PORTLAND, Ore. (KOIN) — About 60,000 gallons of combined sewage overflowed into the Willamette River in Portland in a 23-minute period Saturday afternoon, the Portland Bureau of Environmental Services said.

The overflow was caused by heavy rains that fell in the area and came from a single outfall at NW 110th and Front Avenue, officials said. It began at 4:46 p.m. and ended at 5:09 p.m.

People should avoid contact with the Willamette River in the area of Linnton and the Port of Portland Terminal 4 and downstream until late Monday.

This is the first overflow of 2019, authorities said in a release, and was made up of 80% stormwater and 20% sewage. Before the Big Pipe project of 2011, there were on average about 50 outfalls a year.

About Combined Sewage Overflows

Record rainfall

Both Portland and Troutdale recorded record rainfall amounts for August 10. In Portland, 0.79 inches of rain was recorded, more than doubling the 1957 record of 0.36 inches.

In Troutdale, a record that stood for 54 years — 0.30 inches — was topped when 0.36 inches was recorded.

These are the early reports. A final report from the National Weather Service will be released on Sunday.