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General Information
State(s): Alabama
County(s): Lawrence, Winston
Forest Service Administrative Unit(s):
Southern Region (Region 8) -- National Forests in Alabama
Size: 24922 acres
Elevation Range: 580 - 1,001 feet
Data:
Documents
Resource Concern Thresholds
| AQRV Type: VISIBILITY |
| Sensitive Receptor |
Sensitive Receptor Indicator |
Thresholds |
| Natural Visibilty |
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For sources generally further than 50 km from a Class I area, the visibility threshold for concern is not exceeded if the 98th %ile 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 |
Higher level near-field screening and 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 |
Absolute Contrast |
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 |
Plume blight near-field 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. |
| Plume Blight |
Color Difference Index |
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. |
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| AQRV Type: WATER |
| Sensitive Receptor |
Sensitive Receptor Indicator |
Thresholds |
| Perennial Streams |
Acid Neutralizing Capacity |
In perennial streams, no more than .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 .01 measurable decrease in pH is acceptable |
Pollutant Exposure Concern Thresholds
| Pollutant Exposures |
Level Name |
Thresholds |
| N |
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 |
| N |
EXCEEDANCE |
The Deposition Analysis Threshold for nitrogen deposition is 0.010 kg/ha/yr. Below this, estimated impacts from a source greater than 50km from a FLM Class I Area are considered negligible. |
| O3 |
N100 METRIC |
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. |
| O3 |
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. |
| Q |
QOverD |
For new or modified sources locating greater than 50 km from a Class I area, its impacts will be considered negligible with respect to Class I AQRVs if its total SO2, NOx, PM25, PM10, and H2SO4 annual emissions in tons/yr, based on 24-hr maximum allowable emissions, divided by the distance (km ) from the Class I area (Q/D) is 10 or less. For sources operating less than a year, the emissions must be adjusted to reflect what the emissions would be if the source operated year-round. |
| S |
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. |
| S |
EXCEEDANCE |
The Deposition Analysis Threshold for sulfur deposition is 0.01 kg/ha/yr. Below this, estimated impacts from a source greater than 50km from a FLM Class I Area are considered negligible. |
Natural Background Visibility
| Site Specific Rayleigh scattering coefficient: 11 |
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) |
252 |
84 |
135 |
22 |
188 |
44 |
| Haze Index (dv) |
5.02 |
15.57 |
10.99 |
29.03 |
7.79 |
21.96 |
| For more information on these numbers, click here. |
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