OPINION
Relator, an environmental-advocacy group, asserts that the Minnesota Pollution Control Agency erred as a matter of law in its issuance of a permit regulating ballast-water discharge into Minnesota waters of Lake Superior, arguing that the agency (1) erroneously concluded that it was not required to conduct a nondegradation review, (2) failed to conduct an appropriate nondegradation review, and (3) used an inadequate process to determine how stringent the permit’s terms must be in order to preserve Lake Superior’s existing water quality. Relator requests that we remand for a thorough nondegradation review. Because the Minnesota Pollution Control Agency correctly determined that a nondegradation review was required and because the process it used to conduct the nondegradation review and to adopt the permit terms was neither based on an error of law nor arbitrary or capricious, we affirm.
FACTS
This appeal involves a challenge to the first permit issued to regulate the discharge of ballast water into Minnesota waters of Lake Superior. Ballast water is water that is taken onboard a ship to improve the ship’s stability, draft, and buoyancy. Vessels take on and discharge ballast water as cargo is loaded and unloaded or as weather conditions change. Ballast-water discharge from commercial vessels may contain pollutants in the form of invasive aquatic species. Until recently, ballast-water discharge has not been subject to regulation or permitting requirements under the Federal Water Pollution Control Act (commonly referred to as the Clean Water Act (CWA)), see 33 U.S.C. §§ 1251-1387 (2006), because the United States Environmental Protection Agency (EPA) recognized an exemption for ballast-water discharge.
Nw. Envtl. Advocates v. United States Environmental Protection Agency,
No. C 03-05760 SI,
In 2007, the Minnesota Pollution Control Agency (MPCA) began to develop a permit that would regulate ballast-water discharge into Minnesota Waters of Lake Superior, and it eventually issued Ballast Water Discharge State Disposal System General Permit No. MNG300000 (SDS general permit). Because issuance of the SDS general permit involved the creation of a new regulatory system, MPCA utilized a stakeholder process to develop the permit. MPCA held four public stakeholder meetings to solicit input on issues to be addressed in the permit. MPCA proposed a draft ballast-water-discharge permit and provided public notice of the permit for 30 days. MPCA also provided public notice of a fact sheet explaining the terms of the permit, the conditions of the permit, and MPCA’s rationale for proposing those terms and conditions.
The SDS general permit requires existing ships to comply with the IMO treatment standards no later than January 1, 2016. Ships constructed after January 1, 2012, are required to comply before operating in Minnesota. MPCA based its compliance deadlines on the following factors: (1) the need to develop technology to meet the IMO standards; (2) the need to verify the effectiveness of such technology in freshwater conditions; (3) the need to develop a maintenance system for treatment technology; and (4) the need for existing vessels to go into dry-dock for installation of treatment systems.
Relator Minnesota Center for Environmental Advocacy (MCEA) submitted comments to MPCA raising concerns regarding the proposed SDS general permit. MCEA recommended that the permit be more stringent and argued for adoption of the so-called “California” standards instead of the IMO standards. Other commentators, including representatives from the shipping industry, opined that the draft permit was too stringent, arguing that (1) there is no commercially available technology that can meet the standards; (2) the implementation timeline is too short and unrealistic; (3) vessels that operate solely on the Great Lakes should not be subject to the permit requirements; and (4) the State of Minnesota should not attempt to regulate ballast-water discharge, in light of the EPA’s plan to issue a national pollutant-discharge-elimination-system general permit regulating ballast-water discharge in the near future.
The MPCA citizens’ board held a public hearing on the proposed permit on September 23, 2008. MCEA provided testimony at the public hearing. MCEA asked MPCA to include stricter discharge standards in the permit and to shorten the implementation deadlines. At the conclusion of the public hearing, the MPCA citizens’ board voted unanimously to issue the SDS general permit, and it adopted findings of fact, conclusions of law, and an order authorizing issuance of the permit. MCEA’s certiorari appeal follows.
