LAWRENCE, Kan. -- Zebra mussels have been found in the Lawrence water treatment plant, the city reported Monday.

Lawrence officials said in early October the city performed routine maintenance at its Kaw Water Treatment Plant and discovered the mussels.

Zebra mussels are a highly invasive shellfish with a strong tendency to colonize in fresh water basins. They were first reported in the Great Lakes in 1988. Since that time, zebra mussel populations have spread dramatically throughout the Midwest, southeast and northeastern segments of the United States.

After discovering the mussels, city officials said they notified the Kansas Department of Wildlife and Parks and the Kansas Department of Health and Environment.

According to Lawrence officials, Zebra mussels do not pose a public health concern because they cannot survive the chlorination process used in water treatment. The biggest concern for the city is the impact the creatures will make for maintenance and operations for the intake and raw water processing at the plant.

"Every fall, we clean the basins at the water treatment plant," Charlie Ballenger, Kaw Plant manager, said. "In the future, we may have to look at additional opportunities for cleaning and utilization of aggressive mechanical methods to lessen the effect of the mussels on our operations. The quality and quantity of water produced will not be affected."

The city said they are watching the zebra mussels are of great concern for municipalities and industries due to their rapid ability to multiply and colonize. The mussels can completely cover intake valves, concrete basins and transport lines, city officials said.

In the past week zebra mussels were found in Lake Wilson in western Kansas.

Zebra mussels are spread primarily by people through improper cleaning of boating and recreational equipment. Lawrence officials said the spread of zebra mussels can be prevented by draining all water from boats, live wells and bait wells. Experts said washing the equipment with 140-degree water at a car wash will kill zebra mussels. Drying equipment for five days will also kill mussel larvae.

The Kansas Department of Wildlife and Parks has information about zebra mussels online at its their Web site.