Authored by Daniel Lee

On March 6, 2014, EPA revised its Clean Water Act regulations for construction projects that are required to obtain NPDES permits for discharges of stormwater and other wastewater. The revised regulations clarify required management practices and provide some additional flexibility for implementing them. The revisions include three elements.

First, the rule provides a definition for “infeasible” that further clarifies when construction permittees will be exempted from implementing certain erosion controls. Under the revised regulation, “infeasible” is defined as “not technologically possible, or not economically practicable and achievable in light of best industry practices." 40 CFR 450.11(b).

Second, the rule repeals the controversial monitoring requirements and numeric discharge limits for turbidity, which EPA adopted in 2009 and then “stayed indefinitely” in 2010 in response to a federal court challenge. EPA explained that it repealed the numeric limits because it was concerned that they might create disincentives for managing stormwater through green infrastructure techniques and because additional data would be needed to support specific numeric limits. The rule leaves open the possibility of future numeric limits, but, given the controversy that the limits generated, EPA is not likely to begin developing such limits anytime soon.

Finally, EPA revised and clarified several required management practices. The most substantive changes focus on when soil compaction, soil stabilization, and minimization of exposure is not required. Although the rule retains the basic requirements related to compaction, stabilization, and exposure, it creates an exemption for each category:

  1. Permittees will not be required to minimize soil compaction “where the intended function of a specific area of the site dictates that it be compacted.” 40 CFR 450.21(a)(7).
  2. Permittees “may not” be required to stabilize disturbed areas in “limited circumstances . . . if the intended function of a specific area of the site necessitates that it remain disturbed.” 40 CFR 450.21(b).
  3. Permittees will not be required to minimize exposure of various construction materials “in cases where the exposure to precipitation and to stormwater will not result in a discharge of pollutants, or where exposure of a specific material or product poses little risk of stormwater contamination (such as final products and materials intended for outdoor use).” 40 CFR 450.21(d)(2).

The changes give significant flexibility to local permitting authorities to address site-specific circumstances where a given type of erosion mitigation may be infeasible.