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Letter: Post-Mortem of the March 24-25, 2020 Alum Treatment of Waughop Lake

Submitted by Don Russell, Lakewood.

Preface: In my 4/17/20 paper titled WAUGHOP LAKE POST-ALUM TREATMENT REPORT under the caption Consequences I stated:

The carp/largemouth bass fishery in Waughop Lake will likely no longer exist as a result of the lethal effect of a sudden change in the osmotic pressure of the water induced by two 40 mg Al/L alum treatments (one in March a second in June 2020) to which they have already been and will be exposed. And, because of the low alkalinity and sulfate induced acidity of the lake any subsequent fish species (trout) introduced into the lake will likely succumb as a result of exposure to aluminum ion and sulfur compound (sulfate and sulfide) toxicity.

This predicted consequence did not happen after the March 24-25, 2020 alum treatment of Waughop Lake for the reason described below.

Reason why there was no lethal effect

Because of the shallowness of the water all along the southwest-west-northwest shore of Waughop Lake the alum application barge could not discharge alum and sodium aluminate into a significant area of the winter rain expanded portion of the lake. The extent of this non application area is shown in the below two photographs taken in October 2019.

Upon the return of winter rains the lake level rose approximately 22 inches to inundate this entire previously dry and fall exposed area of Waughop Lake as note in the below photograph.

The very large rain water inundated area of Waughop Lake that could not be accessed by the alum treatment barge provided a safe refuge for the carp and bass population as they fled the deeper alum treated portions of the lake that were accessible to the alum treatment barge. It was in this inundated area that the carp engage in their annual spawning activity.

It wasn’t until the middle of May that the surviving carp and bass left the untreated rain water induced shallow areas of the lake and returned to the main portion of the lake that the carp and bass fishery for the post 3/24-25/20 alum treatment fish survivors resumed.

A second alum treatment is scheduled for June/July. This will significantly increase Waughop Lake’s concentration of toxic aluminum and sulfate-sulfide. It will be interesting to see what the second alum treatment does to the carp and bass fishery and aquatic plant population.

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