Friday, December 21, 2012

Antidegradation Requirements and Impaired Waters Requirements Under Draft MDA Storm Water Permit

Maryland Department of the Environment (MDA) is issuing a draft General Permit Number 12-SW of stormwater discharges from industrial facilities. MDA has chosen to base the state’s permit on the EPA’s Multi-Sector General Permit (MSGP). The final permit is expected to be issued in early 2013.

Read a summary of the key changes to the Maryland General Permit.

Information about Maryland General Permit SWPPP Template and Compliance Plan

The draft permit contains new, specific WQBEL requirements applicable to impaired waters and antidegradation policies:

  • Discharges to Impaired Waters – The permit contains requirements for new and existing discharges to impaired waters with or without EPA approved or established TMDLs. New dischargers are only eligible for discharge authorization if they demonstrate that there is either no exposure of stormwater to the pollutant for which the water is impaired, or the impairment pollutant is not present at the facility, or that the discharge is not expected to cause or contribute to a water quality standards exceedance. For existing discharges to impaired waters with State approved or established TMDLs, MDA will determine if more stringent requirements are necessary to ensure that the permittee is discharging consistent with the TMDL and applicable WLA.
  • Antidegradation Requirements – MDA has clarified its expectation of operators to meet antidegradation requirements as part of the permit authorization process as well as to comply with permit provisions after authorization to discharge is received. If an NOI indicates that an operator is seeking coverage for a new discharge to a Tier 2 water, MDA will determine if additional requirements are necessary to be consistent with the applicable antidegradation requirements, or if alternatively, an individual permit application is necessary. New dischargers are no longer eligible for coverage under this permit for discharges to waters designated as Tier 3 for antidegradation purposes.

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