Small MS4 Coalition v. Dept. of Environment

Maryland Small MS4 Coalition, et al. v. Maryland Department of the Environment No. 25, September Term 2021 Environmental Law – Administrative Law – Clean Water Act – Stormwater Discharge Permits – Stare Decisis. Under the Clean Water Act and a similar State statute, the Maryland Department of the Environment develops and issues permits for regulating stormwater pollution to municipal separate storm sewer systems (“MS4s”) in Maryland. In Maryland Department of the Environment v. Anacostia Riverkeeper, 447 Md. 88 (2016), in response to a challenge by environmental advocates, the Court of Appeals held that permits issued to “large” MS4s satisfied the minimum requirements of the Clean Water Act. In Maryland Department of the Environment v. County Commissioners of Carroll County, 465 Md. 169 (2019), cert. denied, 140 S. Ct. 1265 (2020), in response to a challenge by two counties that operate MS4s, the Court held that permits issued to those “medium” MS4s were lawful under the Clean Water Act even if some permit conditions exceeded the minimum requirements of the Act.

In this case, a county operating a “small” MS4 challenges the general permit issued for 35 small MS4s in Maryland on grounds similar to those raised in the Carroll County case and asks the Court to reconsider its decision in that case. The Court holds that, pursuant to the doctrine of stare decisis, its prior holdings govern this case. Accordingly, the Court concludes that the general permit is not unlawful to the extent it may exceed a minimum requirement of the Clean Water Act known as the “MEP standard” to protect water quality standards and that, by including “minimum control measures” required by federal regulations under the Act and referencing areas beyond the MS4 service area, the permit does not unlawfully make the county responsible for discharges by third parties. Circuit Court for Queen Anne’s County IN THE COURT OF APPEALS Case No. C-17-CV-18-000162 OF MARYLAND Argued: December 7, 2021 No. 25 September Term, 2021 MARYLAND SMALL MS4 COALITION, ET AL.

V. MARYLAND DEPARTMENT OF THE ENVIRONMENT *Getty, C.J., *McDonald Watts Hotten Booth Biran Adkins, Sally D. (Senior Judge, Specially Assigned), JJ. Per Curiam Opinion McDonald, Hotten, and Adkins, JJ., concur. Getty, CJ., Watts, and Booth, JJ., concur in the judgment.

Filed: June 1, 2022 *Getty, C.J., and McDonald, J., now Senior Pursuant to Maryland Uniform Electronic Legal Judges, participated in the hearing and Materials Act (§§ 10-1601 et seq. of the State Government Article) this document is authentic. conference of this case while active 2022-06-01 16:09-04:00 members of this Court; after being recalled pursuant to Maryland Constitution, Article IV, Section 3A, they also participated in the Suzanne C. Johnson, Clerk decision and adoption of this opinion. The goal of the federal Clean Water Act is to make the nation’s waters fishable and swimmable by eliminating pollutant discharges into those waters.1 To achieve that goal, the Act requires a permit for all effluent discharges into waters of the United States, including discharges into the Chesapeake Bay and its tributaries. Under the Act and the State water pollution control statute, Respondent Maryland Department of the Environment (“the Department”) develops and issues such permits to municipal separate storm sewer systems (“MS4s”) in Maryland, which are classified as “large,” “medium,” or “small.” Beginning in the 1990s, the Department issued permits for owners and operators of large and medium MS4s. In 2016, in response to a challenge by environmental advocates, this Court held that permits issued by the Department to large MS4s satisfied the minimum requirements of the Clean Water Act.

Maryland Department of the Environment v. Anacostia Riverkeeper, 447 Md. 88 (2016) (“Anacostia Riverkeeper”). In 2019, in response to a challenge by two counties that operate medium MS4s, the Court held that permits issued to those MS4s were lawful under the Clean Water Act even if some permit conditions exceeded the minimum requirements of the Act. Maryland Department of the Environment v. County Commissioners of Carroll County, 465 Md. 169 (2019), cert. denied, 140 S. Ct. 1265 (2020) (“Carroll County”). In Carroll County, the counties asserted, among other things, that the permit terms unlawfully (1) included requirements 1 See 33 U.S.C. §1251 (a). that went beyond the Act’s “maximum extent practicable” (“MEP”) standard and (2) regulated areas of a county outside the MS4’s watershed region.

In this case, Petitioner Queen Anne’s County (“the County”), which operates a small MS4, brought this action for judicial review of a general permit that the Department issued for operators of 35 small MS4s in Maryland, including the County. The Circuit Court for Queen Anne’s County concluded that the decision in Carroll County addressed the issues raised by the County and affirmed the permit. On appeal of that decision, the Court of Special Appeals reached the same conclusion. Before us, the County again raises the grounds that the Court addressed in Carroll County and asks the Court to reconsider its key holdings in that case.

We hold that, pursuant to the doctrine of stare decisis, the holdings of Carroll County apply in this case. We hold that this case is governed by this Court’s prior case law and presents neither a material difference nor a change in circumstance that would justify reconsideration of this Court’s Carroll County decision. Accordingly, conditions based on regulations of the Environmental Protection Agency (“EPA”) in the general permit for small MS4s are not unlawful simply because they may exceed the minimum requirements of the Clean Water Act, such as the MEP standard. In addition, an impervious surface restoration requirement in the permit, which is similar to but less onerous than a permit 2 requirement assessed in Carroll County, does not unlawfully make the County responsible for discharges by third parties.2 I Regulation of Water Pollution under the Clean Water Act Pollution can enter waterways in many ways, but the Clean Water Act3 sorts all sources of pollution into two categories – point source and nonpoint source pollution.

Carroll County, 465 Md. at 184 . The Clean Water Act defines “point source” as “any discernible, confined and discrete conveyance,” and thus includes classic conveyances such as an industrial drainage pipe. 33 U.S.C. §1362 (14). Undefined by the statute, “nonpoint source” includes dispersed runoff from rainwater or snowmelt that sweeps over buildings, farms, and roadways, and that carries pollutants and pesticides into navigable waters, their tributaries, and groundwater. See Carroll County, 465 Md. at 184 & n.3.

Given the unpredictable and amorphous nature of nonpoint source pollution, the Clean 2 Four members of the panel – Judge McDonald, Judge Hotten, Judge Biran, and Judge Adkins – join this per curiam opinion. Three members – Chief Judge Getty, Judge Watts, and Judge Booth – join in the judgment, but not the per curiam opinion. Judge McDonald has filed a concurring opinion, which Judge Hotten and Judge Adkins join. Judge Watts and Judge Booth have each filed concurring opinions and join each other’s concurring opinion.

