¶ 1. Appellants Energize Vermont, Inc. and several individuals challenge the Vermont Public Service Board (PSB)’s affirmance of a permit issued by the Agency of Natural Resources (ANR), approving an operational-phase stormwater management plan for appellee Green Mountain Power (GMP), with respect to the Kingdom Community Wind Project (Wind Project) on Lowell Mountain in Lowell, Vermont. Although appellants raised a variety of challenges to the operational-phase permit, as well as other permits, on appeal to the PSB, the only issue maintained on appeal to this Court is the narrow one of whether ANR complied with certain requirements of its own Vermont Stormwater Management Manual (VSMM) in granting the operational-phase permit. We affirm.
¶ 2. The facts of this case are undisputed. The Wind Project is a wind-powered electric generation facility involving twenty-one wind turbines, along with access roads, a substation, an operations building, and power lines. Because the project contains over twenty-seven acres of impervious surfaces, GMP is required to maintain a permit from ANR to regulate management of its stormwater runoff as long as the project is operational. 10 V.S.A. § 1264(a)(11). In granting the permit, ANR is required to ensure that the permit is “consistent with, at a minimum, the 2002 Stormwater Management Manual [VSMM].” Id. § 1264(e)(1).
¶ 3. The VSMM contains regulatory requirements for storm-water treatment practices, known as STPs, which are designed to manage stormwater runoff. Because the parties’ arguments rely in large part on the language of the VSMM, we describe the VSMM in detail here. The VSMM is divided into three sections. Section 1 is titled “Stormwater Treatment Practice Sizing Criteria.” It sets out five distinct “treatment standards” for water quality, channel protection, groundwater recharge, overbank flood protection, and extreme flood protection. This appeal concerns only the Wind Project’s compliance with the channel protection treatment standard.
¶ 4. Subsection 1.1.2 sets forth the standards for channel protection treatment. It begins: “To protect stream channels from degradation, storage of the channel protection volume (CPv) shall
be provided by means of 12 to 24 hours of extended detention storage (ED) for the one-year, 24-hour rainfall event.” The subsection provides a bulleted list of criteria that “shall be applied” to evaluate channel protection volume and STPs for channel protection.
¶ 5. Section 2 of the VSMM is titled “Acceptable Stormwater Treatment Practices.” Subsection 2.1 is also titled “Acceptable STPs” and states: “This section outlines STPs that can be used to meet the . . . treatment standards set forth in section 1. These acceptable STPs can be used alone, or in combination, to meet the required treatment standards.” VSMM 2.1. The Wind Project has not used an “acceptable STP” as defined by subsection 2.1.
¶ 6. Subsection 2.5 is titled “Alternative STP Designs.” It states:
The stormwater treatment field is rapidly evolving and new stormwater management technologies constantly emerge. A permit applicant may propose and [ANR] may allow the use of STPs other than those listed [above] if the permit applicant can demonstrate to [ANR]’s satisfaction that the proposed alternative STPs will attain the applicable treatment , performance standards for [the five treatment standards contained in VSMM Section 1]. Proposals for use of alternative treatment systems will require consideration of the design through the use of the individual permit application process.
There are two methods by which a designer may propose an alternative system design evaluation: through consideration of an existing-alternative system . . . ; or through a new design-alternative system proposed for use in Vermont.
Subsections 2.5.1 and 2.5.2 pertain to “Existing Alternative Systems” and “New-Design Alternative Systems,” respectively. The parties agree that the Wind Project’s stormwater treatment practices make up a “new-design alternative system,” not an “existing alternative system.”
¶ 7. Subsection 2.5.2 states:
The performance standard for STPs shall meet the applicable treatment standards specified in section 1.1, and shall have the capability to achieve long-term performance in the field. For an alternative STP to be submitted to [ANR] for consideration, a designer’s certification of compliance, including pertinent design information must be provided. This certification must provide details, with a reasonable level of surety, on how the system will achieve the requisite performance standards.
If a proposed alternative STP design is successfully approved by [ANR], then this alternative will be available for use by other permit applicants, if determined appropriate by [ANR].
¶ 8. The Wind Project uses an STP known as “level spreaders.” The level spreaders function by collecting stormwater in a trough and then dispersing, the water across a level edge, through a vegetated buffer. Level spreaders are not specifically referenced in the VSMM. Level spreaders do not meet the default requirements, under subsection 1.1.2, for channel
¶ 9. Appellants contend that the language of subsection 1.1.2 mandates the use of extended detention storage unless a project qualifies for an alternative design standard using VSMM section 3 credits. Under appellants’ reading, the only way to use an alter
native design standard to satisfy the channel protection requirement is by using the credits in section 3, which appellees have not done. Appellants argue that to allow ANR to interpret its manual differently would violate the plain meaning of the regulation and therefore would also violate our instruction that “[a]n administrative agency must abide by its regulations as written until it rescinds or amends them. Otherwise, people will not know how to conduct their affairs.”
In re Peel Gallery of Fine Arts,
¶ 10. This appeal first went to the PSB pursuant to 10 V.S.A. § 8506. Review in the PSB was de novo, although the Board is required to apply “the substantive standards that were applicable before the secretary.” Id. § 8506(e).
