Dr. Merritts observing a steep bank of sediment built up behind a milldam in MD
MOTIVATION
WSI was formed in 2016 as an outgrowth of the groundbreaking research that began in 2005 by Drs. Dorothy Merritts and Robert Walter on the farm of Joseph and Linda Sweeney. However, the history of WSI goes back centuries...
HISTORY
In the 17th, 18th and 19th Centuries settlers who came to America cleared land for farming and dammed water to operate mills. By 1840 there were over 65,000 water-powered mills in the United States. Behind these mill dams, sediment accumulated in ponds over the course of many decades. As the Industrial Revolution progressed these mill dams came into disuse, were ultimately abandoned and the dams breached. The sediment left behind slowly eroded and flowed downstream into larger waterways, carrying with it high amounts of Nitrogen and Phosphorus. This has created an environmental hazard to waterways like the Chesapeake Bay.
RESEARCH
In their teaching and research, Drs. Merritts and Walter observed that streams in mid-Atlantic Piedmont were deeply incised into the landscape with steep banks containing high amounts of sediment. After further research, they hypothesized that this was the result of not only deforestation and agricultural practices as was thought at the time, but also the practice of damming water for power. As a result of the deposition of sediment on top of the original valley bottom, great amounts of Nitrogen and Phosphorus were being carried downstream in the sediment, contributing to the pollution of the Chesapeake Bay.
Dr. Merritts observing a steep bank of sediment built up behind a milldam in MD
After years of investigation, Drs. Merritts and Walter tested this hypothesis with a restoration project in 2011 at Big Spring Run (BSR), Lancaster County, Pennsylvania. Click here to see the entire BSR project. The data from this project continues to confirm that removal of the sediment which contains Nitrogen and Phosphorus can dramatically reduce the amount of these pollutants finding their way to the Bay.
Suspended sediment in Lancaster County, PA