Chief Judge Getty joins both Judge Watts’ and Judge Booth’s concurring opinions. 3 Formally, the name of the statute is the Federal Water Pollution Control Act, which was significantly amended in 1972 to create the pollution discharge permitting program that is at the foundation of this case. However, practitioners and courts (including the Supreme Court) have adopted the “more appealing” name “Clean Water Act” associated with certain 1977 amendments of that statute to refer to these provisions. See Jeffrey G. Miller, The Supreme Court’s Water Pollution Jurisprudence: Is the Court All Wet?, 24 Va. Envtl.

L.J. 125 , 131 n.30 (2005). 3 Water Act primarily targets point sources of pollution, using point source permits as its primary enforcement mechanism. Id. at 184 . A. Point Sources and NPDES Permits As a starting point, the Clean Water Act prohibits all point source pollutant discharges into the waters of the United States,4 unless a permit allows the discharge. 33 U.S.C. §§1311 (a), 1362(12); see Anacostia Riverkeeper, 447 Md. at 96 . Thus, as a general rule, to lawfully discharge from a point source into a waterway such as the Chesapeake Bay or its tributaries, one must have a permit, i.e., a National Pollutant Discharge Elimination System (“NPDES”) permit. 33 U.S.C. §1342 .

NPDES permits set effluent limitations5 for point source discharges, capping the amount of various pollutants that may enter the water. Id. The standards are primarily based on what is reasonably achievable with available technology, but permit standards become more stringent if further reduction of pollutants is necessary to protect water quality. 33 U.S.C. §1311 (b)(1). Congress entrusted administration of the NPDES permit program primarily to the EPA. 33 U.S.C. §1319 , 1342(a)(1).

The EPA may delegate that authority to a state so long as the state’s law establishes a parallel permitting program consistent with the Act. 33 4 Undefined by the statute, the precise scope of the phrase “waters of the United States” has sometimes been the subject of litigation. See, e.g., Rapanos v. United States, 547 U.S. 715, 724 (2006) (plurality opinion). This case does not present that issue, as there is no question that the Chesapeake Bay and its watershed fall within the jurisdiction of the Clean Water Act. See also 33 U.S.C. §1267 . 5 An “effluent limitation” is “any restriction established by a State or the [EPA] on quantities, rates, and concentrations of chemical, physical, biological, and other constituents which are discharged from point sources into navigable waters, the waters of a contiguous zone, or the ocean, including schedules of compliance.” 33 U.S.C. §1362 (11). 4 U.S.C. §1342 (b).

EPA designation of a state permitting agency indeed is the rule rather than the exception.6 In Maryland, the Department is the NPDES permitting authority. See Maryland Code, Environment Article (“EN”), §9-253; COMAR 26.08.04.01. The State water pollution control law also directs the Department to adopt regulations concerning water quality standards and to regulate the discharge of pollutants into Maryland waterways. EN §9-314.

B. Effluent Limitations in Point Source Permits Although the Act distinguishes between point and nonpoint sources of pollution, pollutants do not, and accomplishment of the statutory purpose inevitably involves some interplay in the regulation of the two sources of pollution. Under the Act’s statutory framework, nonpoint source pollution affects the stringency of a typical NPDES point source permit. Aside from technical limitations on effluent discharges, typical NPDES permits – for example, a permit for an industrial drainage pipe – must include “any more stringent limitation, including those necessary to meet water quality standards.” 33 U.S.C. §1311 (b)(1)(C); 40 CFR §130.7 (c)7; see Carroll County, 465 Md. at 187 . “Water quality standards” are targets set by the states and approved by the EPA. 33 U.S.C. §1313 . Among 6 See EPA, NPDES State Program Authority, (May 17, 2022), https://www.epa.gov/npdes/npdes-state-program-authority [https://perma.cc/RBU3- Z2YQ] (listing only Massachusetts, New Hampshire, and New Mexico as states without any delegation of NPDES program authority). 7 Cf.

COMAR 26.08.03.01C(2)(b) (“Best available technology shall be required as the minimum for all permitted discharges. If it is determined that compliance with the established water quality standards will not be achieved through [best available technology], additional treatment shall be [required].”). 5 other things, water quality standards are based on designated uses for the state’s bodies of water, such as “recreation” or “public drinking water supply.” See Carroll County, 465 Md. at 186 . Both point and nonpoint sources impact water quality, but the Act’s enforcement mechanism is through point source permits. Thus, if there is an excess of nonpoint source pollution impairing a body of water – despite the measures taken to reduce nonpoint source pollution – point source permits must impose a “more stringent limitation” to counterbalance the nonpoint source pollution and protect the water quality. “Water quality standards are retained as a supplementary basis for effluent limitations, however, so that numerous point sources, despite individual compliance with effluent limitations, may be further regulated to prevent water quality from falling below acceptable levels.” EPA v. California ex rel.

State Water Res. Control Bd., 426 U.S. 200 , 205 n.12 (1976). Thus, water quality standards provide the link for how point source regulation under the Act accounts for nonpoint source pollution. See American Farm Bureau Federation v. EPA, 792 F.3d 281, 299 (3d Cir. 2015); Friends of the Earth, Inc. v. EPA, 446 F.3d 140, 143 (D.C. Cir. 2006).

C. MS4s MS4s are a subset of point sources of pollution discharges. They are ubiquitous in the daily life of those who live in an urban or suburban area. They consist of drains along roads and other conveyances for the collection and transport of rainwater and snowmelt – and everything else washed in with the water. Unlike a combined sewer system, an MS4 does not mix run off with sanitary sewer water; rather, it collects, transports, and deposits 6 untreated stormwater into local waterways.

In 1987, Congress amended the Clean Water Act to include specific permitting standards for MS4s, which have been elaborated in the EPA’s regulations.8 See 33 U.S.C. §1342 (p); 40 CFR §§122.30 -.37. The fundamental issues in this case are whether the Department, as the NPDES permitting authority for Maryland, may mitigate nonpoint source pollution to protect water quality standards when issuing permits for point sources, such as MS4s, and, if so, whether the scope of such regulation may extend in certain ways beyond the MS4’s system. The Court has already answered these questions in the affirmative – once with large MS4s and once with medium MS4s. The same answers pertain to small MS4s.

II Permitting of MS4s – Standards and Process A. New Statutory Standard with a Phased Approach The Clean Water Act provides for a phased, flexible approach to the permitting of MS4s. In particular, the Act states: Permits for discharges from municipal storm sewers— (i) may be issued on a system- or jurisdiction-wide basis; (ii) shall include a requirement to effectively prohibit non-stormwater discharges into the storm sewers; and 8 After the initial passage of the Clean Water Act, the EPA attempted to exempt MS4s from the permitting requirement for point sources. A federal court of appeals held that the EPA lacked authority to grant such an exemption. Natural Resources Defense Council, Inc. v. Costle, 568 F.2d 1369 (D.C. Cir. 1977).