ISSUES
I. Did MPCA erroneously interpret the nondegradation rule?
II. Did MPCA fail to conduct an adequate nondegradation review?
III. Did MPCA fail to ensure that the standards it adopted to regulate ballast-water discharge will preserve Lake Superior’s existing water quality?
ANALYSIS
This court reviews a final decision of the MPCA under the Minnesota Admin
“[Decisions of administrative agencies enjoy a presumption of correctness, and deference should be shown by courts to the agencies’ expertise and their special knowledge in the field of their technical training, education, and experience.”
Reserve Mining Co. v. Herbst,
The supreme court has summarized the approach to judicial review of agency decisions concerning regulations as follows: (1) “when a decision turns on the meaning of ... an agency’s own regulation, it is a question of law that [appellate courts] review de novo”; (2) “when the language of the regulation is clear and capable of understanding, [an appellate court] give[s] no deference to the agency’s interpretation and may substitute [its] ... judgment for that of the agency”; and (3) “when the relevant language of the regulation is unclear or susceptible to different reasonable interpretations, ... [an appellate court] will give deference to the agency’s interpretation and will generally uphold that interpretation if it is reasonable.”
In re Annandale NPDES/SDS Permit Issuance,
MCEA argues that this court should remand the SDS general permit on three grounds. First, MCEA asserts that
I.
Under state and federal law, MPCA is the Minnesota state agency charged with enforcing and administering the federal CWA and regulations promulgated under the CWA. Id. at 510 (citing Minn.Stat. § 115.03, subds. 1, 5 (2006); 40 C.F.R. § 123.25(a) (2006)). MPCA is authorized and required to administer and enforce all laws relating to the pollution of any waters of the state. Id., subd. 1(a). MPCA is authorized to require and issue a general, state disposal-system permit for ballast-water discharge under Minn.Stat. §§ 115.03, subd. 1(e), 115.07 (2008), and Minn. R. 7001.0030 (2007). MPCA is authorized to issue a single general permit to a category of permittees whose activities are the same or substantially similar, under Minn. R. 7001.0210 (2007).
Pursuant to its authority under the CWA, the EPA requires each state to develop a nondegradation policy that meets minimum standards. 40 C.F.R. § 131.12(a) (2008). A state’s policy must be designed to maintain the level of water quality necessary to protect existing water uses. See id. (a)(1). Minnesota’s nonde-gradation policy is set forth in Minn. R. 7050.0180 (2007). The rule sets out the policy of MPCA to prohibit or control new or expanded discharges to protected water. 1 Minn. R. 7050.0180, subp. 1. Sub-part 6 of the rule addresses restricted discharges and states:
No person may cause or allow a new or expanded discharge of any sewage, industrial waste, or other waste to any of the following waters unless there is not a prudent and feasible alternative to the discharge:
A. Lake Superior, except those portions identified in subpart 3 as a prohibited discharges zone;
[[Image here]]
If a new or expanded discharge to these waters is permitted, the agency shall restrict the discharge to the extent necessary to preserve the existing high quality, or to preserve the wilderness, scientific, recreational, or other special characteristics that make the water an outstanding resource value water.
Id., subp. 6 (emphasis added). The rule prohibiting new or expanded discharge allows for an exception when there is no “prudent and feasible alternative to ... discharge.” Id.
Lake Superior is designated as protected water under the nondegradation rule, and MCEA does not claim that there is a prudent and feasible alternative to ballast-water discharge into Lake Superior.
Id.,
The alleged error concerns the definition of “expanded discharge.” The nondegra-dation rule defines an “expanded discharge” as
a discharge that changes in volume, quality, location, or any other manner after the effective date the outstanding resource value water was designated ... [as protected water], such that an increased loading of one or more pollutants results. In determining whether an increased loading of one or more pollutants would result from the proposed change in the discharge, the agency shall compare the loading that would result from the proposed discharge with the loading allowed by the agency as of the effective date of [the protected water] designation....
