Cyanos Activity August 11

Water is clean for recreation.

Disclaimer: The information presented below reflects conditions throughout the lake and may differ from conditions on specific shorelines. For information regarding beach closings please contact the Torrington Area Health District or local town officials.

Water clarity at both the Center Lake and North Bay increased by slightly more than 0.5meters to average 3.1 meters.  Lake-wide Secchi disk depth ranged between of 2.8 – 3.2 (only 2 of 14 stations had clarity <3m).   Total cyanobacteria numbers remained at about the same level but 1) No Anabaena was present, and 2) all Aphanizomenon and Woronichnia cells were dead.  Small clusters of Gleocapsa appeared in North Bay but none was seen in Center Lake Station.   Dissolved oxygen concentrations at the surface throughout the lake were normal, between 8.0 mg/L and 8.5 mg/L, representing a saturation level only slightly above 100% (ranged between 101.9% and 106.8%).  Percent saturation of dissolved oxygen just above 100 % suggests good mixing and no oxygen consumption occurring in the water, as well as low plankton photosynthesis that were significantly decreased since August 1^st. 

Water temperature decreased again between August 1 and August 11, going from 28^oC to 25^oC.   Chart below shows fluctuations in surface temperature during the 2017 season showing the frequency of decreases in surface water so far this year.  Typical warmest water occurs between July 15^th and August 15^th so it is unlikely that the lake will get much warmer for the rest of the season unless we experience more heat waves. 

Bottom water anoxia was not uniform around the lake.  Of the 8 stations with water 5 meters of water depth only 4 had anoxic water at 5 meter others had greater than 1 mg/L.  Six of the seven stations situated in water of 5.5 meters depth or greater had anoxic water at the bottom.  As of August 11 distribution of anoxic bottom water appears to cover about 220 acres or about 23% of the 947 total acres of the lake.

Bantam Lake, CT 2017 Cyanobacteria Cell Count and CT DPH 2017 Recreational Waters Category Guidelines (Green = Safe, Yellow = Caution, Red = Posted Advisory)

Bantam Lake, CT 2017 Secchi Depth

Surface Water Temperatures at Bantam Lake through August 11, 2017.

Data is collected and analyzed by Northeast Aquatic Research, who is contracted by Bantam Lake Protective Association.