Wastewater overflows at two spots
The city's wastewater infrastructure experienced overflow conditions Oct. 23 on Boones Ferry Road at Oakridge Road and also near the Lake Grove Swim Park on Lakeview Boulevard in Lake Oswego.
The city received many calls from residents who wondered if the spill was related to the sewer interceptor capacity, according to city Recorder Robyn Christie. She said the overflow had nothing to do with the under-the-lake interceptor, which the city plans to replace in a project that begins next year.
The Lake Oswego City Maintenance Services Department was able to respond quickly to both problems.
At one location, crews found a downstream manhole in the middle of Boones Ferry Road was blocked by a large amount of asphalt from a recent paving project performed by a private paving contractor, Lakeside Industries, of Portland.
This caused the upstream line to slowly back up until it overflowed.
A couple weeks before the overflow, Lakeside Industries was working a paving machine on Boones Ferry, when the machine caught a manhole lid and a few cubic yards of asphalt was dumped into the hole. Elilzabeth Papadopoulos, director of the city's Maintenance Services Department, said the sewage 'took a long time to back up' and once it did caused sewage to seep out a manhole upstream.
City crews chipped away at the asphalt - enough to get sewage flowing again. The contractor then came and removed the remainder of the asphalt.
A blockage near the swim park was caused by the surge of flow from the opening of the Boones Ferry line, officials said. The overflow amount was about 300 gallons at the swim park.
As a result of the overflow in Oswego Lake, city officials advised residents in the vicinity to protect themselves, children and pets from direct contact with lake water that may have been subjected to contact with untreated sanitary wastewater for 72 hours.