In a set of final amendments to 40 CFR Part 450, the EPA has formally removed the numeric turbidity effluent limit from its effluent limitations guidelines (ELG) for the construction and development (C&D) point source category.  The amendments also include a new key definition and changes to certain nonnumeric provisions. 

The numeric limit, which was included in the Agency’s 2009 ELGs for the C&D category, was promptly challenged by industry groups and the U.S. Small Business Administration, which argued that the Agency grossly underestimated the cost of meeting the limit.  The EPA eventually conceded that it had misinterpreted data it had obtained from technology vendors.  Specifically, the Agency stated in the rule that the limit could be achieved with a passive technology that would result in costs of about $1,500 per acre; but in fact the limit the Agency had set was the result of an advanced active technology that industry claimed would cost closer to $11,000 per acre. 

Industry initiated litigation, but the EPA decided to stay the requirement and, in December 2012, agreed with the petitioners to start a rulemaking that would remove the numeric limit and amend other provisions.

‘Not technologically possible’

In addition to excising the numeric effluent limit and its monitoring requirement (40 CFR 450.22(a) and (b)), the current amendments effect the following:

• Add 450.11(b) to define infeasible as “not technologically possible, or not economically practicable and achievable in light of best industry practices.”  No definition was included in the 2009 rule.  The EPA recognized this as a regulatory gap since many of the non-numeric requirements in the C&D rule are mandatory “unless infeasible.”
• Revise 450.21(a)(1) to require control of stormwater volume and velocity to minimize soil erosion and pollutant discharges.
• Revise 450.21(a)(2) to require control of stormwater discharges, including both peak flows and total stormwater volume, to minimize channel and stream bank erosion and scour in the immediate vicinity of discharge points.
• Revise 450.21(a)(6) to require provision and maintenance of natural buffers around waters of the United States and direct stormwater to vegetated areas and maximize stormwater infiltration to reduce pollutant discharges, unless infeasible.
• Revise 450.21(a)(7) to minimize soil compaction.  Minimizing soil compaction is not required where the intended function of a specific area of the site dictates that it be compacted.
• Revise 450.21(b) to require that stabilization of soil in disturbed areas be initiated immediately whenever any clearing, grading, excavating, or other earth-disturbing activities have permanently ceased on any portion of the site, or temporarily ceased on any portion of the site and will not resume for a period exceeding 14 calendar days.  In lieu of vegetative stabilization, the permitting authority may allow alternative stabilization measures in arid or drought-stricken areas.  In limited circumstances, stabilization may not be required if the intended function of a specific area of the site necessitates that it remain disturbed.
• Revise 450.21(d)(2) to require minimization of exposure of building materials, building products, construction wastes, trash, landscape materials, fertilizers, pesticides, herbicides, detergents, sanitary waste, and other materials present on the site to precipitation and stormwater.
• Add 450.21(a)(8) to require preservation of topsoil, unless infeasible.  Preserving topsoil is not required where the intended function of a specific area of the site dictates that the topsoil be disturbed or removed.

Data requested

Regarding the numeric limit on turbidity, the EPA adds that it has not dismissed the idea of instituting such a requirement in the future and encourages interested parties to continue submitting data and information with respect to numeric discharge standards at C&D sites.

EPA’s amendments to the ELGs for the C&D point source category were published in the March 6, 2014, FR.