In 1987, Congress amended the Act to phase in the permitting of MS4s and to provide specific permitting standards for that purpose. Water Quality Act of 1987, Pub. L. No. 100-4, 101 Stat. 7, 69 (1987); see also Anacostia Riverkeeper, 447 Md. at 96 -100 & nn.3, 6; Carroll County, 465 Md. at 243-46 . 7 (iii) shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the Administrator or the State determines appropriate for the control of such pollutants. 33 U.S.C. §1342 (p)(3)(B). The phased approach to MS4 permitting was adopted to allow additional time for the development of those permits.

The time was needed because the standard end-of-the- pipe treatment technology used for typical NPDES point sources would not be effective and permitting authorities would have to develop new types of permits that would be more comprehensive than the typical NPDES permit. A key legislative advocate of the 1987 MS4 amendments stated during the floor debate that the MS4 permits would “go far beyond the normal permits” and be “in effect … programs for stormwater management….” Remarks of Senator Robert R. Stafford (R. Vt.), Chairman of the Senate Committee on Environment and Public Works, presenting the Conference Report on Water Quality Act of 1986, 132 Cong. Rec. at 32381 (October 16, 1986).9 The EPA has implemented the MS4 permitting program in two phases. Phase I involved permitting those systems with the greatest potential to pollute waterways, generally as defined by population – denominated “large” or “medium” MS4s – or as specially designated by the permitting authority.

Carroll County, 465 Md. 243 -45. In Maryland, the Department began issuing those permits during the 1990s. Some challenged 9 Although the Water Quality Act of 1986 was passed by Congress, it was pocket- vetoed by President Reagan. In early 1987, Congress again passed the bill as the Water Quality Act of 1987 and, when the President vetoed the bill, overrode the veto.

The bill was enacted as Public Law 100-4. 8 the permits as too stringent (Carroll County); others challenged the permits as not stringent enough (Anacostia Riverkeeper). In both instances, this Court held that the permits were lawful under the EPA’s regulations and the Clean Water Act. See Part III of this opinion. Phase II included “small” MS4s – generally MS4s serving an area that has a population of less than 100,000 and either includes an urbanized area or is specially designated by the permitting authority.

See 40 CFR §122.32 (a). The EPA adopted regulations for the permitting of Phase II MS4s in 1999 and updated those regulations in 2016. See Regulations for Revision of the Water Pollution Control Program Addressing Storm Water Discharges, 64 Fed. Reg. 68,722 (Dec. 8, 1999) (“EPA 1999 Small MS4 Permit Regulations”); National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System General Permit Remand Rule, 81 Fed. Reg. 89,320 (Dec. 9, 2016) (“EPA 2016 Small MS4 Permit Regulations”);10 see also Carroll County, 465 Md. at 245 . In Maryland, the Department first issued a general permit for small MS4s in 2003.11 This case concerns the second generation of that general permit. 10 The initial Phase II regulations were challenged in federal court.

While the court largely rejected those challenges, it remanded those regulations back to the EPA because they lacked procedures for review by the permitting authority, public notice, and the opportunity to request a hearing. Env’t Def. Ctr. v. EPA, 344 F.3d 832 , 840, 843 (9th Cir. 2003); see also EPA 2016 Small MS4 Permit Regulations, 81 Fed. Reg. at 89,323. 11 See Maryland Department of the Environment, Maryland’s NPDES Municipal Separate Storm Sewer System (MS4) Phase II General Permits, https://mde.maryland.gov/programs/water/stormwatermanagementprogram/pages/npdes_ ms4_new.aspx [https://perma.cc/B9CC-5AMF]. 9 B. EPA Standards for Small MS4 Permits 1. Terms and Conditions The EPA regulations for small MS4 permits set forth standard permit conditions, a few of which are particularly pertinent to this case.

First, any small MS4 permit “must include permit terms and conditions to reduce the discharge of pollutants from the MS4 to the maximum extent practicable (MEP), to protect water quality, and to satisfy the appropriate water quality requirements of the Clean Water Act.” 40 CFR §122.34 (a).12 Permit terms “may include narrative, numeric, or other types of requirements.” Id. Second, a small MS4 permit must include six specific minimum control measures: (1) Public education and outreach on storm water impacts; (2) Public involvement/participation; (3) Illicit discharge detection and elimination; (4) Construction site storm water runoff control; (5) Post-construction storm water management in new 12 This opinion, like the EPA’s MS4 regulations, uses the acronym “MEP” as a shorthand for the phrase “maximum extent practicable.” It is but one of the many terms of art in environmental law that are perhaps better known by their acronyms than their formal names. The Clean Water Act and its regulations have spawned a plethora of such terms and acronyms – for example, the BMP (“best management practices”) that may be deployed to achieve the MEP standard or beyond. In addition, under the Act, pollutant discharges are to be initially controlled with BPT (“best practicable control technology”), followed by later imposition of the more stringent BATEA (“best available technology economically achievable”), whereas non-toxic pollutants are subject to the ostensibly less stringent standard of BCT (“best conventional-pollutant control technology”).

See 33 U.S.C. §§1311 (b)(1)(A), 1311(b)(2)(A), 1311(b)(2)(E). The Act assigns new sources their own standard – BADT (“best available demonstrated control technology”). 33 U.S.C. §1316 (a)(1). While these acronyms have their uses, they can sometimes make analysis challenging. See Entergy Corp. v. Riverkeeper, Inc., 556 U.S. 208, 220-21 (2009) (attempting to analyze an issue by setting a hierarchy of standards under the Act – each standard known by an acronym and each beginning with the word “best”). 10 development and redevelopment; and (6) Pollution prevention/good housekeeping for municipal operations. 40 CFR §122.34 (b).

Finally, as appropriate, the permit is to include “[m]ore stringent terms and conditions, including permit requirements that modify, or are in addition to, the minimum control measures based on an approved total maximum daily load (TMDL) or equivalent analysis, or where the [permitting authority] determines such terms and conditions are needed to protect water quality.” 40 CFR §122.34 (c). In the context of this regulation, the acronym “TMDL,” which stands for “total maximum daily load,” refers to the level of a pollutant that a water body can tolerate without violating applicable water quality standards. 33 U.S.C. §1313 (d)(1)(C); 40 CFR §§130.2 (i), 130.7(c)(1); see generally Carroll County, 465 Md. at 190-93 . State permitting agencies across the United States have developed a wide variety of such conditions in MS4 permits to protect water quality.13 2. Impervious Surfaces, Urbanization, and Small MS4s Impervious surfaces that do not absorb rainwater have long been recognized as a key cause of water pollution and the resulting impairment of water quality, particularly in 13 For example, MS4 permits in other states have conditions such as installing animal waste collection stations at municipal parks (Washington), retrofitting at least 18 million square feet (0.65 square miles) of impervious surface during the permit term (Washington, D.C.), removal of more than 100,000 pounds of trash annually from waterbodies (Washington, D.C.), distributing and planting 4,000 trees to improve pollutant uptake (Arlington Co., VA), investigating and creating an inventory of pollutant sources (Pennsylvania), routinely cleaning sewers (Denver, CO), pre-wetting of road ice (New Hampshire), and installation of new dog waste clean-up signs and bag dispensers (San Francisco, CA).

