City of Lake Oswego

Stormwater and Surface Water Program

Program Description

 The City’s Healthy Watershed’s Program is the lead program in the City’s efforts to protect water quality.  The City of Lake Oswego operates a surface water management utility that includes ”all natural and man-made facilities utilized by the Surface Water Utility to regulate the quantity and quality of surface water, including drainage easements, culverts, storm drains, catch basins, stream corridors, rivers, ponds, wetlands and impoundments.”  The goal of the program is to reduce pollutants to the maximum extent practicable (MEP). 

The City of Lake Oswego’s stormwater system is not connected to the City’s wastewater system.  As a result, stormwater enters receiving waters untreated.  Stormwater and other “nonpoint source discharges” (NPS) are regulated by the 1972 Federal Clean Water Act through the National Pollutant Discharge Elimination System (NPDES) permit program.  The State of Oregon Department of Environmental Quality administers this permit program in Oregon for the United States Environmental Protection Agency (USEPA).

The Federal Clean Water Act and the State of Oregon mandate that the City of Lake Oswego be issued a NPDES Phase I permit.  The City of Lake Oswego shares a permit with twelve other jurisdictions including Clackamas County, City of Gladstone, City of Happy Valley, City of Johnson City, City of Milwaukee, City of Oregon City, City of Rivergrove, City of West Linn, City of Wilsonville, Oak Lodge Sanitary District, Clackamas County Sanitary District #1 and the Surface Water Management Agency of Clackamas County.

The Healthy Watersheds program also provides technical expertise and guidance to all City departments to ensure implementation and compliance with the NPDES Permit, TMDL Water Quality Management Plans, and other surface water related issues.

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Clackamas County Group MS4 Phase I Stormwater Permit

Reissued Mar. 16, 2012UPDATED!

A municipal separate storm sewer system (MS4) is a conveyance or system of conveyances (e.g., roads with drainage systems, municipal streets, catch basins, curbs, gutters, manmade channels or storm drains) owned or operated by a governmental entity that discharges to waters of the State. 

City of Lake Oswego NPDES MS4 Permit and Permit Evaluation Report UPDATED!

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Current Projects:

BMP Manuals

• EPA-NPDES-National Menu of Stormwater Best Management Practices

Education and Outreach

Annual Reports

Coming Soon!

Maps

To visit the City’s Map Center, click here

Total Maximum Daily Loads (TMDLs) and Water Quality Management Plans

Tualatin River TMDL (includes Oswego Lake TMDL)

Willamette River TMDL (includes Tryon Creek and Springbrook Creek TMDL)