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.
Tryon Creek Sewage Treatment Plant (STP): Final NPDES Wastewater Permit Related Documents
Waterbody: Willamette River at about River Mile (RM) 20.3.
Acute Mixing Zone: 20 feet downstream from the outfall multi-port diffuser.
Acute Mixing Zone Surface Area: MZ width not given in the permit or fact sheet and SA is not yet determinable.
Chronic Mixing Zone: 200 feet downstream.
Chronic Mixing Zone Surface Area: MZ width not given in the permit or fact sheet and SA is not yet determinable.
Chronic Mixing Zone Volume: MZ width is not given and the MZ volume is not yet determinable. However, DEQ does provide a Willamette River MZ depth of 50 feet in the fact sheet (see page 5, Section - Outfalls).
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