The U.S. Supreme Court issued a ruling in the County of Maui v. Hawaii Wildlife Fund case on April 23. The central question in the case was whether discharges to groundwater that in turn enters a navigable water requires a National Pollutant Discharge Elimination System (NPDES) Permit under the Clean Water Act (CWA). The CWA forbids “any addition” of any pollutant from “any point source” to “navigable waters” without an appropriate permit from the Environmental Protection Agency (EPA). By a 6-3 majority, the court ruled that the CWA requires a permit when there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge. The court left the job of defining functional equivalency up to the EPA or through future court decisions. This decision has the potential to impact existing federal groundwater regulations as well as state law and authority over groundwater. It also has implications for activities involving groundwater recharge, other recycled water uses, low impact development, and green infrastructure.

“BC is ready to use hydrology tools to characterize the groundwater-surface water connection.”

Kelly Collins