BARRIER PROTECTION ISLANDS

What are Barrier Islands?

Barrier islands are natural formations across many different coasts; Georgia in particular has an established natural chain of barrier islands. These islands arecritical to maintaining the Georgia coast as they protect the coast from the direct force of the Atlantic ocean. But, despite their utility to the coast of Georgia, these barrier islands have a rich ecosystem and culture that is massively affected by the force of the Atlantic ocean. BARRIER, aims to provide a barrier island chain similar to the natural system FOR the natural barrier island system. This becomes increasingly critical as we see an increase in sea level rise and the intensity of storm events. What is dredge?

Dredge is a process of removing sediment from the base of a body of water and relocating it. This is a common practice as sediment continuously travels and caves into waterways, causing disruptions. For example, the Savannah River is periodically dredged to maintain depth for cargships and other river traffic. Currently, this dredged material sits offsite, relatively useless. The idea behind BARRIER is to use this valuable, dewatered sediment in combination with future dredge sediment from the Savanna River to create barrier islands off the coast of Georgia. Starting in Savanah and reaching down towards Brunswick.

Sand motor, a term and concept created by Rijkswaterstaat (the Dutch Mistry of Infrastructure and Water Management Works is a form of self-sustaining beach nourishment. A concentration of sediment is placed at the peak of the coast, facing toward the strongest of the longline currents coming from the north, and over time, these currents drag the sediment lower and lower on the coast, continuously supplying the beach with new sediment. A miniature sand motor is on all of these islands to sustain island despite the erosive nature of the ocean and its currents over time.

What are these islands made of?

The core of these islands is recycled concrete, surrounded by course dredge s etement and topped with finner dredge sand on the top. These islands are also populated with many coastal plants to establish a root system and healthy ecosystem such as, Scarping, Sea oats, Morning glories, Mully grass, Marsh elder, Live oaks ect...

Where do these islands go?

Determining the optimal location for these man-made islands is no simple task. There are endless factors that must be considered in this decision-making process. Using various research materials and technologies, BARRIER determined the location for 6 barrier islands off the coast of one of the most vulnerable natural barrier islands, Tybee Island, as well as its surrounding coast. Factors such as navigational routes, protected wildlife habitats, artificial reef systems, distance from shore, ocean depth, wind and current pat terns, and existing river deltas were considered in the placement of these six protective islands. Additionally, the distance of these islands from the existing coastline was decided in a balance between being far enough away to prevent blocking views, creative marshes, and unsafe currents on the coast and being close enough to be protective and access relatively shalow water. These islands are placed within a range of 3-7miles of the shore.

Inspired by ancient roman aqueducts, which have stood the test of time, these underwater barriers act as a filter, essentially allowing the passage of sediment and sea life toward the island while filtering out a bit of the energy coming from the ocean’s force. Ideally, the layering of these arches would create a net-like effect that would deposit sediment onto the exterior beach of these islands. During low tide the tops of these would be visible, but they would mostly be underwater structures. These will act as an extra layer of protection for the island but also a line of defense in the instance of a storm event.