EPA Set To Reissue Construction Stormwater Permit Sans Turbidity Limits
January 24, 2012

The reissuance of the U.S. Environmental Protection Agency’s (EPA) Construction General Permit (CGP) for stormwater discharges – due out by Feb. 15, 2012 – will not include a numeric turbidity limit or associated monitoring and reporting requirements, according to latest reports. Instead, EPA is seeking more industry data to correct an error that resulted in a faulty turbidity limit established in the 2009 “Effluent Limitation Guidelines” for the “Construction Development Industry” (C&D ELG) rule.  EPA will need many more months to gather better data, propose a correction rule for public comment and then take final action on a revised limitation.

Prior to discharging stormwater, construction operators must obtain coverage under a National Pollutant Discharge Elimination System or NPDES permit, which is administered by either EPA or the state (if it has been authorized to operate the NPDES stormwater program), depending on where the construction site is located.  Whenever EPA promulgates an ELG rule for a specific category of dischargers or pollutants, it must be included in all applicable federal and state NPDES permits.  As such, EPA plans to include in the final 2012 CGP the parts of the 2009 C&D ELG rule that list mandatory erosion and sediment controls and pollution prevention measures that must be used on every active jobsite covered by the NPDES permit program (40 CFR Part 450.21).  (These non-numeric “effluent limits” were not present in the 2008 CGP.)  On the other hand, EPA is NOT including the numeric turbidity limit of 280 nephelometric units in the final 2012 CGP permit because EPA withdrew that part of the 2009 C&D ELG rule (40 CFR Part 450.22) to correct a calculation error.

Once final, EPA’s 2012 CGP will apply in four states—Idaho, Massachusetts, New Hampshire, and New Mexico—as well as the District of Columbia, Puerto Rico, most Indian lands, and the U.S. territories. The remaining 46 states are required to incorporate the non-numeric portions to the December 2009 C&D ELG rule that remain in effect (see 40 CFR Part 450.21) into their construction permits upon the next reissuance. States will likely look to EPA’s 2012 CGP as a template.  EPA provided the following guidance to states in a recent Fact Sheet: “For states needing to finalize their CGP before the effective date of the corrected numeric limit, EPA advises them to issue their permit without the numeric limit.”

Industry continues to push EPA to extend the current federal CGP through the end of 2013 to provide the Agency with much-needed time to resolve the legal challenges currently pending against the C&D ELG rule.

EPA Requesting Additional Data on Dirt in Construction Site Runoff

EPA has indicated that it remains committed to developing a rule that would set a first-time numeric limit on how much dirt is allowed in stormwater that runs across a construction site.  EPA published a Federal Register notice on January 3 requesting additional data on the performance of technologies in controlling turbidity levels (a measure of water clarity) in construction stormwater discharges.  EPA said it will use the data and information submitted by the public to set a new (i.e., “corrected”) numeric turbidity limit for construction site runoff.

EPA emphasized that it is “especially interested in receiving data on the performance of passive and semi-passive treatment approaches” as well as data collected both before treatment and after treatment practices.  EPA also is interested in knowing the costs, effectiveness, and feasibility of different technologies to control total suspended solids, settled solids, suspended sediment and turbidity in construction site stormwater.

A passive treatment technique is one in which a polymer chemical is added to a water channel to remove sediment and turbidity, while a semi-passive technique involves the use of pumps to move the water through a channel or manifold containing the chemical where the water will be treated for sediment and turbidity removal.  The agency is seeking comment on the types of technologies because what it considered “passive technology” was successfully challenged in industry’s lawsuit as an active treatment process, resulting in a faulty turbidity limit in the 2009 effluent guidelines.

In addition, EPA requested information on other relevant topics including sample collection, applicability to electric transmission line construction, cold weather considerations, and the ability of small construction sites to meet a numeric standard. EPA will accept comments until March 5. AGC is currently reviewing the notice and plans to issue a comprehensive response.

EPA’s decision to slow down and collect more construction stormwater data bolsters AGC’s long-standing argument that a nationally applicable numeric limit is neither defensible nor practical because terrain, geography and rainfall vary significantly in most regions of the country.  So far, EPA has presented only impossible-to-meet standards and unclear monitoring and reporting requirements.

Once EPA finalizes its corrected numeric limit rulemaking, all states must incorporate the limit into their state-issued permit(s) the next time they are re-issued.  (Right now, as explained above, all permits that are re-issued must include the other non-numeric requirements of the Dec. 2009 C&D ELG – see 40 CFR Part 450.21 – that are currently in effect.) Any state that is due to re-issue any construction stormwater permit before EPA finalizes its corrected numeric limit rulemaking should issue its permit without a numeric limit.  See EPA’s Fact Sheet: Stay and Correction of the Numeric Limit for the Construction and Development ELGs (PDF).

Why is EPA revising Its 2009 Numeric Turbidity Limit?

Under court order, the Bush administration issued “Construction & Development Effluent Limitation Guidelines” (C&D ELG rule) in December 2009, setting a numeric turbidity limit of 280 nephelometric turbidity units (NTU) (74 Fed. Reg. 62995-63058).  Industry challenged the ELG rule in the U.S. Court of Appeals for the 7th Circuit, charging that the modeling data used in generating the turbidity limit is flawed – as pointed out in two separate legal petitions filed by industry and the U.S. Small Business Administration (Wisconsin Builders Association v. EPA, 7th Cir., No. 09-4113, 8/24/10).  After EPA re-examined the data underlying its prior turbidity limit, it conceded it had “improperly interpreted the data” and the calculations supporting the 280-NTU effluent limit were no longer adequate.  This prompted EPA to seek a court order to revisit the NTU number.  EPA asked the court to hold the case in abeyance so it can address “a flaw in the rule.” Effective January 4, 2011, the EPA stayed implementation of the ELG pending correction of a calculation error (76 Fed. Reg. 22886, April 25, 2011).

Subsequently, the EPA submitted a proposed revision of the turbidity limit to the Office of Management and Budget (OMB) but withdrew the proposal and decided to seek additional treatment performance data from construction sites before proposing a revised numeric ELG.  EPA published a notice on January 3 requesting additional data on the performance of technologies in controlling turbidity levels (a measure of water clarity) in construction stormwater discharges (77 Fed. Reg. 112).  

For more information, contact Leah Pilconis at pilconisl@agc.org or see AGC’s environmental news page at http://news.agc.org/topics/environment. For technical questions, contact Jesse Pritts in EPA’s Office of Water’s Engineering and Analysis Division at (202) 566-1038 or at pritts.jesse@epa.gov or visit EPA’s website.