Id., subp. 2(C) (emphasis added).
MPCA states that Lake Superior was designated as protected water on November 5, 1984. 2 MPCA concluded that vessels that were in operation at the time of Lake Superior’s 1984 designation as protected water will not generate an expanded discharge within the meaning of the non-degradation rule. MPCA reasoned that a change in ballast-water discharge from vessels in operation on Lake Superior pri- or to 1984 is unlikely to result in increased pollutant loading because (1) “the size and number of ballast water tanks are fixed when a ship is constructed”; and (2) “MPCA applied its technical expertise [to] conclude that the environmental threats from ballast water discharges have remained relatively unchanged since 1959.”
MCEA argues that MPCA misinterpreted the term “expanded discharge” by focusing solely on potential changes in the volume of ballast-water discharge. MCEA correctly notes that an “expanded discharge” may also result from changes in “quality, location, or any other manner.” Id. And MCEA correctly argues that the potential inclusion of new invasive species in ballast-water discharge would constitute a change in quality. But a change in the quality of discharge does not result in an “expanded discharge” under the rule unless “an increased loading of one or more pollutants” results. Id. And an increased loading in pollutants does not result unless the loading that results from the proposed discharge is greater than the loading allowed as of the effective date of the protected-water designation. Id.
MCEA misstates the standard for determining whether a change in discharge causes an increased loading of pollutants, claiming that the relevant comparison is between “the loading of each pollutant in the discharge with the loading of each pollutant on the [date] the waterbody was designated [as protected water],” or between “future pollutant loads expected from the proposed discharge [and] the historic pollutant loads as of the effective date of the receiving water’s [protected] water designation.” Based on this incorrect
Applied to the current facts, the nonde-gradation rule requires MPCA to compare the pollutant loading that will result from ballast-water discharge after implementation of the SDS general permit (the proposed discharge) with the pollutant loading from ballast-water discharge that was allowed when Lake Superior was designated as protected water. Because pollutant loading from ballast-water discharge was unrestricted at the time of Lake Superior’s 1984 protected-water designation, the restricted pollutant loading that will result from the proposed discharge will not result in increased pollutant loading. By definition, the proposed discharge does not constitute an “expanded discharge.” See id. Thus, MPCA did not err in interpreting the regulatory language concerning “expanded discharge.”
Moreover, MPCA recognized that any vessels operating on Lake Superior that came into existence after 1984 generate new discharges. A “new discharge” is defined as “a discharge that was not in existence on the effective date the outstanding resource value water was designated as” protected water. Id., subp. 2(B). Because the nondegradation rule unequivocally requires restrictions “to the extent necessary to preserve existing high [water] quality” whenever a new discharge to protected water is permitted, MPCA recognized that the nondegradation rule applied. Id., subp. 6. Thus, regardless of its failure to consider factors other than volume in its assessment of the potential for an “expanded discharge,” MPCA correctly determined that a nondegradation review was required during the permitting process, and remand is inappropriate. See Minn. R. Civ. P. 61 (stating that “[t]he court at every stage of the proceeding must disregard any error or defect ... which does not affect the substantial rights of the parties”).
II.
MPCA maintains that it conducted an adequate nondegradation review. MCEA contends that MPCA failed to conduct a nondegradation review. Alternatively, MCEA contends that the MPCA’s purported nondegradation review was inadequate and not entitled to judicial deference. MCEA bases its contentions on the lack of evidence in the record regarding (1) an assessment and characterization of Lake Superior’s existing water quality (i.e., a baseline standard) and (2) an analysis and discussion of the effects of new invasive species on existing water quality.
