Harrell, J.
This appeal flows from a petition, filed in the Circuit Court for Queen Anne's County, requesting judicial review of a final determination of the Maryland Department of the Environment ("Department"), appellee, to issue a conditional general stormwater discharge permit to a number of operators of "small" municipal separate storm sewer systems (MS4s) (we shall do a deeper dive explaining this term shortly), including Queen Anne's County ("the County"), appellant. The circuit court affirmed the Department's final determination.
The County noted an appeal from the decision of the circuit court, presenting the following questions for our consideration:
For the following reasons, we shall vacate, in part, the judgment of the circuit court and remand to that court with instructions to remand the matter to the Department for further proceedings consistent with this opinion. We shall affirm otherwise the judgment.
BACKGROUND
A. Statutory and Regulatory Scheme
The permit here was issued by the Department pursuant to authorization under the federal Clean Water Act, 33 U.S.C. § 1251 through § 1388 ("CWA"). Congress enacted the CWA in 1972 to "restore and maintain the chemical, physical, and biological integrity of the Nation's waters." 33 U.S.C. § 1251(a). One of the core provisions
"Through the National Pollution Discharge Elimination System ("NPDES"), 33 U.S.C. § 1342, either the Environmental Protection Agency ("EPA") or an EPA-approved state, such as Maryland, may issue permits exempting a discharger from this prohibition." Maryland Department of the Environment v. Anacostia Riverkeeper, 447 Md. 88, 96, 134 A.3d 892 (2016) (footnote omitted). The Department is authorized by the EPA to administer the NPDES program in Maryland. Id. (citing Code of Maryland Regulations ("COMAR") 26.08.04.07).
Maryland's NPDES permit program must be consistent with the CWA and with EPA guidelines. 33 U.S.C. § 1342(c)(2). "To achieve water quality standards, the [CWA] requires that discharge permits include pollution controls for point sources." Carroll County, 465 Md. at 186, 214 A.3d 61 (citing 33 U.S.C. § 1311(b)).
"`Generally speaking, the NPDES requires dischargers to obtain permits that place limits on the type and quantity of pollutants that can be released into the Nation's waters.'" Anacostia Riverkeeper, 447 Md. at 96, 134 A.3d 892 (quoting S. Fla. Water Mgmt. Dist. v. Miccosukee Tribe, 541 U.S. 95, 102, 124 S.Ct. 1537, 158 L.Ed.2d 264 (2004)). "These limits are called effluent limitations."
At issue in this appeal is a permit for a type of "point source" discharge known as a municipal separate storm sewer system, commonly referred to as an MS4. "An MS4 is a network of conveyances (including storm drains, gutters, and other drainage systems) designed to carry only stormwater (as opposed to a `combined sewer system' that conveys both sanitary sewage and stormwater)." Carroll County, 465 Md. at 188, 214 A.3d 61 (citing 40 C.F.R. § 122.26(b)(8)). "Stormwater" is the "rain and snowmelt that filters through the soil and courses over surfaces — collecting pollutants along the way — before passing through the municipal storm sewer systems and into waterbodies." Anacostia Riverkeeper, 447 Md. at 97, 134 A.3d 892 (footnote omitted).
MS4s differ from other "point sources" of water pollution, such as a discharge pipe from a factory, in that the quantity and quality of stormwater that is conveyed by an MS4 into a waterway varies, depending on weather and land use practices. Carroll County, 465 Md. at 188-89, 214 A.3d 61. In addition, it is "difficult
"Best management practices," or, as they are commonly referred to, "BMPs," "have been a long-standing control or effluent limitation in MS4 permits." Anacostia Riverkeeper, 447 Md. at 99, 134 A.3d 892 (citing 40 C.F.R. §§ 122.44(k)(2) and (3)). EPA regulations define BMPs as "[m]ethods, measures or practices selected by an agency to meet its nonpoint source control needs." 40 C.F.R. § 130.2(m). "BMPs include but are not limited to structural and nonstructural controls and operation and maintenance procedures." Id. The EPA has defined BMPs more specifically, stating that "BMPs can be either nonstructural (good housekeeping practices, pollution prevention, contour plowing, cover crops) or structural (wet or dry detention ponds), and can include treatment requirements, operating procedures, and practices to control site runoff, spillage, or leaks."
The NPDES discharge permit program for MS4s has been put into operation in two phases, beginning with systems serving larger and denser populations. Phase I included "large" MS4s, which serve populations of 250,000 or more, and "medium" MS4s, which serve populations of 100,000 to 249,999. Carroll County, 465 Md. at 243-44, 214 A.3d 61.
