The states of the Chesapeake Bay watershed pledged yesterday to so sharply curtail the runoff of harmful nutrients and sediments into the estuary that it will be stricken from the federal "dirty water" list within 10 years--the first time a specific compliance date has been set.

If the states reach the goal of "a bay that is clean enough, healthy enough, improved enough to surpass standards set by the Clean Water Act," Maryland Gov. Parris N. Glendening (D) said, "it would be one of the largest bodies of water to ever show such an improvement."

In part because of earlier agreements among the surrounding states, the health of North America's largest estuary has improved since the mid-1980s. The Chesapeake Bay Foundation, a private monitoring group, now rates its condition at 28, up from 23 on a scale of 100, with 100 being equal to the bay's pristine status three centuries ago.

But with pressure on water quality and bay life rising as population in the watershed does, the states released a draft agreement of their most ambitious agenda yet for pushing the bay farther up the scale of progress. Though there was disagreement on one key proviso, the representatives of the Chesapeake Executive Council who gathered in a huge, white tent erected on the lawn of an outdoor education center a short walk from the Severn River, a major bay tributary, promised to:

* Increase oyster populations tenfold by 2010. Officials were unable to provide the current total, saying data is still being gathered and analyzed.

* Restore 25,000 acres of wetland by 2010. That would represent only a small fraction of the nearly 2 million acres of wetland lost in the watershed since the 1780s, but would be a significant boost in the current annual restoration total of about 1,700 acres.

* Give the public 30 percent more places at which to reach bay waters. At the moment, there are slightly more than 500 sites where the public can gain access to the bay, its tidal tributaries and the Susquehanna River, said John Davy, chairman of the public access work group.

Perhaps the most daunting challenge, however, will be to meet federal clean water standards within a decade. Although members of the Chesapeake Executive Council--the District, Maryland, Pennsylvania, Virginia, the Environmental Protection Agency and a largely legislative group called the Chesapeake Bay Commission--have nearly met a goal set in 1987 of reducing nitrogen and phosphorus levels by 40 percent by 2000, that effort pales compared with the "enormous undertaking" of achieving full compliance with the Clean Water Act by 2010, said Tom Simpson, a Maryland official who serves as chairman of a nutrient subcommittee.

"But we're going to do it," Simpson said.

That effort, however, has been complicated at the outset by friction between Virginia and its five partners over how to stem the annual disappearance of 90,000 acres of open space in the watershed as suburban sprawl advances. That loss of natural filters enables more nutrients and sediments to wash into the bay and its tributaries, which reduces sunlight and oxygen and enhances algae growth, making it more difficult for aquatic life to survive.

All but Virginia want to set a goal of cutting the annual loss of open space by 30 percent within 10 years. But John Paul Woodley, Virginia's secretary of natural resources, has argued that land-use planning is the purview of local governments and that Virginia Gov. James S. Gilmore III (R) has no power to promise a numeric reduction.

Unable to bridge the difference, the five other members included the 30 percent pledge in the draft agreement anyway, with a large asterisk noting that there was not unanimity.

"The Clinton-Gore administration believes there should be a numeric goal in there," EPA Administrator Carol M. Browner told the meeting here, echoing Glendening's comments and those of prominent environmental groups.

The public can review the draft agreement on the Chesapeake Bay Program's Web site, www.chesapeakebay.net or by calling 1-800-YOUR BAY for information. Comments will be accepted through March 31.

CAPTION: Gov. Parris N. Glendening looks over some oysters from the Severn River with sixth-graders Chris Tipton, left, and Jordon Conway, both from Fort Meade.