Those of you who deal with construction-site erosion and sediment control measures or with site inspections have probably been anticipating EPA’s Effluent Guidelines for Discharges from the Construction and Development Industry. The final rule 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.
In the draft rule, published last year, EPA proposed a numeric limit of 13 nephelometric turbidity units (NTU) for discharges from some construction sites—those that covered 30 acres or more, had an R factor of 50 or greater, and had at least 10% clay content. The final rule modifies that limit in a number of ways, but the short version is that the agency has set a limit of 280 NTU for sites that must meet a numeric limit.
The public comments EPA received on the draft guidelines (which it covers in great detail in the final document) included many objections to the 13-NTU limit: it was even lower than the background turbidity in some areas, and it would cost too much to achieve (even EPA acknowledged that an advanced treatement system would likely be needed in most cases). You can see past discussions of the proposed limit from Erosion Control magazine’s web site here and here.
The new 280-NTU numeric limit in the final rule applies to construction activities disturbing 10 acres or more (contiguous or not) at one time. These 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, detailed in section X.B of the final rule.
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?