In 2002, the community surrounding East Twin Lake, in Montmorency County, Michigan, recognized that there was an enormous amount of sediment building in their lake. Many residents believed it to be largely sawdust left from a lumber mill that burned down nearly 100 years ago. The community sought out a way to remove or reduce the amount of sediment in the lake and what they found led to amazing results.East Twin Lake relatively shallow lake. Most of the depths range from four to eight feet with the deepest parts being 26 feet. The lake bottom consists of a hard sandy surface. The biggest problem area is in the west side of the lake where the lumber mill once operated. In this area, which consists of about 160 acres, sediment occupies up to six feet of the eight foot depth. After learning of this problem, the community began to gather information of what they could do to remove or reduce the amount of sediment. The first option was to dredge, but the cost was one that the community could not bare. The second option was to apply biological agents, but the thought of dumping barrels of these agents into the pond was unappealing and is a process that much continually be repeated. The third option was to add aeration to the lake. With the help of Vertex Water Features, the East Twin Lake community chose the option of adding eight compressors that would feed three diffusers each. The units installed were Vertex Air 3XL systems. http://www.vertexwaterfeatures.com
The community understood that the sediment created low oxygen levels in the muck. Knowing that low oxygen levels are undesirable, the community wished to employ the use of diffused aeration. The aeration units pump air into the water and through diffusers which have rubber membranes that have very tiny holes in them. These diffusers create columns of tiny air bubbles that circulate the lake's water from bottom to top. As this water is exposed to the air it is oxygenated, thus increasing the oxygen level of the lake.
The results were incredible. After two and a half year of the units operating 24 hours a day between the months of April and November, it was determined that East Twin Lake had two feet less sediment. TWO FEET! After expecting only six inches per year, the community was amazed.
In 2004, the amount of dissolved oxygen in the lake was 4.3mg/l which is fairly low. By 2005, that number nearly doubled to 8.5mg/l and maintained similar levels through 2007, the end of the case study. The percentage of muck remaining in the pond during this period dropped down below 45% and the biological oxygen demand dropped below measurable levels from 58.0 which essentially meant that previous locations in the lake with heavy sedimentation completely lacked oxygen. These results are simply incredible.
This case study demonstrates the value of aeration in all freshwater bodies of water. The benefits are amazing. Can you imagine reducing the amount of sediment in your lake or pond by over 50%. While this can't prevent dredging at some point in the life of the pond or lake, it can certainly delay the need and keep the pond healthier in the mean time.
http://facebook.com/solitudelakemanagement
http://facebook.com/vertexwaterfeatures
Resource
No comments:
Post a Comment