Bow River Basin

The Alberta government has a five-year agreement with TransAlta to modify operations at several TransAlta facilities to help protect communities along the Bow River against the impacts of both floods and drought.

Modified Operations Agreement with TransAlta

The Alberta government is committed to ensuring our province is prepared for the potential of future flooding and drought. Leveraging existing TransAlta infrastructure is an effective option to help protect communities along the Bow River.

Terms of the Agreement

  • Compensation paid to TransAlta is $5.5 million per year
  • Five-year agreement beginning in May 2016
  • Modified operations period at Ghost Reservoir is from May 16 to July 7, primarily for flood mitigation purposes
  • Year-round modified operations at Barrier Lake, Upper Kananaskis Lake, and Lower Kananaskis Lake, primarily for drought mitigation purposes

Frequently Asked Questions - Updated May 2018

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TransAlta Agreement Details

What is included in the agreement between TransAlta and the Province of Alberta?

Flood Management: The agreement allows the Province to set elevations on the Ghost Reservoir during the period of May 16 to July 7 until 2021, which is typically the highest storm risk period of the year. By keeping the reservoir lower during this period there is more space to store flood events thereby lowering peak flows downstream of the dam or, at the very least, delaying those peaks.

Drought Management: The agreement includes the ability of the government to have TransAlta store water in the Kananaskis system to be used in periods of low flows in the Bow River. This part of the agreement is year-round for the duration of the agreement.

Why is the government paying TransAlta to modify operations at some of their facilities?

As per the 5 Year agreement, reservoir levels at TransAlta facilities will now be set by the Province based on flood or drought mitigation needs. Compensation paid to TransAlta is intended to offset the estimated commercial loss TransAlta will incur due to modified operations at the four facilities included in the agreement. These reservoirs are designed and operated to produce electricity. The lower the water level, the less electricity TransAlta is able to produce.

Did the government consult with impacted residents?

Yes, officials met with impacted residents, business owners, recreational users and other key stakeholders in 2015 and 2016, through a series of open houses, to explain the agreement and to identify and discuss issues related to low water levels at Ghost Reservoir. Moving forward, seasonal operating information can be found on the "Provincial Rivers App".

How does the agreement with TransAlta relate to the mandate of the Bow River Working Group?

The Bow River Working Group, jointly chaired by the Province and the City of Calgary, has completed their assessment of flood and drought mitigation options for the Bow River from the Banff National Park boundary through to Medicine Hat. They are currently being reviewed by the Government of Alberta. This includes recommendations on a combination of new structural projects and modified operations at TransAlta facilities. Because of the amount of storage required to meet flood and drought mitigation goals, the use of TransAlta infrastructure will almost certainly be a significant part of any potential mitigation solutions for the Bow River.

Flood Storage

How much flood storage is provided through the new agreement with TransAlta?

Up to 65 million cubic metres of storage will be available at Ghost Reservoir for flood mitigation purposes. Up to 40 million cubic metres may be available at the Kananaskis-area reservoirs further upstream for drought mitigation. The amount of storage available will vary each year based on prevailing conditions.

Residents around Ghost Reservoir claim the storage available wouldn’t prevent flooding in the event of another 2013-level flood, so why bother lowering the reservoir at all?

65 million cubic metres is a significant amount of storage. While it’s true that this would not completely prevent flooding if we experienced an exact repeat of the 2013 event, it would effectively mitigate smaller floods like the one Calgary experienced in 2005 and provide benefits to communities downstream, as well.

The 2013 flood was a rare event and there is tremendous value in mitigation projects that can prevent smaller floods, which are much more common. Flood storage at Ghost Reservoir does provide peak flow attenuation, but just as importantly, it also delays peak flows downstream. This is critical when evacuating major population centers.

What other opportunities are there to store water in southern Alberta?

Recent grant approvals through the Watershed Resiliency and Restoration Program will see over 500 hectares of wetlands created or restored, mostly in southern Alberta. Wetlands are very effective for improving both flood and drought resiliency.

What are the implications for Calgary and other Bow River Communities?

The ability to attenuate high flows on the Bow River will help reduce the impact of major floods and can potentially eliminate smaller floods in communities along the watershed, including Calgary. During times of drought, water stored in upstream reservoirs (Kananaskis System) can be released into the Bow River to maintain environmental flows, for municipal drinking use and for use in irrigation, thereby helping to protect valuable crops.

What is 2018 reservoir operations looking like?

Government is working closely with TransAlta to assess what elevations reservoirs should be set at going into this coming operating reason. Looking at current snowpack conditions in the mountains, baseline river flows and the Provincial Water Supply Outlook, conditions are looking to be above average to much above average coming into this summer.

Much above average snow in the mountains means storm events could generate higher flood flows but also means a higher likelihood of being able to fill the reservoir later in the summer. For these reasons the Ghost Reservoir level will be set lower than last year, at 1185 metres to start the control period.

