The Dickson Dam was host to RDRWA board members and guests on Tuesday October 17th. The purpose was to tour the facilities, learn about dam operations, and better understand the dam’s important role in the watershed.
The Dickson Dam was built in 1984 and is operated by the Government of Alberta – Ministry of Agriculture & Irrigation. Its main purpose is to provide an assured water supply to downstream municipalities, but it also provides secondary benefits such flood control, improved water quality, recreation, hydroelectric power generation, and more flexibility in meeting Alberta’s commitment to sharing water with Saskatchewan.
“Prior to the dam’s construction, flows in the Red Deer River dropped to as low as 2 cubic metres per second (cms) at the City of Red Deer. By using water from the spring and summer runoff to fill Gleniffer Lake Reservoir, operators are able to release a minimum flow of 16 cms during winter months.” (AEPA, 2023) This improves water quality in winter months and ensures municipalities have adequate water throughout the year.
The dam operators showed us how they closely monitor all available real-time river flow and precipitation stations, while utilizing forecasts from the River Forecast Centre and Environment Canada. “If there is adequate storage in the reservoir, the Dickson Dam can regulate small and medium sized floods and potentially minimize impacts downstream. The larger the flood, however, the less ability the reservoir has to attenuating downstream flows.”
Due to recent upgrades, the dam is now better equipped to handle high inflows and has a maximum discharge capacity of 6,280 cms during a major flood event. Much higher than the largest recorded flow of 1,930 cms in the year 1915, or the flood in 2005 which peaked at 1,570 cms. Without the Dickson Dam holding back water during floods, both the 2005 and 2013 flood would have been approximately 30% greater by volume.
While the presentation highlighted the benefits of flood reduction, there were timely questions from attendees about the impact of drought. According to operators, the reservoir did reach a very low level in 2001 where the water surface elevation was 937 metres, which is about 4 metres below the spillway crest elevation. So if there were prolonged reductions to the spring snowmelt in the Red Deer River headwaters near Skoki valley, or if summer precipitation continues to decline, then the accumulated impact from year-to-year could lead to declining water levels and difficulty refilling the reservoir. Although that has thankfully not been the case recently, the recent dry conditions were certainly on the minds of those attending.
The day ended with an outside tour of the spillway gates and reservoir dykes. Although the wind was blowing strongly, we found some shelter above the spillway and enjoyed the sunshine and beautiful views of our watershed. It was an educational day and we were very thankful to the Central Operations staff for hosting us!