Rocky EEP Preliminary Findings Report Summary February 2005

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1 This is a DRAFT summary of the NC Ecosystem Enhancement Upper Rocky River Local Watershed Plan Preliminary Findings Report. The original, 157 page document can be found here: The summary was produced in 2010 by NCSU student Robert Monk. Rocky EEP Preliminary Findings Report Summary February Introduction The NC Ecosystem Enhancement Program (NCEEP) has initiated comprehensive watershed planning efforts in certain high priority local watersheds. NCEEP selected the Upper Rocky River watersheds (which includes Tick Creek) as high priority areas for planning due to two primary factors: (1) documented water quality and aquatic habitat problems in selected stream segments, and (2) ongoing threats to local watershed health which may be attributed to impacts from urban/suburban development, clearing of riparian buffers, agricultural activities and or other nonpoint sources. 2 Physical Features The Rocky River LWP study area is a part of the upper Cape Fear River Basin encompassing three 14 digit hydrologic units at about 177 square miles. The three hydrologic units are the Upper Rocky River, the Middle Rocky River, and Bear Creek. The study area comprises a portion of the upper Rocky River main stem and the following watersheds: North Prong Rocky River, Greenbrier Creek, Nick Creek, Loves Creek, Varnell Creek, Meadow Creek, Tick Creek, and Bear Creek. The study area skips the Rocky River mainstem between Tick and Bear Creeks. The Rocky River watershed study area originates in Randolph and Alamance Counties, running south southwest through western Chatham County. Approximately 90 percent of the study area is located in western Chatham County. Two impoundments located along the Rocky River within the LWP study area serve as the drinking water supply for Siler City and some surrounding communities. Public access to the lake is restricted. The Rocky River Reservoir is located approximately four miles due north of Siler City. Storage capacity was increased in 1988 to 424 million gallons, an increase from 60 million gallons. The enlargement raised the water level by 10 feet. Siler City is currently undertaking efforts to expand the capacity of the lower reservoir. The Rocky River study area lies within the Carolina Slate Belt and is typically characterized by well drained, moderately permeable soils.. About 65 percent of the entire study area is classified as forest and wetland, about 2.5 percent is developed or disturbed, 31 percent is in agricultural uses, and 1 percent is open water. Page 1 of 6

2 3 Preliminary Functional Assessment Stream segments in the headwater areas of the Rocky River are classified as Water Supply 3 (WS 3), indicating waters protected as water supplies within low to moderately developed areas. The best use of these waters is defined as a source of water supply for drinking, culinary, or food processing purposes for those users where a more protective WS I and WS 2 classification is not feasible and any other best usage specified for Class C waters. All remaining perennial stream segments in the study area are Class C waters. The best of use of Class C waters should support aquatic life propagation and maintenance of biological integrity. Class C is the minimum designation standard for all freshwaters in North Carolina. Several stream segments including the main stem of the Rocky River from its source to the Rocky River Reservoir and the entire length of Love s Creek as well as Tick Creek. The Rocky River Reservoir watershed is primarily agricultural with some pasture immediately adjacent to the lake. The lake was sampled by the division of water quality during the summer of 2003 and found to have nutrient enrichment characterized by nuisance algal blooms. Benthic macro invertebrate samples have been collected from two main stem Rocky River Locations and three tributaries, Loves Creek, Tick Creek, and Bear Creek. There are five sampling sites on Loves Creek and one on a tributary, two sites on Tick Creek and three on Bear Creek. Both Tick Creek stations received Good Fair ratings from their most recent sampling event, and the habitat score at the SR 2120 station reflected adequate benthic habitat quality. Tick Creek had a decline in fish diversity from Excellent in 1994 to Fair in Bioclassifications and habitat scores for the Loves Creek watershed are generally poor when compared to the remainder of the study area. Of the 13 sites surveyed for bioclassifications, Loves Creek and Tick Creek were the only sites with any historically poor classifications. Loves Creek and Tick Creek also had the lowest habitat scores in the study area. Severe bank erosion and bank trampling from cattle were evident in Tick Creek. There is limited water quality data available within the study area. Due to the limited number of water quality monitoring sites in the study area, future sampling is necessary. 4 Assessment Information Land Use The most recent Land Cover Database indentifies two classes of residential land, low intensity and high intensity. In low intensity, constructed materials account for 30 to 80% of the total area while high intensity areas are covered % constructed materials. Office/light industrial and commercial/heavy industrial land use make up about 2 percent of the Rocky River Watershed. Agricultural areas including cropland, pasture, Page 2 of 6

