LANCASTER, Pa. — Members of the Chesapeake Bay Commission recently toured several Lancaster County legacy sediment sites as part of a two-day quarterly meeting in Lancaster.

The tour, organized with the assistance of The Water Science Institute, provided before and after examples of water quality impairments and improvements, including the Big Spring Run restoration experiment in West Lampeter Township.

The experiment, led by Franklin and Marshall College researchers, is jointly monitored by the state Department of Environmental Protection, the U.S. Geological Survey, U.S. Environmental Protection Agency, Elizabethtown College, Lancaster Farmland Trust and other partners.

It is part of a continuing scientific evaluation focused on the results of legacy sediment removal and re-establishment of aquatic ecosystems.

Legacy impairments are generally considered to be the result of past land-use practices, such as mill dams, logging and farming, that buried stream valley bottoms in thick layers of sediment.

An explanation of the project, now in its fifth year of post-restoration monitoring and experiments, was presented by Franklin and Marshall College researchers Dorothy Merritts and Robert Walter, who were instrumental in identifying the consequences of legacy sediment impairments in riparian ecosystems.

The project included the removal of 44 million pounds of sediment and with it more than 50,000 pounds of total phosphorus and 60,000 pounds of nitrogen.

Chief among the latest findings is research showing dramatic reductions in surface water temperatures and nitrogen, the re-establishment of threatened species of plants, colonization by the green frog and a 50 percent reduction in sediment leaving the restored ecosystem.

Joseph Sweeney, director of The Water Science Institute, said the experiment has created a 12-acre area that includes 4.5 acres of restored aquatic ecosystem reconnected to its upland valley and providing additional habitat and stormwater retention.

Sweeney said the entire sediment removal project cost less than 1.5 cents per pound.

Source: The Water Science Institute.