1998 Year of the Ocean Ocean Energy and Minerals 



construction and in most public works projects such as roads and streets, dams, airports, bridges, 

 and tunnels. The exhaustion of existing reserves, zoning, government regulations, and competing 

 land uses are increasingly restricting the production of construction aggregate from the land, and 

 thus encouraging the use of offshore aggregate sources close to coastal population centers. 



The greatest use in the United States of offshore sand and gravel is for beach 

 renourishment and coastal restoration and protection. With increased development adjacent to or 

 near the coastline, and the natural processes of landward migration over time, there has been a 

 steady increase in the number and size of beach renourishment projects. Traditional approaches 

 to prevent coastal erosion (e.g., jetties and groins) are no longer acceptable in many areas, having 

 become too expensive, ineffective, or damaging to the environment. Beach renourishment, 

 although expensive and short-lived in some cases, is now a widely accepted method of restoring 

 an eroded coastline. 



Recent changes in wetland regulation sometimes mandate the building of new wetlands 

 to offset those that have been destroyed and much of the material to construct coastal wetlands 

 will be supplied by offshore dredging. Marine sand may also be used for capping both recent and 

 former offshore dump sites. 



Portions of the OCS areas surrounding the United States, especially in the northeast, 

 contain an abundant supply of sand and gravel, much of it near growing metropolitan areas 

 where demand is greatest. The detailed distribution and characteristics of these resources is 

 known in only a few areas. Resource characterization studies are needed to better understand the 

 potential development of resources in specific localities. 



Environmental and physical oceanographic studies are needed to better understand the 

 possible impacts of dredging to ocean and seafloor life and the coast. Costs are generally greater 

 for mining offshore sand and gravel than for onshore deposits, but these costs may be offset by 

 lower transportation costs for the delivered product and by a possible reduction in environmental 

 impacts onshore. These advantages have prompted commercial interests to examine further the 

 feasibility of developing marine sand and gravel resources. 



Current Uses of Offshore Sand and Gravel 



Offshore sand and gravel use is an established industry in several countries, most notably 

 Japan, the United Kingdom, Denmark, and the Netherlands. Japan obtains most of its 

 construction aggregates from offshore deposits, and the offshore dredging industry in the United 

 Kingdom is growing steadily. The technology developed and the experience gained by these 

 countries in dealing with economic and environmental issues should prove useful for future 

 development of U.S. offshore sand and gravel resources. Major technological developments in 

 dredging, coming largely from the Netherlands and Japan, have occurred over the past 1 years. 

 Innovations include high-capacity underwater pumps and multiple-booster pumps, which enable 

 operation in deeper water and the pumping of sand as far as 7 miles from the dredge to the 

 shoreline. 



D-13 



