Fishteck and others are correct. In my past job was as a consultant, I was involved in preparing work plans for this type of work. Prior to any work than may discharge or cause disturbance in flowing waters in Alberta, a work plan must be submitted and approved by AEP. The work program will include measures to mitigate impact to the waters and the aquatic environment. Downstream threshold limits (based on upstream levels and distance downstream from the work activities) on turbidity, total suspended solids and other work specific parameters are set. Upstream and downstream monitoring must be conducted and managed by qualified professionals. Exceedances of the threshold limits must be reported to AEP followed with an action plan to reduce the possibility of future exceedences. I know its not perfect folks, but engineering consultant professionals and AEP will monitor potential impact to the waters during the instream work. However as others have indicated, call the AEP line if you see excess silt or impact, or feel the appropriate efforts are not being done.