Time, Distance, Hydrogeology, & the U.S. Supreme Court’s Decision in The County of Maui vs. Hawaii Wildlife Fund, et al.

On April 23, 2020, the U.S. Supreme Court issued an opinion regarding the Federal Water Pollution Control Act (also known as the Clean Water Act) and its application to groundwater. The Clean Water Act regulates the “addition” of any pollutant from a “point source” to “navigable waters” and only authorizes such discharges pursuant to a permit issued either under the U.S. Environmental Protection Agency (EPA’s) National Pollution Discharge Elimination System or an authorized state agency.


In the Maui case, the County of Maui operates a wastewater reclamation facility which collects sewage from the surrounding area, partially treats it, and pumps the treated water through four wells hundreds of feet underground. This effluent, amounting to about four million gallons each day, then travels a further half mile or so through groundwater to the Pacific Ocean. In 2012, several environmental groups brought Clean Water Act citizen’s suit against Maui. The environmental groups claimed that Maui was discharging a pollutant to navigable waters (the Pacific Ocean) without a NPDES permit. The District Court relied on a detailed study of the discharges and found that a considerable amount of effluent from the wells ended up in the ocean. It wrote that, because the “path to the ocean is clearly ascertainable,” the discharge from Maui’s wells into the nearby groundwater was “functionally one into navigable water” (U.S. District Court Opinion, 2014). The District Court granted summary judgment in favor of the environmental groups. The Ninth Circuit affirmed the District Court, but it described the relevant statutory standard somewhat differently using the term “fairly traceable” as the nexus standard between the point source and the navigable waterway.


The central question for the Supreme Court to consider was whether the Clean Water Act “requires a permit when pollutants originate from a point source but are conveyed to navigable waters by a non-point source”   U.S. Supreme Court Opinion, 2020). In this case, the interim non-point source conveyance was groundwater, an environmental matrix that traditionally has not been subject to Clean Water Act requirements. The Supreme Court rejected the “fairly traceable” standard as overly broad and concluded that the Clean Water Act would require a permit if the addition of the pollutants through groundwater is the “functional equivalent” of a direct discharge from the point source into waters of the United States.


From the perspective of many hydrogeological professionals and environmental consultants, one of the more surprising aspects of the case was the test proposed by the Court to determine when a discharge is the functional equivalent of a direct discharge. The Court acknowledged the complex technical issues that would need to be evaluated (and possibly quantified) in making this determination. These include complex hydrogeologic and fate and transport factors, including the following:


1.  Transit time

2.  Distance traveled

3.  Nature of the material through which the pollutant travels

4.  Extent to which the pollutant is diluted or chemically changed as it travels

5.  Amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source

6.  Manner by, or area in which, the pollutant enters the navigable waters

7.  Degree to which the pollution (at that point) has maintained its specific identity


Although not intended to be a bright-line test, the Court has opened the door to some fairly complex hydrogeological methods – including quantitative and qualitative modeling – that would need to be employed to determine whether the discharge in question is the functional equivalent” of a direct discharge to the navigable waterways in question, even if the analysis is limited to what the Court defines as the two most important factors: time and distance. The method employed to determine functional equivalency will be an added technical task that will impact how a potential discharger applies for a permit and how future permitting decisions will be made by EPA and the states. With the functional equivalency test in place as guidance, the Supreme Court remanded the case for further consideration and decision making by the lower court. It will be interesting to see how these hydrogeological factors are treated and employed on remand, and whether the functional equivalency test will be expanded to other environmental programs.


About First Environment’s Litigation Support Group

First Environment is a leading expert in the fields of environmental fate and transport theory and modeling.  Our hydrogeologists have developed various qualitative and quantitative subsurface contaminant migration models in support of NPDES, SPDES, and NJPDES permitting; groundwater remediation; contaminant fate and transport modeling; water resource development; and litigation involving cost recovery, insurance, Natural Resource Damages, and remedial cost estimates and allocation.


If you would like to know more about this subject or have questions about hydrogeological and environmental fate and transport modeling, please contact us.

Arthur Clarke, JD

Market Area Director – Litigation and Regulatory Compliance

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Art has more than 30 years of experience as an environmental chemist, regulatory manager, and environmental attorney. He specializes in litigation support, transactional support, due diligence, and regulatory compliance matters and has extensive technical experience as both a project manager and analytical chemist. Art regularly oversees facility compliance auditing and pre-acquisition investigations. He also provides regulatory counseling and consulting to clients appearing before state and federal administrative agencies, administrative law proceedings, and plenary courts. Art assists with negotiations regarding permitting and regulatory compliance matters, and also supports regulatory enforcement defense. He has designed and implemented regulatory compliance and auditing programs for a number of clients, and has created subject matter newsletters and alerts to private and public sector clients. In addition, Art has led international and domestic due diligence teams in the investigation and assessment of pre-acquisition liabilities. He also counsels clients on sustainability matters, renewable energy, and green leases. As First Environment’s corporate quality assurance manager since 2010, he develops and manages the firm’s quality programs; authors standard operating procedures; and oversees execution of program and project plans, audits, and corrective actions.