New & Events
Tennessee's proposed new construction general stormwater permit - Be aware of the changes
Stites & Harbison, PLLC, Client Alert
As reported on our blog, the Division of Water Pollution Control issued a draft of the new proposed Construction General Stormwater Permit (“CGP”) on September 21, 2010. The new version provides some substantial improvements over the 2005 permit, but also adds some new wrinkles. The Division has scheduled a series of public hearings across the state beginning October 27, 2010, in Nashville. Written comments will be accepted for 10 days following the hearings.
The Draft CGP has a much better description of who is required to submit a Notice of Intent (“NOI”) and a description of their respective responsibilities. For example, it clarifies “primary permittee” and “secondary permittee” and explains in some detail the responsibilities of each. This clarification is particularly useful for a commercial builder in a subdivision, who may be primary or secondary permittee depending on the circumstances. A commercial builder who buys one or more lots from the owner/developer become the primary permittee for that portion of the site and must submit a new NOI. Or the commercial builder could be hired by the lot owner to build a structure, in which case the contractor would be the secondary permittee.
The Draft CGP also provides a very handy list of definitions and acronyms. One of the definitions, for example, is the “2-year and 5-year design storm depths and intensities.” Sediment basins are required to meet either the 2-year or 5-year design storm depending on whether the receiving stream is exceptional or impaired. Many permittees are frustrated when the basins are designed for the 2-year storm volume, but fail during a storm of high intensity in a short period of time. The definition provides a hyperlink to NOAA guidance. A quick click, for example, shows that the 2-year 24-hour storm for Nashville is 3.37 inches and the 5-year storm is 4.11 inches. For intensity, the 2-year storm is 0.14 inches per hour and the 5-year storm is 0.17 inches per hour.
The permit clarifies that a NOC will not be issued in areas where an ARAP is required for areas in active construction until coverage under the ARAP is granted. The permit allows coverage with justification in the stormwater pollution prevention plan (“SWPPP”). Thus it appears that coverage could be granted when the SWPPP is designed to project the area covered by the pending ARAP and could permit construction to proceed.
Section 3.1.1 of the Draft CGP requires a licensed professional engineer or landscape architect to perform quality assurance of erosion prevention and sediment control (“EPSC”) by performing site assessments for construction sites involving drainage to outfalls totaling 10 or more acres or 5 or more acres if draining into impaired or exceptional waters. These inspections are required quarterly and monthly respectively. Because this type of professional is required to design the EPSCs, it allows the professional to make in the field design adjustments when necessary. Thus the role of the professional will be much more active.
The Draft CGP requires more specificity in EPSC drawings. At least two EPSC plan sheets are required for disturbance under 5 acres and three for those over 5 acres. The plans would show the phasing from initial disturbance to final grading.
The Draft CGP adds requirements for temporary stabilization of steep slopes. The current requirements in the CGP are that temporary or permanent stabilization is required 15 days after construction. The addition of steep slope stabilization (20% grade or greater and elevation change of 20 feet or more) requires stabilization of such slopes within 7 days of construction.
The Draft CGP requires for the first time a 30-foot natural riparian buffer adjacent to all streams measured from top of bank. It allows averaging as long as the minimum width remains 15 feet and appears to maintain but clarify that some encroachments may be allowed if best management practices (“BMPs”) are used that provide equivalent protection to a receiving stream. This would allow construction of sewer lines, roadways, and greenways where appropriate BMPs are in the SWPPP and justification is made. The buffer requirement does not apply to uses in existence on the effective date of the NOI for coverage.
Issues Related to Impaired or Exceptional Waters
In the prior CGPs, discharges to impaired or exceptional waters were allowed as long as the permittee complied with the enhanced BMP requirements (60-foot buffer, 5-year storm, additional basins, etc.). The Draft CGP appears to allow that practice to continue, but contains somewhat conflicting statements. For example, it prohibits additional loadings of sediments if that is the cause of the impairment. For Exceptional Waters (formerly Tier II), the permit does not allow discharges that would cause degradation. The permit then states that the CGP could be used for additional discharges if the permittee complies with the enhanced buffer zone, the 5-year storm event, and other management requirements. Thus, the applicant may be tasked with proving that the installation of BMPs and other requirements of the CGP are sufficient to prevent degradation, rather than the presumptive approval in the current CGP.
