Geometry of Profiles Across Inner Continental Shelves of the Atlantic and Gulf Coasts of the United States.
COASTAL ENGINEERING RESEARCH CENTER FORT BELVOIR VA
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Along most of the U.S. east and gulf coasts from Long Island to the Mexican Border, bottom profiles extending over the Inner Continental Shelves normal from the coast display a characteristic two-sector shape. Near the coast, the shoreface profile sector is steep and concave-up the seaward ramp sector is planar with a gradual slope away from the coast. As part of the Beach Evaluation Program at this Center, 9 profiles extending from the coast 30.5 km 19 miles seaward at each of 49 localities were averaged to mathematically characterize the profiles and to develop and test criteria for discriminating among groups of profiles. Results indicate Inner Continental Shelf profiles can be mathematically defined by 4 parameters a ramp slope 0 - 0.00107 b depth of the ramp at the shoreline, when the ramp is extended as a straight line below the shoreface sector 0 - 24.7 meters, 0 - 81 feet c distance from the shoreline to the shoreface-ramp boundary 0.2 - 20.6 km, 0.12 - 12.9 miles and f index of concavity of the shoreface sector 0.21 - 1.72. Values in parentheses are the range of values obtained for the 49 averaged profiles. An equation was developed to define bottom depth as a function of distance from shore incorporating these four parameters. Computed depths using the equation were found to be generally within 5 of actual profile depths. In most cases, no relationship was found between the geometric characteristics of the shoreface and the ramp.
- Physical and Dynamic Oceanography