EPA, Compendium of MS4 Permitting Approaches, Part 3: Water Quality-Based Requirements (Apr. 2017), https://www.epa.gov/sites/default/files/2017- 06/documents/part3-sw_compendium_wqbels_508.pdf [https://perma.cc/C6TS-Z7Z7]. 11 urban areas. EPA 1999 Small MS4 Permit Regulations, 64 Fed. Reg. at 68,725. Typically, stormwater drains into the natural vegetation and soil, which act as a natural filter for many pollutants. Id.

With increased development and the proliferation of impervious surfaces – roofs, driveways, roads, and parking lots – the ground no longer absorbs and filters the stormwater as effectively. Id. Instead, stormwater washes over those surfaces, picking up pollutants along the way while gaining speed and volume. Id.

What results is a stormwater flow with greater volume, pollutants, and temperatures that directly impairs nearby receiving waters. Id. When the EPA initially adopted the small MS4 regulations, it noted that this phenomenon is especially true for the Chesapeake Bay region. EPA 1999 Small MS4 Permit Regulations, 64 Fed. Reg. at 68,725.

It pointed to a modeling system developed for the Chesapeake Bay that demonstrated that contamination of the Bay and its tributaries from runoff is comparable to, if not greater than, contamination from industrial and sewage sources. Id. (citing R. Cohn-Lee & D. Cameron, Urban Stormwater Runoff Contamination of the Chesapeake Bay: Sources and Mitigation, 14 The Environmental Professional 10- 27 (1992)). The EPA specifically targeted small MS4s located in urbanized areas for regulation because “studies and data show[ed] a high correlation between degree of development/urbanization and adverse impacts on receiving waters due to storm water.” Id. at 68,751. 3.

Choice of General Permit or Individual Permit The regulations for permitting small MS4s provide some administrative flexibility for small MS4 permittees. In contrast to federal regulations governing large and medium 12 MS4s, the regulations for small MS4s strongly encourage the use of general permits applicable to multiple MS4s to reduce administrative costs and burden. See 40 CFR §§122.28 (d); see also EPA 1999 Small MS4 Permit Regulations, 64 Fed. Reg. at 68,737. The owner or operator of a small MS4 may either accept the terms of a general permit or opt for an individual permit for its system.

See 40 CFR §122.33 (b). Moreover, the owner or operator of a small MS4 located within the same urbanized area jurisdiction as a medium or large MS4 may seek to be listed as a limited co-permittee with the larger MS4 permittee. 40 CFR §122.26 . C. MS4 Permitting Process in Maryland In Maryland, discharge permits are issued under both the Clean Water Act and a parallel State program. Carroll County, 465 Md. at 185 .

The process by which the Department issues such permits is set forth in EN §1-601 et seq. The Department is to publish notice of applications for permits. EN §1-602, 1-603. The Department publishes notice of a “tentative determination,” which includes a draft permit available for public inspection and copying, and certain other documents.

EN §§1-604, 1-606(d). The notice is followed by a period during which the Department may receive written comments on the draft permit and hold a public hearing. EN §1-604(a)(3)-(4). In certain circumstances, such as when it receives comments adverse to the tentative determination, the Department is to proceed to issue a final determination.

EN §1-604(b). If no adverse comments are received and no other circumstances require preparation of a final determination, the tentative determination becomes the Department’s final decision on the permit. EN §1- 13 604(b)(3). This permit process is not considered to be a contested case proceeding for purposes of the Maryland Administrative Procedure Act.

EN §§1-101(b), 1-601(b). A final determination of the Department is subject to judicial review by a party that meets threshold standing requirements and that participated in the public comment process. EN §1-601(c). Judicial review is based on the administrative record before the Department.

EN §§1-601(d), 1-606(c). That record consists of, among other things, the draft permit, the Department’s written basis for its final determination, documents supporting the stated basis, comments on the draft permit, responses to any such comments, and tapes and transcripts of public hearings. EN §1-606(c). Judicial review is limited to issues raised during the public comment process, unless the objections were not reasonably ascertainable during that process or arose afterward.

EN §1-601(d). Judicial review begins in the relevant circuit court14 pursuant to the procedures set forth in EN §1-601 et seq. and Maryland Rule 7-201 et seq. (rules governing actions for judicial review when a statute authorizes such review). There is a right to appeal the decision of the circuit court to the Court of Special Appeals.

EN §1-601(e)(2). III Prior Maryland Decisions Concerning MS4 Permits As noted earlier, this Court has previously reviewed challenges to MS4 permits issued by the Department in two cases. One case involved permits issued to five jurisdictions that operated systems designated as “large” MS4s; the other case concerned 14 Venue is appropriate in a circuit court for a county in which the activity governed by the permit will occur. EN §1-601(e)(1). 14 permits issued to two counties that operated systems designated as “medium” MS4s.

Each of the permits involved similar terms and conditions. In the first case, environmental advocates challenged permit terms as not stringent enough to satisfy the Clean Water Act; in the second case, the counties challenged their respective permits as too stringent and exceeding the Department’s authority under the Act. In both cases, this Court affirmed the Department’s authority and obligation to regulate MS4 discharges through the permits in question. A. The Anacostia Riverkeeper Case Anacostia Riverkeeper involved large MS4 permits that the Department had issued to five counties at various times between 2010 and late 2014. 447 Md. at 113 .

Each permit required the permittee to complete restoration efforts with respect to 20 percent of its jurisdiction’s total impervious surface not already restored to the MEP standard. Id. at 123 . In 2014, the Anacostia Riverkeeper and other environmental groups challenged the permits as not stringent enough. They argued, among other things, that the requirement that the permittees restore 20 percent of impervious surface in its jurisdiction was “too opaque” because the permit left permissible mitigation practices undefined and thus allowed the permittees to choose their own stormwater management practices.

Id. The environmental groups argued that the Department could not be certain that such a nebulous requirement would in fact reduce pollution, let alone reduce it to at least the MEP standard, as required by the Clean Water Act. Id. The Court of Special Appeals agreed with the challengers.