Significantly, not all small MS4s are subject to regulation under the NPDES program. Operators of small MS4s, including, but not limited to, systems operated by federal, state and local governments, require a permit to discharge stormwater only if: (1) the small MS4 is located within
To determine whether small MS4s that are located outside of an urbanized area should be subject to regulation, the Department must first "[d]evelop criteria to evaluate whether a storm water discharge results in or has the potential to result in exceedances of water quality standards, including impairment of designated uses, or other significant water impacts, including habitat and biological impacts." 40 C.F.R. § 123.35(b)(1)(i). The permitting authority then must apply that criteria to small MS4s located outside of an urbanized area.
Under certain conditions, the Department may waive or phase-in the requirements applicable to regulated small MS4s. 40 C.F.R. § 122.32(d) and (e); § 123.35(d). Where a general permit is issued, an owner or operator of a small MS4 may request to be excluded from the coverage of the general permit by applying for an individual permit. 40 C.F.R. § 122.28(b)(3)(iii).
The procedure the Department must follow in issuing a permit is set forth in the Environment ("EN") Article. It requires "published notice of permit applications (EN § 1-602), informational meetings (EN § 1-603), and publication of [the Department's] tentative determination (EN § 1-604(a))." Potomac Riverkeeper, Inc. v. Maryland Department of the Environment, 238 Md.App. 174, 204, 189 A.3d 819 (2018). "If the tentative determination is to [issue the permit], EN § 1-604(a)(3) requires [the Department] to prepare a draft permit and `publish a notice of the tentative determination' that provides 30 days for public comment, and, if requested, hold a public hearing pursuant to EN § 1-604(a)(4)." Id.
If, during the notice and comment period, the Department receives comments adverse to its tentative determination, the Department is required to prepare and publish a notice of the final determination. EN § 1-604(b).
A final determination of the Department to issue a discharge permit is subject to judicial review in the circuit court. EN § 1-601(c). The decision of the circuit court may be appealed to this Court. EN § 1-601(e)(2).
B. Tentative Determination
On 22 December 2016, the Department notified the County and 34 other counties and municipalities of its tentative determination to issue an NPDES general permit for discharges from small MS4s. The County was one of 13 newly designated for coverage under the Phase II permitting process. A draft of the permit was made available for review. The Department advised that a public hearing concerning the tentative determination would be held on 6 February 2017, and that written comments concerning the tentative determination would be accepted through 30 March 2017.
Pertinent to this appeal, the Department's tentative determination was that all MS4s throughout the County were subject to regulation under the general permit. The Department's stated justification was that the County as a whole "is located within an urbanized area."
Also relevant is a proposed condition of the permit that requires permittees to initiate efforts to restore twenty percent of the total impervious surface area within the urbanized area of the MS4 jurisdiction that has little or no stormwater management.
C. Comment Period
The County participated in the public hearing. Todd Mohn, the County's Director of Public Works, gave brief comments in which he questioned the County-wide designation based on location within an urbanized area. Mr. Mohn stated that the tentative determination was still under review and that the County reserved the right to provide further comment.
In written comments submitted on 30 March 2017, the County maintained that the scope of the proposed permit was overbroad, as less than four percent of the County fell within an urbanized area as defined by statute and regulation. The County commented further that the draft permit should be clarified to state that the twenty percent restoration requirement applied only to the impervious coverage within the legitimate urbanized area that is served by the County's MS4. The County expressed support for the joint comments submitted by the Maryland Association of Counties, the Maryland Municipal League, and the Maryland Municipal Stormwater Association (collectively, "Associations").
One of the concerns articulated in the Associations' comments was that the Department
In addition, the Associations asserted that the baseline impervious area assessment used to calculate the twenty percent restoration requirement should not include any impervious area not served by the MS4. The Associations maintained that "a permittee is not responsible for nonpoint sources (properties with sheet flow from the parcel[s] into streams, creeks, etc.) and third-party direct dischargers (properties with their own discharge points into streams, creeks, etc.) that do not enter into and are not discharged from the permittee's MS4."
A third concern raised by the Associations is that the twenty percent restoration requirement and other terms of the permit exceeded the "maximum extent practicable" ("MEP") standard for many potential permittees and was therefore unlawful.
D. Final Determination
On 27 April 2018, the Department issued a final determination to issue the general permit, together with a document entitled "Basis for Final Determination" that provided an explanation for its actions and responded to public comments addressed to the tentative determination. The Basis for Final Determination included information regarding a process and criteria used to designate MS4s located in non-urbanized areas. The Department also addressed comments regarding impervious area restoration requirements and concerns about permit conditions in excess of the MEP, into which we shall delve in greater detail later in this opinion.
