EPA’s long-awaited Effluent Guidelines for Discharges from the Construction and Development Industry was issued today, November 23. You can find links to both a brief EPA fact sheet and to the entire rule that will be published in the Federal Register.
Not until page 204 of the 251-page pdf file containing the complete rule (and nowhere at all in the fact sheet) will you find the magic number that we’ve all been waiting for, so I’ll give it to you now: 280.
That requires some explanation. In the draft rule, published last year, EPA proposed a numeric limit of 13 nephelometric turbidity units (NTU) for discharges from some construction sites—namely those that covered 30 acres or more, had an R factor of 50 or greater, and had at least 10% clay content. Although this by no means included every construction site, that number prompted a huge outcry—it was too low, lower even than the background turbitdity level in some areas, some people said, and the cost of achieving such a level imposed too great an economic burden. Even EPA acknowledged that an advanced treatment system would be needed to achieve it in most cases. You can see past discussions of the proposed limit from our site here and here.
EPA has modified this number significantly. The 280-NTU numeric limit in the final rule applies to construction activities disturbing 10 acres or more at one time, and the rule defines this in some detail—the 10 acres don’t need to be contiguous, for example, if they’re all part of the same project, and the idea was to encourage development of a site in phases. The affected sites will be required to take water samples throughout the day, and the average of all the measurements must not exceed 280. (An individual sample above that level is okay as long as the daily average is 280 or less.) If a storm larger than the local 2-year, 24-hour storm occurs, the limitation doesn’t apply that day.
EPA has also made numerous changes to its non-numeric effluent limitations to make them more applicable to all construction sites. These include removing the specific requirements to minimize the amount of exposed soil at one time, to preserve natural vegetation, to provide and maintain natural buffers around surface waters, to establish temporary or permanent vegetation, to divert stormwater runoff from disturbed areas of the site, to establish and maintain perimeter controls, and to use wheel wash stations, among others. You can see a detailed list, as well as the reasons these items were not considered applicable to all sites, in section X.B of the final rule.
Much of the document is devoted to discussion the comments the agency received after publishing the draft guidelines. It outlines many of those comments in detail and explains either why EPA disagreed or how it modified the final rule based on them.
The rule will go into effect in phases: within 18 months of its publication, sites disturbing 20 or more acres will have to begin monitoring and complying with the 280-NTU limit. Four years after the rule’s effective date, sites disturbing 10 acres or more will need to comply.
What do you think of the final rule—does it go far enough? And how well do you think EPA incorporated the public comments it received?