how does dredging work to prevent flooding

He wondered whether he would find effects similar to what he uncovered during a post-doctoral project studying the Ems River estuary on the border of Germany and the Netherlands. Talke combined that old-fashioned sleuthing with high-tech modeling to examine changes in estuaries related to the dredging that began about 150 years ago in port cities. Near Dame Point, the channel was dredged to 18 feet in 1894.

Jacksonville is the small town on the left-hand-side of the image. The earliest records dated to Boston in the 1820s, decades older than those previously available. Each time, they took pictures of the records and returned to Portland State, where Talke’s students painstakingly transferred the information into a digital database of tidal gauge information throughout the 19th century. Over the next few years, Talke and his colleagues unearthed more long-lost tidal tales covering New York, North Carolina, Massachusetts, Florida, Delaware, Virginia and other coastal areas. The scrolls of records that day in 2011 were from Astoria, Oregon, on the Columbia River near where Talke is an associate professor of environmental engineering at Portland State University studying the hydrodynamics of estuaries, rivers and the oceans. Spurred by these tidal records, Talke and his colleagues have created computer models that show how deepening channels to accommodate cargo ships can cause higher tides and dramatically increased flooding from storm surges in some cities. The records are keys not only to understanding the past, but to the future facing cities like Wilmington, North Carolina Jacksonville, Florida Jamaica Bay, New York, and other ports around the country.

'I assumed these records were all lost, and here I am with the keys to the palace.' The paper scrolls, 13 inches wide, stretched to 60 feet long, so Stefan Talke pulled together tables inside the National Archives to unroll the sheets of squiggles tracing the rise and fall of tides dating to before the Civil War.

How does dredging work to prevent flooding