Submitted by Don Russell.
Dear City of Lakewood Council Members,
In a September 1, 2017 article appearing in The Suburban Times titled “The likely effect of the discontinuance of sewage discharge into Waughop Lake” I indicated that the effect was likely to be an increase in the growth of aquatic plants in the lake.
This prediction was important since nutrient polluted lakes generally exist in one of two stable states. One stable state is characterized by having turbid water with a predominate population of harmful Cyanobacteria (aka, blue-green algae). The other stable state is characterized by having clear water with a predominate population of excessive aquatic plants (macrophytes).
Bear in mind that when the Brown & Caldwell study was done in 2014-2015 the lake was being externally nutrient loaded by intermittent discharges of sewage from Pierce College, a situation that had been occurring for many years prior to its discovery in the winter of 2016. This fact was unbeknownst by those monitoring the water quality during the 2014-2015 study. Therefore the impact of this discharge on the biological response of the lake was not taken into consideration by those proposing options for the lake’s remediation.
The focus and conclusion of the B&C study was on internal release of phosphorus from bottom sediments and the treatment options that could address this situation. Removal of the nutrient polluted sediment by dredging was the universally preferred option. A heavy one shot application of alum to inactivate the phosphorus in both the water column and to a certain depth of sediment (B&C 10 cm and Tetra Tech 22 cm) was proposed as a possible 3 to 5 year technique for preventing harmful Cyanobacteria blooms in Waughop Lake until funding for dredging could be obtained.
With the cessation of intermittent sewage discharge into Waughop Lake its condition is likely to change from a turbid Cyanobacteria infested stable state to a clear water excessive aquatic plant stable state. Such a transformation will be hastened by application of a lake-wide alum treatment. Therefore such a heavy one shot lake-wide application of alum at this time is not advisable.
Rather the City should employ the services of either Northwest Aquatic Eco-Systems or AquaTechnex to monitor the lake and each year prescribe and apply the minimal amounts of an herbicide (to control excessive aquatic plant growth), an algaecide (to prevent nuisance filamentous green algae blooms) and a phosphorus inactivation agent (to prevent harmful Cyanobacteria blooms). This is the method by which all other nutrient polluted lakes in Lakewood are managed to assure their safe beneficial recreational use and is far less expensive that a lake-wide application of alum.
The Brown & Caldwell/Tetra Tech prescription (base upon data from a 2014-2015 study) for a heavy lake-wide alum treatment of the water column and varying depths of bottom sediment was designed to address a turbid Cyanobacteria infested lake (a condition that existed prior to the cessation of Pierce College’s discharge of sewage), not on the emerging transformation of the lake to a clear water excessive aquatic plant growth state.
The question arises as to why should you seriously consider what I have stated above. From 2009 through 2016 I was the volunteer Waughop Lake water quality monitor for the Tacoma Pierce County Health Department (2009-2013) and the City of Lakewood (2014-2016). Tom McClellan has been the volunteer Waughop Lake water quality monitor for the City of Lakewood for 2017-2018. It is time for you to seriously consider the merits of what we both have to say about the proper and cost effective management of Waughop Lake’s water quality.Print This Post