Contemporaneous with the final determination, the Department sent a letter to the County, stating a different rationale than in the tentative determination for designating the entire geographic area of the County. In lieu of justifying inclusion of the County as a whole, based on a finding that it was located within an urbanized area, the Department explained, apparently for the first time, that it had evaluated MS4s outside of the urbanized areas and determined that the "County's stormwater discharges result in or have the potential to result in exceedances of water quality standards or other significant water quality impacts," and therefore were subject to regulation pursuant to 40 C.F.R. § 123.35(b)(1)(i).
The Department described the designation process and criteria as follows:
The Department stated that, in accordance with that process and criteria, it had evaluated MS4s in the County that are located outside the urbanized area and made the following findings:
After setting forth its findings, the Department concluded that:
The County did not submit a Notice of Intent, but filed instead a petition for judicial review of the Department's final determination. The circuit court affirmed the Department's decision to approve and issue the general NPDES discharge permit. This appeal followed.
STANDARD OF REVIEW
"In an appeal of the circuit court's review of an agency action, an appellate court reviews the agency's action itself rather than the decision of the circuit court." Carroll County, 465 Md. at 201, 214 A.3d 61 (citing Hollingsworth v. Severstal Sparrows Point, LLC, 448 Md. 648, 654, 141 A.3d 90 (2016)). "Our role is `limited to determining if there is substantial evidence in the record as a whole to support the agency's findings and conclusions, and to determine if the administrative decision is premised upon an erroneous conclusion of law.'" Richardson v. Maryland Dep't of Health, 247 Md.App. 563, 569, 239 A.3d 695 (2020) (quoting Milliman, Inc. v. Md. State Ret. and Pension Sys., 421 Md. 130, 151, 25 A.3d 988 (2011)), cert. denied sub nom. Richardson v. Md. Dep't of Health, 472 Md. 17, 243 A.3d 1205 (2021).
"The standards for judicial review of a discharge permit — and their corresponding levels of deference to the agency — vary depending on whether the court is reviewing an agency's fact findings, discretionary decisions, or legal conclusions." Carroll County, 465 Md. at 201, 214 A.3d 61 (citing Anacostia Riverkeeper, 447 Md. at 118-21, 134 A.3d 892). The Court of Appeals summarized these varying standards as follows:
Id. at 201-03, 214 A.3d 61.
Our review of the Department's final determination to issue the permit is based on the administrative record before the Department. EN § 1-601(d). We limit our review to objections raised during the public comment period. Id. If, however, the petitioner seeking judicial review demonstrates that "(i) [t]he objections were not reasonably ascertainable during the comment period; or (ii) [g]rounds for the objection arose after the comment period[,]" we must remand to the Department for consideration of such objections. Id. Remand is not required "if the proffered new objections are not materially different from objections that were already considered" by the Department. Potomac Riverkeeper, 238 Md. App. at 205, 189 A.3d 819.
ANALYSIS
The County identifies two provisions of the permit as relevant to this appeal. The first is the designation of the area subject to regulation. The County argues that the Department's designation of areas outside of the actual urbanized area of the County (1) exceeded the Department's authority, (2) was procedurally deficient, and (3) was not supported by substantial evidence.
The second provision the County challenges is the requirement that it commence restoration efforts for twenty percent of impervious acreage within the urbanized area. The County asserts that this condition unlawfully makes it responsible for third-party and nonpoint source stormwater discharges.
The County further asserts that the Department lacks authority to impose conditions that exceed the "maximum extent practicable" standard, and, therefore, the restoration requirement and any other permit conditions that exceed that standard are invalid. We shall address the County's contentions in turn.
I. Designation of Area Subject to Permit
The County concedes that the portion of its MS4 that is located in the actual urbanized area is subject to regulation under the CWA. The County asserts, however, that the Department's designation of MS4s outside of the urbanized area, based on purported links to broader and perhaps non-contemporary water quality impairments, was contrary to federal and State law because (1) the Department did not provide notice of the process or criteria used in the designation process until after the opportunity for public comment expired, and (2) the Department's finding of a causal or potentially causal connection
The Department maintains that the County had ample opportunity to raise concerns regarding the area of designation because the County participated in informal discussions regarding the designation criteria in the federal regulations and their applicability to the County. The Department asserts further that, based on data showing impairments in water quality in rivers and streams flowing through the County, it was reasonable for the Department to find that County-operated MS4s located outside of the urbanized area at least contributed potentially to excesses in water quality standards or resulted in other significant water quality impacts in the County.