3 and hay land make up approximately 30 percent of the study area. The poultry and cattle population for Chatham County was estimated at 7 million birds and 16,000 to 17,000 head of cattle and manure from these animals supplies fertilizer in excess of agricultural needs with the exception of nitrogen which is a cause of pollution. About 82 percent of agronomic needs are supplied by manure. Pollutant loading from cow manure is particularly problematic when cattle feeding areas are located adjacent to riparian areas. Overgrazing near or adjacent to streams increases sediment loads. Cattle trampling may compact soils and further decrease runoff infiltration rates. Croplands have been identified in previous studies as having high potential for producing large sediment and nutrient loads to areas streams. Sub watersheds with the highest nutrient loading rates are seen in the headwater areas of the Rocky River, Loves Creek, Johnson Creek, Mud Lick Creek, Varnell Creek, Tick Creek, and some areas of Bear Creek. Preliminary results indicate high percentages of buffer disturbance in urban areas and agricultural areas. Streams near Siler City and in high agricultural areas showed the highest levels of disturbance. Buffer disturbances are commonly associated with lawn maintenance, cattle access to streams, farming operations and construction activities. The percent of vegetated wetlands in the riparian buffer ranged from 0 to 100 percent, with a mean of 56 percent. Within the Rocky River study area, the North Carolina Natural Heritage program has designated six sites as significant natural heritage areas. Three significant natural heritage areas lie outside the study area but are aquatic habitats and thus affected by preservation activities within the study area. They are the Upper Rocky River Aquatic Habitat, Rocky River Basalt Bluffs and Levees, Wood s Mill Bend, 902 Laurel Bluffs and Mussel Beds, Bear Creek Aquatic Habitat, Lower Rocky River/Lower Deep River Aquatic Habitat, Rocky River Dragonfly Riffles, Donnelly Hardpan Bog, and Old Railroad Heath Glades. The sub watersheds in the headwaters of Bear Creek received the highest total score for quality of terrestrial habitat and potential for preservation sites. 5 Summary of Land Use Planning The Rocky River Local Watershed Protection (LWP) study area comprises six local government jurisdictions: Chatham County (63.20 percent); Siler City (25.62 percent); Randolph County (4.67 percent); Liberty (1.08 percent); Staley (0.40 percent); and Alamance County (5.03 percent). Chatham County has two distinct planning areas in the Rocky River watershed: the water supply protection area north of the water supply intake extending to the county line (34.44 sq. mi.) and the unincorporated area to the north and south of the Siler City extraterritorial jurisdiction (ETJ) and extending to the LWP study area boundary (82.89 sq. mi.). Within a 2,500 foot corridor along the Rocky River, residential development is limited to one house Page 3 of 6

4 per 5 acres. Chatham County s vision for these planning areas is to maintain rural and agricultural land uses. The Chatham County land use development plan defines rural as 1 to 5 acres per house. Fifty percent of the development tract is preserved in open space. The Siler City ETJ area is currently un zoned except for the river corridor however; the Town of Siler City land development plan provides a vision for the area. General Residential development (2 to 4 units per acre) is planned for the areas south, west, and north of the city limits. Major industrial and mixed use development is planned along the old highway 421 and new highway 421 corridors, north and east of the existing city limits. Rural and agricultural land uses are planned for the northern portion and the southern half of the Extraterritorial Jurisdiction. This area is projected to be low density development with no public water and sewer service provided in the future. Siler City has very protective river and stream buffer requirements: within a 2,500 foot corridor along the Rocky River, 200 foot buffers are required along perennial and intermittent streams. Outside this corridor, 100 foot and 50 foot buffers are required along perennial and intermittent streams. Randolph County and its incorporated towns of Liberty and Staley are in the northwestern headwaters of the LWP study area. The area is characterized by farmland and low intensity urban development. In Low Density Development, single family residential development is limited to two houses per acre or 24 percent built upon area for all other residential and nonresidential development. In High Density Development, residential and nonresidential development cannot exceed 50 percent built upon area, development must control the runoff from the first 1 inch of rainfall, ten percent of the jurisdiction may develop up to 70 percent built upon area without storm water controls, and a 100 foot buffer is required for all development exceeding the low density requirements. The Randolph County Growth Management Plan 2002 shows the Town of Liberty more than doubling its municipal area in the coming years. Alamance County s jurisdiction in the Rocky River watershed is predominately farmland (crops and hay/pastures). Unless the existing regulations are significantly strengthened, a number of high quality (total score of 9 to 11), and very high quality (total scores greater than 11), habitat areas are threatened in Rocky River s planned rural areas. Most of the streams and watersheds in Chatham County s water supply watershed zone have medium to high erosion risk factors. If current zoning continues, or if the housing density in the agricultural and rural district averages 2 acres or less per lot, significant stream erosion is likely to occur. The Tick Creek watershed south of Siler City has medium to high erosion risk factors. The envisioned agricultural district in these sub watersheds would need to average 3 to 5 acre lots or clustered residential design to mitigate potential erosion impacts. For the most part, the Page 4 of 6

