Beach Nourishment

Framework for Dredged Material Management

May 2004

seed-eating birds and small mammals. Larger tracts may be managed for a variety of

wildlife including waterfowl, game mammals, and rare or endangered species. The

knowledge that a disposal site will ultimately be developed into a useful area, be it a

residential area, a park, or wildlife habitat, improves public acceptance of the dredged

material disposal alternative.

Many island habitats have been created by placement of dredged material, varying

in size and characteristics and ranging in age from newly formed to those estimated to be

50 years old. The primary wildlife species utilizing dredged material islands as part of

their life requirements are species of colonial-nesting waterbirds. Natural islands have

been altered and developed to such a large extent that some areas no longer have coastal

islands that are still suitable wildlife habitat. Dredged material islands have provided this

vital habitat in many areas.

Aquatic habitats are typical submerged habitats extending from near sea, river, or

lake level down several feet. Aquatic habitat development is the establishment of

biological communities on dredged material placed at or below mean tide in coastal areas

and in permanent water in lakes and rivers. Potential developments include such

communities as tidal flats, seagrass meadows, oyster beds, clam flats, fishing reefs, and

freshwater aquatic plant establishment. The bottom of many water bodies potentially

could be altered using dredged material; this could simultaneously improve the

characteristics of the site for selected aquatic species.

6.2.2 Beach Nourishment

Shore erosion is a major problem along many ocean and estuary beaches and the

shoreline of the Great Lakes. Beach nourishment is usually accomplished by dredging

sand from inshore or offshore locations and transporting the sand by truck, by split-hull

hopper dredge, or by hydraulic pipeline to an eroding beach. These operations may result

in displacement of the substrate, changes in the topography or bathymetry of the borrow

and replenishment areas, and destruction of nonmotile benthic communities. However, a

well-planned beach nourishment operation can minimize these effects by taking

advantage of the resiliency of the beach and nearshore environment and its associated

biota, and by avoiding sensitive resources. When dredged material is used for beach

nourishment, it should closely match the sediment composition of the eroding beach and

be low in fine sediments, organic material, and pollutants. Beach nourishment and

protection can also be accomplished by placement of dredged material mounds or berms

on the bottom, where much of the material would be carried by wave action to the beach.

6.2.3 Aquaculture/Mariculture

Because of the increasing difficulty and expense of obtaining CDFs for use as

single purpose disposal areas, the development of a multiple-use strategy such as

aquaculture or mariculture is desirable. Dredged material containment sites commonly

possess structural features such as dikes and water control devices that may enhance their

suitability as aquaculture areas. It is possible that future site availability would be