A compromise that Sens. John W. Warner (R-Va.) and Charles McC. Mathias (R-Md.) apparently reached last month over federal funding for dredging shipping channels to ports in their states has collapsed, in part the victim of a mixup in the drafting of a committee report.

Yesterday each senator was charging that the other side misinterpreted the original agreement.

"I was under the impression that we had reached a fair and equitable agreement," Warner said yesterday. "I'm optimistic that it can be worked out if other senators will be reasonable about it."

Maryland's Mathias has said he never agreed to the terms of the compromise that Warner had hailed in mid-August.

The compromise, fashioned by the Senate Committee on Environment and Public Works last month, amended the $10 billion Water Resources Development bill to match a House bill passed in June.

The amendment says that the costs of dredging East Coast shipping channels deeper than 45 feet -- such as Hampton Roads and Baltimore -- would be divided equally between federal and local authorities.

This would mean Hampton Roads would receive $250 million from the federal government for its $500 million dredging plan. Under the original bill Hampton Roads would have received no federal funding for dredging.

According to Mathias, the compromise was supposed to allow Baltimore to continue receiving 70 percent of its dredging funds -- or $310 million -- from the federal government.

But Sen. James Abdnor (R-S.D.), who helped forge the compromise, said an error by the committee staff had given Baltimore a better deal than had been agreed to in the Maryland-Virginia compromise. So the following day he inserted a report into the Congressional Record that said he planned to put Baltimore into the same category as other 45-feet ports, with its project funding split 50-50 with the federal government.

This would increase Maryland's share of dredging costs by $73.5 million. "I strongly object to changes along these lines," Mathias said in a letter last week.

The original compromise was a significant victory for Virginia. The state's shippers want to deepen channels so that supercolliers -- the largest coal-carrying ships -- can use Virginia ports. Those ships often cannot be loaded in Norfolk and Newport News to their maximum capacities because they would hit the channel bottom.

The Senate conferees are expected to meet Monday on the issue.