![]() Sheet piles are supported in a vertical position between the wales and secured to them with nails. Some permeable timber groins have also been built by leaving space between the sheetings. A common type of sheet pile timber groins (heavily used in coastal areas around New York) is usually supported by wales and round piles. A few jetties and shore-connected breakwaters have also been constructed using a sheet piling design. By far, the vast majority (over 80 percent) of all such structures are located in the New York District, the only Corps region reporting sizeable numbers of such structures. Groins, constructed and maintained entirely without Federal funds, account for 90 percent of all coastal structures utilizing sheet piling. Sheet pile types include timber, steel and concrete sheet piling structures. Other smaller numbers of these structures include crib-type construction (two percent) and combinations of wooden cribs with concrete caps and steel cells (four percent). Type of Structure/Construction Material UtilizedĪpproximately 51 percent of all coastal and navigation structures in the United States were constructed using sheet pile while an estimated 43 percent contain rubble stone (Table 2). NUMBER OF JETTIES, GROINS AND SHORE-CONNECTED BREAK BY U.S. Over 81 percent of these breakwaters are located in the Galveston and Chicago Districts as well as in the Pacific Ocean Division. In addition to another 111 breakwaters constructed by the Corps but maintained by non-Federal parties, there are 66 other such structures entirely built and maintained by state and local funding. Other Corps offices with sizeable numbers of these structures include the Alaska District and the pacific Ocean Division, both with 26. The New England Division with 52, and the Detroit District with 60, contained the largest number of Corps-maintained breakwaters. In 1981, this agency maintained 76 percent or 2118 structures nationwide. Similar to maintenance responsibilities with jetties., the Corps of Engineers performs most of these functions on breakwaters. Although a total of 3619 other (non-Corps and private) groins were reported, this estimate is considered rather low by Corps district personnel since it may not include the hundreds of smaller groins abutting private, residential shorefront properties. These districts presently provide normal maintenance and perform necessary repairs to a number of such groins, 23 and 11, respectively. However, in the case of multipurpose projects providing for navigation as well as shore protection in the Galveston and Los Angeles areas, maintenance responsibility is vested in the Federal government. ![]() Maintenance of such shore erosion control structures is generally a non-Federal responsibility. Army Corps of Engineers, a large percentage (66 percent) or 127 groins are maintained by non-Federal parties. Of the 192 groins constructed by the U.S. ![]() There are no Corps-maintained jetties in the Chicago and Norfolk Districts or in the Pacific Ocean Division. The Detroit District maintains the largest number of jetties (80), followed by the Jacksonville District with 118 New England, 36 Buffalo, 28 and Baltimore, 23. Non-Federal parties (state and local governments) have constructed 121 jetties and have sole maintenance responsibilities for these structures and for five other jetties built by the Corps of Engineers. The number of existing groins in actuality may be considerably higher due to the large number of smaller structures of this sort (<20 feet), owned and maintained by private individuals and not included in district inventories.Ībout 711 percent of all jetties nationwide are presently maintained by the U.S. Army Engineer Institute for Water Resources, it is estimated that there are 1180 jetties, 328 shore-connected breakwaters and 36811 groins in these districts. Based on questionnaire data provided to the U.S. Army Corps of Engineers districts comprising the coastal and Great Lakes regions of the United States contain approximately 11500 navigation and shore protection structures (Table 1). For a complete version of this document click here.
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