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Beneficial Uses Of Dredge Material
It saves tax dollars that would otherwise be spent on finding and managing disposal sites. It avoids habitat impacts that disposal may cause. It saves capacity in existing disposal sites. It can be a low-cost alternative to purchasing expensive fill for construction projects. It can be used to enhance or restore habitat. The Corps has always participated in beneficial uses projects, as long as the cost did not exceed that of the government's other diposal options. Historically, the focus of maintenance dredging was to provide safe channels in the most economical way. The Corps could utilize beneficial use activities only if they did not increase costs. During the 1970s and 1980s the Corps of Engineers began to actively seek out beneficial uses for dredged material that included environmental improvement and reclamation projects. The change in project planning was the result of several factors: Social pressure for Federal agencies to become more environmentally responsible. Realization that dredged material disposal sites were almost full at many projects. The passage of "cost sharing" legislation. Under the new laws, the Corps can share in the costs of some beneficial uses of dredged material projects, even when the environmental projects cost a little more. Dredging Operations Technical Support discusses beneficial uses of dredged material and provides case study examples. Several broad categories of beneficial uses are discussed based on how the dredged material is used: Habitat Development - Habitat development refers to the establishment and management of relatively permanent and biologically productive plant and animal habitats. Within any habitat, several distinct biological communities may occur. Wetland, upland, aquatic, and island habitats may all be developed at a single site. Habitat development is most often planned near remote dredging locations where there is more undeveloped land and less human use. Beach Nourishment - Shoreline erosion is a problem along many ocean beaches and the shoreline of the Great Lakes. Beach nourishment with dredged sand is one of the most desirable and cost-effective ways to accomplish shore protection. Where possible, the replacement sand is placed directly onto the shore. In some areas, beach nourishment has been accomplished by building mounds of sand directly offshore of a beach, where waves and currents transport it onto the beach naturally. Shoreline Stabilization and Erosion Control - Like beach nourishment, shoreline stabilization projects use dredged material to replace eroded sediments. Then, the stabilization projects are grassed or structurally stabilized. If protected by revetment walls or grassed over, these would represent one-time opportunities for the use of dredged material. But in many cases, the dredged material is expected to eventually erode away and be replaced when necessary. Parks and Recreation - Recreation on dredged material containment sites is one of the most common land uses of dredged material sites, in actual acres. This is not surprising, since there is a high demand for recreational sites in urban areas where much dredging occurs. These converted dredged material sites typically provide public access for water-related recreational activities. The nature of recreation sites - lots of open space and lightweight structures - is especially suited to fine-grained dredged material, which is generally not good foundation material for more substantial structures. When planned and developed thoughtfully, recreational sites can become a valuable community asset, not only for the recreation opportunities they provide for residents, but for the business opportunities that recreation activities generate. Agriculture, Forestry, and Horticulture - The use of dredged material sites as pasture land and cropland has been successfully combined with active dredging projects. Dredged material has also been used occasionally to improve farm soil. Inactive dredged material sites have been used for forestry, but forestry use of active sites is not very practical. The length of time needed to grow even quickly yielding stands of trees, like Christmas trees, is longer than the time between dredging cycles. Construction and Industrial Use - This refers to the use of dredged material for such things as port development, airports, and urban and residential developments. Historically, dredging and shoreline developments in urban areas have gone hand in hand. Major portions of the San Francisco, California, Galveston, Texas, and Portland, Oregon industrial and residential areas are built on dredged material fill (to name only a few locations). In most cases, the planning for port improvements and water-dependent commercial developments relies on the use of dredged material for construction fill. Strip Mine Reclamation and Solid Waste Management - Dredged material as top cover on landfills and to refill old mining sites has been successfully implemented around the United States. In Portland, Oregon, backfilling the holes left by an old, in-water aggregate-mining operation fulfills several needs. The deep water created by decades of mining is being reclaimed for eventual habitat development and recreational use. In addition, under carefully managed operations, selected deep-water areas can be used to isolate and cap contaminated dredged material generated by river clean-up activities in Portland's historical industrial waterfront. Multiple Purpose - Some communities use the development of a new disposal site to meet other local planning goals. A disposal site having combinations of uses may be developed. For example, wetland, upland, island, and aquatic habitats may be developed and the site may be used for fishing and hunting. A recreational boat marina may also be included in the development plans. Derek Van Eenenaam Article Directory: http://www.articledashboard.com |
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