In response to a complaint from an ice fisherman in 2001, both TransAlta and Alberta Environment have undertaken numerous water quality investigations at Lake Wabamun. The studies that have been completed over the last several years by Alberta Environment have examined the Trends in Water Quality, Metals and Trace Organics in Sediments, Significance of Sediment Quality on Aquatic Organisms, and Disinfection Byproducts. An overall statement from Alberta Environment was that swimming and playing in Lake Wabamun is no more of a concern than in any other lake in Alberta.

Click here to read a summary of the Alberta Environment reports.

TransAlta has also conducted studies in conjunction to Alberta Environment’s work. Notably, TransAlta was required to complete a risk assessment as it relates to heavy metals. Preliminary conclusions that were drawn from the risk assessment indicated that there are no increased risks to human, wildlife or fish as it relates to the metals present in the water, sediment or soil. The final report has yet to be released as it is being reviewed by Alberta Environmental and Capital Health.

Ash Lagoon Tour

In August 2002, members of the Executive Committee and a councilor from Parkland County toured the Ash Lagoon at the Wabamun Generating Plant. The attached aerial photograph depicts the Ash Lagoon, relative to the Wabamun Plant.

The Ash Lagoon is made up of three separate ponds into which water mixed with ash is discharged and allowed to settle over a period of time. The ash results from the coal which is burned to generate electricity at the Wabamun Plant. There are two types of ash generated by the burning of coal: fly ash and bottom ash. Fly ash is very light and is collected within the stacks by the air handling equipment that is required at the plant. The air handling equipment is capable of collecting up to 99.7% of the ash, with an estimated 0.3% of the ash being discharged to the atmosphere. The collected fly ash is returned to the mine or sold to make cement based products.

Bottom ash collects at the base of the stacks and is mixed with water to form a slurry before being discharged to the Ash Lagoon. Location A on the attached air photo is where the slurry is initially discharged to the Ash Lagoon. This area is known as the primary settling pond. The transfer of water from the primary (A) to secondary (B) pond is via an overflow ditch between two berms. At this point, the vast majority of ash has settled out and the water clears as it moves towards the secondary (B) pond. The water further clears in the secondary (B) pond and eventually flows via a near surface horizontal culvert, which only allows the near surface water to spill into the tertiary (C) pond. Water in the tertiary (C) pond flows around a manmade peninsula before passing through a man made marsh area, which serves as a form of natural treatment. The final holding (D) pond allows for final clarification of the water before it spills into a discharge culvert for ultimate release to Lake Wabamun.

Click here to view the aerial photo

Along the discharge stream, a continuous monitoring station has been installed. At this location, pH and flow are constantly being monitored. There is also an auto-sampler at this location which allows for water samples to be collected every 20 minutes over a 24 hour period (3 times a week). At the end of the 24 hour period, the sample is retrieved and submitted for laboratory analysis for parameters as determined by Alberta Environment under their permit to operate the lagoons.

The water that was being discharged from the lagoons at the time of our tour appeared very clear with no evidence of turbidity. The vegetation around the Lagoons was dense and lush and there were no apparent bank slumps or failures that would give rise to disturbing the settlement process. The Executive Committee also observed an array of groundwater monitoring wells around the lagoon which are monitored once a year by TransAlta. A considerable amount of water fowl was also evident on the pond during the tour.

The committee has requested copies of the annual monitoring report with respect to groundwater quality and the discharge stream from the Ash Lagoon.