EPA Publishes Enforceable Numeric Limits on Stormwater Discharges from Construction Sites
On December 1, 2009, the United States Environmental Protection Agency ("EPA") published new requirements for the discharge of stormwater from construction sites. See 70 Fed. Reg. 62995 (Dec. 1, 2009). These requirements, labeled Construction and Development Effluent Limitation Guidelines ("C&D ELG"), are significant because they impose for the first time numeric limits on stormwater discharged from construction sites.
What Are the New Limits? - Prior to the adoption of these regulations, National Pollution Discharge Elimination System ("NPDES") permits issued for the discharge of stormwater from construction sites generally only contained non-numeric, performance-based effluent limitations in the form of properly installed and maintained best management practices ("BMPs"). In the new regulations, EPA set a maximum daily average numeric limit of 280 NTU (a turbidity measurement) for covered construction sites nationwide. The numeric limit set forth in the C&D ELG is not applicable on days when the construction site receives rainfall in excess of a two year, 24 hour storm. EPA also required a series of mandatory BMPs to control stormwater from construction sites.
How Are Permittees Affected?- The imposition of this C&D ELG means that construction-related NPDES permittees, in addition to maintaining stormwater BMPs, will be required to (a) monitor their stormwater discharges for turbidity, (b) report the results of the monitoring, and (c) use the appropriate control technologies to ensure that their stormwater discharges do not exceed the numeric standard of 280 NTU. EPA's new rule also allows delegated states to set their own requirements for sampling discharges, although EPA intends to issue guidance on this topic shortly.
The C&D ELG sets forth a phase-in schedule for the turbidity limitation as follows: for construction sites with 20 acres or more of earth disturbance in existence at one time, the C&D ELG is effective on August 2, 2011; for construction sites with ten acres or more of earth disturbance in existence at one time, the C&D ELG is effective on February 2, 2014. EPA's notice states that when the earth disturbance at a construction site goes below the minimum acreage, the C&D ELG is no longer applicable; if the site should subsequently exceed the minimum acreage, the C&D ELG would again be applicable.
How Does This Affect State-Delegated Programs? - Since NPDES permitting authority has generally been delegated to the states, EPA's notice states that "the implementation date of the new requirements will vary depending on when the [delegated] states reissue their permits." For those states which have not been delegated NPDES permitting authority for stormwater discharges from construction sites (e.g. Idaho, Massachusetts, New Hampshire and New Mexico, along with certain tribal lands and federal facilities in other states), EPA states that it will be revising the federal Construction General Permit on or before its current expiration date of June 30, 2011 to include the C&D ELG.
In states delegated NPDES permitting authority for stormwater discharges from construction sites, it will be up to each state to incorporate the C&D ELG into its permitting program. Therefore, the incorporation of the C&D ELG into state-issued General Permits may not be uniformly timed across the country.
For example, the Pennsylvania Department of Environmental Protection ("PADEP") recently reissued its NPDES General Permit for Stormwater Discharges Associated with Construction Activities ("PAG-02"). In its notice of reissuance, PADEP acknowledged that EPA recommended that PAG-02 be renewed for only two years, which it was, rather than for five years, to allow for more timely incorporation of the C&D ELG into the next reissuance of PAG-02. Changes to New Jersey's general permit for the discharge of stormwater from construction sites will similarly be considered prior to the expiration of New Jersey's general permit in February 2012. In contrast, the Maryland Department of the Environment agreed in settlement of an environmental group's lawsuit to reopen Maryland's general permit for discharges of stormwater from construction activities to "add provisions consistent" with EPA's C&D ELG within three months of EPA's "final adoption" of the C&D ELG.
What Else Is EPA Doing? - Of looming significance, EPA also announced that it is developing minimum national standards for effluent limitation guidelines to be imposed on development sites post-construction. EPA stated its intention to announce these post-construction ELGs by November 2012.
The feasibility of meeting the 280 NTU limit set forth in the C&D ELG has been questioned by commentors on the proposed rule, and the imposition of any numeric limit represents a radical new environmental permitting requirement for the construction and development industry. For these reasons, it is possible that the C&D ELG will be the subject of legal challenges.