It concluded that the permits set “aspirational goals rather than particularized objectives” and 15 held that they failed to satisfy federal and State MS4 permit standards. Md. Dept. of the Env’t v. Anacostia Riverkeeper, 222 Md. App. 153, 176 (2015). This Court disagreed. The Court described the role of TMDLs in setting water quality standards for discharge permits.

Anacostia Riverkeeper, 447 Md. at 100-04 . The Court emphasized that, unlike a typical NPDES permit, a permit for an MS4 need not require the numerical specificity that might be found in a typical NPDES permit. 447 Md. at 126 . Rather, the Clean Water Act affords the Department significant flexibility in establishing controls for MS4 permits – which is necessary, given the challenges in regulating what goes in and comes out of a storm sewer system. Id. at 127 .

Thus, the Court held that the 20 percent impervious surface restoration requirement satisfied both the State stormwater permitting standards and the MEP standard in the Clean Water Act. Id. at 126, 128-29 . B. The Carroll County Case Three years later, conditions in Maryland MS4 permits were challenged from the opposite perspective. In that case, two counties that operated medium MS4s argued, among other things, that conditions similar to those at issue in Anacostia Riverkeeper required too much of the counties and exceeded the requirements of the Clean Water Act.

Carroll County, 465 Md. at 199-200 . A few key holdings from that case are particularly pertinent to this appeal. 1. Going Beyond the MEP Standard to Protect Water Quality As in Anacostia Riverkeeper, a key aspect of the permits at issue in Carroll County was a 20 percent restoration requirement for untreated impervious surfaces. 465 Md. at 16 199. The purpose of that permit condition was to reduce stormwater pollution discharged into the Chesapeake Bay to protect water quality, regardless of whether that pollution travelled directly into the Bay or first detoured through the county’s sewer systems.

One of the counties argued that the impervious surface restoration requirement exceeded the statutory MEP standard of the Clean Water Act and was therefore unlawful. The county and the Department appeared to agree that this permit condition went beyond the MEP standard. Id. at 213 . Thus, one of the issues in Carroll County was whether the terms of an MS4 permit could go beyond the MEP standard in order to satisfy water quality standards.

In its opinion in that case, this Court noted that, in a typical NPDES permit, there would be no question that the Department is to consider water quality standards in designing a permit – in fact, such consideration is required by the Act. Typical point source permits must impose technology-based limitations on discharges as well as “any more stringent limitation … necessary to meet water quality standards.” Carroll County, 465 Md. at 187 (quoting 33 U.S.C. §1311 (b)(1)(C)). Thus, “regardless of whether a waterway is over-polluted due to point sources, nonpoint sources, or some mixture of both, the Act authorizes the imposition of water quality based controls on point sources, in addition to the most stringent technology based controls.” Id.; see also EPA v. California ex rel. State Water Res.

Control Bd., 426 U.S. 200 , 205 n.12 (1976). The Court also observed that an MS4 permit is not a typical NPDES permit; MS4s differ from “end-of-pipe” point sources and have a different permit standard. Carroll County, 465 Md. at 188-89 . Although MS4s are classified as point sources and the EPA 17 chose to regulate MS4s within the framework of the NPDES program, NPDES permits for MS4s are more flexible and implement pollution mitigation programs that serve as surrogates for typical NPDES requirements.

Id. at 234-37 . Thus, the question in Carroll County was whether this more flexible approach for MS4 permits likewise allowed consideration of water quality standards to set conditions that went beyond the MEP standard. To answer that question, the Court looked to the text of the statute, the EPA’s regulations, and prior case law considering the issue. The Court concluded that a permit could include conditions beyond the MEP standard to satisfy the water quality standards established for the Chesapeake Bay and its tributaries.

The Court first turned to the text of the statute. Under the Clean Water Act, MS4 permits “shall require controls to reduce the discharge of pollutants to the maximum extent practicable, including management practices, control techniques and system, design and engineering methods, and such other provisions as the [EPA] Administrator or the State determines appropriate for the control of such pollutants.” Carroll County, 465 Md. at 215 , quoting 33 U.S.C. §1342 (p)(3) (emphasis added). The county argued that “such other provisions” were limited to what was necessary to satisfy the MEP standard, and therefore the MEP standard set a ceiling on MS4 regulation. Id. at 216 .

This Court rejected that argument, holding that the phrase “such other provisions” authorized the Department to 18 include permit conditions in addition to the MEP baseline in order to satisfy water quality standards. Id. at 217 .15 Observing that the EPA was entitled to deference concerning its interpretation of the Clean Water Act in its regulations, the Court then considered the EPA’s MS4 regulations. The EPA’s position for many years was that MS4 permits (like typical NPDES permits) must achieve compliance with water quality standards. 465 Md. at 219 & n.47. At first, the EPA based this conclusion on the requirement that typical NPDES permits must include “any more stringent limitation … necessary to meet water quality standards.” Defenders of Wildlife v. Browner, 191 F.3d 1159, 1164 (9th Cir.), opinion amended on denial of reh’g, 197 F.3d 1035 (9th Cir. 1999); 33 U.S.C. §1311 (b)(1)(C).

The Court noted that the EPA’s initial position was partially rejected by a federal appellate court, which held that the Clean Water Act did not compel, but rather conferred discretion on, MS4 permitting agencies to include permit conditions based on water quality standards that exceed the MEP standard. 465 Md. at 219 -20 (citing Defenders of Wildlife v. Browner, 191 F.3d at 1164 ). In response to that decision, the EPA had modified its interpretation of the statute in accordance with that decision, and provided that permitting agencies had discretion to include effluent limitations beyond the MEP standard in MS4 permits to satisfy water quality standards. Id. at 220-21. 15 The Court also examined the legislative history of the Water Quality Act of 1987, which had amended the Clean Water Act to include the phased MS4 permit program. Id. at 218.

Upon review of federal legislators’ generalized, aspirational statements, the Court concluded that the legislative history was “not especially illuminating” on this particular issue. Id. 19 The Court concluded that the Department, in developing the permits at issue in Carroll County, had “acted consistently with the EPA’s interpretation of [the Act] – that is, that the Act authorizes permitting agencies to include water quality based effluent limitations in MS4 permits without reference to the MEP standard.” Carroll County, 465 Md. at 224 . The Court further reasoned that the EPA’s interpretation was a reasonable construction and deserved deference. Id.

Accordingly, the Court held “that the Department did not act unlawfully in including a water quality based effluent limitation (the impervious surface restoration requirement) not subject to the MEP standard in the County’s permit.” Id.16 The Court also rejected the county’s argument that, even if permissible under the Act, the impervious surface restoration requirement was arbitrary and capricious. Id. at 224-27 . 2. The Geographic Scope of an MS4 Permit Condition Another key issue in Carroll County involved the geographic scope of an MS4 permit. Both counties argued that, regardless of whether a permit could implement requirements based on water quality, the scope of the regulatory conditions in a permit was necessarily limited to the specific discharges authorized by the permit.

