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 |
Cirque Lakes |
Acid Neutralizing Capacity |
For cirque lakes that have a baseline Acid Neutralizing Capacity of <200 ueq/l, no decrease in ANC is acceptable. |
Cirque Lakes |
Acid Neutralizing Capacity |
For cirque lakes that have a baseline Acid Neutralizing Capacity of 200-400 ueq/l, no more than a 10% decrease in ANC is acceptable. |
Cirque Lakes |
Base Cations |
No decrease in the base cations in cirque lakes is acceptable. |
Cirque Lakes |
Cation Exchange Capacity |
No decrease in the cation exchange capacity of cirque lakes is acceptable. |
Cirque Lakes |
Conductivity |
No change in the conductivity of cirque lakes is acceptable. |
Cirque Lakes |
Trace Metals |
No increase in the trace metals found in cirque lakes is acceptable. |
Cirque Lakes |
pH |
For cirque lakes that have a baseline pH of >7.0, no more than a 0.5 decrease in pH is acceptable. |
Cirque Lakes |
pH |
For cirque lakes that have a baseline pH of 6.6-7.0, no more than a 0.1 decrease in pH is acceptable. |
Cirque Lakes |
pH |
For cirque lakes that have a baseline pH of <6.6, no decrease in pH is acceptable. |
Cloud Water |
Acid Neutralizing Capacity |
For cloud water that has a baseline Acid Neutralizing Capacity of 200-400 ueq/l, no more than a 10% decrease in ANC is acceptable. |
Cloud Water |
Acid Neutralizing Capacity |
For cloud water that has a baseline Acid Neutralizing Capacity of <200 ueq/l, no decrease in ANC is acceptable. |
Cloud Water |
Base Cations |
No decrease in the base cations in cloud water is acceptable. |
Cloud Water |
Cation Exchange Capacity |
No change in the cation exchange capacity of cloud water is acceptable. |
Cloud Water |
Conductivity |
No change in the conductivity of cloud water is acceptable. |
Cloud Water |
Trace Metals |
No increase in the trace metals found in cloud water is acceptable. |
Cloud Water |
pH |
For cloud water that has a baseline pH of <6.6, no decrease in pH is acceptable. |
Cloud Water |
pH |
For cloud water that has a baseline pH of 6.6-7.0, no more than a 0.1 decrease in pH is acceptable. |
Cloud Water |
pH |
For cloud water that has a baseline pH of >7.0, no more than a 0.5 decrease in pH is acceptable. |
Headwater Systems |
Acid Neutralizing Capacity |
For headwater systems that have a baseline Acid Neutralizing Capacity of 200-400 ueq/l, no more than a 10% decrease in ANC is acceptable. |
Headwater Systems |
Acid Neutralizing Capacity |
For headwater systems that have a baseline Acid Neutralizing Capacity of <200 ueq/l, no decrease in ANC is acceptable. |
Headwater Systems |
Base Cations |
No decrease in the base cations in headwater systems is acceptable. |
Headwater Systems |
Cation Exchange Capacity |
No change in the cation exchange capacity of headwater systems is acceptable. |
Headwater Systems |
Conductivity |
No change in the conductivity of headwater systems is acceptable. |
Headwater Systems |
Trace Metals |
No increase in the trace metals found in headwater systems is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of >7.0, no more than a 0.5 decrease in pH is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of <6.6, no decrease in pH is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of 6.6-7.0, no more than a 0.1 decrease in pH is acceptable. |
Water Chemistry |
Acid Neutralizing Capacity |
For waters with a baseline Acid Neutralizing Capacity of 200-400 ueq/l, no more than a 10% decrease in ANC is acceptable. |
Water Chemistry |
Acid Neutralizing Capacity |
For waters with a baseline Acid Neutralizing Capacity of <200 ueq/l, no decrease in ANC is acceptable. |
Water Chemistry |
Base Cations |
No decrease in water chemistry base cations is acceptable. |
Water Chemistry |
Conductivity |
No change in water chemistry conductivity is acceptable. |
Water Chemistry |
pH |
For waters that have a baseline pH of <6.6, no decrease in pH is acceptable. |
Water Chemistry |
pH |
For waters that have a baseline pH of 6.6-7.0, no more than a 0.1 decrease in pH is acceptable. |
Water Chemistry |
pH |
For waters that have a baseline pH of >7.0, no more than a 0.5 decrease in pH is acceptable. |