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The recent rupture of the Bearspaw feeder main in Calgary has raised significant concerns regarding the city’s water infrastructure. This incident, which occurred in June, was classified as a low probability failure in a city assessment prior to the break.
The findings from the report presented to the city’s infrastructure and planning committee reveal critical insights into the factors that led to this event and the subsequent actions that need to be taken.
Assessment and classification of the Bearspaw feeder main
According to the city’s asset management quadrant, the Bearspaw feeder main was categorized as “high impact, low probability.” This classification indicates that while the failure of this line would have severe consequences, the likelihood of such an event occurring was deemed low.
However, this assessment has been called into question by city officials and residents alike, especially given that this line supplies 60% of Calgary’s drinking water. Ward 1 Coun. Sonya Sharp expressed her concerns, stating that the feeder main should have been prioritized as a high-risk asset.
Factors contributing to the rupture
The report, which spans nearly 600 pages, identifies several factors that contributed to the failure of the Bearspaw feeder main. Among these are microcracking and stress corrosion cracking, which were exacerbated by high chloride levels in the soil surrounding the pipe.
These elevated chloride levels are believed to be linked to road salt used for de-icing, raising concerns about the long-term effects of urban infrastructure on water supply systems. Steve Wyton, the city’s head of asset management, noted that certain areas along the road exhibited significantly higher chloride concentrations, which could have played a role in the deterioration of the feeder main.
Future actions and accountability
In light of the incident, city officials are taking steps to address the issues identified in the report. Plans are underway to conduct further studies on the increased chloride levels and to enhance soil sampling along critical feeder mains. The city administration has acknowledged the need for improved inspection protocols and maintenance strategies to prevent similar occurrences in the future. Mayor Jyoti Gondek emphasized the city’s accountability in delivering reliable public services, stating, “When something fails, it’s on us.” As the costs for repairs are estimated to reach between $35-45 million, it is clear that the implications of this incident will be felt for some time.
