Over the years, the Three Lakes have been the subject of various studies. The first one we know of was in 1936 as part of a state wide assessment of glacial lakes. Unfortunately we do not have a copy of that study at this time, but we have many other reports. A long timeline of studies will enable studies of trends and changes that may be subtle. Historical data can also help identify the cause when the appearance or conditions of the lake changes abruptly.

Water Quality

CSLAP, the Citizens Statewide Lake Assessment Program, enables volunteers to assess water quality every two weeks during the summer. All three lakes have been tested as part of this program since 2006. Waccabuc was also in the program from 1986 – 1996. Physical and chemical attributes are assessed, and recently algal composition and harmful algal blooms have been included in the analysis.

Plant Surveys

Understanding the plant communities and densities helps us track changes in the plants – and in lake quality – over time.  Plant surveys may also detect invasive plants in time to take control actions.

Goop and Zoop

Studies of algae and zooplankton, the small animals that consume algae, can help us understand the food web at the base of lake ecology.  Understanding the algal community has also become more important as we develop a better understanding of the Harmful Algal Blooms (HABs) that can contain toxins.

Lake and Watershed Plans

From 2002 to 2006, the Three Lakes Council hired Michael Martin, of Cedar Eden, as a consultant. The reports provide fundamental information about the impacts of land use and the hydrology of our lakes, and are the foundation of our lake management plan.  We also have summaries of the state of the lakes prepared by ABI, our consultant after 2007.

Union Carbide and Aeration

In 1972, Union Carbide approached the Three Lakes Council with a proposal to install aerators in Lake Waccabuc to study their impact on improving lake conditions. The aerators were installed in 1973 and operated by Union Carbide through 1975. The conclusion of the study was that the aerators had a positive impact on the overall fishery of the lake, especially the cold water fishery. There was a possible positive impact on nutrients in the first year of operation (1974 report), but that impact was not found in the other years. (1975 nutrients, 1975 report)  The study indicated that a system two to three times as large might have had a significant impact in the internal phosphorous loading.  (Published article).

When aerators were installed by Union Carbide in 1973 they were sized to meet the oxygen demand in the hypolimnion (the bottom layer of the lake) at that time. Old records are scarce, but those found so far indicate that over the intervening decades the amount of oxygen in this bottom layer suffered a severe decline, despite the aerators. For example, in 1975, the hypolimnion had 5-6 ppm of oxygen.  In 1985, 4-5 ppm oxygen was recorded. Maintenance was performed on the aerators around 2000. In 2002, 2003, and 2004 less than 1 ppm of oxygen was measured in the hypolimnion. Based upon these measurements, either the aerators were not functioning well or the phosphorous loading in the lakes increased to the point that the aerators were not able to keep up.  In 2005, we decided not to power the aerators, and to use the money saved by not running the aerators for the testing and analysis needed to determine further actions.  

SUNY Purchase

In 1976, three SUNY Purchase students analyzed the characteristics of Lake Waccabuc and three other Westchester County lakes to determine their eutrophic state. These are very limited with only two readings for Lake Waccabuc and one reading for each of the other lakes. (1, 2, 3)

In 1979, a SUNY student conducted a study of the impact of nutrients on blue-green algae in Lake Waccabuc.

In 1981, a SUNY student reviewed the eutrophic health of Lakes Waccabuc and Oscaleta based on data collected from June, 1979 to August, 1980.  The professor critiqued that paper and made recommendations for basic lake monitoring.

SUNY students continued to monitor various characteristics of the Three Lakes through 1983. In 1983, they issued a status report.

Other Reports

2013 – Pesticides.  We participated in a pilot to test for pesticides.  The results are preliminary.

2007 – Paleolimnology – a study of the sediments of Lake Oscaleta and Lake Waccabuc.  We don’t have a report yet, but a summary of the purpose and sampling is available.

2000 – West Point cadets evaluated Septic System Alternatives for the Three Lakes Watershed, and recommended a GIS system and resident education.

1970 – Robert L. Johnson of Cornell reported on the aquatic plants of the three lakes.

Town Wide Lake Management Plan

Lewisboro hired EcoLogic, LLC to report on the state of the lakes and prepare a lake management plan and recommend town-wide management actions.  Fact sheets on each lake are included.