Based on our review of the administrative record, we conclude that, pursuant to EN § 1-601(d), remand is required because the grounds for the Department's ultimate determination that there was a link between the County's MS4s and water quality impairments were not reasonably ascertainable during the comment period, but were evident only when the final determination was issued, after the comment period expired. We explain.
When the Department issued its tentative determination and published the draft general permit for public comment, the justification for designating all County-operated MS4s for regulation under the general permit was they were "located within an urbanized area." The County objected to that justification on grounds that only a small area of the County was actually an urbanized area. In the Department's final determination, however, it revised its justification for designating all MS4s in the County, asserting that, based on criteria which apparently had not been made public previously, the Department had determined that "[s]tormwater discharges inside and outside of the County's urbanized area contribute to [] water quality impairments[,] and future MS4 discharges have the potential to cause significant water quality impacts."
The Department's contention that the County had an opportunity to object to the Department's designation of MS4s outside of the urbanized area prior to the issuance of the final determination is not supported by the record. The email correspondence that the Department highlights in support of this contention was sent prior to the tentative determination and explains the designation of the entire County pursuant only to the urbanized area criteria in 40 C.F.R. § 122.32(a)(1). The Department points also to documentation that demonstrates generally that the County participated in informal meetings regarding the Department's tentative determination. We can find nothing in that documentation, or elsewhere in the record, however, demonstrating that, prior to the expiration of the comment period, the County was put on notice of the Department's determination that MS4s outside of the County's actual urbanized area were subject to regulation based on a purported link to water quality impairments, pursuant to 40 C.F.R. § 123.35(b)(1)(i). Nor does it appear that such a determination was a foreseeable response to the comments made during the public comment period. Cf. Potomac Riverkeeper, 238 Md. App. at 211, 189 A.3d 819 (holding that interested parties had adequate opportunity to anticipate and comment on terms of final permit as such terms were a reasonably foreseeable response to public comments). We conclude that the County's objections to the final determination regarding the area of designation were not "reasonably ascertainable" during the comment period, but were evident
Consequently, pursuant to EN § 1-601(d), remand is required to allow the County an opportunity to comment on the Department's determination that MS4s outside of the urbanized area of the County are subject to regulation under the NPDES, and so that the Department may consider the County's objections. To those ends, we shall vacate the circuit court's judgment affirming the Department's final determination as it pertains to the area of the County that is subject to regulation under the general permit and remand to the circuit court with instructions to remand to the Department for further proceedings consistent with this opinion.
Because the County concedes that the portion of its MS4 located within the actual urbanized area is subject to the permitting requirements of the Clean Water Act, we shall consider the remaining issues as they may apply to whatever the permit area turns out to be.
II. Responsibility for Nonpoint Source Runoff and Third-Party Discharge?
The County contends that the Department exceeded its jurisdictional authority by imposing permit conditions that assign responsibility to the County to remediate pollutants in stormwater that does not enter the County's MS4, such as nonpoint source runoff or third-party discharge. In support of this contention, the County relies on 40 C.F.R. § 122.26(a)(9)(i)(A), which, as it applies to small MS4s, provides that "for discharges composed entirely of storm water ... operators shall be required to obtain a NPDES permit only if ... [t]he discharge is from a small MS4 required to be regulated pursuant to [40 C.F.R.] § 122.32." (emphasis added).
On this point, the County focuses primarily on the requirement to restore twenty percent of all untreated impervious surface within the urbanized area. Because the entire urbanized area of the County is not served by the County's MS4, requiring restoration of twenty percent of the total impervious surface area within the urbanized area makes the County responsible for nonpoint source runoff that does not enter and therefore is not discharged from its MS4. Similarly, the County claims that the total impervious surface in the urbanized area includes privately-owned industrial, residential, and commercial developments that often have their own stormwater drainage systems and, therefore, the requirement to restore twenty percent of the total impervious surface area in the urbanized area assigns responsibility for third-party point source discharge that is not discharged from the County's MS4.
