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Water Quality

There are many imminent threats to Maine lakes. Near the top of the list, and perhaps the most pervasive, is the potential for lakes to become nutrient enriched and more biologically productive as a result of development in lake watersheds. The result is a decline in water clarity (transparency), due to an increase in the growth of algae. Excess algae in lake water can cause a disturbance to the normal equilibrium of the aquatic ecosystem. As algae die and decompose, bacteria consume the oxygen that is dissolved in the water.  In addition, high levels of algae growth can lead to a decline in oxygen levels, especially during the warm summer months. Oxygen loss can reduce critical habitat for coldwater fish (trout and salmon), and it can accelerate the decline of water quality.

LEA classifies Keoka Lake as a HIGH degree of concern (2018).  Water quality concerns for Keoka include:

  • Low oxygen levels, especially at lower depths,

  • Inadequate cold-water fish habitats,

  • High deep-water phosphorous levels, and

  • Elevated gloeotrichia levels

At the 2019 Annual meeting, the KLA membership approved funding for a new LEA initiative to acquire information on the chemical, biological and physical processes that occur within lake systems using multi-parameter monitoring probes called Sondes. These instruments acquire simultaneous, geo-referenced data on turbidity, pH, oxygen, temperature and algal populations.  The initiative will spatially map the surface water quality of lake systems.  This project uses a boat-mounted, flow-through system that generates rapid, high intensity measurements of surface conditions all over the lake.  This survey was conducted on July 26, 2019 on Keoka.

The Sonde survey was condcuted on Keoka Lake on July 26, 2019.  Interpolation of the survey data will produce a snapshot-in-time of the status of entire lake status.  This type of high-resolution, spatial assessment has been done by a few other researchers in the country, but the methodology is still fairly new.  The data will be published on this site as it becomes available.