On May 24, 2022 the sewer collections division received notice at 6:30 a.m. from the Coppermine WRF plant operator that the plant was not receiving normal flows. Upon review of the data, it was discovered that flows began decreasing on 5/23/24. Collections staff immediately began checking major pump stations that send flow to Coppermine WRF. All pump stations were in normal operation and working properly. Collections staff then met with engineering and operations staff and split the assignment of walking creeks and major forcemains to look for anomalies.
At 11:10 a.m. collections staff found visual evidence of a possible spill and continued tracking the source.
At 11:20 a.m. the source was located in a vacant wooded field, on a cross country run of pipe, and was pinpointed where it was bubbling to the surface in and at the edge of the creek.
At 11:30 a.m. the 8-inch force main was isolated from a parallel 14” forcemain stopping the overflow. Isolating the 8-inch force main restored the 14” inch forcemain to pressure which allowed it to carry flow to the plant.
The failed section of the force main was excavated and replaced and flow restored to both the 8-inch and the 14 inch force mains on 5/24/22. A total of 934,955 gallons of untreated sewage entered a tributary to Rakestraw Creek. This volume was estimated based on actual flows received at the Coppermine WRF on 5/23/22 and 5/24/22, compared to average plant flow. After the repair, lime was applied to neutralize conditions. Notices are placed where the public may access the tributary. Our team implemented a stream monitoring program immediately upon locating the spill.