Improving the resiliency of our utilities

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Communities count on us. We count on each other. Our purpose statement speaks to the essential nature of the services our people provide. In 2018, public opinion research found that Edmontonians rated critical utility and health infrastructure as the most important community assets to protect from flooding — even more important than their own homes.

Several of EPCOR's critical utility assets are located next to the North Saskatchewan River, including Edmonton's two water treatment plants and a major electrical sub-station, each of which is at risk from flood events. We're implementing protection plans for these assets to protect them from 1:200-year flood events, and in some cases, from 1:500-year floods. These investments are partly offset by federal and provincial grant funding.

We have further studies underway across the full range of its operations, examining the potential impacts of extreme weather events on the ability to deliver reliable utility services. This will result in additional action plans to improve system resiliency and reliability.

​Scenario planning: Understanding the risks from extreme river flooding

The worst flood experienced in Edmonton since modern records have been kept occurred in June 1915. Considered a 1:180-year event, it resulted in widespread destruction of Edmonton's river valley and the relocation of most businesses to higher ground.

Our Edmonton water treatment plants supply water to nearly one-third of Alberta's population. Both are located next to the river, with infrastructure at varying elevations and extensive below-grade facilities, including reservoirs.

We conducted scenario planning for a recurrence of a 1915 flood event. The analysis predicted that river flood water would enter the water treatment plants across overland flood plains and through underground waste stream/overflow piping systems that discharge to the river. Critical electrical infrastructure, chemical storage facilities and reservoirs would all be damaged.

The immediate impacts and aftermath would be considerable. Forecasts indicate that without improvements to protect the water treatment plants, the ability to treat water could be interrupted for three to 10 months, and a boil water advisory would need to remain in place until the entire distribution and transmission network is flushed and disinfected. Until water production is restored, customers would be supplied with water trucked-in as part of EPCOR's Emergency Water Supply Plan.

A disruption of this scale would have a substantial impact to the regional economy, and the direct costs to EPCOR would be extensive.

​Protecting utility infrastructure from extreme river flooding

In 2018, we initiated a multi-year capital program to improve the flood resiliency of Edmonton's water treatment plants. These efforts have been extended to critical electrical infrastructure also located in the river valley.

The Flood Protection Project will provide protection for a 1:500 year flood through investments of $36.9 million, which are further supported by $21 million in federal and provincial grant funding. The investments will reduce the risk of catastrophic damage to the water treatment plants and electricity infrastructure during a flood, and enable the facilities to resume potable water treatment as quickly as possible following an extreme flood event.

As we work towards full protection for the plants by 2027, there are different levels of protection being put in place along the way. Investments include:

• Critical asset protection or relocation through hardening of underground reservoirs and chemical storage tanks against flood-related structural damage, and the raising of key electrical infrastructure above flood water heights (completion in 2023)
• Backflow prevention from waste stream outfalls which stops the backflow of flood water through process drains, preventing indoor flooding of buildings and treatment process equipment contamination (completion in 2023)
• Prevention of overland flood inundation using embankments and barriers to connect existing high ground around the treatment plants (completion in 2027)

Overland Flood Prevention: 2​021 Update

The first two phases of work were originally targeted for completion in 2023, and are now expected to be complete by 2024. This is the result of refinements to the project design and schedule, including the timing of staggered shutdowns to the two water treatments plants while their electrical infrastructure is being relocated.

The primary focus over the past year was on engagement with residents located near the water treatment plants and with key Indigenous stakeholders. Multiple online workshops were held with community members and site tours were held with First Nation Elders and knowledge keepers to discuss work that will take place on these lands of historical significance and meaning.

Two rounds of engagement sessions gathered valuable input as we consider placement of berms and walls for permanent barriers, development of embankments, and community preferences for the look of these protective assets. A third round of engagement on flood barrier designs, including berms and walls, is planned for 2022.

Construction moved forward on protective berms around the E.L. Smith power feed access tunnel, which supplies power from the Petrolia Substation, and progress continued on designs for embankments for both plants, including precise specifications for how high and wide the embankments will need to be for protective purposes.

For immediate physical protective measures, barriers were installed in 2021 to protect the pump house at Rossdale, providing some level of assurance and a measure of redundancy when the larger-scale project is completed.​​​

​Framework for drinking water emergencies

Scenario planning and business continuity planning are key tools used to manage and mitigate risk, including climate adaptation risk. In addition to extreme flooding events, EPCOR water treatment operations could be disrupted by a range of high-impact, low-probability events, including other types of natural disasters, extended river contamination and physical attack.

We worked with key stakeholders to develop a drinking water emergency exercise plan for the Edmonton and region water system. The plan focuses on how to supply customers with drinking water in the event of a disruption to the water treatment plants. The work has been documented in a Framework for Drinking Water Emergencies in the Greater Edmonton Region, an Emergency Drinking Water Supply Plan, and a five-year exercise plan. Critical to these plans is the ability to quickly access alternative water supplies and to mobilize physical distribution of water to residents in Edmonton and the surrounding regions.

Protecting water supply ​​by limiting loss: 2021 Update

Part of improving the resiliency of our utilities is limiting the loss of treated water that we greatly value for communities. This includes losses from water main breaks, reservoir leaks or major incidents, as well as inaccurate meters.

Water loss within the Edmonton system did increase somewhat in 2020 (reporting for this measure lags by one year), but was within a normal range of variability that can be seen over time. A key contributor to keeping overall water loss performance stable at 6.2% in 2020 was the addition of the Vista Ridge pipeline in the U.S.. This new 143-mile transmission line now serves about 20% of the City of San Antonio’s water needs. As a new asset, and a single transmission line, Vista Ridge has lower water loss than water distribution systems, which include infrastructure built over many years and feature an extensive network of water distribution mains.​