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This overhead photo shows the roughly 480 feet between of a City of Gladstone storm and sewer outfall pipe (green mark at left) and the Lake Oswego-Tigard River Intake Pump Station. (City of Gladstone photo)

A raw sewage discharge into the Clackamas River reported this week in Gladstone does not pose a threat to drinking water at a nearby, upriver water treatment plant, officials said Thursday.

Gladstone's storm and sewer outfall pipe is located about 480 feet downriver of the Lake Oswego-Tigard River Intake Pump Station, which is where water is treated for about 100,000 people in those communities, officials said. As a result, outflow from the water and sewer pipe would not flow past the water treatment station.

Gladstone officials announced Wednesday that heavy rains "overtaxed the waste water and storm water systems in Gladstone, resulting in a discharge of raw sewage at the storm water outfall at the south end of Portland Avenue at West Clackamas. Area residents are reminded to avoid contact with the Clackamas River for several days due to this discharge."

The location of the outfall pipe was moved at least a decade ago to be farther from the water intake station, said Kari Duncan, Lake Oswego water treatment plant manager.

The Lake Oswego-Tigard River Intake Pump Station is one of five water intake stations on the Clackamas River served by various water entities, Duncan said. The furthest upriver station is located in Estacada, she said.

-- Allan Brettman