974 resultados para Long Beach Island
Resumo:
Issued July 1977.
Resumo:
This report summarizes the impact of Hurricane Allen (August 1980) on dune configuration, sand accretion or erosion, and changes in the vegetation on north Padre Island. Four experimental foredunes, the result of grass plantings from 1969 to 1973, and an unplanted control section were monitored in 1975-1977 and also in 1981. The 1981 posthurricane data were compared where possilbe, with the previous studies. Foredune elevation surveys were completed in March 1981; accompanying vegetation transects were made in July 1981. Hurrican Allen causes erosion of the dune face of all the experimental dunes, but caused a breach in only one dune. The beach elevations had returned to approximately prehurricane heights by the time the area was resurveyed. The unplanted control dune provided little resistance to waves generated by the storm and a large quantity of sand was deposited inland.
Resumo:
"Prepared for U.S. Army Engineer District, Galveston, Galveston, Texas."
Resumo:
"February 1985."
Resumo:
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.