Repair work on the hot spots along the feeder main pipeline is complete as of June 25, with crews currently backfilling the construction sites.
The paving work is scheduled to begin very soon, along with site cleanup, stated Calgary Mayor Jyoti Gondek in an afternoon update.
Welding was completed last night and final repair activities were completed this morning. City officials said an immediate and longer term rehabilitation plan is needed for this pipe. Work has started to understand what the plan will look like.
Next, the City of Calgary’s water team is going to begin a four step process, involving filling the pipe, flushing the pipe, testing the water, and then stabilizing the system. Each step carries risk.
A concern is that something will break when repressurizing the pipe but the City has contingency plans in place. The pipe will slowly be brought into service.
Valves to the empty 4.5 kilometres of pipe will open, using 14 million litres of water to fill. This work can start as early as Wednesday night with two days to complete. Acoustic monitors will measure any further breaks.
The flushing phase means pushing treated water through the system, the intent is to fully replace the water in the feeder main to ensure it is clean. Flushed water will exit through hydrants and hoses in Edworthy Park.
After this, water samples will be taken to the lab for testing. If there are any concerns with the results, the pipe will have to be flushed again.
Stabilizing the system, which includes adding pressure, will take about three to five days. The risk is highest at this stage due to increased pressure.
If all goes well, the work of returning the City’s water system to regular service could be done sooner than expected, stated Gondek.
The Calgary feeder main broke on June 5, disrupting the city's water infrastructure and creating a water crisis for Calgary and surrounding communities that use its water, including Airdrie. A week after work began to fix the main break, the City discovered five more hot spots that needed immediate repairs.
Concerns about allowing the Calgary Stampede to go ahead were also addressed with the City stating this festival has a huge economic impact on the City. Measures are in place for the festival to conserve water.