The Department responds that neither the impervious restoration requirement nor any other provision of the general permit makes the County responsible legally
A. Chesapeake Bay TMDL and the Maryland Watershed Implementation Plan
Under the CWA, each state is directed to "identify waterways for which technology based effluent limitations are not achieving water quality standards." Carroll County, 465 Md. at 191, 214 A.3d 61 (citing 33 U.S.C. § 1313(d)(1)(A)) (footnote omitted). "If water quality standards are not being met in a waterway due to excess levels of a particular pollutant, the state is to determine the maximum amount of that pollutant that the waterway can receive without violating water quality standards — i.e., the TMDL [total maximum daily load] for that pollutant as to that waterway." Id. (citing 33 U.S.C. § 1313(d)(1)(C)). In other words, a TMDL is a "cap on the pollutant[,]" or, as it is sometimes referred to, a "`pollution budget' or `pollution diet.'" Id. (citation omitted).
Generally, pollution limits established in a TMDL are apportioned to the relevant sources of that pollution, which include point sources and nonpoint sources. Carroll County, 465 Md. at 192, 214 A.3d 61 (citing 40 C.F.R. §§ 130.2(i), 130.7(c)). As alluded to earlier, a point source is defined as "any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, channel, [or other types of conveyance], from which pollutants are or may be discharged." 33 U.S.C. § 1362(14). By contrast, nonpoint source pollution "comes from dispersed areas like farms or fields where water runs off the land without being collected or channeled into a point source." Carroll County, 465 Md. at 184, 214 A.3d 61 (footnote omitted). "The [CWA] does not require permits for nonpoint sources or otherwise directly regulate them[,]" although states, including Maryland, have regulatory programs that address nonpoint sources of water pollution. Id. at 185, 214 A.3d 61.
"The portion [of pollutant limits] assigned to each relevant point source is called a `wasteload allocation.'" Id. at 192, 214 A.3d 61 (citing 40 C.F.R. § 130.2(h)). "The portion assigned to each nonpoint source is called a `load allocation.'" Id. (citing 40 C.F.R. § 130.2(g)). "[T]he TMDL — in the sense of a numeric amount — for a given pollutant for a particular waterway is the sum of the wasteload allocations, the load allocations, the natural background, and the margin of safety." Id. (citing 40 C.F.R. §§ 130.2(i), 130.7(c)(1)).
In 2010, the EPA established a TMDL for the Chesapeake Bay, as part of an effort to restore the water quality of the Bay. See Anacostia Riverkeeper, 447 Md.
To achieve the goals of the Bay TMDL, the EPA directed each Bay jurisdiction to create a "Watershed Implementation Plan" ("WIP"), which "functions as a `roadmap' for how and when the State will reach the pollution reduction goals set forth in the Bay TMDL." Carroll County, 465 Md. at 194-95, 214 A.3d 61 (citing Anacostia Riverkeeper, 447 Md. at 109, 134 A.3d 892). Each state was expected to subdivide the Bay TMDL allocations among pollutant sources and evaluate "current legal, regulatory, programmatic and financial tools available to implement the allocations; identify and rectify potential shortfalls in attaining the allocations; describe mechanisms to track and report implementation activities; provide alternative approaches; and outline a schedule for implementation." Chesapeake Bay TMDL Executive Summary, 8-9.
Maryland's WIP subdivided the Bay TMDL according to the following source sectors: wastewater, septic systems, regulated stormwater, sediment and erosion control, concentrated animal feeding operations, agriculture, atmospheric sources, and "other sources." Maryland's Final Phase I Watershed Implementation Plan — Executive Summary (Dec. 3, 2010) ("Maryland WIP"), ES-8.
B. General Permit Impervious Restoration Requirement
The Maryland WIP strategy to implement impervious surface restoration
In addition to calculating the total impervious acres within the urbanized area, each permittee must submit information regarding the acreage within that area that is already treated with BMPs. The restoration requirement applies to twenty percent of the total impervious surface in the urbanized area that has no such treatment. The general permit requires permittees to commence restoration activities that will achieve the twenty percent restoration requirement by 2025.
C. Maryland Department of the Environment v. Carroll County, et al.
The potential impact of this case compels a closer look. In 2014, Carroll County and Frederick County ("counties") were issued renewed Phase I permits for their respective medium MS4s. Carroll County, 465 Md. at 197, 214 A.3d 61. The permits included a requirement to restore twenty percent of impervious surface based on a county-wide total of unrestored impervious surface, although the counties' MS4s serve only a portion of the counties' geographic area. Id. at 230-31, 214 A.3d 61. The counties appealed, asserting the same argument made here: specifically, that NPDES permits regulate discharges of pollutants only from the MS4 itself, and, therefore, the county-wide baseline for impervious surface restoration exceeded the Department's authority under the CWA, as it made effectively the permittees responsible for discharges that never entered their MS4 systems. Id. at 231-33, 214 A.3d 61. The Court of Appeals rejected that argument and upheld the county-wide impervious surface calculation as a basis for restoration requirements. Id. at 264, 214 A.3d 61.
