66 D11. Marine/Coastal Science (Posters)

Sunday, 22 March 2020
1:30 PM - 5:30 PM
Grand Ballroom E–G

FEASIBILITY STUDY ADDRESSING THE CHRONIC HARBOR SILTING ISSUE IN GEORGETOWN, SC

Paper number: 66-8
Program: Technical Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

The Georgetown inner harbor is a vital historic site with a wealth of traditional businesses but also heavy local industry. Full access from the river side is key to ensure a navigable inner harbor, which has a chronic silting issue at its entrance. In 1949, The Sampit River, a fast-flowing tidal river, was converted from a harbor meander into a kind of artificial oxbow to create a shortcut for ships. This alteration has resulted in rapid silting of the inner harbor. Since then, dredging the harbor loop was always required and its termination in 2006 led to immediate harbor shallowing. This study seeks for a lasting, sustainable, and cost-efficient technical solution against the massive mud accumulation.

The main idea is to either regenerate the bottom current or to keep the suspended sediment out of the harbor loop. At the same time, it’s crucial to ensure that any kind of engineering solution will not lead to excessive negative effects along the waterfront and its infrastructure. Water level and turbidity data from several strategic sites in and around the harbor along with sedimentological and geochemical properties of the seabed sediment are fed into a numerical model. First, simulations of modern water flow conditions together with modern sediment transport and settling processes were entered into the model. Currently, several potential technical solutions are being explored using the model to observe long term effects. It turns out that simply closing the artificial shortcut again would lead to major unwanted erosion along the city bank but also to silting off the main docks, thus prohibiting the return of the river to its natural shape. The poster discusses the benefits and consequences of other possible solutions on the revitalization of a man-made oxbow lake.

Geological Society of America Abstracts with Programs. Vol. 52, No. 2

doi: 10.1130/abs/2020SE-345268

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