Despite our best efforts and a significant amount of time and energy put into the project by ACA staff, our aeration program for 2015/16 has not produced the results we were hoping for. As stated previously, because of criminal liability issues associated with Sec 263 of the Criminal Code, we changed our aeration program this winter from the usual surface aeration to a sub-surface diffuser system. We hoped that by using the sub-surface diffuser system, we would be able to continue to provide enough dissolved oxygen (DO) into the water column to maintain fish over the winter, while at the same time containing the opening in the ice created by the aeration, through the installation of a dock and chain-link system.
Our original plan was to aerate only a portion of the lakes this winter to test the sub-surface diffuser system; however, at the request of the Minister of Environment and Parks, we proceeded with the implementation of aeration systems at all the lakes we would normally aerate. Fortunately, Alberta Environment and Parks was able to take over aeration using surface aerators at two locations, along with two municipal governments and one private individual. You will note in the table below, with the participation of these groups, five of the fifteen lakes that ACA would normally aerate over winter were aerated using surface aeration.
Unfortunately, we experienced more difficulties with the sub-surface diffusers than we had expected. Containing the hole created in the ice within the dock system proved to be a difficult task, particularly with the warm winter conditions we experienced this year. As a result, in many instances we were forced to reduce the amount of air being pumped by the diffusers into the water column. While this change allowed for the hole to be contained, it appears in most cases it reduced the amount of oxygen entering into the water column to the point at which the aeration was ineffective at maintaining adequate DO levels.
We are currently working with Alberta Environment and Parks to resolve the aeration issue to ensure that surface aeration can be re-implemented at all lakes in 2016/17.
The table below provides an update as to the aeration system and effectiveness at each lake as of March 1, 2016.
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NAME
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AERATION SYSTEM
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COMMENTS
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NORTHWEST REGION
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|
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Cecil Thompson Pond
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MD surface aeration
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DO level good. Good potential for fish to survive.
|
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East Dollar Lake
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ACA diffuser
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DO low. Limited potential for fish survival. Dead trout have been observed.
|
|
Figure Eight Lake
|
AEP surface aeration
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DO level good. Good potential for fish to survive.
|
|
Spring Lake (Grande Prairie)
|
Fall aeration only
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This lake is normally only aerated in the fall. DO level good. Good potential for fish to survive.
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Sulphur Lake
|
AEP surface aeration
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DO level good. Good potential for fish to survive.
|
|
Swan Lake (Grande Prairie)
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County surface aeration
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DO level good. Good potential for fish to survive.
|
|
CENTRAL REGION
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|
|
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Beaver Lake
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diffusers shutdown Feb 5
|
DO becoming a concern. Potential for some fish loss.
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|
Birch Lake
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No aeration
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DO still ok. Good potential for fish survival.
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Fiesta Lake
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diffusers shutdown Jan 28
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DO low. Limited potential for fish survival. Dead minnows have been observed.
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|
Hansen Reservoir
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No aeration
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Low DO levels prior to equipment being installed as a result aeration was not initiated. Limited potential for fish survival.
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Ironside Pond
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Diffusers shutdown Feb 5
|
DO becoming a concern. Potential for some fish loss.
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|
Mitchell Lake
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Diffusers shutdown Jan 18
|
DO still ok. Good potential for fish survival.
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|
Millers Lake
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ACA diffuser
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DO low. Limited potential for fish survival. Dead trout have been observed.
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|
Muir Lake
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ACA diffuser
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DO becoming a concern. Potential for some fish loss.
|
|
Spring Lake (Stony Plain)
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Private surface aeration
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DO level good. Good potential for fish to survive.
|
|
SOUTH REGION
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|
|
|
Coleman Fish and Game Pond
|
ACA diffuser
|
DO are a concern. Potential for fish loss.
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Please contact TODD ZIMMERLING at todd.zimmerling@ab-conservation.com or 780-903-3377 with any questions or concerns.