The Court of Appeals began its analysis that led to that holding by noting that "the impervious surface restoration term is a water quality based effluent limitation authorized by 33 U.S.C. § 1342(p)(3)(B)(iii)."
The Court then noted that, according to EPA regulations, water quality based effluent limitations, such as impervious surface restoration, must be "derived from applicable water quality standards, without reference to a practicability test."
In explicating its rationale, the Court noted with approval an EPA policy allowing permitting authorities to allocate pollutant loads between point and nonpoint sources as needed to achieve the TMDL limit, "including potentially ratcheting up the requirements on point sources when necessary." Id. at 236, 214 A.3d 61. The Court concluded: "[t]hus, nonpoint source pollution reduction may be assigned to point sources — i.e. through wasteload allocations in the development of TMDLs." Id. at 237, 214 A.3d 61.
The Court noted further that, pursuant to 40 C.F.R. § 122.44(d)(1)(vii)(B), point source permits must "contain effluent limitations consistent with the `assumptions and requirements' in wasteload allocations in applicable TMDLs."
Id. at 238, 214 A.3d 61.
D. Analysis
The Department's response to adverse comments to the tentative determination to require MS4 permittees to restore twenty percent of untreated impervious surface throughout the urbanized area of the permittee's jurisdiction, including acreage that is not served by the MS4, was as follows:
We agree with the Department that, under Carroll County, the general permit condition that requires the County to commence restoration efforts on twenty percent of the impervious surface in the urbanized area does not exceed the Department's jurisdiction because just as in Carroll County, the permit condition at issue in this appeal is "a numeric water quality based effluent limitation corresponding to Maryland's stormwater wasteload allocation within the Bay TMDL." 465 Md. at 238, 214 A.3d 61.
The County attempts to distinguish Carroll County, asserting that the rationale for upholding the restoration requirement for medium MS4 operators was that responsibility for pollutant loads from nonpoint sources "had been ... assigned to [medium MS4 operators] in the Chesapeake Bay TMDL." The County argues that the Bay TMDL, which was issued in 2010, did not "assign" responsibility to small MS4s for nonpoint source runoff and, therefore, the rationale in Carroll County does not apply here. We disagree.
As discussed, Maryland's WIP, which was submitted in 2010, the same year as the TMDL was established, called for an impervious surface restoration provision in all MS4 permits, including permits to be issued, beginning in 2012, to small MS4s, during Phase II of the permitting process. The Court of Appeals noted that the general permit applicable to Phase II small MS4s includes an impervious surface restoration term, Id. at 229 n.58, 214 A.3d 61, but the Court did not limit its holding to Phase I permits. Accordingly, we find no merit in the County's claim that Carroll County is distinguishable because the permittees in that case were medium MS4s that had previously been "assigned" responsibility for nonpoint source pollution.
As the Court of Appeals observed, pursuant to 40 C.F.R. § 122.44(d)(1)(vii)(B), "the discharge permit for each point source is to contain water quality based effluent limitations consistent with the `assumptions and requirements' of the wasteload allocation for that source in any applicable TMDL." Id. at 193, 214 A.3d 61. We find nothing in the federal regulations to suggest that a new discharge permit that is issued after a TMDL has been established is exempt from water quality based effluent limitations consistent with attaining that TMDL. We agree with the Department that the notion that the County advances — that the consistency requirement does not apply to any MS4 that was unregulated when the Bay TMDL was issued in 2010 — is contrary to the premise of a TMDL, which is "designed to achieve water quality standards." Id. at 235, 214 A.3d 61.
In sum, we conclude that the impervious surface restoration requirement in the general permit, like that in Carroll County, is an authorized water quality based effluent limitation that represents a valid reallocation of pollutant loads from nonpoint sources to point sources and that implements a stormwater wasteload allocation in the Bay TMDL.
III. Permit Conditions in Excess of the Maximum Extent Practicable?
As we noted earlier in this opinion, it is not feasible to apply numeric effluent limitations to the regulation of stormwater. Accordingly, "Congress adopted a flexible approach to the control of pollutants in MS4s." Anacostia Riverkeeper, 447 Md. at 98, 134 A.3d 892. (citing 55 Fed. Reg. 48,038). In lieu of numeric effluent limitations that are applied to other point sources, municipal stormwater permits "shall require controls to reduce the discharge of pollutants to the maximum extent practicable...." 33 U.S.C. § 1342(p)(3)(B)(iii).
