LANCASTER, Pa. -- A commission that oversees Susquehanna River basin water use granted the city of Aberdeen a permit yesterday to draw from a Harford County scenic river to provide water to Aberdeen Proving Ground. But it postponed a decision on the city's more controversial request to take additional water for its own use.

The Susquehanna River Basin Commission also added a provision that allows the city to divert some of APG's unused supply for municipal use in times of emergency.

Since the chemical perchlorate was discovered in the city's well field this year, town officials have been concerned that the chemical contamination could force a shutdown of all or part of the well system, leaving the city without adequate water supplies.

Douglas Wilson, mayor of Aberdeen, said in prepared remarks that the city is "deeply thankful for the emergency water provision."

Residents who live in northern Harford, however, were angry that they had not been informed of the new provision ahead of time.

Charles Day, a board member of the Deer Creek Watershed Association, said it was obvious the city had known about the change ahead of time, "but the people who live in the watershed and are affected by this were not given a chance to know about this modified proposal."

The commission also placed several conditions on the permit, which included stricter limits on when the water can be drawn and a one-year deadline for the city to work out an agreement for a backup water source when Deer Creek's level is too low to tap.

The city applied for both permits about 18 months ago after it won APG's water service contract in 1999 and took over the base's water treatment plant and equipment.

The city can draw up to 3.15 million gallons of water a day to serve the proving ground. In its second permit, it seeks to draw 3.5 million gallons a day to serve the city system.

The decision on that permit is scheduled for February, when the group meets in Harrisburg, Pa.

"The next level of discussion on this is where it's going to get real complicated," said Scott Foti, commission chairman.