In a push to protect Lake Manassas from aggressive zebra mussels and homeland security threats and to boost public safety, Manassas leaders have officially banned boats from the reservoir.

The 770 acre-lake between Gainesville and Fauquier County provides water to about 200,000 residents of Manassas, Manassas Park and Prince William County.

Last week, Manassas City Council members unanimously approved an ordinance that makes boating on the reservoir illegal. The offense is a class one misdemeanor, punishable by a maximum fine of $2,500 and up to one year in jail.

The city first prohibited boating at the lake after its privately run marina closed in 1995, said Jim Johnston, Manassas water and sewer superintendent. The logic was that without a central launching point for boats, the city could not monitor boats' comings and goings. This would make it difficult to maintain clean, safe waters.

But city ordinances were not officially changed.

After the Sept. 11, 2001, terrorist attacks, followed by the discovery of invasive zebra mussels in the nearby quarry more than a year later, city officials began to take another look at the situation.

"It all came to a head," Johnston said.

The city realized it could not monitor the lake for the full range of chemicals and biological agents used by terrorists today, he said.

The city also does not have the controls to monitor such public safety threats as drunk boaters, Johnston said. Additionally, boats that use gasoline engines could contaminate the water.

The Haymarket quarry where the invasive zebra mussels were discovered is just 300 feet from Broad Run, a tributary to Lake Manassas and the Occoquan Reservoir, which together provide water to 600,000 people. The dime-size mussels have been known to kill off marine life, clog drinking water intakes and cling to anything solid.

"It could cost Manassas and Fairfax County up to $850,000 a year if Lake Manassas and Occoquan Reservoir were infested," Johnston said, citing findings by Virginia's Department of Game and Inland Fisheries.

The city would like to eventually reopen a marina -- preferably a privately operated one, but the difficulty lies in gaining public access. The city owns Lake Manassas, but the land surrounding it belongs to Prince William County or is in private hands.

"We may be three months or we may be three years from finding a location," Johnston said. "And then it would be up to the discretion of City Council whether they allow a public boat ramp."

About $600,000 in federal and Fairfax County Water Authority funds have been committed to efforts to do away with the Haymarket quarry's mussels, Johnston said. The Prince William County Service Authority, Prince William and Manassas are also considering making donations.

"The key is that the eradication begins before cold weather," Johnston said. "This is the season . . . to get it started." Officials should know in several weeks when the work can begin, he said.

City officials also reported that damage from the remnants of Hurricane Ivan will cost Manassas and its residents more than $3.3 million.

When the storm tore through the city Sept. 17, it caused major damage to nine residences and affected a total of 114 businesses, residences and other structures, said Michael C. Moon, the city's public works director. Most of the damage occurred in the city's Oakenshaw and Battery Heights neighborhoods, city officials said. To repair the structures will cost about $3.3 million.

Additional costs of about $51,000 were incurred by the city, including overtime. Five city departments were involved, and the city's emergency operations center was up and running during the storm. Almost $10,000 extra will be needed to repair damage to Oakenshaw Park and fences in the city.