The future health of the Chesapeake Bay may well depend in part on how much respect we pay to history. Granted, it may be a small part. But as we struggle to piece together workable plans to improve the Bay's water quality, the little pieces are what make up the big picture. For proof, we need only to recognize the link between muskets and mollusks.

More than a century and a half ago in the mid-Atlantic, from the rolling countryside of lower Pennsylvania to tidewater Virginia, Union and Confederate soldiers fought at scores of locations during the bloodiest and most tumultuous period of our nation's story.

The settings of the most famous killing fields-Antietam, Gettysburg, Spotsylvania-are recognized as hallowed ground and attract tourists from around the world. Less remembered are clashes that occurred at such places as Glendale in Virginia and on farmland along Maryland's Monocacy River, although the latter's once nearly forgotten episode in the state's Civil War annals has gained deserved prominence as "the battle that saved Washington."

Aside from the obvious historical context, these and the region's many other Civil War sites share an important geographical kinship: They lie within the Bay's 64,000-square-mile watershed, where pollutant runoff into the narrowest tributary often ends up in the Chesapeake and contributes to the continuing degradation of the country's largest estuary.

In some cases, the practice of commemorating Civil War battles by setting aside portions of land to honor the fallen began shortly after the fights themselves. Although it was certainly an unintended consequence in the beginning, battlefield preservation, particularly where it is practiced around creeks and rivers, has the added green benefit of reducing the amounts of upstream nitrogen and phosphorous that can flow downstream toward the Bay. And by ensuring that undeveloped open space remains free from future commercial and residential development, stormwater runoff is minimized.

As part of the Chesapeake 2000 agreement to help clean up the Bay, Virginia, Maryland and Pennsylvania officials set a goal of preserving 20 percent of the watershed by 2010. Noting that the watershed loses about 100 acres a day to development and timbering, Virginia Gov. Tim Kaine in 2006 pledged to protect 400,000 acres, an ambitious goal that the current economy may make impossible to meet. But recently, Governor Kaine and others formally announced that Slaughter Pen Farm, a privately owned 208-acre tract adjacent to the historic Fredericksburg Battlefield, had been secured for preservation. The amount of land may be a drop in the proverbial bucket, but its location near the heavily developed Rappahannock River shoreline means more open space will be spared from the bulldozer. Every bit helps.

At first glance, efforts to help save the Bay by managing what flows into it and to preserve part of our history by rescuing threatened tracts of Civil War battlefields may seem to be unrelated goals. Wisely, the nonprofit Civil War Preservation Trust doesn't see it that way. By touting environmental stewardship as a byproduct of setting aside endangered property, the private organization appeals to a larger constituency. It's a battle plan where both green advocates and Civil War re-enactors find themselves on the same side.

The Trust recently released its annual report listing the 25 battlefields nationwide facing the most serious threats from development. Not surprisingly, nearly half of the locations are within the Chesapeake Bay watershed. One of them, the Monocacy National Battlefield near Frederick, came distressingly close to having its relatively pristine countryside and buffered shoreline disturbed by a 150-foot-tall stack for a proposed trash incinerator. After much opposition from residents and the National Park Service, local officials voted to set aside the project. Still, the battlefield is threatened by a planned widening of Interstate 270 that bisects the site. From Hunterstown outside Gettysburg to Cold Harbor near Richmond, similar encroachments could permanently spoil the historic landscape and ultimately impair Chesapeake Bay water quality.

Given the incredibly rich history-from pre-colonial to modern times-of the watershed region, the natural symbiosis between historic preservation and restoring ecological balance need not be limited solely to events of the Civil War era. Of course, it is not practical, acknowledging the real growth needs of many communities and the enormous land mass touched by the Civil War and other milestones, that every place can be preserved as it was.

But as we approach 2011, the beginning of the Civil War Sesquicentennial, we can take this opportunity to honor the past and help restore the Bay at the same time. Protect a battlefield. Save the Bay.