5 streams with medium to high risk of erosion are in the developed portion of Siler City. The North Prong Rocky River and Greenbrier Creek have medium risk factors for erosion. Half acre lots would pose a significant threat of erosion in these sub watersheds. The Rocky River and North Prong Rocky River are in the planned primary growth area, which will include high density, mixed use urban development. Such development could cause significant erosion in the headwaters of the Rocky River watershed. Farms that are preserved and maintained in the future should be encouraged to use best management practices to the maximum extent possible: As agricultural land is converted to forest land or developed land in the future, reduction in sediment delivery to the stream system will take place due to the decrease in disturbed soils from agricultural practices. Those sub watersheds with excessive sediment loading also have streams with medium to high erosion risk factors. Land disturbed for development, road building, utilities, will need added attention to sedimentation and erosion controls and enforcement. Tetra Tech estimated existing phosphorus loading in the Rocky River sub watersheds based on the potential for septic tank loading, farmland runoff, urban runoff, and soil erosion. Many sub watersheds in the southern half of the Rocky River watershed are still primarily forested. 6 Prioritizing Functional Stressors and Areas for Detailed Assessment Agricultural management practices appear to be the most widespread cause of watershed function degradation, although the magnitude of urban stressors and potential of future urbanization around Siler City is expected to make urban sources of water quality stressors increasingly important over time. The greatest threats to existing watershed functions appear to be occurring in the Upper Rocky River area, associated with intensive agricultural activities including cropland and pasture with extensive land application of manure and pervasive lack of sufficient riparian buffers. Upland runoff is influenced by a variety of land management practices including cropland and pasture management in rural areas and creation of impervious surfaces in urban settings. Nutrient concentrations have not been identified as a significant threat to the health of flowing streams within the study area. Based on the results of the scoring analysis, the sub watersheds with the highest stress levels are central Siler City, Lower Loves Creek, Middle Tick Creek, Rocky River Headwaters, Liberty South, Middle North Prong, and Johnson Creek. The majority of the degraded sub watersheds are located in the upper portions of the study area. Only three Bear Creek HU sub watersheds were determined to be functionally deficient, primarily due to nutrient loading concerns. Agricultural activities are generally the primary sources of the stressors. MR12 and MR18 in the Middle Rocky River HU had good priority scores as well, with high percentages of forest cover and wetland content. Sub watersheds UR08, UR11, UR13, MR10, and MR20 had the next highest priority scores with associated potential functional benefits. Page 5 of 6

6 7 Indicators and Assessment Tools Agricultural Practices that affect sediment and nutrient loadings also have a secondary affect on bacteria reduction. For rural areas, agricultural BMPs will be recommended on a watershed scale, providing general information regarding practices that could alleviate excessive nutrient and sediment loadings to local streams. 8 Additional Data Needs The primary water quality issue is sediment loading from both upland and stream bank erosion. Both sediment sources are linked to agriculture and pasture management issues. Urban areas contribute to stream bank erosion due to increased flows. Nutrient loading to area streams is an issue of concern in areas receiving land application of chicken manure and in areas where cattle directly deposit manure onto pastures and into stream channels. Fecal coliform bacteria loading from both chicken and cattle manure is a third issue of concern. Water quality issues related to residential and urban land uses are to be examined in several small watersheds in the middle portions of the study area, particularly around Siler City. There is a water quality monitoring station on Bear Creek with monthly ambient sampling wand storm peak samples. Page 6 of 6