NEHALEM BAY STP - Mohler, Oregon Wastewater Treatment Plant

NEHALEM BAY STP is a municipal wastewater treatment plant located in Mohler, Oregon, serving a population of about 4,700. Situated in Tillamook County, the plant is part of the region's infrastructure for managing domestic wastewater in a coastal setting. The plant has a designed capacity of 1.00 million gallons per day. As a US facility, it operates under the Clean Water Act, requiring an NPDES permit issued by the Oregon Department of Environmental Quality. Treatment standards are set based on the receiving water body's sensitivity and the plant's discharge volume. The plant's treated effluent likely discharges into the Nehalem River system, which flows to Nehalem Bay and then to the Pacific Ocean. This coastal watershed supports salmon runs and diverse aquatic life, making effective treatment essential for protecting downstream ecosystems.

The Nehalem River watershed drains the northern Oregon Coast Range into Nehalem Bay, a coastal estuary that supports salmon, steelhead, and cutthroat trout. The bay and river provide critical habitat for migratory birds and marine species. Discharges from the plant must meet strict water quality standards to protect these ecologically sensitive waters and the downstream Pacific Ocean.