"Maximum extent practicable" is not defined in the CWA or by the EPA. The "EPA has intentionally not provided a precise definition of MEP to allow maximum flexibility in MS4 permitting[,]" based on the rationale that "MS4s need the flexibility to optimize reductions in storm water pollutants on a location-by-location basis." EPA, National Pollutant Discharge Elimination System—Regulations for Revision of the Water Pollution Control Program Addressing Storm Water Discharges — Final Rule, 64 Fed. Reg. 68722, 68754 (December 8, 1999) (codified at 40 C.F.R. § 122.34).
The County maintains that, aside from the impervious surface restoration requirement, the permit contains other beyond-MEP conditions that cannot be considered "water quality based effluent limitations," and, therefore, are not valid under Carroll County. Specifically, the County points to permit conditions that require mapping of the MS4 system, screening of outfalls, and implementation of "good housekeeping" plans for municipal properties where specified "key" activities are conducted.
The Department responds that the mapping, good-housekeeping, and pollution prevention permit conditions are water quality based conditions because they control indirectly the discharge of pollutants, but that, in any event, federal regulations allow imposition of conditions that are not "water quality based" if needed to protect water quality. Alternatively, the Department submits that the conditions challenged by the County do not exceed MEP and/or are otherwise authorized under federal law.
Permit requirements for small MS4s are set forth in 40 C.F.R. § 122.34. Subsection (b) of the regulation provides that such permits must "include requirements that ensure the permittee implements, or continues to implement" six "minimum control measures" ("MCMs") in the following categories: (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 development and redevelopment; and (6) pollution prevention/good housekeeping for municipal operations. 40 C.F.R. § 122.34(b). The permitting authority must identify the minimum elements for each MCM, although the regulations set forth specific minimum requirements for some MCMs and provide general guidance.
The Mapping requirement
To implement the MCM, which is aimed at the detection and elimination of illicit discharges into the MS4, regulated small MS4s are required to develop a system map. In pertinent part, the regulation provides that, "at a minimum," the permittee must be required to develop a map showing "the location of all outfalls and the names and location of all waters of the United States that receive discharges from those outfalls[.]" 40 C.F.R. § 122.34(b)(3)(i)(A). The draft permit that accompanied the tentative determination required permittees to maintain a map of the MS4 "which identifies all pipes, outfalls, inlets, stormwater management best management practices (BMPs), illicit discharge screening locations, and surface waters[.]"
In response to public comments regarding the required map features, the Department explained that "BMPs that manage stormwater are part of an MS4 and therefore are required to be mapped under this
The Department acknowledged that "the number of inlets could be substantial and will require a significant effort to map[,]" and, on those grounds, removed inlets from the mapping requirements for the current permit term. The Department noted that language in the final permit was "revised to include stormwater conveyances to clarify that the MS4 is not limited to pipe infrastructure."
In the final permit, the mapping condition reads as follows:
The County asserts that the mapping requirement is beyond MEP because it "far exceed[s]" federal requirements. We are not persuaded so. The federal regulation requires that "at a minimum," permittees must be required to map outfalls and receiving waters. 40 C.F.R. § 122.34(b)(3)(i)(A). It is otherwise up to the permitting authority to identify additional minimum elements to ensure that permittees develop, implement, and enforce a program to detect and eliminate illicit discharges into the MS4. Moreover, subsection(c) of the regulation vests the Department with discretion to include "[m]ore stringent terms and conditions, including permit requirements that modify, or are in addition to, the minimum control measures ... where the [Department] determines such terms and conditions are needed to protect water quality." 40 C.F.R. § 122.34(c)(1). In accordance with the regulations, the Department identified two other map elements that it deemed essential: stormwater conveyances and BMPs.
As noted previously, in reviewing the exercise of discretion by an agency in its decision making, we do not substitute our judgment, but rather defer to the agency, unless its discretion was exercised unreasonably or without a rational basis. Carroll County, 465 Md. at 202, 214 A.3d 61. We are satisfied that the Department articulated a rational basis for requiring map features in addition to the minimum requirements set forth in the regulation.
The County asserts further that the Department's decision that the mapping requirement does not exceed MEP is not supported by substantial evidence. Again, we disagree.
In response to comments that the mapping requirement "may not be practical[,]" and is "well beyond an MEP level of effort over the five-year permit term," the Department
The County appears to interpret the phrase "continually mapping" as evidence that existing small MS4s had been unable to comply with mapping requirements. Based on that interpretation, the County argues that the Department "failed to address how it is practicable for newly designated Small MS4 permittees to complete the onerous mapping process" in five years when other permittees had been working on their maps for over a decade. We disagree with the County's interpretation of the Department's response.
