Manassas is asking residents and businesses to practice voluntary water conservation, but officials have resisted initiating a drought watch--stage one of a new drought emergency plan the City Council is expected to adopt at its next meeting Sept. 13.

"Because of the regional impact of this extremely dry summer following a dry summer last year, we want to remind citizens that water is a resource, and they should use it wisely," said Allen P. Todd, Manassas utilities director. Utilities officials said Manassas water levels remain high, despite the region's worst drought since the Depression.

The drought plan, unveiled Wednesday, outlines a four-step response to water shortages, ranging from a voluntary 15 percent reduction in usage--a drought watch--to mandatory 45 percent reductions enforced by fines and termination of water service.

The plan, which was written by a council-appointed water supply advisory task force, calls for a drought watch when water reservoir levels drop from 85 percent to 55 percent of total usable volume. Currently, the city's primary water source, Lake Manassas, a man-made reservoir located southwest of the city, is at about 78 percent capacity.

However, a $500,000 inflatable rubber bladder that was added to the dam in February increased the total capacity of the lake by 1 billion gallons, or 28 percent. The city's water supply as of Friday was two inches more than its total capacity last year.

Considering the region has not seen significant rainfall since several heavy showers in March, "the timing of the bladder was very fortunate," Todd said. "I would like to say it was good planning, but I can't take that credit."

Without the bladder, water levels would be six feet below the original dam, and if this summer's drought conditions were to persist into the fall, water levels might have dropped to last December's historic low of nine feet below capacity.

This week's rain did very little to refill Lake Manassas.

The creation of the plan had nothing to do with this summer's dry conditions. The water supply task force was convened in January to evaluate the city's drought emergency procedures following last year's six-month drought.

The task force prepared the report--which cost an estimated $20,000 to $25,000--by planning for the Depression-era 1931-32 drought, which would have drained Lake Manassas had it existed then. With the new contingency plan, under that severe a drought Lake Manassas would still have an adequate water supply, Todd said. "Being prepared is most important. We wanted a plan that would provide an action plan for the worst drought imaginable."

The emergency plan is the culmination of a series of efforts by the city to shore up its water supplies.

In July, after months of negotiations, Manassas entered into a water exchange agreement with the Prince William County Service Authority that will connect the city's water supply to the Potomac. The agreement, which provides more stability in the water supply, includes the building of a 42-inch pipeline, at a cost of $5.3 million, to connect to the Fairfax water supply, a project that will be funded by a 15 percent increase in residents' water bills starting this year, on top of last year's 14 percent increase. Construction begins in November, and the new pipeline is expected to be in place within 18 months.