A related requirement of the Draft CGP clarifies that SWPPP must comply with the assumptions of the wasteload allocation contained in a total maximum daily load (“TMDL”). Most existing Sediment TMDLs have a numeric wasteload allocation, but provide that the wasteload allocation is addressed by compliance with BMPs contained in the CGP. However, as TMDLs become more sophisticated, it is possible that some sites will be required to calculate pounds per acre per year that can be discharged consistent with the waste load allocation before permit coverage is allowed.
Some environmental groups take the position that no additional sediment can be discharged into these types of waters. Therefore, they advocate not only that the CGP is inappropriate, but that such discharges could not be permitted without triggering an enhanced antidegradation process or prohibiting construction all together. The Draft CGP is confusing on this topic and hopefully will be clarified. On the face page of the Draft CGP, it specifically excepts discharges into impaired or exceptional waters from coverage. The CGP has been used effectively in the past to control excess runoff from sites, and developers should be concerned that a literal interpretation will inhibit environmentally responsible development.
What about the new EPA technology based effluent limitation rules?
EPA issued technology based effluent limitation guidelines ELGs on November 23, 2009. The most controversial component of the ELG was a requirement for a numeric effluent limitation of 280 NTU, beginning August 2, 2011. However, EPA moved to vacate the numeric effluent limitation because of administrative process issues and which was recently granted by the Court. Thus, the Draft CGP, like prior versions, does not contain a numeric effluent limitation for either suspended solids or turbidity.
The Draft CGP does contain the other required non-numeric effluent limitations in the ELG including, including the buffer zone, requirements for phasing, dewatering and sizing. If and when EPA revises and re-imposes a numeric effluent limitation, TDEC may be required to modify the CGP, but as proposed, it is not addressed.
The Draft CGP is much clearer than previous versions, but it still contains language that is the source of misunderstanding in the industry. For example, Section 5.3.2 contains nearly the same language pertaining to discharge quality as the current CGP. One of the most litigated issues is the requirement that “the stormwater discharge must not cause an objectionable cooler contrast in the receiving stream.” The problem with this requirement is that there is no objective standard as to what constitutes “objectionable.” Neither the statute nor Water Quality Control Board rules prohibit objectionable color contrast. The only prohibition in the rules relating to objectionable color is where it impacts recreational uses. Because this prohibition is the established water quality criteria, the permit seems to impermissibly expand the rule.
The Draft CGP does not properly identify what constitutes a violation for failed EPSC measures. Even where the EPSC measures are properly designed and implemented, storm events could overwhelm the proposed measures allowing sediment to leave the site. The permit provides that maintenance should be accomplished before the next storm event but not more than 7 days after discovery. The current inspection reports required by TDEC do not provide proper inputting to describe the repairs, and thus documentation is difficult. If a failure occurs, sediment is removed and the EPSC measures repaired or redone, then there should be no violation. However, it is commonplace for the Division to cite developers for violations even though they have complied with the permit.
Finally, the Draft CGP does not provide incentives for green building or adoption of high quality practices. Many LEED projects gain points by reduction in stormwater through rain gardens and other features. The Division could provide incentives for such projects by providing priority permit review for the NOI as well as any related ARAP.
The Draft CGP is by far the clearest CGP developed by the Division. It obviously builds on experience of the last 20 years in regulating stormwater as the science and knowledge has increased in the industry. Today, the largest percent of enforcement cases by the Division related to construction stormwater. Thus, all developers and contractors affected by the permit should study the proposed Draft CGP and make comments as necessary.
William L. Penny is a member of the firm's Environmental, Natural Resources and Energy Service Group. He has more than 25 years experience in environmental law and concentrates his practice on environmental law, including water quality and stormwater issues, RCRA, CERCLA, Brownfield Redevelopment, water law and low level radioactive waste and environmental litigation.