¶ 11. The PSB rejected appellants’ argument. In keeping with the statutory standard of review, it gave no deference to ANR’s permit decision. It did, however, defer to ANR’s construction of its regulation, adopting a “compelling indication of error” review standard from
In re Electronic Industries Alliance,
¶ 12. The PSB rejected appellants’ argument for two main reasons. First, it held that section 1.1.2 of the VSMM does not have the meaning appellants attributed to it:
significantly . . . the limiting word ‘only’ does not appear anywhere in Section 1.1.2, nor do we read this language to compel that the word ‘only’ was intended to be read into Section 1.1.2. Rather, we read Section 1.1.2 to simply state expressly that in the case of disconnected projects using Section 3 credits, the Alternative Design Standard may be used.
¶ 13. Second, it ruled that
the Legislature intended only for stormwater discharge permits to be ‘consistent’ with the VSMM, as opposed to requiring strict compliance or conformity. The Vermont Stormwater Management Rule similarly states that per mits shall be ‘consistent’ with the VSMM’s treatment standards. Therefore, ANR has discretion to tailor an individual stormwater permit to achieve its intended purpose of protecting water quality so long as such permit is consistent with the VSMM and meets the other statutory criteria for discharge permits.
¶ 14. In conclusion, it held that ANR’s interpretation of the VSMM to allow use of the Alternative Design Standard in this case was not erroneous. It explained that
¶ 15. In commencing our own review, we must first determine the standard of review that applies in appeals from the PSB sitting in its appellate capacity.
*
As all parties noted, we generally give substantial deference to an agency’s interpretation of its own regulations — in this case, ANR’s interpretation of the VSMM.
In re Peel Gallery of Fine Arts,
¶ 16. In
Town of Killington v. Department of Taxes,
we deferred to the administrative decision of the Commissioner of Taxes even after a de novo trial in the superior court.
¶ 17. Like the PSB, we accord substantial deference to ANR’s interpretation of the VSMM. As this is the same standard used by the PSB, we thus review the PSB’s decision de novo.
Travia’s Inc. v. State,
¶ 18. We are not persuaded that ANR’s interpretation of the VSMM is irrational or
¶ 19. Given the deferential standard of review, this straightforward plain meaning analysis needs little elaboration. Appellants have not met their burden. We note, however, that our analysis is fortified by looking to the VSMM as a whole and the intent of the drafters. See
Burke,
¶ 20. Reading the VSMM as a whole reinforces our understanding that this provision — allowing use of section 3 credits as a means of achieving a successful alternative design standard for purposes of the channel protection requirement — does not necessarily preclude other means of reaching the same end. Subsection 2.5, entitled “Alternative STP Designs,” begins by acknowledging that the “stormwater treatment field is rapidly evolving and new stormwater management technologies constantly emerge.” The clear implication of this preface is that ANR aims to be responsive to the need to evaluate new technologies as they arise and will not be bound by obsolete measures. The subsection continues, “the Agency may allow the use of [alternative] STPs ... if the permit applicant can demonstrate to the Agency’s satisfaction that the proposed alternative STPs will attain the applicable treatment performance standards for water quality, groundwater recharge, channel protection, overbank flood protection and extreme flood control.” (Emphasis added.) The key word here is “applicable,” a word which is used in the same fashion in subsection 2.5.2, entitled “New-Design Alternative Systems.” That subsection requires only that alternative STPs “meet the applicable treatment standards specified in section 1.1.” (Emphasis added.) Given the cross-reference to subsection 1.1 generally, the subsection 1.1.2 default standard of extended detention storage for channel protection may not be an “applicable” standard for the alternative- design level spreader STP, because level spreaders use other means of protecting stream channels from degradation — namely dispersion and buffering.
¶ 21. This is not to say that new-design alternative systems are standardless. The VSMM has a more flexible, individualized system of evaluation for new-design alternatives. Subsection 2.5 states, in bold: “Proposals for use of alternative treatment systems will require consideration of the design through the use of the individual permit application process.” This is in
¶ 22. This interpretation is further supported by the legislative intent behind the stormwater permitting program. The statutory directives for the program state that stormwater management should use “structural treatment only when necessary”; that management strategies should be “tailor[ed] ... to the region and the locale”; and that the permitting process should “provide[ ] for the evaluation and appropriate evolution of programs.” 10 V.S.A. § 1264(a). The narrow reading advocated by appellants would be contrary to this intent because it would require GMP to install extended detention storage where not environmentally necessary; to use strategies not tailored to the locale; and to cause the permitting program to adhere to rigid requirements rather than evolve. Notably, although GMP states that the level spreaders are fully installed and operational, appellants have abandoned on appeal any arguments that the level spreaders are environmentally inferior to other STP designs.
¶ 23. In sum, we find no clear and convincing error in ANR’s interpretation of the VSMM to allow an operational stormwater permit for the Wind Project’s level spreaders.
Affirmed.
Notes
This is the first appeal from another agency heard by the PSB pursuant to 10 V.S.A. §8506. In appeals from the PSB’s decisions made within its original jurisdiction, we “accept as true all of the [PSBJ’s findings that are not clearly erroneous, and, in reviewing the [PSBJ’s conclusions, we defer to its particular expertise and informed judgment.”
In re Cent. Vt. Pub. Serv. Corp.,
