Editor’s note: On paper, you’ve got plenty of time to prepare for U.S. EPA’s new stormwater program. Municipal separate stormwater systems (MS4s) will be phased in when their next five-year permit term begins. If the permit renews in 2015 you’ve got two more years to come up with a plan; if it renews in 2014, seven. And when the permit does renew, rules will be phased in year by year.

But. The legal, financial, and operational changes necessary to implement a compliance program are extremely time-consuming. Launching a stormwater utility, for example, takes an average of five years.

Given the task (or tasks) ahead, now’s the time to begin preparing.

The first in a yearlong series on what the agency’s promulgating, this article explains how the most dramatic proposed changes came to be.

Proposed National Rulemaking to Strengthen the Stormwater Program
Proposed permit: June 10, 2013
Final permit: Dec. 10, 2014

Next month: Designating maintenance yards as industrial sources

Expanding the national stormwater program is extremely difficult because the costs and benefits of both the existing and proposed requirements aren’t easily determined. Not all pollutants — everything from fast food wrappers and animal waste to toxic metals and hazardous waste — are mobilized by rain. Treating runoff near its source is usually the best approach, but it’s expensive and often requires additional land.

For all these reasons, U.S. EPA delayed the Proposed National Rulemaking to Strengthen the Stormwater Program several times since 2009 as stakeholders provided additional input on how to achieve this extremely difficult goal. But finally, over the next two years, the agency’s forging ahead with a program that’s more rigorous than the existing one.

EPA breaks stormwater discharge into three categories: construction activities, industrial activities, and two types of MS4s (municipal separate stormwater systems):

  • Large and medium, which consist of entities with 100,000 or more population and are called Phase I MS4s, were regulated in the early 1990s following the Water Quality Act of 1987.
  • Regulations for Phase II MS4s, those under 100,000 in population, were issued in 1999 and states and EPA regions subsequently developed general permits.

Phase I permits are individually written and include a monitoring requirement; Phase II are general permits that do not include monitoring. Needless to say, issuing a general permit for an extremely localized problem doesn’t make much sense. While EPA and state regulators have tried to allow for uniqueness, that would require analyzing each permittee’s problems and solutions as well as their benefits and costs.

National Research Council Report

Recognizing the problems inherent in issuing meaningful permits, the agency in 2006 asked the National Research Council of the National Academies to look into the issue. The resulting 598-page report recommends:

  • Converting the current piecemeal system into a watershed-based permitting system
  • Using an urban stream classification system, such as a regionally adapted version of the impervious cover model, to establish realistic water quality and biodiversity goals for individual classes of subwatersheds
  • Having permittees better monitor runoff to determine what outcomes are needed
  • Integrating construction and industrial site permits under their associated MS4’s jurisdiction
  • Issuing guidance for MS4, MSGP (multisector industrial stormwater general permit), and CGP (construction general permit) permittees on what constitutes a design storm for water quality purposes
  • Issuing guidance on methods for identifying high-risk industrial facilities for program prioritization such as inspections
  • Compiling a national database of both industrial and stormwater control measure effluent quality
  • Developing numerical expressions for maximum extent practicable (MEP).

The report is a scientific review of the issues and problems associated with improving stormwater quality. But it lacks an understanding of the average permittee’s perspective and resources.

In particular, the Clean Water Act includes the caveat that each permittee implement its stormwater program to MEP. But as Urban Stormwater Management in the United States points out, EPA hasn’t provided adequate guidance for defining, measuring, and tracking programs relative to that requirement.

The report also acknowledges that one of its recommendations for defining MEP with numerical expressions — monitoring — is expensive and thus impossible for many permittees: “The challenge of defining MEP as a runoff reduction or pollutant load limit is that considerable scientific and engineering analysis is needed to establish the performance standards, evaluate stormwater control measure (SCM) capability to meet them, and devise a workable computational approach that links them together at both the site and watershed levels.”

Establishing MEP this way may be possible for a large permittee with a real need to do so, but is way beyond the resources of most permittees. Thus, work needs to be done to determine how to make the determination process more practical and achievable for the average permittee.

This is where you come in.