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 |
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 |
Acid Neutralizing Capacity |
For headwater systems that have a baseline Acid Neutralizing Capacity of >400 ueq/l, no more than a 15% decrease in ANC is acceptable. |
Headwater Systems |
Base Cations |
For headwater systems that are in violation of state water quality standards for base cations, no decrease in base cations is acceptable. |
Headwater Systems |
Base Cations |
For headwater systems that are in compliance with state water quality standards for base cations, a base cation decrease of > 0.25 deviations is unacceptable. |
Headwater Systems |
Metal Concentration (Cu, Pb, As, Se, Zn, Ni) |
For headwater systems that are in violation of state water quality standards for metal concentration (Pb, Zn, Hg, As, Cd, Se, Cu), no increase in metal concentrations is acceptable. |
Headwater Systems |
Metal Concentration (Cu, Pb, As, Se, Zn, Ni) |
For headwater systems that are in compliance with state water quality standards for metal concentration (Pb, Zn, Hg, As, Cd, Se, Cu), a metal concentration increase of >0.25 deviations is unacceptable. |
Headwater Systems |
Nitrate |
For headwater systems that are in compliance with state water quality standards for nitrate levels, a nitrate increase of >0.25 deviations is unacceptable. |
Headwater Systems |
Nitrate |
For headwater systems that are in violation of state water quality standards for nitrate levels, no increase in nitrates is acceptable. |
Headwater Systems |
Total Dissolved Nitrogen |
For headwater systems that are nitrogen-limited or co-limited, no increase in total dissolved nitrogen is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of >7.0, no more than a 0.3 decrease in pH is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of 6.5-7.0, no more than a 0.1 decrease in pH is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of >7.0, a pH no lower than 6.7 is acceptable. |
Headwater Systems |
pH |
For headwater systems that have a baseline pH of 6.5-7.0, a pH no lower than 6.5 is acceptable. |
Temporary Waters |
Acid Neutralizing Capacity |
For temporary waters that have a baseline Acid Neutralizing Capacity of >400 ueq/l, no more than a 15% decrease in ANC is acceptable. |
Temporary Waters |
Acid Neutralizing Capacity |
For temporary waters that have a baseline Acid Neutralizing Capacity of <200 ueq/l, no decrease in ANC is acceptable. |
Temporary Waters |
Acid Neutralizing Capacity |
For temporary waters that have a baseline Acid Neutralizing Capacity of 200-400 ueq/l, no more than a 10% decrease in ANC is acceptable. |
Temporary Waters |
Base Cations |
For temporary waters that are in violation of state water quality standards for base cations, no decrease in base cations is acceptable. |
Temporary Waters |
Base Cations |
For temporary waters that are in compliance with state water quality standards for base cations, a base cation decrease of >0.25 deviations is unacceptable. |
Temporary Waters |
Metal Concentration (Cu, Pb, As, Se, Zn, Ni) |
For temporary waters that are in compliance with state water quality standards for metal concentration (Pb, Zn, Hg, As, Cd, Se, Cu), a metal concentration increase of >0.25 deviations is unacceptable. |
Temporary Waters |
Metal Concentration (Cu, Pb, As, Se, Zn, Ni) |
For temporary waters that are in violation of state water quality standards for metal concentration (Pb, Zn, Hg, As, Cd, Se, Cu), no increase in metal concentrations is acceptable. |
Temporary Waters |
Nitrate |
For temporary waters that are in compliance with state water quality standards for nitrate levels, a nitrate increase of > 0.25 deviations is unacceptable. |
Temporary Waters |
Nitrate |
For temporary waters that are in violation of state water quality standards for nitrate levels, no increase in nitrates is acceptable. |
Temporary Waters |
Total Dissolved Nitrogen |
For temporary waters that are nitrogen-limited or co-limited, no increase in total dissolved nitrogen is acceptable. |
Temporary Waters |
pH |
For temporary waters that have a baseline pH of >7.0, no more than a 0.3 decrease in pH is acceptable. |
Temporary Waters |
pH |
For temporary waters that have a baseline pH of >7.0, a pH no lower than 6.7 is acceptable. |
Temporary Waters |
pH |
For temporary waters that have a baseline pH of 6.5-7.0, a pH no lower than 6.5 is acceptable. |
Temporary Waters |
pH |
For temporary waters that have a baseline pH of 6.5-7.0, no more than a 0.1 decrease in pH is acceptable. |