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The Science of Stream Restoration - NYTimes.com <br />?.?ou ?.???k Otmes <br />June 24, 2008 <br />Fol low the Si It <br />By CORNELIA DEAN <br />PPENTEFY.;RI_tdFlLS' FpRMk7 <br />SFaklSGREO E'Y <br />LITITZ, Pa. - Dorothy J. Merritts, a geology professor at Franklin & Marshall College in <br />Lancaster, Pa., was not looking to turn hydrology on its ear when she started scouting possible <br />research sites for her students a few years ago. <br />But when she examined photographs of the steep, silty banks of the West Branch of Little <br />Conestoga Creek, something did not look right. The silt was laminated, deposited in layers. She <br />asked a colleague, Robert C. Walter, an expert on sediment, for his opinion. <br />"Those are not stream sediments," he told her. "Those are pond sediments." In short, the <br />streamscape was not what she thought. <br />That observation led the two scientists to collaborate on a research project on the region's <br />waterways. As they reported this year in the journal Science, their work challenges much of the <br />conventional wisdom about how streams in the region formed and evolved. The scientists say <br />18th- and i9th-century dams and millponds, built by the thousands, altered the water flow in <br />the region in a way not previously understood. <br />They say that is why efforts to restore degraded streams there often fail. Not everyone agrees, <br />but their findings contribute to a growing debate over river and stream restoration, a big <br />business with increasing popularity but patchy success. <br />http://www.nytimes.com/2008/06/24/science/24str...l?_r=1&oref=slogin&ref=science&pagewanted=print (1 of 7) [6/24/2008 12:37;57 PM]