MCEA’s challenge focuses on the form or content of MPCA’s nondegradation review and the process that MPCA used to adopt the treatment standards in the SDS general permit. MCEA argues that a proper nondegradation review requires a baseline analysis of Lake Superior’s existing water quality, an assessment of the risk and manner of water degradation from the individual invasive species believed most likely to invade Lake Superior, and an analysis and determination that the biological-performance standards in the SDS general permit will in fact preserve
Rule 7050.0180 is silent regarding the form and content of a nondegradation review; it does not dictate a particular procedure to be used to determine whether proposed discharge restrictions are adequate to preserve existing water quality. The nondegradation rule simply requires that when a new or expanded discharge is permitted, the acting agency must “restrict the discharge to the extent necessary to preserve the existing high [water] quality.”
Id.,
subp. 6. The rule leaves open the question of how the agency arrives at its determination regarding the necessary restrictions. “When a statute or regulation is silent on a precise issue, that silence may be evidence of ambiguity.”
In re Alexandria Lake Area Sanitary Dist. NPDES/SDS Permit No. MN0040788,
MPCA’s nondegradation review is also entitled to deference because ballast-water discharge was not previously subject to regulation in Minnesota, and MPCA’s issuance of the SDS general permit involved implementation and administration of a new regulatory system.
See Annandale,
In support of its argument that MPCA’s nondegradation review was inadequate and not entitled to deference, MCEA relies primarily on our decision in
Princeton,
MCEA argues that our holding in Princeton requires MPCA to establish a baseline measure of Lake Superior’s existing water quality and to impose restrictions that maintain that baseline. MPCA counters that Princeton is factually distinguishable and does not dictate the procedure, form, and content of MPCA’s nonde-gradation review in this case. MPCA’s argument is persuasive.
Princeton is factually distinguishable in significant respects. In Princeton, the receiving body of water, the Rum River, had not previously been subject to the pollutant discharge at issue. Id. at 108. By contrast, Lake Superior has been receiving ballast-water pollutants without restriction for as long as commercial vessels have operated on Lake Superior. Thus, Princeton involved a situation in which MPCA was required to define the existing quality of protected water in order to ensure that the water quality would not be degraded by a newly permitted pollutant. Id. In contrast, the discharge of ballast-water pollutants into Lake Superior has always been allowed, and MPCA’s permit restricts these discharges for the first time.
Also, the discharge source in Princeton was a single water-treatment plant, as opposed to numerous commercial vessels operating on lakes and oceanic waters. Id. at 98. And the discharge source was fixed and known, unlike this case where the nature of the potential pollutants (i.e., aquatic invasive species) is varied, subject to change, and possibly even unknown, given the number and types of discharge sources. Moreover, in Princeton, MPCA inappropriately focused on the scenic and recreational qualities of the Rum River when granting the permit instead of the need to maintain the river’s existing water quality. Id. at 107. And MPCA erroneously set the permitting restrictions to prevent degradation below ordinary water-quality standards, rather than to preserve the existing water quality. Id. Here, unlike its approach in Princeton, MPCA appropriately focused on the need to maintain Lake Superior’s existing water quality.
Under the circumstances in Princeton— which involved the first permitted discharge of pollutants into the Rum River, an inappropriate focus on the scenic and recreational qualities of the river instead of water quality when granting the permit, and the erroneous use of ordinary water-quality standards as a measure, rather than the existing water quality-MPCA’s process for determining discharge restrictions was arbitrary and capricious.
Id.
at
Having determined that
Princeton
does not dictate a particular form of nondegradation review and that MPCA’s nondegradation review process is entitled to deference, we consider whether MPCA’s review was otherwise arbitrary and capricious. An agency’s decision is arbitrary and capricious if it represents the agency’s “will, rather than its judgment.”
Pope County Mothers v. Minn. Pollution Control Agency,
An “agency’s conclusions are not arbitrary and capricious so long as a rational connection between the facts found and the choice made has been articulated.”
In re Excess Surplus Status of Blue Cross & Blue Shield of Minn.,
MPCA argues that
common sense dictate[s] that by restricting currently uncontrolled discharges MPCA will not only maintain the existing high quality of [Lake Superior], it will enhance water quality. Put simply, however high the existing water quality in Lake Superior is with completely unregulated discharges of ballast water, that water quality will necessarily be maintained and improved through the imposition [of permit restrictions].
