Ultrasound Unit Status Report - 2008

There was no significant improvement in the transparency this year as compared to recent years. Our goal was to reach a transparency of -2.0 m throughout the summer.

During the summer there were several instances when the ultrasound units were disturbed by winds and waves. At times more than a third of the units were not properly placed. (We have now developed a mounting method which should eliminate this problem). Algae growth is cumulative i.e. if the growth occurs and there is still a positive growth factor it will continue to add on. During the periods when the ultrasound units were not operating properly the algae growth would have been higher than expected and putting the units back on would have slowed the growth but not reversed it.

Another measure of water quality is by it’s suitability for use. We have had feedback from many people, that the water was suitable for swimming throughout the summer. They would have liked an increased transparency but found the water satisfactory for swimming. The low transparency would have limited the suitability of the lake for fishing since the fish could not see the bait.

In summary, FLP is disappointed with the low transparency and will continue to work to improve the lake. We intend to install 23 ultrasound units next year and expect to keep them operating properly the whole summer.

As Gladys Yeager has said, “ The Lake took a long while to get this way, we can wish, but should not expect, it to get better rapidly.”

FLP will be working hard to make a cleaner Lake for all of us.

Dr. Jack Solomon

 

Dennis Griswold (Capt. Grizzy), founder and Chairman of Friends of Lake Pocotopaug died unexpectedly Aug. 27th, 2008 from a short-term illness. Owner of The Happiest Paddler & West Shore Marine on Lake Pocotopaug, Dennis dedicated a great deal of his time and energy to the lake and those that used it. He always had a smile and a kind word for those that visited the marina. Once you met Dennis there was an attraction that drove one to know him better. Perhaps it was his love of the lake, knowledge of East Hampton and its residents or just his quirky sense of humor that kept you coming back for more. He was a people person with a eye for business opportunities and a passion for our beloved lake.

Dennis organized Friends of Lake Pocotopaug (FLP) with a goal of restoring the health of our lake water and improving the environment that surrounds it. Starting with a single fund raiser in 2004, a small group of FLP volunteers raised $9,000 which funded improvement at Sears Park. Under Dennis' direction, FLP has grown to be a non-profit public charity corporation that sponsors several events each year in support of that same goal. Since it's inception FLP has raised over $125,000 to improve Lake Pocotopaug and its environs. Dennis' contributions to the Lake and this community are truly immeasurable. We were very blessed to have him lead our efforts for the past 5 years.

In honor of our late chairman, FLP will continue to strive for Dennis' vision of a clean and vibrant Lake Pocotopaug. FLP has established a Dennis Griswold memorial fund. Donations to this fund will be used to support specific lake oriented improvements that the entire community will benefit from.

Donations to the Dennis Griswold Memorial Fund may be made through this website or by mail to:

Friends of Lake Pocotopaug
c/o Nikki O'Neill
P.O. Box 360
East Hampton, CT 06424
                                                                                  Stephen Diemer
                                                                                  FLP Chairman

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Review of Data on Ultrasound Algae Control Demonstration

Ultrasound algae control units were installed in Lake Pocotopaug with increasing numbers over the summer(see Appendix 1). Because of the water flow in the lake complete coverage of the lake is required for definitive proof that the units will clean the whole lake.  Each ultrasound unit treats an area about 1000 feet by 200 feet. We have measured water flows between 1 and 15 feet/minute.  Even at the lowest flow measured the treated water is replaced by adjacent algae laden water in less than 4 hours.  The algae control units take up to 4 days to treat an area and remove the algae so fresh algae is constantly entering the area. Complete coverage of the lake eliminates this effect.

We were hoping that two measurement strategies would give indications that the units were controlling algae. 1) We would make Secchi disc readings near the units and compare them to the readings at the deep spots in the Lake.  Higher transparency at the units would indicate algae control. The water flow into the area of a unit replaces the water in the area of a unit in less than 8 hours so only a small effect should be expected. 2) We placed units in Markham Bay and compared the Markham Bay deep spot with the Oakland Basin deep spot.  Again the water flow into and out of Markham Bay makes the expected change from these readings small.

Friends of Lake Pocotopaug an East Hampton volunteer non profit group, has initiated a test project in the waters of Lake Pocotopaug. Four Ultrasonic Algae Control units are being installed to test their potential for controlling the growth of algae in the lake.

Dr. Jack Solomon a member and Environmental Officer for the group is spearheading the project. Dr. Solomon is also a member of East Hampton’s Lake Commission. Jack explained that these electrical units transmit a complex pattern of ultrasonic vibrations through the water in a radius of 176 degrees and a range of 400 meters. These vibrations cause the vacuoles inside the algae cells to resonate and break, similar to a glass breaking from a high pitch sound. Once broken these algae cells no longer have the ability to grow or reproduce, and they die. The vibrations emitted from the units are harmless to humans, animals, fish and aquatic plants.

Three of these units costing approximately $3,000 each were purchased by Friends of Lake Pocotopaug, the fourth by Dr. and Mrs. Solomon. All have been installed in the lake, in front of private property. The units require a GFI power supply at the shoreline.

Mark Recor a local licensed electrician has volunteered his services in installing the power supply. The property owner is responsible for the control unit’s electrical consumption which is approximately $20 a year. If this test project proves successful, it is estimated that thirty units will be necessary to provide complete coverage of Lake Pocotopaug.

The East Hampton Lake Commission has endorsed this project and will perform the monitoring of the algae in the area protected by the ultrasonic devices.  A group of East Hampton High School students, under the guidance of science teacher Roger Abraham, will assist in the monitoring effort.

Friends of Lake Pocotopaug have been in existence for four years and have raised over $70,000 directed to lake water quality issues. This year, their major fundraiser is a pontoon boat raffle. Tickets can be purchased at Angelicos Lakehouse Restaurant, West Shore Marine, Paul’s and Sandy’s Too as well as many other local businesses.