When applying the substantial evidence test, we review the evidence in the light most favorable to the agency, "because agency decisions are presumed prima facie correct[.]" Maryland State Highway Admin. v. Brawner Builders, Inc., 248 Md.App. 646, 657, 242 A.3d 1188 (2020). We ask "`whether a reasoning mind reasonably could have reached the factual conclusion the agency reached.'" GenOn Mid-Atl., LLC v. Maryland Dep't of the Env't, 248 Md.App. 253, 267, 241 A.3d 40 (2020) (quoting Anacostia Riverkeeper, 447 Md. at 120, 134 A.3d 892). "We defer to the agency's fact-finding and any inferences that the record supports." Id.
Viewing the evidence in the light most favorable to the Department, as well as in context, we construe the Department's explanation to mean that existing small MS4s had been able to comply with requirements to develop and maintain an updated map of their systems, i.e. "continually map" their systems, including charting of inlets. Accordingly, the Department inferred that it would not be impracticable for new permittees to comply with the less demanding mapping condition in the final general permit, which did not require location of inlets because of the "significant effort" involved. We conclude that the record supports the Department's decision that the mapping requirement in the general permit does not exceed MEP.
The Outfall Screening provision
The regulations concerning permit requirements for the illicit discharge detection and elimination MCM provides guidance for permitting authorities, stating that the "EPA recommends that the permit require the permittee to visually screen outfalls during dry weather and conduct field tests of selected pollutants as part of the procedures for locating priority areas." 40 C.F.R. § 122.34(b)(3)(iii). In accordance with that recommendation, the outfall screening provision in the general permit requires permittees to screen twenty percent of total outfalls each year, up to a limit of 100 outfalls annually.
In response to public comments that outfall screening would, for some small MS4 permittees, be equal to what is required for medium MS4s, the Department explained that the decision was based on "current level of effort of existing small MS4 permittees," some of which were "already screening close to 100 structures annually and exceeding requirements by conducting chemical tests of dry weather flows."
The Good Housekeeping provision
Pursuant to 40 CFR § 122.34(b)(6), permits issued to small MS4s must "identify minimum elements and require the development and implementation of an operation and maintenance program that includes a training component and has the ultimate goal of preventing or reducing pollutant runoff from municipal operations." The regulation includes guidance from the EPA which recommends that the permit conditions address the following:
40 C.F.R. § 122.34(b)(6)(ii).
In accordance with that regulation, the general permit issued by the Department requires permittees to "develop, implement, and maintain a pollution prevention plan at publicly owned or operated properties." The plan must include a description of site activities; a list of potential pollutants stored or used on site; written procedures designed to prevent discharge of pollutants; written procedures to address any on site release, spill or leak; and documentation of any such release, spill, or leak and corresponding response actions. The general permit also requires annual training for staff and contractors and documentation of pollution prevention efforts related to application of pesticides and fertilizer, snow and ice control, street sweeping, and inlet cleaning.
Objections to the good housekeeping provisions included comments that it (a) would be too time consuming, due to the number of properties involved, and (b) would serve little purpose, because not all publicly owned or operated properties discharge into the MS4. In response to that comment, the Department added language to the permit to clarify that (a) permittees may create a standard plan for multiple facilities with similar operations, and (b) the requirement applied only to properties where certain "key site activities are performed that have a risk of discharging pollutants into stormwater."
CONCLUSION
Grounds for the County's objections to the determination that there was a link between the County's MS4s outside the urbanized area and water quality impairments were not ascertainable reasonably during the comment period. Accordingly, remand to the Department is required to allow the County an opportunity to comment on that proposed tentative determination.
We hold that, under the Court of Appeals' decision in Carroll County, the Department did not exceed its authority under the Clean Water Act when it directed that the amount of impervious surface to be restored be determined based on the total impervious surface within the urbanized area of the County that has little or no stormwater management.
Finally, we conclude that the Department articulated a rational basis and/or relied on substantial evidence in determining that mapping, outfall screening, and "good housekeeping" permit conditions did not exceed the "maximum extent practicable" standard.
FootNotes
As we understand Carroll County, the Department is authorized to impose an impervious surface restoration requirement that represents a reallocation of nonpoint source discharge to a point source in order to comply with the TMDL. If the Department's determination to include the requirement may be affirmed on that basis, the alternative third-party argument is inconsequential.
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