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Cabinet Mountains Wilderness


General Information

Image of Cabinet Mountains Wilderness

State(s): Montana

County(s): Lincoln, Sanders

Forest Service Administrative Unit(s):
Northern Region (Region 1)

Size: 94272 acres

Elevation Range: 3,000 - 8,738 feet

Image(s): http://www.wilderness.net/images/

Detailed wilderness information: http://www.wilderness.net

GIS Map/Official Boundary: http://www.wilderness.net/NWPS/

Webcam(s): Cabinet Mountains (Gallery)

Data:

Contacts

Documents

Resource Concern Thresholds

AQRV Type: VISIBILITY
Sensitive Receptor Sensitive Receptor Indicator Thresholds
Natural Visibilty 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 %ile change in light extinction is <5% for each year modeled, when compared to the 20% best natural background values.
Natural Visibilty 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 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 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 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.

AQRV Type: WATER
Sensitive Receptor Sensitive Receptor Indicator Thresholds
Water Chemistry Acid Neutralizing Capacity For waters that have a baseline Acid Neutralizing Capacity of <10 ueq/l, no change from the baseline condition is acceptable.
Water Chemistry Acid Neutralizing Capacity For waters that have a baseline Acid Neutralizing Capacity of 100-10 ueq/l, the limit of acceptable change is a cumulative change of no more than 10% from the baseline condition.
Water Chemistry Aluminum Water chemistry aluminum concentrations should not be elevated to > 50 ug/l.
Water Chemistry Anions For waters that have a baseline Acid Neutralizing Capacity of 10-100 ueq/l, the cumulative change in anions should be no more than 10% of the baseline concentration of total base cations and SO4+NO2 should not be elevated to >10% of total base cations in lakes with naturally low anion:cation ratios.
Water Chemistry Water Clarity For water clarity, the cumulative change should be no more than a 10% decrease from baseline.
Water Chemistry pH For waters with a pH baseline of < 6.0, no decrease in pH is acceptable.
Water Chemistry pH For waters with a pH baseline of 6.0-7.0, no more than a 10% change from baseline is acceptable.
Pollutant Exposure Concern Thresholds
Pollutant Exposures Level Name Thresholds
Nitrogen 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.
Q (Sum of SO2+NOx+PM10+H2SO4) 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, 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.
Sulfur EXCEEDANCE The Deposition Analysis Threshold for sulfur deposition is 0.005 kg/ha/yr. Below this, estimated impacts from a source greater than 50km from a FLM Class I Area are considered negligible.
CHANGE 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.
EXCEEDANCE 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.
CHANGE 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.
CHANGE 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.
EXTINCTION 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.
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 %ile change in light extinction is <5% for each year modeled, when compared to the 20% best natural background values.

Natural Background Visibility

Site Specific Rayleigh scattering coefficient: 10 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) 337 272 184 96 259 167
Haze Index (dv) 1.48 3.62 7.52 14.09 4.11 8.5
For more information on these numbers, click here.