- Natural Background Visibility
- AQRV Type VISIBILITY
- AQRV Type WATER
- Pollutant Exposure Concern Thresholds
- General Information
Shining Rock Wilderness is made up of a series of high-elevation ridges on the north slopes of Pisgah Ridge in western North Carolina. Originally 13,600 acres were set aside in the 1964 Wilderness Act. The terrain is extremely steep and rugged, with elevations ranging from 3,200 feet on the West Fork Pigeon River to 6,030 feet on Cold Mountain. Shining Rock Ledge, which forms the backbone of the area, is over 5,000 feet high, with five peaks at 6,000 feet. This diverse topography gives rise to an unusual variety of vegetation. Streams and drainages abound, forming the East and West Forks of the Pigeon River, a major tributary of the Tennessee River.
The Shining Rock Wilderness has been designated as Class I air quality under the Clean Air Act Amendments of 1977 and recent additions to the Wilderness has increased the size to 18,483 acres.
Air Quality Related Values (AQRV)
Shining Rock is unique in the Southern Appalachians, and the entire eastern United States, in providing a feeling of open space and long distance views. In this high-elevation wilderness the visitor can view the vast sweep of land in several directions. This is a unique experience in the Appalachian Mountains. The diverse scenic landscape is an important characteristic of this area and an attribute highly valued by visitors. Most of the current wilderness was logged in the early 1900's. This was followed by extensive wildfires in 1925 and 1942 that left much of the area devoid of trees. Over the years the trees have grown back in most areas, but there are still some grass balds on the ridges. The grass balds within the wilderness are not being prescribed burned and consequently are slowly being overgrown by the surrounding forest. The landscape is comprised of rugged topography; numerous steep, cascading streams. rock outcrops and a mosaic of vegetative communities. Shining Rock, a large, white, quartz outcrop in a heath bald on a prominent peak, is an outstanding feature in this area.
As is typical of eastern forests, the wilderness visitor sees most of the area from up-close, unless they happen to be on one of the grass balds. The long-distance view from these high spots is awe-inspiring. Thousands of non-wilderness users view the wilderness from the roads surrounding the area; the Blue Ridge Parkway, US 276 and NC 215 which are part of the Forest Heritage National Scenic Byway. Shining Rock Wilderness is also viewed from the adjacent Middle Prong Wilderness.
|Natural Background Visibility|
|Site Specific Rayleigh scattering coefficient:||Clearest 20% Natural||Clearest 20% 2000-2004 Baseline||Haziest 20% Natural||Haziest 20% 2000-2004 Baseline||Average Annual Natural||Annual Average 2000-2004 Baseline|
|Standard Visual Range (km)||304||181||124||23||201||68|
|Haze Index (dv)||2.51||7.69||11.47||28.46||6.67||17.51|
Numerous high quality streams dissect the wilderness and provide habitat for native brook trout as well as enhance the recreation experience. Although there are about 2000 miles of trout streams in western North Carolina only a few sustain native brook trout populations. The streams in Shining Rock Wilderness are unique in providing habitat for these native species. The streams are cold, clean and free of siltation and pollution. These qualities plus the beauty of the fast moving water over the rocks are enjoyed by wilderness users.
The vegetation of Shining Rock Wilderness is unique in the type of plants and the mix of plant communities. Spruce-fir, heath and grassy balds cover the highest elevations. The spurce-fir plant community is the southernmost extension of this typically Canadian type. Other forests such, such as northern hardwoods (made up of yellow birch, maple and beech), cove hardwoods (which include tulip poplar, basswood, buckeye, sourwood, and maple), and upland hardwoods (such as oaks, hickory, and ash), are found at the lower elevations.
The combination of spruce-fir forests, heath and grassy balds, northern hardwoods, upland hardwoods and cove hardwoods makes Shining Rock Wilderness a special area. Blueberries are abundant in the wilderness and attract large numbers of visitors when the berries ripen. There are many unusual plants; particularly orchids, ferns and mosses, within these more northern plant communities that give the visitors the feeling of being in New England.
