WHEELING, W.VA., JAN. 9 -- The intricate plans of the best-prepared city on the Ohio River drained away today as an infamous pool of pollution oozed around the bend here on its inexorable journey downstream.

Score another one for the oil slick.

Despite six days of feverish planning to provide a temporary water supply, Wheeling was down to less than a half-day's supply of water by midafternoon and businesses had been ordered to close.

"We're having a lot of problems," said Assistant City Manager Nancy Vapner. "We don't know how long we'll have water."

The problem, some officials acknowledged, is that Wheeling may have prepared too well for the 100-mile-long spill that has been snaking down the Ohio since the collapse of an Ashland Oil Co. diesel fuel tank near Pittsburgh Jan. 2.

Comforted by days of assurances from city officials that the situation was well in hand, many residents apparently did not take the impending slick seriously until the city announced at 5:30 p.m. Friday that it had closed its water intake valve. Then they started filling bathtubs and pots.

By daybreak, the city's main reservoir, capable of supplying all the city's needs for a day or more, was down to six feet from Friday's brimful 22 feet.

Two pipelines hooked to unpolluted water supplies in nearby cities are working, but together provide less than a quarter of the city's needs. Four million-gallon barges that the city had counted on to keep the taps running were out of commission most of the day with pump problems.

"If we have a big fire we're in trouble," said Assistant Fire Chief Gene Barker.

By noon today, the smugness with which this city of 60,000 had awaited the spill's arrival had evaporated. Instead, officials were involved in the familiar activity of deploying water tankers, pleading with recalcitrant businesses and wondering how long the drought would last.

Residents lugged jugs and garbage cans to National Guard mobile tanks that have become as common as coal trucks in the Ohio Valley.

"I may never drink river water again," said Rena Breiding, who was helping her husband, Larry, distribute three trailer-loads of bottled water supplied by the Miller Brewing Co. "Even if the water comes back, I feel that the chemicals they're adding to it to clean it must be bad."

Craig Haas, an employee who volunteered to help unload water at Breiding's beer distributorship, said he was skeptical that the water quality would return quickly, if at all. "You have to wonder how much of it has stuck to the river bottom," he said.

The Ohio flowed placidly by Wheeling today, next to an eerily deserted Main Street. An adult entertainment store, one of the few businesses open, displayed a hastily scrawled apology in its front window: "No restrooms."

No oil sheen was visible. State and federal officials say the diesel fuel has become emulsified in the water, like oil whipped into mayonnaise.

The bitter cold weather, a boon up river a week ago when it congealed the fuel and made it easier for skimming equipment to capture, has become a disadvantage. The river's flow is extremely slow under a thin coat of ice, and the cold keeps the oil suspended in fine drops.

Curt Ridenour, a water specialist with the Ohio Environmental Protection Agency, said that communities along the river will likely have to take precautions for "several weeks, even months."

"Right now, the river is in a falling stage, so some oil is being left along the banks," he said. "When the river rises, some of that will be washed back into the river."

In nearby Steubenville, Ohio, where officials resumed water treatment today after a day's hiatus, residents complained that the water smelled foul and left greasy stains on porcelain.

"We're sorry," said Ashland President Charles Luellen, who paid a call to the Wheeling emergency operations center. "We regret very deeply this accident. One other reason that we are here today is to see what more we can do. We can understand that people are very frustrated and angry . . . . But we regret that they are so angry and so frustrated that they sued us."

Wheeling resident Wilma Landers, a cook at a junior high school, said she is angry but mostly frustrated. "I'd like to take a bath," she said. "I still have water in the tap, but my bathtub's full of water I'm storing to drink."