Plum Island River System Jetty

Slide 1: 

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The River Jetty System : 

The River Jetty System

Slide 3: 

In Colonial times the river delta bar was fused with Plum Island & Salisbury Beaches… Historical Chart, Newburyport Harbour, James Blunt, 1841 Sand was readily available & quickly driven to shore by wave action

Through a combination of wave action & onshore bar migration, the New Point grew north from the base of the “Old Point” as a sand spit… : 

Through a combination of wave action & onshore bar migration, the New Point grew north from the base of the “Old Point” as a sand spit… Source: NOAA, Historical Chart Archives, 1851 The growth & erosion of the New Point was a cyclic one that posed a problem to Shipping. Shallow Sand Bars & a migrating point accounted for many ship wrecks. “ “Old Point” Moses Pettingell 1827 $600

The Granite River Jetties were designed and built to stabilize Plum Island Point & to jettison sand from the River Channel ...thereby eliminating sand bars. : 

The Granite River Jetties were designed and built to stabilize Plum Island Point & to jettison sand from the River Channel ...thereby eliminating sand bars. The effect was like attaching a nozzle to the end of a hose. Beach nourishing sand was being driven offshore via the new river mouth… Fire Hose Jet Effect

“An entire section of Plum Island was created by the addition of the South Jetty to the shore.”*…the Jetty behaved as a groin trapping sand. : 

“An entire section of Plum Island was created by the addition of the South Jetty to the shore.”*…the Jetty behaved as a groin trapping sand. _________ _______ __ 1851 Shoreline ________ Original South Jetty Shore Expanded By Jetty *Wood, Vincent L., Plum Island Recollections, 1995. Quoting Capt. Thomas J. Maddock, U.S. Merrimack River Lifesaving Station, Plum Island, Massachusetts 1897 - 1919 63rd St Houses were built where water once was

The ebb flow plume propels lighter materials some 4.01 miles out to sea… : 

The ebb flow plume propels lighter materials some 4.01 miles out to sea…

…and the River Delta Bar with its supply of sand was dislocated from shore & driven seaward some 900 yards… : 

…and the River Delta Bar with its supply of sand was dislocated from shore & driven seaward some 900 yards… As a result, Sand delivery to shore today, is now protracted & inconsistent.