Liberte Environmental Associates

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.

Wilsonville Sewage Treatment Plant (STP): Final NPDES Wastewater Permit Related Documents

Wilsonville STP - Final Permit

Wilsonville STP - Final Permit Action Letter

Wilsonville STP - Previous Permit

Wilsonville STP - Previous Fact Sheet

Permitted Mixing Zone Size for Toxicity:

Waterbody: Willamette River at about River Mile (RM) 38.6.

Acute Mixing Zone Radius: 15 feet.

Acute Mixing Zone Surface Area: Estimated SA is approximately 707 square feet.

Chronic Mixing Zone Length: 150 feet downstream.

Chronic Mixing Zone Surface Area: Estimated SA is approximately 35,343 square feet.

Chronic Mixing Zone Volume: DEQ does not provide Willamette River MZ depth in the fact sheet so MZ volume is not yet determinable.

*LEA Disclaimer for compiled, unlocked and OCR documents: From time to time LEA will post on this website scanned documents, and additional documents otherwise limited in accessibility. Accordingly, LEA may use document unlocking and optical character recognition (OCR) capabilities to provide accessible, tagged text documents for use by people with visual impairments, and also provide searchable documents. The unlocking and OCR processes are not faultless, and hence LEA cannot guarantee document perfection. However, taking these caveats into account, document accessibility is greatly increased. LEA also posts the original document where necessary, as obtained by LEA, such that users may compare any potential imperfections in the unlocked and OCR documents.

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