Three years after including a numeric turbidity effluent limit in its effluent limitation guidelines (ELGs) for the construction and development (C&D) point source category, the EPA signed a settlement in which it agreed to write a formal proposal to withdraw the requirement.  The settlement agreement was reached with three petitioners–the Utility Water Act Group, Wisconsin Builders Association, and National Association of Home Builders–that alleged that the Agency’s final limit of 280 nephelometric turbidity units (NTUs) was based on flawed interpretation of data.

Previously, the EPA agreed with the petitioners and placed a stay on the numeric requirement; the Agency has now agreed to move to eliminate it altogether.  The agreement includes seven other changes to nonnumeric best management practices (BMPs) included in the final C&D ELGs.

Passive/nonpassive technologies

In its December 2009 rulemaking, the EPA claimed that its 280 NTU ELG limit was based on a passive technology that would result in a compliance cost of about $1,500 per acre in C&D projects.  An NTU indicates lack of clarity in water as measured by an electronic instrument called a nephelometer.  The petitioners countered that the Agency’s numeric limit and the associated cost were in fact based on an advanced active technology that would cost regulated entities about $11,000 per acre to implement and up to $10 billion nationwide for all regulated entities.  The petitioners noted that if the EPA had based its limit on passive technologies, as the Agency claimed it had, the final limit would be in the neighborhood of 800 NTUs.  The EPA ultimately conceded that its rulemaking misinterpreted data developed by vendors of treatment technologies.

Under the agreement, the EPA will propose to eliminate the NTU limit by April 2013 and take final action on that proposal by February 28, 2014. 

Clarified BMPs

In addition to withdrawing the NTU limit, the Agency committed to amending the language in several BMP requirements.  For example, instead of requiring that erosion be controlled downstream of stormwater discharges, the Agency will propose to require the minimization of channel and streambank erosion in the immediate vicinity of discharge points.  Other existing BMPs that generally prohibit soil compaction and require soil stabilization will be changed in the proposal to allow compaction and to not require stabilization under “limited circumstances” when site conditions dictate. 

“This settlement is a win for the environment and for the recovering economy,” said Wisconsin Builders Association Executive Vice President Jerry Deschane.  “The proposed numeric limits were a ‘one-size-fits-nowhere’ approach that would have cost a fortune to implement and would not have improved water quality.  Commonsense best management practices and understandable regulations are the best path to achieving the goals of the Clean Water Act and maintaining housing affordability.”

Click here for EPA’s agreement with the petitioners.