Carroll County, 465 Md. at 229 . In their view, reference to a county-wide baseline of untreated impervious surface area for calculation of the 20 percent restoration requirement “effectively ma[de] 16 The county did not ask the Court to reconsider its holding that permit conditions could exceed the MEP standard. Nor was it one of the issues in the petition for certiorari filed by the other county that was later denied by the Supreme Court. See County Commissioners of Carroll County v. Maryland Department of the Environment, Pet.

No. 19-592, 2019 WL 5802018 . 20 the Counties responsible for pollutants carried by stormwater that does not flow into their MS4s.” Id. In addressing this issue, the Court first noted that nothing in the permit required the counties to undertake restoration requirements outside of the geographic area that drained into the MS4. 465 Md. at 230 . The counties could undertake the 20 percent restoration requirement exclusively within the service area of the respective MS4s such that all improvements designed to comply with the restoration requirement affected only stormwater runoff that first entered an MS4 prior to entering the Chesapeake Bay, rather than stormwater runoff that headed straight for the Bay. The permit imposed no limitation on where the improvements could be made; the broader scope provided greater flexibility to the counties than if it had mandated improvements solely within the MS4 watershed.

Moreover, the Court found that nothing in the text of the Clean Water Act explicitly mandated that these “best practices” occur within the geographic area of the MS4 system. Rather, the Act allowed permits to be issued on a “system-wide” or “jurisdiction-wide” basis. 33 U.S.C. §1342 (p)(3)(B)(i); 465 Md. at 228 . The Court concluded that “the Department’s use of a county-wide baseline as a reference point for calculating the impervious surface restoration condition [did] not exceed the Department’s authority under the Act because the impervious surface restoration condition [is] designed to achieve water quality standards.” 465 Md. at 235 . Nevertheless, the counties argued that the Department’s use of a county’s total impervious surface area as a baseline for the 20 percent restoration requirement exceeded the agency’s authority under the Clean Water Act.

Carroll County, 465 Md. at 231 . 21 According to the counties, an MS4 permit condition could only use a baseline that related directly to discharges of pollutants from the MS4 itself. Id. at 232-33 . The Court found that such an argument undermined the permitting agency’s authority to protect water quality. MS4 permits, like typical NPDES permits, may account for nonpoint source pollution via protection of water quality standards.

While a typical NPDES permit accounts for nonpoint source pollution by increasing the stringency of effluent limitations, no such effluent limitation is possible for MS4 discharges. Carroll County, 465 Md. at 234 , 236 n.66. Instead, the Court noted, MS4 permits impose pollution mitigation programs, such as an impervious surface restoration requirement, as a proxy for a more stringent effluent limitation. Id. at 234 . 3.

Summary In sum, pertinent to this case, the Court held: (1) an MS4 permit may include conditions that go beyond the MEP standard in order to satisfy water quality standards, and (2) such permit conditions may reference areas beyond the boundaries of the MS4 system.17 IV The Present Case This case involves a challenge by Queen Anne’s County to the terms of the general permit for small MS4s developed by the Department. 17 In Carroll County, the counties also objected to their designation as Phase I jurisdictions, asserted that the permits should have provided a water quality trading option, and challenged a somewhat ambiguous permit condition requiring them to cooperate with other entities carrying out responsibilities under State law. The Court rejected those challenges. Carroll County, 465 Md. at 242-63 . Those holdings are not pertinent to the present case. 22 A. The Department Adopts a General Permit for Small MS4s in Maryland 1.

Process for Adoption of the General Permit After the EPA had adopted the initial version of its Phase II regulations for MS4 permits, the Department issued its first general permit for Phase II MS4s, including small MS4s, in 2003. Among other things, that general permit required implementation of the six minimum control measures specified in the EPA regulations. See Maryland Department of the Environment, Fact Sheet (December 2016). Although that general permit had a five-year term, it was administratively extended beyond 2008 by the Department while the EPA Phase II regulations were litigated and ultimately remanded to the EPA for revision.

See Part II.B and footnote 10 of this opinion. In 2016, the EPA issued its revised regulations for small MS4s, and the Department moved forward to develop a new general permit for small MS4s. During mid-2016, the Department consulted with the EPA concerning its draft general permit for small MS4s in light of the EPA’s amended regulations and revised the draft in response to the EPA’s comments. In December 2016, the Department notified the operators of 35 small MS4s in Maryland – six counties and 29 municipalities – of its tentative determination to issue a new general permit for certain small MS4s.

Among those MS4 operators was Queen Anne’s County.18 Relevant to this appeal, the proposed general 18 Queen Anne’s County had not been covered by the initial general permit issued in 2003. As a result of the 2010 census, the Department determined that the County’s MS4 was located in an urbanized area and met the designation criteria for coverage by the EPA’s Phase II regulations. See Small MS4 General Permit at A-2, A-4; see also Maryland Department of the Environment, Designation Letter for Queen Anne’s County (Apr. 27, 2018); 2010 Census Urban and Rural Classification and Urban Area Criteria, U.S. Census 23 permit included a condition that an operator of an MS4 had to restore 20 percent of the total untreated impervious surface area within the urbanized area of the MS4 jurisdiction. The Department held a public hearing on the tentative determination on February 6, 2017, at which the County’s Director of Public Works testified.

In addition, the County submitted written comments by the March 30, 2017 deadline set by the Department, and also joined in comments made by the Maryland Association of Counties and other organizations. Pertinent to this appeal, the County argued that calculation of the 20 percent impervious surface restoration requirement should be based only on acreage in the urbanized area served by the MS4, but that “mitigation efforts … throughout the County … be considered toward meeting the goals of the permit.” The County also joined similar comments made by organizations representing counties and municipalities, arguing that “permittees should be given the flexibility to conduct [impervious surface] restoration anywhere in their geographic area” to limit costs without sacrificing clean water benefits. See Joint Comments of Maryland Association of Counties, Maryland Municipal League, and Maryland Stormwater Association (March 30, 2017) at 6. On April 27, 2018, the Department published its final determination and issued the Small MS4 General Permit pursuant to its permitting authority under State law, as well as its authority as the designee of the EPA for issuance of a NPDES permit.

