On November 23, 2009, the U.S. Environmental Protection Agency (“EPA”) issued a final rule establishing monitoring requirements and a numeric discharge limitation for stormwater discharges from construction sites that disturb 10 or more acres. The final rule, which was published in the December 1, 2009 Federal Register (74 Fed. Reg. 62995), also codifies the existing permit requirement that owners and operators of construction sites larger than one acre must implement a range of erosion and sediment control best management practices (“BMPs”) to reduce pollutants in stormwater, discharges.

The BMPs must be designed, installed and maintained to control stormwater flow and velocity within the site to minimize soil erosion, minimize the amount of soil exposed during construction activity, etc.

The final rule establishes effluent limitations guidelines (“ELGs”) and new source performance standards (“NSPS”) for stormwater discharges from construction arid development sites (to be codified at 40 C.F.R. Part 450). Note that the monitoring requirements and numeric limitation will only apply to construction activity that disturbs 10 or more acres of land area at one time arid, as noted below, these new requirements will be phased in over four (4) years. Please also note that discharges associated with interstate natural gas pipeline construction activity are specifically excluded from the monitoring requirements arid numeric limitation.

The EPA has selected turbidity as the parameter to be monitored to demonstrate that construction stormwater discharges do not adversely impact surface water quality. The final rule specifies a highest allowable daily discharge of turbidity of 280 nephelometric turbidity units (“NTILTs”). The numeric limitation does not apply to stormwater discharges that occur in any day as a result of a storm event in that same day that is larger than the local 2-year, 24-hour storm.

The final standard of 280 NTU’s is significantly less stringent than EPA’s proposed standard of 13 NTUs, which would have required the use of active treatment systems such as polymer-assisted clarification followed by filtration. In the final rule’s preamble discussion, the EPA opines that the 280 NTU standard should be achievable using passive treatment technologies such as conventional erosion arid sedimentation controls, polymer addition to sediment basins, and fiber check darns with polymer addition. The EPA notes, however, that the new rule is a floor and that state and local governments can impose more stringent requirements on stormwater discharges from construction activities.

The monitoring requirements for each construction and development project will be specified on a case-by-case basis in the construction stormwater permits issued for those projects by the federal or state permitting authorities (depending upon whether the state is authorized to issue NPDES stormwater permits).

In recognition of the fact that the numeric limitation represents a significant change for regulation of stormwater discharges from construction activity, the EPA is phasing in the numeric limitation over four (4) years to allow the permitting authorities time to develop monitoring requirements and to allow tire regulated community time to prepare for compliance with the numeric limitation.

Monitoring of discharges and compliance with the numeric limitation will be required beginning on August 2, 2011 for construction activity that disturbs 20 or more acres of land at one time, including non-contiguous land disturbances that take place at the same time arid are part of a larger common plan of development or sale, and by February 2, 2014 for construction activity that disturbs 10 or more acres of land at one time, including non-contiguous land disturbances that take place at tire same time and are part of a larger common plan of development or sale.

Even with the 10-acre threshold for applicability, the EPA estimates that tire numeric effluent limitation arid monitoring requirements will apply to 73 percent of constructed acres annually. Therefore, most contractors and developers should begin to plan now and develop strategies for compliance with the new requirements.

The EPA has not completed the promulgation of rules to limit or control stormwater discharges from construction activities. In that regard, the EPA notes that many states and municipalities are moving in the direction of requiring stormwater discharges from newly developed or redeveloped sites to mimic the hydrology that would have occurred on the site prior to the site being developed.

On October 30, 2009, the EPA initiated another rulemaking proceeding by publishing for public comment a Draft Information Collection Request (“ICR”) (74 Fed. Reg. 56191) seeking information and data to support the rulemaking. Under the ICR, questionnaires will be sent to developers, municipal separate storm sewer systems (“MS4s”) and state governments in order to gather data to assess current practices and regulatory mechanisms; the effectiveness and feasibility of various control technologies, BMPs, and pollution prevention opportunities and their associated potential pollutant reductions and costs; and the possible financial impacts associated with implementing regulations for stormwater discharges in developed and developing areas. The EPA has set a target of November 2012 for the promulgation of a new final rule regulating stormwater discharges.

This information was provided by Joseph R. Brendel, Esq. of Thorp Reed & Armstrong, LLP who can be reached at 412-394-2373 or jbrendel@thorpreed.com for more specific information. It is important to remember that this information is a brief summary of the Law. It constitutes general information on certain provisions of the Law and is not to be read or interpreted as legal advice or an opinion relative to any particular circumstance.