In July 2004, eight Vertex Air 3 XL systems were installed by Tri-County Aquatics in a 60 acre cove of an 830 acre lake. At the time of installation, measurements with a â€˜sludge judgeâ€™ were taken at six locations to determine the amount of muck on the bottom. Three of the sites showed levels of 6 and 7 feet of muck and the average for all 6 sites was 4.3 feet of muck. Oxygen readings were taken at the surface and at the bottom to assess the quality of the water. The dissolved oxygen at the surface was 4 mg/L while the oxygen level at the bottom was 2.0 mg/L. A water sample sent to a lab to determine the BOD (Biological Oxygen Demand) returned results of a BOD of 58.0 mg/L, which is much higher than the available oxygen in the water.
By April 2005, the oxygen level had increased to 10.4 mg/L, which more than satisfied the 0.23 mg/L BOD. The average level of muck at the 6 sites was 3 feet. Minimum amounts of 6 inches were recorded at 2 sites while the maximum level of 5 feet was recorded at another site. Since installation, the average level of bottom muck has decreased by 30.2%.
In April 2006, the oxygen levels were still being maintained at a high level of 9.4 mg/L, while still satisfying the low BOD of 0.3 mg/L. The muck levels were fairly even at all 6 sites, with an average of 2.4 feet. This was a decrease of 44.2% from the first measurements at the time of installation.
In 2007 we can see that the oxygen levels were maintained with an average of 8.3 mg/L, while the BOD remained low with an average of 0.7 mg/L
The next chart shows the amounts of muck at each site for all four sampling years.
The last chart displays the average muck depth and percent remaining over the four year span. We continue to witness a significant reduction of muck. The muck depth from 6 sites averaged 1.9 feet. This is a mean reduction of 6 inches from the previous year, with a 55.8% overall decrease since the installation of the aeration systems four years ago.