Yeah, I'm a worrier

Alum being applied

Forgive me if I have touched on this subject before. After so many posts it is hard to keep track.
 I have been a proponent of using an alum treatment as a means of getting our lake back to a good water quality as a first step in lake and watershed remediation. I have a concern that needs to be investigated before we spend the $200,000 or so that a treatment will cost.
 We all know the lake is at an extremely low level. That was a contributing factor to the lake quality problem last summer. If we carry out the treatment on a still far below pool lake what happens with a heavy rain and field run-off with nowhere to go? The lake will not be skimming over the outlet unless the water level is high enough to allow this to happen. Will the lake again load with nutrients from the run-off and make the alum treatment ineffective? I don't know the answer but we need to know going into this. A decent amount of winter snow and there will be no problem. The treatment will be on a lake at full pool. I am still in favor but it must be handled with care.
Ken Dillenburg