced a Poor NCIBI, as did a fish sample from the Haw River. Lake Hunt and Reidsville Lake, in the Troublesome Creek watershed were evaluated as eutrophic or mesotrophic in 1998. Little Troublesome Creek below the Reidsville WWTP has the most severe water quality problems in the upper Haw River area (Poor fish and benthos ratings). This plant has reduced organic loadings, but still consistently fails toxicity tests. Urban runoff has contributed to the problems in Little Troublesome Creek, with Fair benthos ratings found in 1992 and 1994 above the discharge. This discharger will be relocated to the haw River in 1999 to achieve greater dilution. As the Haw River continues downstream, Reedy Fork and its two major tributaries, North and South Buffalo Creeks join it. There are several major dischargers in the Greensboro area, but the largest of these are the Greensboro T.Z. Osborne South Buffalo Creek WWTP (20 MGD) and the Greensboro North Buffalo Creek WWTP (16 MGD). The Greensboro wastewater plants have been monitored by water chemistry samples at ambient sites, self-monitoring toxicity data, and collections of both benthic macroinvertebrates and fish. The segments of North and South Buffalo Creek in the Greensboro area constitute one of the worst water quality problems in North Carolina. Conductivity continues to increase in these streams (median values are greater than 550 µmhos/cm), nutrient values are high and there are chronically high levels of dissolved copper, zinc and cadmium. Both fish and macroinvertebrate sampling have shown Poor water quality below these discharges. Upstream biological collections have also shown Poor water quality, due to urban stormwater runoff. Areas of better water quality (Good macroinvertebrate bioclassification) are Stony Creek and Haw Creek, tributaries of the Haw River near Burlington. Jordan Creek, a tributary of Stony Creek was Good-Fair. Reedy Fork had a Good-Fair benthos raing in the headwaters in 1993 and 1998. Lake Higgins, Lake Brandt, and Lake Townsend, are in the upstream section of Reedy Fork and were evaluated as eutrophic or mesotrophic in 1998. Reedy Fork below the lakes was also Good-Fair based on fish and benthos collections. Just above the confluence with the Haw River, but below where North and South Buffalo come in, Reedy Fork declined from Good-Fair in 1993 to Fair in 1998, perhaps a result of a spill at the WWTP prior to collection of the basinwide sample. The Haw River near Graham was Good-Fair in 1993 and 1998, using benthos data. In the Burlington-Graham area the Haw River collects the Alamance Creek watershed. Erosion from agricultural land may cause large sediment inputs into streams in this watershed, but Big Alamance Creek and Stinking Quarter Creek received Good-Fair or Good macroinvertebrate bioclassifications. Fish NCIBI data also gave a Good rating to Big Alamance Creek. NCIBI ratings of Fair and Poor were given to Stinking Quarter Creek and both Little Alamance Creeks. Burlington Reservoir, Lake Burlington, and Graham-Mebane Reservoir in this area are eutrophic, while Lake Macintosh was mesotrophic in 1998. 3 The lower reach of the Haw River, above its confluence with B. Everett Jordan Reservoir, is approximately 25 river miles in length and contains many small to medium tributaries. Many of these tributary streams are located within the Carolina Slate Belt ecoregion and are prone to extreme low flow conditions during the summer (see Geology and Soils discussion in Introduction). Good and Good-Fair bioclassifications based on benthic macroinvertebrate samples were assigned to several tributary locations during 1998 surveys: Cane Creek, Collins Creek, Terrells Creek, Dry Creek and Pokeberry Creek. Nonpoint source runoff may account for the water quality deterioration and habitat loss in some tributaries. Fish community structure samples were collected from Collins Creek (Poor), Terrells Creek (Fair) and Ferrells Creek (Good-Fair). Fish assessements may evaluate habitat problems better than benthos data. Cane Creek Reservoir and Pittsboro Lake, on Robeson Creek, were evaluated as eutrophic or mesotropic in 1998. Water chemistry data from the two lowermost Haw River locations indicate an improvement compared to data collected from upstream locations. The same is true for bioclassifications of the Haw River in this reach (Good-Fair at Saxapahaw and Good at US 64 near Pittsboro) when compared to upstream reaches near Burlington and Graham (Good-Fair and Fair). Biological recovery is noted by consistent Good bioclassifications at the US 64 site prior to flowing into B. Everett Jordan Reservoir. B. Everett Jordan Reservoir and Tributaries (Subbasins 5-6) Intensive monitoring and research of the 14,300 acre B. Everett Jordan Reservoir (Jordan Lake) has been performed by State and university personnel since the reservoir was filled in 1981 and DWQ (as DEM) investigations have been conducted since 1983. The reservoir was created for flood control, fish and wildlife habitat, recreation, and water supply. It is now used for water supply by the towns of Cary and Apex. Many complaints about taste and odor in 1995 and 1996 resulted in improving the raw water treatment process. The Haw River makes up 70-90% of the annual flow of Jordan Lake with an average retention time of five days. The New Hope arm of the reservoir has an average retention time of 418 days. Jordan Lake is about five miles in length on the Haw River arm and 17 miles long on the New Hope Creek arm.