Wednesday, September 8, 2010

CT DEP Revised Industrial Stormwater General Permit

The Connecticut Department of Environmental Protection (DEP) has revised the requirements for management of storm water runoff from industrial sites under its General Permit program.
The revised industrial storm water General Permit is scheduled to go into effect Oct. 1, 2011. DEP is in the process of reissuing the existing General Permit so that it will remain in effect until that date. Industrial facilities will automatically remain registered under the existing General Permit once it is reissued. All industrial facilities are required to register for the revised permit by June 1, 2011. To provide compliance assistance to permittees, DEP will conduct outreach on new permit requirements in the fall of 2010.

The most significant new requirements of the General Permit for management of storm water at industrial sites include:

Industrial Sectors
The provisions of the General Permit apply to all sites, however there are additional sector-specific requirements for monitoring and stormwater controls that apply to specific types of industries. The sectors are:

  • asphalt plants;
  • non-metallic mines and quarries;
  • refuse systems;
  • auto salvage yards;
  • scrap recycling facilities;
  • steam electric power facilities;
  • transportation and public works facilities;
  • marinas and yacht clubs and boat dealers;
  • ship and boat building and repair;
  • small scale composting facilities.
The revised permit requires all permittees to conduct visual monitoring of storm water discharges on a quarterly basis and sampling and testing of storm water for 10 parameters on a semi-annual basis. In addition to these standard requirements, some industry sectors have additional parameters that are specific to the industry type, which must be also sampled.

Note: Since the 1980s, the U.S. Environmental Protection Agency (EPA) has collected industry-sector data on stormwater discharge. The linked presentation provides a comparison of these historic industrial stormwater results to the many of the ADEQ stormwater benchmark concentrations. The results are discussed in context of which stormwater benchmark parameters have a higher potential for exceedance of benchmark values. This presentation also discusses which of the industrial sectors have a higher potential for exceedance of their specific benchmark values.

Note: CT uses the same benchmark concentrations used by EPA and many other States; although the this linked presentation was specific to Minnesota, the analysis and conclusions apply to CT.

Link to presentation slides:

Industrial Stormwater Benchmarks – Comparison of New Minnesota Benchmark Concentrations To Historic Industry-specific Testing Results

Impaired waters
The revised permit includes specific requirements for discharges to impaired waters. For existing discharges, a permittee will monitor annually for the pollutant(s) associated with the water impairment. In certain cases, a permittee will have to install additional site controls to improve storm water quality so that the impaired water quality can be improved. New discharges to impaired water will be authorized if the storm water discharge does not contain the pollutant(s) of concern, or if the site prevents the exposure of the pollutant(s) of concern to storm water. However, if the pollutant(s) are present onsite and exposed to storm water, the registrant must demonstrate that the discharge meets requirements in place to meet water quality before the discharge can occur.

Public Notice
The General Permit expands opportunities for public comment and access to information about pending registrations. Pollution Prevention Plans can also be reviewed, with the exception of elements that are trade secrets or otherwise exempt from the disclosure requirements of the state Freedom of Information Act. Notice of pending registrations and the availability of Pollution Prevention Plans for a site will be posted on the DEP website for public review and comment.

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

For further information contact Caltha LLP at or Caltha LLP Website

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