The Chesapeake Bay is at a critical point in its 10,000-year history. The actions taken today and the commitments made as we enter the next millennium will determine whether the bay will live or die.
To put this in perspective, it is important to understand the bay's history. It was created when the last ice age receded and ocean levels rose, flooding the old Susquehanna River valley. The bay's first 9,700 years were largely free from pollution, with too little human settlement to cause any detrimental impact on the vast 64,000-square- mile watershed and the 200-mile main stem.
As colonial settlers arrived forests were cut, land was laid bare for agriculture, roads were built, towns and cities sprang up. The landscape changed, and with the industrial revolution, pollutant-laden waste water was added to the bay. As population centers grew, sewage plants collected, ''treated'' and discharged human waste to the bay. Perhaps most important, the surface of the land became hardened as more of it was paved. This increased the amount of storm-water runoff, a source of pollution equally as damaging as factory and sewage pipes.
During the decades following World War II, all these abuses began to catch up with the Chesapeake. The changes occurred incrementally, but the cumulative impacts were dramatic and widespread. Seafood abundance declined, underwater grasses disappeared, the water looked polluted, and at certain times of the year, when dissolved oxygen levels fell to almost zero, it began to smell. Oysters, a marvelous natural filter, declined by the 1980s to 1 percent of historic levels.
The Chesapeake Bay Foundation, founded in 1966, issued a call to arms with its slogan ''Save the Bay.'' It was criticized as a doomsday organization, because most government officials dismissed the bay's decline as simply a ''natural cycle.''
Sen. Charles McC. Mathias, however, succeeded in 1976 in getting nearly $30 million of federal funds appropriated for a comprehensive study of the bay. By 1982 the results were in. The bay's decline was no natural cycle. The study documented an unprecedented destruction of one of the world's greatest natural resources.
Ten years ago the governors of Maryland, Virginia and Pennsylvania, with the mayor of Washington, the federal Environmental Protection Agency administrator and the chairman of the Chesapeake Bay Commission issued a solemn pledge -- together they would work to save the bay. They and their successors have held to their commitment. The last 10 years have shown impressive action on behalf of the Chesapeake, and there is some evidence that the tremendous amount of time, money and effort is beginning to pay off.
But has the bay been saved? No, not yet. In just the last seven years, oyster harvests have declined by 90 percent, and other species are still in trouble. Nevertheless, water quality indicators are improving, and underwater grasses may be making a sustained comeback. If momentum can be maintained, the bay's other resources should return.
Over the next few decades, 3 million more people are expected to move into the bay region. More polluted sewage will be discharged to the bay; more people will drive more automobiles; more airborne pollutants will reach the bay; farmland conversion will continue as new houses, roads and shopping centers will be built; more marshland and forest will be lost. The loadings of pollutants will increase.
Is this the inevitable result of ''progress?'' It need not be. If we commit to increasing the level of environmental protection, building upon past successes, significant improvements in the bay will result. We must remember that only 10 years ago, achievements that now seem almost routine were viewed as ''impractical,'' ''too ambitious'' or simply ''impossible!''
Phosphate detergents have been banned bay-wide; all fishing for rockfish was halted, the fishery recovered and has been cautiously reopened; the bay is now being managed regionally with cooperation from Virginia, Maryland, Pennsylvania and Washington. Land-use planning for water-quality improvement is gaining acceptance; nitrogen is being removed from targeted sewage-treatment plants, and Pennsylvania has passed a law requiring pollution controls on some farmers.
We must hold out a vision for the bay in 10 years. Oysters (which were once abundant enough to filter the entire bay every four days) should be restored; wetlands and forest acreage should increase, not decline, and underwater grasses, so vital to the bay's health, should once again carpet the bay's shallows. To achieve this vision, a number of bold measures can be pursued. They should include:
* Limiting the harvest of fish and shellfish to no more than nature can sustain on an annual basis.
* Requiring nitrogen removal at all major sewage-treatment plants.
* Requiring farmers with the highest pollution potential to meet standards of performance while increasing incentives for others to comply voluntarily.