Billions spent on southern Alberta’s irrigation network

The history of Alberta’s irrigation districts spans over 125 years.

Within the South Saskatchewan River basin, a scenic tour of the industry’s infrastructure can be made from the foothills in the west to the Saskatchewan border and from the Milk River in the south to the Red Deer River in the north.

Residents could almost be forgiven for taking this infrastructure for granted, viewed as just any other landmark.

WHY IT MATTERS: Showcasing irrigation infrastructure from districts across southern Alberta with its diversity in crop production, conservation of water and helping rural and urban communities alike stay safe from overland flooding drives home its importance.

However, make no mistake — if the billions of dollars worth of infrastructure were ever to falter from lack of maintenance, it would not only disrupt agricultural operations that feed the world but also put southern Alberta communities at significant risk.

The St. Mary River Irrigation District’s (SMRID) Chin Reservoir is located 15 kilometres south-southwest of Taber, Alta., and was built in the 1950s. It takes water out of Chin and puts it into the Stafford Reservoir to feed the main canal, which is 312 kilometres long.

SMRID is in the process of rebuilding the west dam because it has reached the end of its design life, with visions of expanding out to the east as well.

The SMRID manages 15 reservoirs, with Chin the largest, holding approximately 150,000 acre-feet of storage, with the planned expansion projected to add another 50 per cent capacity.

Irrigation district infrastructure has aided a southern Alberta region that has a long history of overland flooding. Rapid mountain snow melt coupled with heavy spring rains used to see the Bow, Elbow and Oldman rivers burst their banks.

Infrastructure failure

“If that dam were to fail, it would wipe out the McCain potato plant,” SMRID general manager David Westwood said during a water management presentation at the recent Alberta Crop Diagnostic Day at the Lethbridge Polytechnic Research Farm.

“It would wipe out the Town of Taber eventually as well.”

A major breach of SMRID dams could flood areas along Chin Coulee, disrupting local highways and infrastructure and cutting off irrigation water supplies. The disaster could reach Medicine Hat an hour east, causing overland flooding in the urban and residential areas.

Westwood told a cautionary tale about a lack of irrigation maintenance in Montana. SMRID shares some of the water system with the St. Mary River, which flows into Alberta from Montana.

The U.S. of Bureau of Reclamation (USBR) built its original irrigation system to divert water near Babb, Mont., and send it through a 29-mile long canal to the North Fork of the Milk River. It feeds the Fresno Dam near Havre, which helps irrigate about 100,000 acres.

Part of the Milk River Project, which began in 1915, had been falling in disrepair ever since, until recently.

In May 2020, a giant drop structure that conveyed water in Montana’s hi-line region failed catastrophically. The result ceased supplemental flows, resulting in limiting agricultural operations, rationing irrigators and municipalities alike in water usage.

That was followed up with a June 2024 structural failure at the St. Mary Siphon, eventually halting flow downstream.

“That prevented all the water going to them for the entire irrigation season,” Westwood said.

“The USBR, they built it and they told the farmers that they should pay for it to keep it up. The farmers said we had no money, so it just kept falling into further disrepair until it finally broke.”

Billions in infrastructure

The USBR has learned its lesson and has now invested more funds in its irrigation infrastructure through WaterSMART grants, the Bipartisan Infrastructure Law (BIL) and the Inflation Reduction Act.

Inversely, Westwood applauded the provincial and federal governments for their support of irrigation in Alberta. Since 1969, the combined efforts of irrigation districts, the provincial government and Canada Infrastructure Bank have invested more than $1 billion in irrigation infrastructure in southern Alberta.

“The Alberta government has done a phenomenal job. I strongly feel they are investing in agriculture because they see the return,” said Westwood.

“Every dollar they’ve invested in irrigation infrastructure leads to about $3.60 of GDP return. That’s why they do it. It’s really good for the province.”

SMRID operates approximately 2,500 km of canals and pipelines, delivering water from the St. Mary and Waterton reservoirs southward and eastward, serving an area from Lethbridge to Medicine Hat.

Westwood estimated that if all of SMRID’s infrastructure would need to be replaced in today’s dollars, it would likely cost $2 billion.