NPDES Permits Potentially Affecting Water Quality
Final NPDES Wastewater Permits - Issued by Oregon Department of Environmental Quality
This list consists of permit documents* (see end) made available by Oregon DEQ and is not all inclusive. All documents are PDF except where indicated.
Pacific City Sewage Treatment Plant (STP): Final NPDES Wastewater Permit Related Documents
Pacific City STP - Final Permit. This document is also provided as permit in html format*.
Pacific City STP Final Fact Sheet and Reasonable Potential Analysis (RPA). This document is also provided as fact sheet in html format*.Permitted Mixing Zone Size for Toxicity:
Waterbody: Nestucca River at about River Mile (RM) 1.5. Discharge located in tidal estuary affected by the Pacific Ocean.
Acute Mixing Zone: 10-foot radius about a 36-foot long diffuser. See Fact Sheet.
Acute Mixing Zone Surface Area: Estimated SA is 1,034 square feet.
Acute Mixing Zone Volume: DEQ fact sheet shows a minimum depth of about 8 ft above the diffuser so the Acute MZ volume is approximately 8,273.3 cubic feet (i.e., 61,884 gallons).
Chronic Mixing Zone: 100-foot radius about a 36-foot long diffuser.
Chronic Mixing Zone Surface Area: Estimated SA is 38,616 square feet.
Chronic Mixing Zone Volume: DEQ fact sheet shows a minimum depth of about 8 ft above the diffuser so the Chronic MZ volume is approximately 308,927 cubic feet (i.e., 2.3 million gallons).