Sewage Leak into Cowichan River
On Tuesday, there was an incident where some quantity of sewer from the City of Duncan system entered the Cowichan River. With the information available, the Vancouver Island Health Authority does not believe there is any public health risk based on results of the river water sampling that has been conducted.
On Tuesday September 3, 2013 at 3pm a local resident reported witnessing sewage entering the Cowichan River from a storm water pipe between the Silver Bridge and the Black Railway Bridge.
The City Crew was immediately dispatched to investigate.
All indications are that the system, which was constructed many years ago, overflows into the storm water river outfall for the Mall area if there is a significant enough backup in the Cowichan Way sewer main.
The investigation revealed a compressor malfunction at the City of Duncan’s Cowichan Way Sewage Pump Station. The City crew immediately restarted the compressor and started to draw down the sewage level in the pump station.
By 4:00pm the sewer water level was at a level below the sewer overflow pipe invert and the situation was under control.
It was identified that the visual warning device on the top of the pump station was malfunctioning. This warning device identifies when the pump station has reached the high water mark which is normally long before any crucial level.
The City is not aware of any similar incidents in the past.
On Wednesday morning the City crew collected three water samples one upstream, one downstream, and one at the river outfall to be tested for fecal, coliform and ecoli.
The Crew did not find any remnants of sewer debris in the surrounding area or shoreline, that morning.
The Provincial Emergency Program (PEP), Ministry of Environment, and Vancouver Island Health Authority (VIHA) were all informed of the incident.
On Friday morning, the City Crew plugged the overflow pipe in order to prevent such incidents from happening again, crews have also been directed to monitor the pump station daily and the City is working to connect the station to its newly activated SCADA system.
On Thursday, results of the water samples were returned and provided to VIHA. VIHA staff are not concerned about the results, which were within reasonable limits due to sufficient dilution in the river. Follow up samples were taken on Friday morning.
“This incident is obviously extremely serious, and I can assure residents that it is the City’s highest priority to prevent such an incident in the future.” stated Peter de Verteuil, City of Duncan Chief Administrative Officer.
Cowichan Tribes has been notified by Health Canada and they have posted a warning at a small beach along the river downstream for precautionary purposes only.
It is estimated that approximately 200-260 litres per hour could have been discharged, but it is difficult to know how long this had been occurring before it was noticed.