Thus, MPCA maintains that it is unnecessary to determine Lake Superior’s existing water quality in order to determine the permit terms necessary to maintain that quality.
Given the deferential standard of review and the fact that ballast-water discharge into Minnesota waters of Lake Superior has previously been unrestricted, we cannot conclude that MPCA’s decision to establish permit terms without a baseline analysis of Lake Superior’s existing water quality was arbitrary and capricious. Nor do we conclude, as MCEA argues, that MPCA’s failure to address the risks associated with “each new invasive species that has arrived over the past 24 years, or of likely future arrivals” renders its nonde-gradation review process arbitrary and capricious. While MCEA’s suggested analysis might be prudent, under a deferential standard of review we cannot say that MPCA’s nondegradation review was arbi
III.
Finally, MCEA argues that the terms of the SDS general permit will not preserve Lake Superior’s high water quality. Specifically, MCEA argues that MPCA fails to identify evidence of a water-quality-based rationale for rejecting more stringent performance standards than the IMO standards and for rejecting a shorter implementation timeline. MPCA counters that it reasonably concluded that it had satisfied the nondegradation rule by adopting the most stringent treatment requirements that have been developed and that will actually be achievable during the term of the permit.
The record demonstrates that MPCA chose the IMO standards after consideration of the reasonably available and pertinent data, and review of the treatment standards believed to best preserve Lake Superior’s high water quality. MPCA staff evaluated the status and available performance data of 15 separate treatment systems. With regard to MCEA’s preferred standards, the “California” standards, MPCA determined that because there was no evidence that those treatment standards would be technologically achievable during the term of the permit, inclusion of those standards would not guarantee greater protection for Lake Superior’s existing high water quality. MPCA reasonably concluded that adopting more stringent standards, in the absence of technology to meet those standards, would “not result in meaningful protection for Minnesota’s aquatic environment.”
With regard to the implementation time-line, MPCA considered the following factors: (1) the need to develop technology to meet the IMO standards; (2) the need to verify the effectiveness of such technology in freshwater conditions; (3) the need to develop a maintenance system for treatment technology; and (4) the need for existing vessels to go into dry dock for installation of treatment technology. MPCA recognized that it will take time to develop the technology necessary to implement the IMO standards and additional time to implement that technology. MPCA reasoned that vessels need to go into dry dock for installation of treatment systems and that the available space for dry-dock installation is limited. MPCA established 2016 as the deadline for final implementation of the permit restrictions for existing vessels and reasonably expects that implementation will be an ongoing process prior to that deadline. Vessels constructed after January 1, 2012 must be compliant when they begin operating on Minnesota waters of Lake Superior.
In adopting water-treatment standards and a timeline for implementation of those standards, MPCA reasoned that water quality will not be maintained and improved by the adoption of treatment standards and an implementation schedule that are unachievable. MPCA’s reasoning is sound. It is not our role to reweigh policy determinations that require an agency’s technical knowledge or experience.
See Annandale,
DECISION
MPCA correctly determined that non-degradation review was required when it issued a permit regulating ballast-water discharge into Minnesota waters of Lake Superior. The process that MPCA used to conduct its nondegradation review and to adopt permit terms is entitled to judicial deference. Because MPCA’s nonde-gradation review process and the resulting permit terms are neither based on an error of law nor arbitrary or capricious, we affirm.
Affirmed.
Notes
. The nondegradation rule defines water designated as "[o]utstanding resource value waters” as "waters of the state with high water quality, wilderness characteristics, unique scientific or ecological significance, exceptional recreational value, or other special qualities which warmnt stringent protection from pollution.” Minn. R. 7050.0180, subp. 2(A) (emphasis added). For purposes of this opinion, we refer to "outstanding resource value water” as "protected water.”
. MCEA does not challenge MPCA’s assertion regarding the date of Lake Superior's protected-water designation.