See Maryland Bureau (Oct. 8, 2021), https://www.census.gov/programs- surveys/geography/guidance/geo-areas/urban-rural/2010-urban-rural.html [https://perma.cc/XS94-BVGP] (download the “Percent Urban and Rural In 2010 by State and County” Excel sheet, see Column N urbanized area data reported for “Queen Anne’s”) (reporting 24,966,886 square meters of Queen Anne’s County designated as “urbanized area”). 24 Department of the Environment, NPDES General Permit for Discharges from Small Municipal Separate Storm Sewer Systems, General Discharge Permit No. 13-IM-5500, General NPDES Permit No. MDR055500 (April 27, 2018) (“Small MS4 General Permit”); see also Fact Sheet (December 2016). In a document entitled Basis for Final Determination, the Department explained decisions made in issuing the permit and responded to some of the public comments that had been made with respect to the draft general permit. Among other things, the Department adopted the recommendation made by the County and others and allowed impervious surface restoration credit for measures taken “anywhere within the jurisdiction.” Basis for Final Determination at 14. The Department also indicated that an owner or operator of a small MS4 retained the option to seek an individualized permit in lieu of accepting the conditions of the general permit.

Small MS4 General Permit at 18-19. 2. Terms and Conditions of the General Permit Parts I and II of the Small MS4 General Permit describe the scope of the permit and certain procedural requirements for an MS4 owner or operator to obtain coverage under the permit. Small MS4 General Permit at 1-2. Part III of the permit states generally that owners and operators of MS4s covered by the permit must implement programs for controlling stormwater discharges in compliance with the Clean Water Act and related regulations.

Small MS4 General Permit at 3. The bulk of the permit’s substantive requirements appear in Part IV and Part V of the permit. The permit provides that compliance with these two Parts satisfies the EPA’s 25 MS4 permit standard, i.e., reduction of the discharge of pollutants to the maximum extent practicable and protection of water quality standards. Small MS4 General Permit at 3.

Part IV provides details concerning implementation of the six minimum control measures, as developed and required by the EPA in its regulations. Small MS4 General Permit at 3-11. Part V sets out the obligations of a permittee as to impervious surfaces. That Part states that the impervious surface restoration requirement is intended to make progress toward achieving pollutant reductions specified in Maryland’s Watershed Implementation Plan (“WIP”).

Small MS4 General Permit at 11. In contrast to a similar requirement in permits for medium and large MS4s, Part V of the permit requires small MS4 permittees to identify untreated impervious surfaces only within the urbanized area, not the entire jurisdiction. Id. at B-10; see also Basis for Final Determination at 14 (explaining that the Department tailored the baseline calculation to urbanized areas in response to comments received during the comment period). Of those surfaces, the permittee identifies those that have little or no existing stormwater management (e.g., street sweeping, storm drain cleaning, land cover conversion).

See Maryland Department of the Environment, Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated (August 2014) (“Accounting Guidance”) at 4. Of this untreated impervious surface area, a county must develop and implement stormwater management for 20 percent of those untreated impervious surfaces by 2025. Small MS4 General Permit at 12-13. Thus, to calculate its restoration requirement, the permittee must determine how many acres of impervious surfaces exist within its urbanized area, determine what portion of those surfaces are 26 untreated, and then divide that untreated portion by five – i.e., calculate the 20 percent target required by Part V of the permit.

Part VI of the permit details recordkeeping and reporting requirements for purposes of assessing compliance with the permit conditions. Small MS4 General Permit at 15-16. Part VII of the permit contains miscellaneous standard permit conditions and sets forth, among other things, the potential penalties for violation of the permit under the Clean Water Act, as well as under various provisions of the Environment Article of the Maryland Code. Id. at 16-20.

B. The County Seeks Judicial Review of the General Permit On May 25, 2018, pursuant to EN §1-601, the County filed a petition for judicial review of the Department’s final determination on the Small MS4 General Permit in the Circuit Court for Queen Anne’s County.19 In July 2018, the County asked the Circuit Court to stay its consideration of the petition on the ground that similar issues were to be decided by this Court in Carroll County, which had not yet been argued or decided. The Circuit Court acceded to that request. Following the publication of this Court’s decision in Carroll 19 The petition identified the petitioners as “Queen Anne’s County and Cecil County (together, the ‘Maryland Small MS4 Coalition’),” all represented by the same counsel. Cecil County later withdrew from the case and dismissed its appeal in the Court of Special Appeals.

The Maryland Small MS4 Coalition, described in the petition as an unincorporated association with an address in Queen Anne’s County, remains the lead petitioner in the caption of the case, but Queen Anne’s County is the only MS4 operator pursuing judicial review of the general permit in this case. The City of Havre de Grace separately filed a petition for judicial review of the Small MS4 General Permit in the Circuit Court for Harford County. In the Matter of Mayor and City Council of Havre de Grace, No. C-12-CV-18-000164. That case was dismissed in November 2021 for lack of prosecution. 27 County, the Circuit Court issued its decision affirming the Department’s final determination with respect to the Small MS4 General Permit.

Memorandum and Order Affirming Agency Decision, In re: Maryland Small MS4 Coalition, et al., No. C-17-CV- 18-000162 (October 17, 2019). The County pursued an appeal of that decision in the Court of Special Appeals. In a reported opinion authored by Judge Glenn T. Harrell, Jr., the Court of Special Appeals largely affirmed the decision of the Circuit Court. Maryland Small MS4 Coalition v. Maryland Department of the Environment, 250 Md. App. 388, 434 (2021).

However, the intermediate appellate court remanded the case to the Department to allow the County to provide additional comments with respect to certain aspects of the Department’s tentative determination.20 Id. The County filed a timely petition for a writ of certiorari, which we granted. The County raises two issues: (1) Whether the impervious surface restoration requirement in the permit unlawfully makes the County responsible for discharges by third parties and nonpoint source runoff; (2) Whether the minimum control measures included in the permit unlawfully impose requirements beyond the MEP standard. With respect to both issues, the County argues that this Court should reconsider its holdings in Carroll County. 20 The Department did not seek further review of the court’s directions concerning the remand, and that part of the decision of the Court of Special Appeals is not before us. 28 V Standard of Review A. Judicial Review of Administrative Action As with other instances of judicial review of a final action of an administrative agency, this Court reviews directly the final determination made by the Department on the permit, not the intervening decisions of the Circuit Court and Court of Special Appeals.

Carroll County, 465 Md. at 201 . However, “[t]hat does not necessarily mean that we need cast aside the work of our colleagues on the intermediate appellate court.” Sturdivant v. DHMH, 436 Md. 584, 587-88 (2014). In this context, the standard of review applied by a court to the Department’s determination, and the corresponding level of deference to the Department, varies depending on whether the court is reviewing fact findings, discretionary decisions, or legal conclusions. Fact Findings.

