Base lake to close temporarily to eradicate zebra mussel population Published Aug. 20, 2008 By 55th Civil Engineer Squadron Environmental Flight OFFUTT AIR FORCE BASE, Neb -- Although most visitors wouldn't know it, the Offutt Base Lake was invaded several years ago and it's time for the species to be removed. Zebra mussels, an invasive species of the mollusk family commonly called clams that grow to between .5 and 2 inches in size, were discovered in the lake in April 2006 by the 55th Services Squadron commander and later confirmed by a representative of the Nebraska Game and Parks Commission. Zebra mussels, which originated in Europe, are believed to have made their way to the United States in 1988, probably in ballast water in large ocean going ships. Environmental engineers believe the mussels, prevalent in the Great Lakes area, probably made their way to Offutt's lake on a personal fishing boat transferred here from the North Eastern United States. Because stopping the spread of zebra mussels is imperative, base officials closed off the outlet tubes that lead to the Missouri River for drainage some time ago, confining them to the lake. They also prohibited private boats from using the lake. In the lakes or waters, zebra mussels tend to deplete the available supply of plankton, an oxygen producer and food source for other organisms. In addition, the spread of zebra mussels poses maintenance problems for power and water utilities and others industries that pump water from waterways. Zebra mussels attach themselves to inlet pipes and pumping equipment, foul the machinery and restrict the flow of water to the utility/industrial plant. The removal of the zebra mussels and replacement of equipment is also extremely costly. The base formed a working group in March 2007 to address the problem for both control and eradication options. The group consists of representatives from the Nebraska Game and Parks Commission, U.S. Fish and Wildlife, Environmental Protection Agency, Nebraska Department of Environmental Quality, Nebraska Department of Agriculture, Corps of Engineers, OPPD/NPPD, base personnel and Departments of Natural Resources from Iowa and Kansas and meets quarterly. Its last meeting was held three months ago to approve the proposed action plan. During past meetings numerous control and eradication options were discussed and analyzed using information gathered from all over the United States from people and agencies that have been involved with zebra mussels in the past. Based on the results of those meetings, the working group, with various approvals, decided to use copper sulfate crystals to eradicate the zebra mussels and to hire a contractor with extensive knowledge of biology, chemistry and engineering to coordinate the eradication project. This contract has been awarded. Approximately mid-September, the contractor will apply copper sulfate crystals to the lake in a dosage to obtain a 1.0 part per million, or ppm, copper concentration. In the application process, to obtain a consistent 1 ppm across the lake, there may be areas of higher concentration. It is anticipated that this level may be maintained for up to five days. There should be no risk to humans at this level, according to health officials, as it is below the maximum contaminate level of 1.3 ppm for copper in drinking water. However, as a precaution and following guidance from regulatory agencies, the base lake will be closed to fishing, boating and contact - both human and pet -- until monitoring of the lake confirms the levels of copper are below 1.3 ppm. The base lake will also be closed to visitors/traffic during application except for occupants of the Fam Camp and base members with horses at the stables. For the copper sulfate to function properly, the entire lake must be treated within 48 hours of initiating application. Signs will be posted around the lake stating the lake is closed and to keep pets away. At 1.0 ppm the copper is toxic to the zebra mussels and to the aquatic plant life, but not other animal life. However, although the application doesn't directly harm the fish population, residual effects of the application may cause fish to die. After the copper sulfate procedure is completed, the contractor will continue monitoring the lake late into the Calendar year. If zebra mussels are found, a second application is expected to be applied in the Spring of 2009.