Alberta, TransAlta reach agreement to protect Calgary and other Bow River communities from flood and drought

The province of Alberta has entered into a five-year agreement with power generation and wholesale marketing company TransAlta that will provide flood protection to Calgary, reduce the impacts of drought and help communities adapt to a changing climate.

The five-year agreement allows the province to modify operations at the Ghost Reservoir for flood mitigation purposes from May 16 to July 7 each year and adjust reservoir levels at three Kananaskis-area reservoirs year-round to supplement flows on the Bow River during dry periods, or provide additional flood storage, Alberta Environment and Parks (AEP) said in a press release on Wednesday.

The Alberta government will provide TransAlta with $5.5 million in compensation annually for five years to offset the impacts that modified operations will have on TransAlta’s ability to generate power at these facilities, AEP said. However, TransAlta added in a statement, “as far as possible, this agreement has been structured to be break-even. TransAlta expects to cover lost revenue if and when water levels must be lowered and power cannot be generated for customers, but does not expect to make a profit.”

The AEP release noted that modified operations at TransAlta facilities provide an important layer of resilience in a changing climate where flood and drought events are expected to become more common and more severe. Modified use of existing water management infrastructure complements the province’s other flood and drought resiliency efforts, including community-level mitigation, new flood hazard mapping and the restoration of wetlands and riparian areas.

Last year’s agreement provided the province with up to 65 million cubic metres of flood storage at Ghost Reservoir during the high run-off season. The new agreement provides the same use of Ghost Reservoir, plus year-round control of reservoir levels at Barrier Lake, Upper Kananaskis Lake and Lower Kananaskis Lake.

Initial reservoir target levels will be set prior to each operating season based on the provincial Water Supply Outlook, snowpack and soil moisture conditions and prevailing weather patterns, the release said. However, water levels will fluctuate during the modified operations period to reflect ongoing risk assessments for both flood and drought.

“Both flood and drought are serious concerns in southern Alberta,” said Shannon Phillips, Minister of Environment and Parks, in the release. “This agreement provides more storage capacity and greater flexibility to help protect communities along the Bow River from the potentially devastating effects of flood and drought and the uncertainties of a changing climate.”

Kim Sturgess, chief executive officer of Alberta WaterSMART, added that “this is a positive step towards collaborative water management in the Bow River basin. Successful implementation hinges on the flexibility and responsiveness of water managers to flood and drought conditions, and provides the opportunity for all of us to learn by doing.”