Maryland Department of Environment v. Anacostia Riverkeeper, 134 A.3d 892

Background

MDE issued five-year NPDES MS4 permits to Anne Arundel, Baltimore City, Baltimore County, Montgomery, and Prince George’s Counties requiring programs and specific actions (including restoring 20% of pre-2002 impervious surfaces) to reduce stormwater pollutant discharges to the maximum extent practicable (MEP).
Permits incorporate Maryland Stormwater Design Manual (2000) BMPs, and reference an MDE Guidance (Accounting for Stormwater Wasteload Allocations and Impervious Acres Treated) that prescribes models, a credits-to-acres accounting method, and use of 2002 as the baseline year.
Permits require annual monitoring (chemical, biological, physical) at selected sites, pollutant load estimation, watershed assessments, TMDL implementation plans to address WLAs, and adaptive management (MDE review and required BMP/program modification if progress toward WLAs is lacking).
Environmental groups (“Water Groups”) challenged the permits on multiple grounds: that the 20% restoration mandate is vague/unenforceable or not MEP-compliant; that TMDL/WLA implementation plans constitute post-issuance permit modifications that evade public participation; that monitoring is insufficient to yield representative data or assure compliance; and that MDE’s use of the Guidance and 2002 baseline is arbitrary.
The Court of Appeals applied substantial evidence and arbitrary-and-capricious standards (with deference to agency expertise on scientific matters) and consolidated review of the substantively similar permits.
Holding: Court upheld MDE’s issuance of the permits in all respects — reversing the Court of Special Appeals (Montgomery County) and affirming circuit court judgments for the other counties.

Issues

Issue	Plaintiff's Argument	Defendant's Argument	Held
20% restoration requirement: specificity, measurability, enforceability under MEP	20% surrogate is opaque; no numeric pollutant standard or clear definition of "not restored to the MEP"	MDE tethered 20% to BMPs in the Manual and WQv performance standard; surrogate approach allowed under MEP; credits/accounting make it measurable and enforceable	Upheld: 20% requirement complies with MEP; BMPs and WQv supply specificity; credits make it measurable/enforceable
Use of 2002 baseline and Guidance methodology	Selection of 2002 is arbitrary and conflicts with later ESD-as-MEP regulatory definition	2002 marks the start of performance-based BMP requirements (Manual adoption); ESD regulation applies to future development, not restoration; Guidance reasonable	Upheld: choice of 2002 and Guidance methodology supported by substantial evidence and not arbitrary
TMDL/WLA implementation plans and public participation	Plans (developed post-issuance) are effectively permit modifications / contain enforceable compliance schedules and so require pre-issuance public notice and comment	BMPs and options were incorporated and previously subject to public comment; plans are implementation roadmaps drawing from an already-public menu; the permits preserve public review at the county-plan stage plus 30-day comment requirement; adaptive oversight remains	Upheld: post-issuance plans do not unlawfully evade public participation; incorporation by reference and county-level notice satisfy requirements
Monitoring: sufficiency to produce representative data and assure compliance	Permits lack federally required representative monitoring program and site-selection rationale; reducing chemical sites undermines representativeness and compliance assurance	MDE adopted a ‘‘three-legged stool’’ (chemical, biological, physical), increased event sampling, orchestrated site selection statewide, and required monitoring tied to load estimates, BMP assessment, and adaptive modifications	Upheld: monitoring scheme yields representative data and supports compliance monitoring; MDE’s changes fall within EPA guidance and are not arbitrary

Key Cases Cited

Piney Run Pres. Ass’n v. Cnty. Comm’rs of Carroll Cnty., 268 F.3d 255 (4th Cir. 2001) (background on state administration of NPDES)
S. Fla. Water Mgmt. Dist. v. Miccosukee Tribe, 541 U.S. 95 (U.S. 2004) (NPDES permits impose effluent limitations)
Tualatin Riverkeepers v. Or. Dep’t of Envtl. Quality, 230 P.3d 559 (Or. Ct. App. 2010) (BMPs as effluent limitations)
Am. Farm Bureau Fed’n v. EPA, 792 F.3d 281 (3d Cir. 2015) (TMDLs as informational and WIP reliance)
Natural Res. Def. Council, Inc. v. EPA, 808 F.3d 556 (2d Cir. 2015) (deference/arbitrary and capricious standard and monitoring flexibility)
Natural Res. Def. Council v. EPA, 966 F.2d 1292 (9th Cir. 1992) (statutory flexibility for MS4 regulation)
Envtl. Def. Ctr., Inc. v. EPA, 344 F.3d 832 (9th Cir. 2003) (permitting authority must meaningfully review permittee-designed programs; contrasts with scheme reversed in that case)
Motor Vehicle Mfrs. Ass’n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29 (U.S. 1983) (standard for arbitrary and capricious review)