Submitted by Don Russell.
In response to my request that you (Lakewood City Council) reevaluate your decision to approve the lake-wide application of alum to Waughop Lake, Jason Whalen responded by stating: “I trust you will read the “rest of the story” and response prepared by our Public Works Director, as well as the reports prepared by the City on this issue.” He goes on to state: “Removal of bottom sediments through hydraulic dredging is simply not a viable option (in terms of massive expense-in the millions-and impact to the park and park users) when compared to the alternative of alum treatment.”
I have read the “rest of the story” article, the Waughop Lake Management Plan, and the reports prepared by the City on this issue. Here is what the Waughop Lake Management Plan and Tetra Tech’s report state:
The initial lake-wide alum treatment prescribed by Brown & Caldwell is estimated to cost $210,000 with no further costs for the duration of its 3 to 5 years life expectancy, whereas dredging is expected to cost from $2.7 to $17.0 million with no further costs for 50 years or more thereafter.
The initial lake-wide alum treatment prescribed by Tetra Tech is estimated to cost $780,000 and require additional maintenance costs of $50,000 each year thereafter. Tetra Tech estimates the cost of dredging to be from $7.9 to $31.6 million with no further costs for 50 years or more thereafter.
Who is the reader of the Lake Management Plan (LMP) and Tetra Tech report to believe?
The Council approve Waughop Lake Management Plan proposed a two phase approach for implementing the Plan as follows:
Phase 1 would consist of a whole-lake alum treatment to remove phosphorus from the water column and inactivate phosphorus in 10 cm of the sediment. During this phase, the City would collect the additional sediment data needed to refine the construction cost estimates and support permit applications for dredging. [By contrast Tetra Tech proposes a whole-lake alum treatment to remove phosphorus from the water column and inactivate phosphorus in 80 cm of the sediment.]
Phase 2 would involve dredging to remove phosphorus-rich bottom sediments from the lake bottom. Dredging is expected to be the most effective long-term measure for reducing Cyanobacteria blooms because it would remove phosphorus-rich sediments that have been accumulating from farming and other human activities over the past ~ 100 years.
Apparently the City staff and Council, without requesting proposals and cost estimates from reputable dredging contractors, has decided based upon wildly divergent and questionable cost estimates provided by Brown & Caldwell and Tetra Tech, that the “massive expenses” associated with dredging makes it “simply not an option”. The Public Works Director’s “the rest of the story” merely provides the rationalization to support the City’s dredging is “simply not an option” assertion.
None of the above makes much sense when the most practical and lowest cost option for assuring safe beneficial recreational use of Waughop Lake (until the dredging option can be implemented) is to merely apply light annual combination doses of a herbicide (to control aquatic plant growth), an algaecide (to prevent filamentous green algae blooms), and a water column only phosphorus inactivation agent (alum, lanthanum enriched clay, or iron) to prevent harmful Cyanobacteria blooms. This is the method used in all the other nutrient polluted lakes (Gravelly, Louise, Steilacoom) in Lakewood. The annual cost of such treatment would be in the range of from $50,000 to $75,000.
The benefit of this minimal chemical application option is that applications can be designed to address likely plant, algae and Cyanobacteria responses to the nutrient load (which varies) in the lake at the beginning of each season, costs are reasonable, there is no disruption of park activities, and there is no significant adverse impact on the quantity and quality of bottom sediments that will ultimately have to be removed if Waughop Lake is to survive as a lake, rather than become a wetland and eventually a meadow.
For the above reasons the City Council Members should reconsider their decision to approve the application of dozens of tons of alum to Waughop Lake.
For additional background information, read “The likely effect of the discontinuance of discharge into Waughop Lake“.