Briefly, the HLLT is a collaborative effort between Towns of Falmouth and Windham, the Highland Lake Association, the Department of Environmental Protection and Cumberland County Soil and Water Conservation District to work together to improve and maintain the water quality of Highland Lake for the benefit of the residents, the Towns, and future generations.
The meeting focused on four topics:
A review of what we know about Highland Lake.
Phosphorus levels have gradually risen over the past 40 years.
From 2014-2017, the lake exhibited a nuisance bloom (secchi disk readings <2 meters for approximately 4 weeks).
In 2018 & 2019, the pattern of reduced secchi disk readings occurred but did not reach the level of a nuisance bloom.
The picocyanobacteria has been identified as Cyanobium (generally non-toxic, very small, single-celled strain).
Presentation of 2 new hypotheses (if verified could explain the cause of the picocyanobacteria bloom).
Hypothesis 1 – changing grazing patterns within the food chain are causing the bloom.
Hypothesis 2 – windy activity on the lake could be a driver of increased phosphorus in the water column (phosphorus fuels the bloom).
Initial identification of the water quality sampling protocol for the 2020 season to further delineate the cause(s) of the bloom.
Dr Wilson indicated the goal will be to equip volunteer water quality monitors at Highland Lake to implement an effective sampling protocol to gain more insight as to why the bloom occurs.
What residents can do now.
There is too much phosphorus in Highland Lake. The major source of phosphorus is erosion from the watershed. It is important for residents to understand that individual efforts to reduce runoff from their property and the road in their association is imperative for a healthy lake. While the cause of the bloom is unclear, we do know that phosphorus increases the intensity of the bloom.
In the coming months, the HLA will be working with road associations and individual residents in the ongoing effort to reduce erosion, and thereby reduce phosphorus inputs into HL.
For detailed information about the Highland Lake water quality situation and hypothesis 1&2, as well as hints for the 2020 sampling protocol, go to https://www.windhammaine.us/DocumentCenter/View/5531/2019-Highland-Lake-Science-Roundtable-Summary.