EPA has issued its final rule on effluent discharges for construction and development. This page has links to the rule, a brief fact sheet, and some background on its development.
The bottom line: There are still no numeric turbidity limits.
As you might remember if you’ve been following the ins and outs of the rule over the last few years, it has been a long, contentious road to get to this point. EPA first developed effluent guidelines for the construction and development industry in 2000, but withdrew its proposed guidelines in 2004. There followed lawsuits from environmental organizations and states for failing to promulgate the regulations; a court decision ordered EPA to publish its proposed C&D regulations by December 1, 2008, and to publish the final rule by December 1, 2009.
In 2008, EPA met the first deadline and issued proposed guidelines with a numeric limit of just 13 nephelometric turbidity units (NTUs) for some construction sites. EPA acknowledged that meeting the 13-NTU limit might require active treatment systems on some or all of these sites. The limit would have applied to larger sites—30 acres or more—in areas with high rainfall energy and clayey soils. You can see a summary of the rule here, as well as a recap of a discussion forum at IECA’s 2009 conference with representatives from EPA, the California State Water Resources Control Board, and the construction industry.
After the public comment period, EPA revised those proposed guidelines. Objections to the 13-NTU limit included the prohibitive cost of meeting such a low turbidity limit, as well as the fact that 13 NTUs is lower than background turbidity in some areas. The revised guidelines published in the Federal Register in late 2009 included a numeric turbidity limit of 280 NTU for sites of 10 acres or more. The rule was supposed to be implemented in phases, beginning with larger sites and gradually including smaller ones. A summary and links to the Federal Register can be found here. This article from Erosion Control provides a more complete analysis of the rule and some of the ongoing objections to it.
In November 2010, EPA stayed that 280-NTU limit, saying that it wanted to revisit how the limit had been calculated. In August 2011, EPA withdrew its proposed rule on the grounds that it needed to gather more data before reaching a final decision. This notice, published in the Federal Register in January 2012, provides a recap of how the 280-NTU limit was originally calculated and why it was being reconsidered. It also contains summaries of the technologies needed to meet a specific numeric limit, defines what EPA means by “passive treatment,” includes a discussion of the limitations of sampling equipment and practices, and addresses comments EPA received regarding the potential toxicity of chemicals used in treatment systems to reduce turbidity.
When EPA issued its new five-year Construction General Permit in February 2012, it did not include a numeric limit as many people had expected it to. It did, however, incorporate many other aspects of the 2009 effluent limitation guidelines—the narrative part of those guidelines, essentially—including those relating to erosion and sediment control provisions like natural buffers, sediment discharge controls, soil stabilization, and guidelines on the use of treatment chemicals to reduce turbidity. At the time the new CGP was issued, EPA stated that even if it established a numeric limit within the next five years, it would not modify the CGP to include that limit but would instead incorporate it into the next iteration of the CGP.
Whether you agree with the decision to eliminate the numeric effluent limit for construction sites, the process has been an interesting one to watch, not least to see how comments from the ESC industry and from the development community influenced EPA’s various iterations of the rule. The non-numeric requirements of the rule still stand, updated with a few clarifications in this 2014 version.