For fact findings, a reviewing court applies the “substantial evidence” standard, under which the court defers to the facts found and inferences drawn by the agency when the record supports those findings and inferences. Anacostia Riverkeeper, 447 Md. at 120 ; Carroll County, 465 Md. at 201-02 . Matters Committed to Agency Discretion. With respect to matters committed to agency discretion, a reviewing court applies the “arbitrary and capricious” standard of review, which is “extremely deferential” to the agency.

This standard is highly contextual, but generally the question is whether the agency exercised its discretion “unreasonably or without a rational basis.” Carroll County, 465 Md. at 202 (citations omitted). Under this 29 standard, a reviewing court is not to substitute its own judgment for that of the agency and should affirm decisions of “less than ideal clarity” so long as the court can reasonably discern the agency’s reasoning. Id. Legal Conclusions.

With respect to an agency’s legal conclusions, a reviewing court accords the agency less deference than with respect to fact findings or discretionary decisions. Anacostia Riverkeeper, 447 Md. at 122 . In particular, a court will not uphold an agency action that is based on an erroneous legal conclusion. Id.

However, in construing a law that the agency has been charged to administer, the reviewing court is to give careful consideration to the agency’s interpretation. Carroll County, 465 Md. at 202 - 06. B. The Doctrine of Stare Decisis The issues presented for decision in this case are closely related to those decided in the Anacostia Riverkeeper and Carroll County cases. The doctrine of stare decisis – a Latin phrase meaning “to stand by things decided” – is inevitably an important consideration in our decision.

That doctrine “encourages the consistent development of legal principles, public reliance on our judicial decisions, and the perceived integrity of the courts.” State v. Stachowski, 440 Md. 504, 520 (2014). Aside from two “extremely narrow” exceptions, the Court does not disturb the holdings of prior decisions. DRD Pool Serv., Inc. v. Freed, 416 Md. 46, 63 (2010). Those exceptions are when a prior decision was “clearly wrong and contrary to established principles,” or when there have been “significant changes in the law or facts.” Id. at 64 ; see also Wallace v. State, 452 Md. 558, 582 (2017); Lawrence v. State, 475 Md. 384, 416 (2021). 30 Although the doctrine of stare decisis is not absolute, the Court is particularly “reluctant to depart from the principle of stare decisis” in those “areas of the law [where] people do plan and arrange their affairs for the future in reliance upon this Court’s prior rulings.” Austin v. City of Baltimore, 286 Md. 51, 68 (1979) (Eldridge, J., concurring).

Decisions concerning a complex administrative scheme fall into this category. See People v. Mendoza, 23 Cal. 4th 896, 924 (2000) (“A key consideration in determining the role of stare decisis is whether the decision being reconsidered has become a basic part of a complex and comprehensive statutory scheme, or is simply a specific, narrow ruling that may be overruled without affecting such a statutory scheme.”); see generally Richard J. Pierce, Jr., Reconciling Chevron and Stare Decisis, 85 Geo. L.J. 2225 , 2244 (1997). VI Discussion The County presents the same questions, slightly rephrased, that were previously answered in the Carroll County decision.

The County’s arguments boil down to two fundamental issues: (1) whether a permit condition may reference an area beyond the scope of the permittee’s MS4 system, and (2) whether permit conditions may exceed the MEP standard. Both of those questions were answered in Carroll County and application of the holdings in that case to this one is relatively straightforward. Unsurprisingly, the County requests that the Carroll County decision be revisited. We address first whether there is a basis for deviating from the doctrine of stare decisis.

Concluding that there is not, we then apply the holdings of that case to the questions before us. 31 A. Application of the Doctrine of Stare Decisis As indicated above, the Court generally will overrule a prior decision only when that decision was “clearly wrong” or when there has been a “significant change in the law or facts” since the prior decision was issued. 1. Whether Carroll County was “Clearly Wrong” The holdings in Carroll County that the Department may include permit conditions beyond the MEP standard and allocate nonpoint source pollution to MS4 permits to protect water quality were not “clearly wrong.” As the decision in Carroll County elaborated, those conclusions are supported by the plain text of the statute, by the EPA’s formally articulated interpretation of the Act as well as regulations adopted under the Act, and by the extant federal case law. Carroll County, 465 Md. at 210-24 . With all of these sources supporting the Department’s view that it may consider water quality standards in devising conditions for an MS4 permit, one cannot say that Carroll County was “clearly wrong.” The County, however, contends that the holding in Carroll County concerning the role of the MEP standard was “contrary to plain language of the statute,” citing a dissent in Carroll County.

While we respectfully acknowledge there often can be multiple interpretations of a statutory text, we do not disturb this Court’s original interpretation simply because we were asked twice. Moreover, the construction of the statutory text in Carroll County reflects the current interpretation of the statute by the EPA. If the Court was “clearly wrong” in that case, so too is the EPA. Tellingly, no court has concluded that the EPA’s interpretation is wrong. 32 Aside from pointing to the dissent in Carroll County, the County asserts that the decision in that case was inconsistent with the decision in Anacostia Riverkeeper.

However, in Carroll County, the Court explained how this argument mischaracterizes the Anacostia Riverkeeper decision: [T]he holding in Anacostia Riverkeeper was in response to a challenge from a different perspective. Environmental groups argued that the permit term was inadequate to comply with the MEP standard. Here, Frederick County argues, from the opposite perspective, that the permit term unlawfully exceeds that standard. However, for the reasons explicated in the text, we disagree and reach the same outcome that Anacostia Riverkeeper did – that the permit term is valid and authorized by the Act. 465 Md. at 213 n.41; see also Part III of this opinion.

The two decisions are thus quite consistent. In response to challenges from environmental groups, the Anacostia Riverkeeper decision concluded that the permit conditions in question satisfied the baseline MEP standard. In response to a converse challenge from permittees, the Carroll County decision concluded that the Act authorizes permit conditions beyond the MEP standard for the purpose of satisfying water quality standards. Together, the two decisions stand for the proposition that MS4 permit conditions must meet the MEP standard, but may do more to protect the water quality of a waterway.

These two holdings are not in conflict with one another. 2. Whether There has been a “Significant Change” of Circumstances The County argues that, subsequent to the Carroll County decision, “significant actions by the EPA and the Department” amount to a change in the law or facts that counsel against application of the principle of stare decisis. 33 With respect to the EPA, the County points to settlement agreements that the EPA entered into with two states in December 2020 that resolved ongoing litigation and resulted in permit modifications. An agency and a regulated party may decide to settle a case for a variety of reasons – saving the time and resources that would be devoted to litigation, obtaining an expeditious result, and avoiding the risk of an adverse precedent. It would be inappropriate to infer a significant change in the EPA’s interpretation of the Clean Water Act simply from its decision to settle two cases shortly before a change in federal administrations.

In any event, whatever potential change in a policy that may be