PUBLISHED: 21 March 2014

Boil Water Advisories and Drinking Water

During the 2013 Flood, boil water advisories were issued for: Canmore, Black Diamond, Siksika First Nation, Exshaw, Lake Louise, High River, Harvie Heights, MD of Big Horn and Kananaskis[1].

Although water quality was affected, a lot of damage was avoided due to preparation, technological advancements and knowledge and dedication of staff and plant operators.


Calgary’s drinking water was unaffected during the 2013 Flood. During the flood, there were reports of Calgarians purchasing emergency supplies of bottled water (and isolated reports of price gouging for bottled water and other items[2][3]) but no boil water advisory ever was issued for Calgary. Although water quality remained good a city-wide mandatory outdoor water restriction was issued to reduce strain on water treatment systems[4].

Glenmore and Bearspaw Water Treatment Plants

Reviews conducted in 2001-2002 indicated that both the Bearspaw and Glenmore Water Treatment Plants needed extensive upgrades, and in 2003 The City of Calgary began renovations[5]. Bearspaw Water Treatment Plant was renovated in 2004 and upgrades to the Glenmore Water Treatment Plant were completed in 2011. Part of these upgrades was the construction of a pre-treatment facility that uses Actiflo filtration system[5].

Performance during the 2013 Flood: During a flood, debris and soil washes into the river making the water ‘turbid’ and flood water can be heavily polluted with viruses, bacteria and parasites[6]. Torrential rain began on June 19th and on June 20th communities began to declare states of emergency. Calgary water treatment plants had about 10 hours to prepare for dramatically increase flow rates and an influx of highly turbid waters.

Turbidity (NTU) is used to measure the cloudiness of water. Muddy water has ‘high turbidity’ while clear water would be classified as having ‘low turbidity’. Drinking water should have a turbidity of 5 NTU or less[7]. The seasonal average for raw water from the Bow River is 10 NTU but during the flood, clarity reached 4,000 NTU[5]. The second challenge for Calgary water treatment operators during the 2013 Flood was the velocity of flood waters. Normal flow rates on the Bow River in June are 500 m3/s but during the flood water flowed at 1,750 m3/s . Similarly, normal flow rates on the Elbow River increased from a seasonal average of 150 m3/s to 700 m3/s [8].

Despite the extraordinary conditions, the Bearspaw and Glenmore Water Treatment Plants were able to produce water at 0.05 NTU, well within drinking water guidelines. Mayor Naheed Nenshi said that boil water advisories and restrictions were avoided due to earlier investment in water treatment infrastructure[5]. Without these investments in water treatment infrastructure, water treatment operators argue that the impact of the flood would have far more widespread[9].  Although the technological advancements were critical to avoiding a city-wide impact, trained use of this technology by Calgary water treatment operators was also a key factor.  

Bonnybrook Water Treatment Plant

While the Glenmore and Bearspaw Water Treatment Plants were able to cope with increased demands, the Bonnybrook Water Treatment Plant was inundated with floodwater. In the days following the flood, the Bonnybrook Treatment plant was only able to filter solid materials larger than 6 millimetres[10]. The City was forced to dump raw sewage into the Bow River and for a time, the plant did not meet provincial water standards[10]. However, despite the extensive damage the plant was up to compliance four weeks after the flood [9].

High River

High River was one of the hardest hit areas but damage to the city’s water system was minimized due to the actions of water treatment plant operators. Instead of evacuating, Operators Chad Moore and Colin Andrews chose to remain at the plant and control water pressure to prevent broken water lines. Moore and Andrews reduced and maintained pressure in the distribution system and monitored for turbidity spikes.  If the water lines had broken it would have cost millions of dollars to repair and would have likely meant High River residents would have been without potable (or drinking quality) water for weeks. Although there was a boil water advisory issued for High River, this advisory was lifted for most of the town on July 10[11].

Medicine Hat

Medicine Hat had more time to prepare than residents closer to headwaters. Canadian Forces soldiers were able to build a dike around the city’s water treatment plant which minimized the impact on drinking water. Although water on the Saskatchewan River reached a peak flow of 5,300 m3/s, experience from flooding in 1995 helped to prepare residents[12].

Turner Valley & Black Diamond

On June 20th, Water Treatment Plant in Black Diamond was shut down due to flood related safety concerns[13]. Two of three supply wells in Turner Valley were damaged beyond repair with the third well required restoration. In Black Diamond, the Water Treatment plant and two of the three supply wells were damaged beyond repair[14]. As of December 2013, Black Diamond was still using water from neighbouring Turner Valley while a long-term water solution for residents are still being considered.

A detailed list of water damaged infrastructure from across Alberta can be found here: This list is updated by the Government of Alberta as information becomes available.

[1] Huffington Post Alberta. (June 6, 2013). “Canmore Flooding Prompts Boil Water Advisory for Entire Town”. Retrieved from

[2] Strapagiel, L. (June 23, 2013) “Accusations of price gouging in flooded Calgary”. Retrieved from

[3] CBC News (June 22, 2013). “Calgary flood victims angered by allege price-gouging”. Retrieved from

[4] City of Calgary Newsroom. (June 22, 2013). State of Local Emergency – Update 2 p.m., Saturday, June 22 [Press Release]. Retrieved from

[5]The Peg Magazine. (Septermber, 2014). Top-Noth Water Treatment Plant Proves its Worth. The Peg, 78-80. Retrieved from 



[8] For a comprehensive list of river flows across Alberta during the flood visit: 

[9] Interview with City of Calgary officials 

[10] CBC News. (June 27, 2013). Avoid Driving, city warns after Calgary floods. CBC News Calgary. Retrieved from

[11] Alberta Government. (July 10, 2013). High River Boil Water Advisory Update [Press Release]. Retrieved from 

[12] CTV Staff. (June 24, 2013). Medicine Hat flood waters begin to recede, 1000 homes damaged. CTV News. Retrieved from

[13]  Huffington Post Alberta. (June 23, 2013). Medicine Hat Flood 2013: Residents Ordered to Leave Home. Huffington Post Alberta. Retrieved from

[14] Town of Black Diamond. (October 4, 2013). Flood Recovery Update – 2013 [Newsletter]. Retireved from