Navigating the Background Off-Ramp on the Industrial General Permit Highway
The new Industrial General Permit (IGP) allows dischargers to demonstrate that a Numeric Action Level (NAL) exceedance is attributed to the presence of a pollutant in the natural background that has not been disturbed by industrial activities. Although, the Natural Background Pollutant Source Demonstration Report can be submitted at any time, most dischargers who pursue the Background Demonstration Report option will likely submit a report after reaching Level 2 Status, which could occur in the 2017-2018 reporting year. However, IGP dischargers should be anticipating their exceedance response action loops now as they collect new water quality monitoring data and contemplate future compliance risks under the new IGP. Not only will NALs apply, but also potentially Total Maximum Daily Load (TMDL) Water Quality Based Effluent Limitations (WQBELs) when they get incorporated into the IGP.
Level 2 Status dischargers that cannot demonstrate their NAL exceedances are due to natural background conditions or due to non-industrial pollutant sources, due to a lack of data will be required to submit an Industrial Activity Best Management Practices (BMPs) Demonstration Report, evaluating additional BMP options, including physical, structural, or mechanical devices to minimize contact of pollutants with storm water. The cost of structural and treatment control BMPs is potentially high, especially for facilities requiring retrofitting. The theme of this year’s conference “Stormwater – Are We Making a Difference?” is especially relevant to this topic. Treating NAL exceedances that are due to natural background conditions is not money well spent and does not result in an improvement of overall water quality. Although Background Demonstration Reports will be challenging, this permit-allowed pathway provides an opportunity to avoid unnecessary BMP expenditures to treat naturally occurring constituents. This presentation will identify available background monitoring datasets relative to IGP NALs and example TMDL WQBELs, identify IGP constituents where background demonstration may be feasible, and report typical “background” concentrations ranges for these constituents, and discuss monitoring strategies to collect data to support a Background Demonstration Report. A hypothetical timeline for background demonstration report submittal will also be discussed.