Submitted by Don Russell, Lakewood.
In an article that appeared in the September 1, 2017 edition of The Suburban Times I described the likely biological response of Waughop Lake as a result of Pierce College discontinuing its discharge of raw sewage into the Lake.
My 2017 prediction and recent developments
Alum treatments are administered to prevent phosphorus release from nutrient polluted lake bottom sediments. Alum applications result in significantly improved water clarity and temporary prevention of toxic algal blooms. In a shallow lake the usual biological response to an alum treatment and its water clarifying effect is prolific aquatic plant growth. Apparently, the cessation of sewage discharge into Waughop Lake has created the very condition that one expects after an alum treatment.
The beneficial recreational uses (e.g., fishing, boating, swimming) of Waughop Lake will be seriously impaired as a result of an alum treatment. When the fall die-off of the plant biomass occurs its bacteria decomposition in the lake may cause dissolved oxygen depletion and a fish kill. That which washes ashore will undergo bacterial decomposition that will create a foul odor that will adversely affect all park attendees.
The 2017 cessation of raw sewage discharge into Waughop Lake has now changed its biological response from experiencing recurring toxic cyanobacteria blooms to facilitating excessive aquatic plant growth. An alum treatment is effective in preventing toxic cyanobacteria blooms, but ineffective in preventing excessive aquatic plant growth. There are only three effective treatments for preventing excessive aquatic plant growth, i.e., annual harvesting, remove the bottom sediment that fosters their growth, or annual application of an herbicide.
Recent development: So far this season Waughop Lake has not experienced a harmful cyanobacteria bloom, nor is it likely too. Instead the lake is experiencing excessive aquatic plant growth that has rendered fishing in the lake almost impossible.
Lakewood’s $200,000 Brown & Caldwell Waughop Lake Management Plan recognized that Waughop Lake’s toxic algae blooms are the result of 65 years of Western State Hospital discharging slaughtered animal waste, manure and human sewage and 40 years of Pierce College intermittently discharging human sewage into Waughop Lake.
The Plan stated that the appropriate action to restore the beneficial uses of Waughop Lake is to remove the nutrient rich layer of sediment that has built up on the bottom of the lake as a result of these discharges. B&C assigned a $2.7 to $17.9 million cost estimate to remove this layer of nutrient polluted sediment “depending on sediment removal technique, disposal and treatment requirements”.
The Plan also indicated that the phosphorus contained in the water column and 10 cm of bottom sediment could be inactivated by a $210,000 lake-wide alum treatment. Such a mitigation strategy would likely prevent harmful Cyanobacteria blooms from occurring in the lake for from 3 to 5 years, after which ongoing repeated alum treatments would be necessary until the lake fills in and becomes a hydrogen sulfide emitting swamp.
What the Plan did not indicate was that an alum treatment would pollute Waughop Lake’s bottom sediments with toxic aluminum and various sulfur compounds (sulfate and sulfides). The existence of these pollutants will not only negate the commercial value of Waughop Lake’s nutrient rich sediment as a soil amendment material, it will significantly increase the cost of any future sediment removal and disposal operation.
No effort was made by City staff to explore how the lake’s nutrient rich layer of sediment could be removed for $2.7 million or less. No request for State funding to remove the layer of nutrient rich sediment laid down by the discharges of two State owned institutions was made. No opportunity was afforded the public to be involved and participate in considering other mitigation strategies (e.g., $50,000 annual cost to apply a combination of an herbicide, algaecide and phosphorus inactivation agent) and other remedial sediment removal options, such as a combination of lake level drawdown and dry and wet sediment removal techniques.
Mother nature, in response to Pierce College’s discontinuance of discharging its raw sewage into Waughop Lake, has done what TetraTech’s prescribed and highly inflated $420,000 alum treatment cost was intended to do. However, Mother Nature now challenges us with what to do about the excessive aquatic plant growth that now denies park goers safe beneficial recreational use of Waughop Lake.
Mother Natures’ message to all who will listen is: Remove the layer of nutrient polluted sediment that you irresponsible humans laid down in Waughop Lake’s bottom sediments!