The work of two Franklin & Marshall College scientists who have rocked the Chesapeake Bay cleanup world will be the cover story in Science magazine on Friday.

The world's leading journal of scientific research chronicles the startling discovery of Dorothy Merritts and Robert Walter in 2002. Much of Lancaster County's infamous runoff of soil, they determined, is due not to farm erosion but buried sediment left over from Colonial-era mill dams.

Merritts, professor of earth and environment, and Walter, associate professor of earth and environment, are a husband-and-wife team, and they've made the term "legacy sediment" a buzz word on the local, state and national conservation scenes.

The New Era first wrote about the two scientists' iconoclastic findings in 2004 and has followed the subsequent stir in several stories since.

The couple informed the New Era earlier this month that their research had been accepted by Science for publication.

The team stumbled into the discovery while researching why heavy amounts of soil were ending up in Lancaster County streams, decades after farmland conservation practices had been implemented.

The county's steep-cut banks just didn't seem natural to the scientists.

Using clues such as old tree stumps buried up to 20 feet below the present-day floodplain, they determined that nearly 500 mills and mill ponds had turned most Lancaster County streams into virtual lakes.

Over many years, sediment built up behind the impoundments. Streams today are still slicing through that soil, whisking it away and eventually into the Susquehanna River and Chesapeake Bay.

At a workshop in 2006, Walter estimated that as much as 50 to 80 percent of the sediment suspended in the streams that drain into the Conestoga River emanates from legacy sediment.

The hitherto unknown source of erosion has had profound implications for environmental agencies on many levels.

Merritts and Walter have been awarded state and federal grants, and they have been sought-after speakers at forums and seminars around the country.

The Pennsylvania Department of Environmental Protection has created a Legacy Sediment Workgroup to study the statewide implications of mill dams, and the workgroup is developing a new strategy specifically aimed at repairing streams that have the old trapped sediment.

The Pennsylvania Fish and Boat Commission, Pennsylvania Farm Bureau and consultants are members of the group.

The Chesapeake Bay Commission, responsible for stemming the flow of sediment and fertilizers into the ailing bay, is very interested in the ongoing research.

 The U.S. Environmental Protection Agency also has taken notice, and the legacy sediment issue is being studied in states surrounding Pennsylvania.

The discovery even has implications for entities such as golf courses, which often are built atop floodplains.

Farming interests, long maligned for being the primary culprit in polluting the Chesapeake Bay, are following the developments closely.

Science magazine is published by the American Association for the Advancement of Science and has the largest paid circulation of any peer-reviewed general science journal in the world. The magazine is dedicated to publishing cutting-edge research.

The article will be published Friday in Science and will be available online on the magazine's Web site at www.scienceonline.org.

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