Up to date information on all reservoir elevations, river flows and proposed forecasted operations will be posted on the "Provincial Rivers App", like last year.

This is looking like an above average year from a water supply perspective. How will you manage these reservoirs in light of current conditions?

Major floods are rare, but they are difficult to predict and their impacts can be devastating. Water levels at TransAlta reservoirs included in this agreement will fluctuate during the modified operations period to reflect ongoing risk assessments for both flood and drought. The new agreement with TransAlta includes the Kananaskis sub-basin, which provides the Province with potentially more storage options to supplement flows in the Bow River during dry years. This is a key element in adapting to weather extremes brought on by climate change.

Initial reservoir target elevations prior to each operating season will be based on the provincial Water Supply Outlook, snowpack and soil moisture conditions, and prevailing weather patterns. In wet cycles, reservoir levels will be kept lower to facilitate potential flood storage. During dry cycles, target elevations will be kept higher to offset potential water shortage conditions later in the season, but still allow the reservoir to be lowered up to five days prior to a flood event. Seasonal operational targets will be posted under Forecaster’s Comments at:

Wells and Water Supply Management

What should residents near Ghost Reservoir do if they are having issues with their wells during the control period?

A study was completed by an independent engineering consultant on behalf of the department to determine how domestic wells may be impacted at different reservoir elevations. While the study is complete it did not provide any conclusive information on connectivity between the reservoir and the groundwater characteristics within the Village. The department has provided a temporary water supply to residents who identified well issues during the control period and will continue to do so for the life of the agreement.

Will the aquifer study include actual studies of all the residents’ wells? Changes in water quality and pressure were noted last year in many of the resident wells.

The department’s engineering consultant contacted all licensed water well owners within the Village in the summer of 2016 and requested completion of a detailed questionnaire to identify wells that have experienced issues in the past. The consultant also visited several private wells for inspection and gathering of technical information including water levels and pump test results. The study also utilized existing information for licensed wells within the Ghost Lake Village and published geological information for this area as key inputs for their analysis.

Alberta Environment and Parks is working with the Village administration to ensure that if residents experience water issues directly linked to reservoir operations, they will be supplied with supplementary water similar to last year. This involved trucking and piping water to affected residents as required.

What happens if residents in the summer village have repeated issues with their wells?

The first point of contact for municipal water supply is the local municipality. For general inquiries, residents can contact the department Information Centre:

What is the status of emergency water supply at Ghost Lake Summer Village?

A portable pump and piping will be supplied to the Village and in place until the reservoir rises. This is to ensure firefighting equipment is reliably connected to a water supply.

Other Local Impacts

Will the government compensate landowners and businesses around Ghost Reservoir for the impacts caused by lower water levels at Ghost Reservoir?

No. Lower water levels at Ghost Reservoir during the period of this agreement are still within the operating limits of TransAlta’s water licence.

When will the Parks boat launch be extended to provide access to the reservoir during the control period?

Alberta Parks is planning to extend their existing boat launch the spring of 2018 to allow better access to the reservoir during the control period.

How will lack of access to a water supply for fire prevention affect residents’ insurance? This should not be at their expense and should be covered by the government. Is this a possibility, and why not?

Ghost Lake Village and the rural municipality are responsible for fire suppression services. Alberta Environment and Parks has supplied the Village with a large mobile pump (and appropriate training) to aid the Village in fire suppression and will do so again for 2018 should that be required. If residents have concerns regarding insurance they should get in contact with their insurance provider.

The land values for Ghost Lake Village residents have been affected significantly. Taxes have not decreased but in fact increased over the last few years. Why has there been no compensation or lowering of taxes for the residents? When residents in other areas have been compensated for flood mitigation issues why are Ghost Lake Village residents also not compensated?

Residents are reminded that Ghost Lake Reservoir is a "reservoir" and will fluctuate over a broad range of elevations. As mentioned earlier, this year’s elevations during May were not unprecedented and closer to historical norms. The reservoir is being operated within its licensed range and has, historically, been at these levels.

Issues regarding municipal taxes should be discussed with the municipality. The province has not compensated other residents near flood mitigation projects. Some flood mitigation projects have a land acquisition requirement in order to proceed. Acquiring land to build a project is not the same as compensating residents for minor impacts.

There have been concerns raised regarding cattle, additional fencing requirements and access to water from the lake. Will the government provide funding for fencing and other means for watering the cattle?

No. Residents are reminded that Ghost Lake Reservoir is a "reservoir" and will fluctuate over a broad range of elevations. As mentioned earlier, planned reservoir levels during May are not unprecedented and closer to historical norms.

More Information

Have a question about the modified operations agreement between the Alberta government and TransAlta? Contact the Information Centre:


Page Information

Updated: May 17, 2018