Alberta's irrigation districts span more than 125 years and billions of dollars of infrastructure across the South Saskatchewan River basin, from the foothills to the Saskatchewan border and from the Milk River to the Red Deer River — infrastructure that, if it faltered for lack of maintenance, would disrupt agriculture and put southern Alberta communities at risk, AG Canada reports from an article first published in Alberta Farmer Express.

The St. Mary River Irrigation District's Chin Reservoir, 15 km south-south-west of Taber and built in the 1950s, feeds the Stafford Reservoir and a 312 km main canal. SMRID is rebuilding Chin's west dam, which has reached the end of its design life, and plans to expand eastward; Chin, the largest of the district's 15 reservoirs, holds about 150,000 acre-feet, and the expansion would add roughly 50%.

'If that dam were to fail, it would wipe out the McCain potato plant,' SMRID general manager David Westwood said at Alberta Crop Diagnostic Day at the Lethbridge Polytechnic research farm. 'It would wipe out the Town of Taber eventually as well.' A major breach could flood Chin Coulee, cut highways and irrigation supply and reach Medicine Hat an hour to the east; the district's reservoirs have also tamed the overland flooding that once followed rapid snowmelt on the Bow, Elbow and Oldman rivers.

Westwood pointed to Montana, which shares the St. Mary River system, as a cautionary tale: the US Bureau of Reclamation's Milk River Project, begun in 1915, fell into disrepair after farmers were told to fund its upkeep and could not; a large drop structure failed in May 2020 and the St. Mary Siphon in June 2024, halting flows for an entire irrigation season and rationing irrigators and towns alike. The bureau has since invested through WaterSMART grants and federal infrastructure laws.

By contrast, irrigation districts, the Alberta government and the Canada Infrastructure Bank have invested more than $1 billion in southern Alberta irrigation since 1969. 'Every dollar they've invested in irrigation infrastructure leads to about $3.60 of GDP return,' Westwood said. SMRID runs about 2,500 km of canals and pipelines from the St. Mary and Waterton reservoirs to serve the area from Lethbridge to Medicine Hat; replacing it all today would cost an estimated $2 billion.

Source: AG Canada