Resource Concern Thresholds
|AQRV Type: VISIBILITY|
|Sensitive Receptor||Sensitive Receptor Indicator||Thresholds|
|Natural Visibility||Light Extinction||In specific Class I areas to maintain consistency with Regional Haze implementation plans or BART, the visibility threshold for concern is not exceeded if the 98th percentile change in light extinction is <5% for each year modeled, when compared to the 20% best natural background values.|
|Natural Visibility||Light Extinction||For sources generally further than 50 km from a Class I area, the visibility threshold for concern is not exceeded if the 98th percentile change in light extinction is <5% for each year modeled, when compared to the annual average natural condition value for that Class I area.|
|Plume Blight||Absolute Contrast||Screening Analysis: For near field sources (within 50 km of a Class I area), no additional analysis will be requested if screening analysis of a new or modified source can demonstrate that its emissions will not cause a plume with hourly estimates of DeltaE (color difference index) greater than or equal to 2.0 or the absolute value of the contrast greater than or equal to 0.05 when modeled against natural conditions.|
|Plume Blight||Absolute Contrast||Refined Analysis: No further analysis will likely be requested if a new or modified source can show that impacts from a new or modified source will stay with the threshold of DeltaE <1.0 and |C| <0.02 modeled against natural conditions.|
|Plume Blight||Color Difference Index||Screening Analysis: For near field sources (within 50 km of a Class I area), no additional analysis will be requested If screening analysis of a new or modified source can demonstrate that its emissions will not cause a plume with hourly estimates of DeltaE (color difference index) greater than or equal to 2.0 or the absolute value of the contrast greater than or equal to 0.05 when modeled against natural conditions.|
|Plume Blight||Color Difference Index||Refined Analysis: No further analysis will likely be requested if a new or modified source can show that impacts from a new or modified source will stay with the threshold of DeltaE <1.0 and |C| <0.02 when modeled against natural conditions.|
|AQRV Type: WATER|
|Sensitive Receptor||Sensitive Receptor Indicator||Thresholds|
|Perennial Streams||Acid Neutralizing Capacity||In perennial streams, no more than 0.1 microequivalent/liter measurable decrease in acid neutralizaing capacity is acceptable|
|Perennial Streams||Chronic Acid Neutralizing Capacity||To maintain healthy biological functioning in perennial streams, the chronic acid neutralizing capacity must be >= 25 ueq/l.|
|Perennial Streams||Chronic pH||To maintain healthy biological functioning, the chronic pH of perennial streams must be >= 6.0.|
|Perennial Streams||Episodic Acid Neutralizing Capacity||To maintain healthy biological functioning in perennial streams, the episodic acid neutralizing capacity must be >= 0 ueq/l.|
|Perennial Streams||Episodic pH||To maintain healthy biological functioning, the episodic pH of perennial streams must be >= 5.5.|
|Perennial Streams||pH||In perennial streams, no more than 0.1 measurable decrease in pH is acceptable|
|Pollutant Exposure Concern Thresholds|
|Pollutant Exposures||Level Name||Thresholds|
|Nitrogen||DEPOSITION||Nitrogen deposition may be expected to cause cation leaching in soils when N levels are greater than 12 kg/ha/yr. Below 5 kg/ha/yr, negative effects to soil and vegetation are not expected|
|Nitrogen||EXCEEDANCE||The Deposition Analysis Threshold for nitrogen deposition below which estimated impacts from a source are considered negligible is 0.010. kilograms/hectare/year.|
|Ozone||W126||Biomass reduction of ozone sensitive species may occur when the W126 ozone metric (for April-September) is ≥ 14.5 ppm-hours. This should be evaluated in conjunction with the N100 value.|
|Ozone||N100||Biomass reduction of ozone sensitive species may occur when the number of hours from APRIL-SEPTEMBER with an ozone concentration greater than or equal to 0.100ppm equals or exceeds 4. This should be evaluated in conjunction with the W126 value.|
|Sulfur||DEPOSITION||Sulfur deposition may be expected to cause cation leaching and increased aluminum toxicity in soils when levels are greater than 20 kg/ha/yr. At 5 kg/ha/yr or below, sulfur negative effects to soil and vegetation are not expected.|
|Sulfur||EXCEEDANCE||The Deposition Analysis Threshold for sulfur deposition below which estimated impacts from a source are considered negligible is 0.010 kg/ha/yr.|
|Forest Service Administrative Unit(s):||Southern Region (Region 8) -- National Forests in North Carolina|
|Elevation Range:||3,180 - 6,030 feet|
|Detailed wilderness information:||https://www.wilderness.net|
|GIS Map/Official Boundary:||https://www.wilderness.net/NWPS/|