The province of Alberta and TransAlta have reached an agreement to protect communities along the Bow River from flood and drought by using the company’s reservoir system in exchange for $5.5 million each year over the next five years.
The five-year agreement will provide flood protection for Calgary, reduce the impact of drought and help communities adapt to a changing climate, according to a government press release announcing the initiative at the end of April.
TransAlta, through the agreement, is allowing the government to modify operations at Ghost Reservoir for flood mitigation purposes from May 16 to July 7 each year. As well, the province can adjust reservoir levels at three Kanananskis-area reservoirs throughout the year to supplement flows in the Bow River during dry periods, or provide additional flood storage.
“Both flood and drought are serious concerns in southern Alberta,” said Minister of Environment and Parks Shannon Phillips. “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.”
With flood and drought events expected to become more common and more severe with a changing climate, modifying operations at TransAlta facilities is another layer of defence for developed areas in the Bow River watershed.
Modified use of existing water management infrastructure, according to the government, complements its other flood and drought resiliency efforts, including community-level mitigation, new flood hazard mapping, and restoration of wetlands and riparian areas.
Last year, the agreement provided the province with up to 65 million cubic metres of flood storage at Ghost Reservoir during the high runoff 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. However, water levels will fluctuate during the modified operations period to reflect ongoing risk assessments for both flood and drought.
The cost to Albertans for the use of the reservoir system, most of which is located in provincial parks, is $27.5 million over the five-year term of the agreement.
