Groundwater flow path from the County of Maui’s Wastewater Reclamation Facility to the Pacific Ocean. This facility is the subject of the U.S. Supreme Court case. An extensive hydrogeologic study was completed to map how pollutants travel through groundwater to the Ocean. Source: Lahaina Groundwater Tracer Study
On Thursday, April 23, the U.S. Supreme Court ruled in County of Maui v. Hawaii Wildlife Fund, setting an important, but difficult to implement, precedent for determining when National Pollutant Discharge Elimination System (NPDES)[1] permits are required for discharges to groundwater.
How this Case Came to Be
The County of Maui discharges treated municipal wastewater to the ground through four wells about a half-mile from the Pacific Ocean. Multiple environmental groups sued under the Clean Water Act, alleging that the discharge required an NPDES permit.
The U.S. District Court agreed with the environmental groups, concluding that a permit was required because the discharge was “functionally one into navigable water.” The Ninth Circuit Court affirmed, establishing a test that permits are required when “pollutants are fairly traceable from the point source to a navigable water.”
The County appealed to the U.S. Supreme Court. EPA weighed in, offering an Interpretive Statement that concluded that all releases of pollutants to groundwater are excluded from the Clean Water Act’s permitting program, “regardless of a hydrologic connection between the groundwater and a jurisdictional surface water”.
The Supreme Court set aside the prior approaches by the District Court and Ninth Circuit, and did not give deference to EPA’s opinion, instead crafting their own solution that NPDES permits apply “to a discharge (from a point source) of pollutants that reach navigable water after traveling through groundwater if that discharge is the functional equivalent of a direct discharge from the point source into navigable waters.”
In a recent blog post, attorneys from Stoel Rives view the Court’s decision as taking the middle ground, resulting in the need for potentially difficult case-by-case evaluations based on the non-exclusive list of seven factors the Court defined as important for functional equivalence:
Transit time
Distance traveled
The nature of the material through which the pollutant travels
The extent to which the pollutant is diluted or chemically changed as it travels
The amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point sources
The manner by or area in which the pollutant enters the navigable waters,
The degree to which the pollution (at that point) has maintained its specific identity
Hydrogeologic Science to Increase in Relevance
The opinion established time and distance as the most important factors in most, but not all, cases.
This emphasis will likely prove problematic, because time and distance, while important, are often not enough, by themselves, to resolve the question of whether pollutants are being transported to a surface water. Should it matter how close (in time or distance) a discharge is to a surface water, if the subsurface conditions provide adequate treatment? In many cases, the other factors identified by the court may prove more important. These questions will likely only be resolved through hydrogeologic studies, and in many cases litigation, at the expense of the individual dischargers.
Implications for Pacific Northwest Businesses and Municipalities
This decision has relevance to businesses and municipalities in the Pacific Northwest that discharge stormwater or wastewater to ground. We expect to see increased attention from regulatory agencies and environmental groups focused on discharges to groundwater. In particular, facilities that are currently exempt from the Industrial Stormwater General Permit because they only discharge to ground should carefully examine their discharge relative to this decision.
To learn more and discuss the relevance of this case further, contact Senior Associate Water Resources Engineer Owen Reese at oreese@aspectconsulting.com or 206-838-5844.