Code of Vermont Rules › Agency 12 - AGENCY OF NATURAL RESOURCES › Sub-Agency 030 - DEPARTMENT OF ENVIRONMENTAL CONSERVATION › Chapter 036 - VERMONT STORMWATER MANAGEMENT MANUAL RULE › Section 12 030 036 - VERMONT STORMWATER MANAGEMENT MANUAL RULE

Current through June, 2024
PART 1.0 INTRODUCTION AND PURPOSE
1.1 Regulatory Authority and Applicability
Authority. This Rule establishes the post-construction
				  stormwater treatment standards for projects subject to stormwater discharge
				  permitting in Vermont, and is adopted pursuant to
				  10
				  V.S.A. §
												1264.
Applicability. The standards established in this Rule shall
				  be applied by the Agency, pursuant to the Agency's Stormwater Management Rules,
				  through general and individual permits.
Key Words. Designers are required to adhere to the applicable
				  stormwater treatment standards and required performance criteria in this
				  Manual. Specific words are used to indicate whether a particular design
				  standard or criterion is required or optional. For purposes of this Manual,
				  these terms and their meanings are as follows:
[] "Must," "shall," and "required" mean the design standard
				  or criterion is required; it is not optional.
[] "Should" means a design standard or criterion is a
				  well-accepted practice or a satisfactory and an advisable option or method, but
				  is optional; it is not required.
[] "May" means a design standard or criterion is recommended
				  for consideration by the designer, but is optional; it is not required.
1.2 Anti-Degradation
The 2017 VSMM is adopted in conformance with the Department's
				  Interim Anti-Degradation Implementation Procedure (October 2010).
The development of the 2017 VSMM was informed by an extensive
				  stakeholder process and review of existing storm water standards in place
				  nationally. As a result of this process, this Manual includes the highest
				  practicable level of STPs. Additionally, the 2017 VSMM development process took
				  into account anti-degradation requirements and the socioeconomic effects of
				  requiring certain practices.
The practices in the Manual will be reviewed in cycles not to
				  exceed five years to ensure that the required practices remain the highest
				  level of cost-effective STPs. Where warranted based on this review, the Agency
				  will revise the 2017 VSMM to add, remove, or modify practices to ensure ongoing
				  compliance with the anti-degradation requirements of the Vermont Water Quality
				  Standards.
1.3 Protection
				of Groundwater
The 2017 VSMM applies the best available treatment and
				  disposal technologies for the management of stormwater, for ensuring that
				  groundwater is not depleted by development, and for the protection of
				  groundwater quality.
During development of the 2017 VSMM, the Agency relied upon
				  the best available information and a public stakeholder process to evaluate the
				  use of STPs and design strategies for the protection groundwater. An extensive
				  review of available data suggests that unmanaged stormwater is unlikely to
				  exceed primary groundwater enforcement standards. Consequently, the
				  infiltration of stormwater managed in conformance with this Manual is unlikely
				  to violate primary groundwater enforcement standards at any applicable point of
				  compliance.
Stormwater that is infiltrated in conformance with the 2017
				  VSMM receives pre-treatment, treatment, and is subject to source controls and
				  seasonal-high groundwater table separation requirements that are likely to
				  mitigate potential contamination. Further, this Manual specifies the
				  established set backs for structural infiltration STPs from source water
				  protection areas, drinking water sources, and wastewater disposal areas. In
				  addition, the 2017 VSMM prohibits use of infiltration-based STPs to treat
				  stormwater runoff that comes in contact with "hotspot" land uses or activities
				  that may present a greater risk to groundwater quality. Finally, the
				  Groundwater Recharge Standard set forth in this Manual ensures that groundwater
				  recharge will be maintained at pre-development levels based upon prevailing
				  mapped hydrologic soil groups (HSGs).
The 2017 VSMM will be reviewed and, if necessary, revised
				  every five years to assure that the VSMM continues to apply the best treatment
				  and control technologies. The Agency reserves the right to disallow the
				  infiltration of stormwater or to require additional protective measures on a
				  case-by-case basis if warranted by credible and relevant information available
				  to the Agency during the review of an application.
Based on the foregoing, permitted stormwater discharges to
				  groundwater managed in accordance with a stormwater system designed to the
				  standards of the 2017 VSMM are compliant with the State's policy regarding the
				  protection of groundwater as contained in 10 V. S.A. §§ 1390, 1392,
				  1410, the Groundwater Protection Rule and Strategy (Environmental Protection
				  Rules, Chapter 12), and the Underground Injection Control Regulations
				  (Environmental Protection Rules, Chapter 11), including section 11-301
				  "Prohibitions."
1.4
				Effective Date and Transition
Effective Date. This Rule shall take effect on July 1,
				  2017.
Transition. Unless an applicant chooses to apply the
				  standards in the 2017 VSMM, the standards in the 2002 VSMM shall apply to a
				  project if the redevelopment or expansion is a public transportation project,
				  and as of January 1, 2017, the Agency of Transportation or the municipality
				  principally responsible for the project has initiated right-of-way valuation
				  activities or determined that right-of-way acquisition is not necessary for the
				  project, and substantial construction of the project commences within five
				  years of the effective date of this Rule.