A study commissioned to look at ground water in a watershed east of Ponoka found there is plenty available and that the lakes are not being drained by water usage.
Hydrogeological Consultants Limited (HCL) presented its findings regarding the special Chain Lakes area study at an open house on May 11 at the Scott School Hall, hosted by the Friends of the Chain Lakes Society.
Ponoka County CAO Charlie Cutforth explained the study was a first step in planning for the future of the area.
“Because of the zoning of the area surrounding the lakes, which may allow limited residential or resort development, the county felt the need to prove there would be an adequate supply,” he said, adding the study was triggered by a request from local residents.
“It was also hoped the study would provide area residents with a level of comfort should there be any further development and give the county some good information to go on.”
HCL’s principle hydrogeologist Roger Clissold spoke to a small crowd about what went into compiling the study and some of the findings. Overall, Clissold found the amount being used by authorized users — at around 763 cubic metres per day — is nearly equal to the estimated 900 cubic metres per day of water running into the Chain Lakes.
“The Chain Lakes basin is 73 square kilometres and has a total of 276 water wells — or about two to three per acre. The amount being used is around what a population of 3,000 would use daily,” he explained.
That amount doesn’t include the 200 or so domestic water wells, which consume 683 cubic metres per day, far below the protected level outlined in the provincial Water Act.
Clissold added the study only looked at ground water, but suggested the Chain Lakes are likely being fed by runoff from both rain and aquifers flowing, courtesy of natural springs hitting the surface.
“Most of the rain runs off into the lakes and some goes into the ground, helping to recharge an aquifer. All of this is done locally, as water doesn’t flow too far,” he said.
“But it’s just a guess as to how much ground water flows into a lake, since it’s very difficult to calculate as you can’t measure it. Aquifers are dynamic and water is constantly moving. You can only calculate volume and see trends.”
Clissold then noted only one aquifer of the few that are in the basin would actually contribute runoff to the Chain Lakes, since it is above lake level and other runoff would be lost to evaporation and absorption by plants or fields. However, he added there is no way to determine if that is indeed taking place.
Something comes close to showing how much water is available is apparent yield — a calculation based on data that can be quite vague and covers an area, instead of an aquifer.
“The majority of our water well data comes from water well drilling reports that are not great and have little details,” he said.
“However, the majority of the basin has an apparent yield between 20 and 100 cubic metres per day, while some areas — mostly in the southern end of the basin — produce a significant amount of water between 100 and 300.
“And, even with the five monitoring wells, we have not seen a lot of decline in water levels even with more development.”
Another outcome that surprised Clissold was the levels of total dissolved solids (TDS) in the water.
“Historically, ground water in Alberta doesn’t meet the Canadian TDS objective of 500 milligram per litre and seldom do we see levels below that,” he said. “In the Chain Lakes, about half of the basin is less than 500.”