Strategic placement of dredged sediment in Louisiana’s Atchafalaya River has helped create an island spanning about 35 hectares, turning material removed from the river into a growing landform.
The project began in 2002 near Horseshoe Bend, where engineers placed between 0.5 million and 1.8 million cubic yards of dredged sediment at a mid river site every one to three years. Over time the deposited material was reshaped by natural river processes contributing to the formation and expansion of Horseshoe Island.
The project was part of an Engineering With Nature approach that sought to combine river management with environmental benefits. As the island grew it reduced the river’s cross sectional area and increased water flow through the navigation channel helping reduce sediment buildup and the need for maintenance dredging.
An ecological survey by the US Army Engineer Research and Development Center in 2013 found that the island had developed a mix of wetland and upland habitats. Researchers recorded vegetation, wildlife and soil characteristics and identified four distinct ecological communities.
The findings highlight how strategically managed dredged material can be used not only for river maintenance but also to support the development of new habitats and wetlands.