CARSTAIRS - The Town of Carstairs council has received and reviewed a report prepared on the issue of water infiltration in the municipality’s water treatment system and how it might be addressed going forward.
The Carstairs Flow Monitoring for Infiltration Under Dry Events - Technical Memorandum report was presented to council during the recent, regularly-scheduled council meeting.
“We are examining the issue right now,” mayor Lance Colby told the Albertan. “We are looking at getting it fixed and gathering information. We want to prevent infiltration of water into our lagoon, stop it from happening.”
ISL Engineering and Land Services Ltd. recently completed a flow monitoring analysis (FMA) and prepared the report for the Town of Carstairs. The analysis was undertaken to locate likely areas of significant infiltration under dry event or groundwater infiltration.
“The excess water entering the sanitary system, often referred to as GWI, typically comes from groundwater seeping into sewer pipes through cracks, leaky joints or deteriorating infrastructure,” the report states.
“Analyzing this flow is crucial because excessive infiltration can overwhelm wastewater systems, leading to environmental issues, increased treatment costs, and reduced system efficiency.”
To complement the FMA, the municipality had requested the company prepare a supplementary technical memorandum regarding the findings of the FMA and recommendations for infiltration reduction.
“The town is looking for recommendations on how to combat areas of significant GWI in Carstairs based on the data collected in the FMA, supplemented with recommendations for additional areas of investigation to further pinpoint sources of GWI.”
The analysis found Carstairs is “currently facing infiltration in the wastewater system, leading to excess volumes of flow treated at the lagoon. This study supplements the findings of flow monitoring by providing further contest into potential sources of GWI and solutions to mitigate the GWI.”
The report concludes, in part, that the town is spending approximately $132,000 a year to treat excess water that has infiltrated into the system based on an assumed average treatment cost of $1.50/cubic metres and analyzing the data between the two stations (in town) that were measured in January 2025.
Regarding possible mitigation measures to address concerns, the report states, “Depending on the location and severity of issues, there are several mitigation strategies ranging from full sewer replacement and upgrades to less invasive options such as installing sewer and manhole liners, and disconnecting known infiltration sources, such as weeping tiles and sump pumps.
“ISL recommences installation of lining into the pipes from Highway 580 (station 1) to the Havenfield Driver Connection (station 2). The recommendation will also the town to save on treating excessive groundwater entering the sanitary system while also having the least amount of disruption to its surroundings.”
Based on past projects, the lining of the section of main, as well as two manholes, is estimated to be $175,000, the report states.
The complete report and related documents is available for viewing on the town’s website.
Council received the report as information and will be continuing to examine the issue going forward, said mayor Colby.
