Coastal & Marine Geology Program > National Assessment of Coastal Change Hazards > Open File Report 03-337

An Overview of Coastal Land Loss: With Emphasis on the Southeastern United States

USGS Open File Report 03-337

by: Robert A. Morton

Summary Introduction Physical Agents of Land Loss: Waves, Currents, & Storm Surges Landslides & Cliff Retreat Sediment Budget Relative Sea Level Climate & Land Loss Role of Shoreline Characteristics: Composition, Induration, & Saturation Coastal Morphology & Vegetation Role of Human Activities: Introduction Transportation Coastal Construction River Modification Hydrocarbon & Groundwater Extraction Climate Alteration Coastal Excavation Wetland Losses Acknowledgments References

Role of Human Activities: Introduction There is increasing evidence that recent accelerated land losses in many coastal regions are largely anthropogenic and attributable to human alteration of the littoral system and wetland environment. Land losses indirectly related to human activities are difficult to quantify because they promote alterations and imbalances in the primary factors causing land loss such as sediment budget, coastal processes, and relative sea level (Fig. 2). Coastal construction, land excavation, and extraction of hydrocarbons and groundwater now account for the greatest losses of wetlands and barrier islands where these natural resources have undergone intensive economic development for more than 50 years. Human activities causing land loss are discussed according to their impacts on the physical agents (Fig. 1). The linkage between human activities and the physical agents is as follows: transportation networks tend to increase erosion, coastal construction projects typically increase deficits in the sediment budget, subsurface fluid extraction and climate alterations accelerate submergence, and excavation causes direct losses of land. continue to Transportation

Coastal & Marine Geology Program > National Assessment of Coastal Change Hazards > Open File Report 03-337