902 resultados para Beach
Resumo:
"August 1979."
Resumo:
Beach profile line data collected from 32 profile sites along Long Beach Island, New Jersey. A total of 2,158 profile line surveys were examined, using empirical eigenfunction analysis and other measures of beach variability. Most profile lines have shown an accretionary trend since 1962 with rates between 2.3 and 0.24 meter per year in spite of erosion estimates due to sea level rise on the order of 0.68 meter per year. A great deal of variability in profile line change takes place along the beach, increasing from north to south, due to the location of profile lines relative to structures and offshore linear shoals. Detailed closely spaced profile lines taken over a year in a groin field near the north end of the island indicate littoral transport directions shift from north to south. Evidence of a littoral transport node near the north end of the groin field has been found. Net transport of the node is toward the south, but the rate could not be established due to lack of adequate wave data. Profile line variability within groin cells shows that single profile lines are not sufficient to determine the net change within a cell. The design of future beach monitoring studies should consider coastal structures, offshore bathymetry, the method of analysis, and the scales of processes under study. A coastal storm in November 1968 moved the MSL back as much as 22 meters; however, the beach recovered without artificial measures. The offshore bathymetry shows a series of shoreface-connected linear shoals at several locations along the island. Limited data show that these have remained stable and that most beach variability takes place in water shallower than 3 meters.
Resumo:
"March 1981."
Resumo:
A comprehensive engineering analysis of the coastal sediment transport processes along a 42-kilometer segment of the North Carolina shoreline from Wrightsville Beach to Fort Fisher is presented. Included in the analysis is an interpretation of the littoral processes, longshore transport, and the behavior and success of beach nourishment projects at Wrightsville Beach and Carolina Beach, North Carolina. The historical position of the MLW, MSL, and MHW contours, relative to a fixed base line, is plotted for the period between 1964 and 1975. An equivalent volumetric erosion or accretion between successive surveys is determined by multiplying the average excursion distance of the contours by a constant of proportionality. The plots of excursion distance versus time for the MLW, MSL, and MHW contours also show the time response of the beach fills. This response is described by a mathematical function. The alongshore components of wave-induced energy flux are also determined within the study area through wave refraction analysis. This information, together with the information on volumetric change, is used in a sediment budget analysis to determine the coefficient of alongshore sediment transport and the inlet trapping characteristics. (Author).
Resumo:
The long-term effects of beach nourishment on the benthic infauna and surface sediments of Panama City beaches were investigated. Forty-seven stations located on nine transects between West Pass and Philips Inlet, and two nourishment borrow sites were sampled in November-December 1979 and May 1980. The data collected were compared to prenourishment base-line information collected by Saloman (1976). Abiotic parameters, water temperature, dissolved oxygen and salinity were measured. Sediments were analyzed for particle-size distribution, percent organic carbon and percent carbonate. Benthic macroinvertebrates were represented by 162 taxa of 14 major animal phyla. Species composition and faunal densities varied seasonally. Polychaetes and amphipods were the most abundant animal groups; a small number of species were dominant at nearly all stations. Species diversity was lowest in the swash zone and sandbar stations and highest offshore. Sediment composition was similar to that of Saloman's (1976) study within limits of sampling and processing errors. Faunal composition was found to be different from 1976 but was attributed to normal seasonal and spatial variations. Based on benthic community analyses and sediment parameters, no significant differences were found between nourishment borrow sites and surrounding areas and in the nearshore areas where beach nourishment was conducted. No long-term adverse effects of beach nourishment were detected. (Author).
Resumo:
This report gives biological and physical oceanographic data from baseline work, and studies of dredged and undredged sediments before and after dredging (9-meter contour) for beach nourishment at Panama City Beach, Florida. These studies were designed to show major short-term environmental effects of offshore dredging and included analyses of hydrology, sediments, and benthos. (Author).
Resumo:
Long-term changes in the beach fauna at Duck, North Carolina, were investigated. Twenty-one stations located on three transects on the oceanside and twenty-four stations located on three transects on the sound side were sampled seasonally from November 1980 to July 1981. The data collected in this study were compared to a previous study conducted in 1976 (Matta, 1977) to investigate the potential effects of the construction of the CERC Field Research Facility pier on the adjacent beaches. No effects on the benthic fauna were found. Changes observed in the benthic macrofauna on the ocean beaches were well within the range attributable to the natural variation of an open coast system. The ocean beach macrofauna was observed to form a single community migrating on an off the beach with the seasons. On the sound beaches, changes were detected in the benthic macrofauna; however, these were attributed to a salinity increase during the 1981 sampling year. (Author).
Resumo:
In October 1980 the U.S. Army Corps of Engineers conducted a beach nourishment project at the Lexington (Michigan) Harbor on the southwest shore of Lake Huron, a project designed to mitigate beach erosion attributable to the installation of the harbor. In response to a request from the Coastal Engineering Research Center (CERC), the U.S. Fish and Wildlife Service's Great Lakes Fishery Laboratory conducted a Corps-funded study from June 1980 to October 1981 along a 8.4-kilometer segment of shoreline adjacent to the harbor to determine the effect of the Corps' beach nourishment project on the nearshore aquatic environment. The study performed by the service included aerial photographic surveys of the study area; measurement of dissolved oxygen, turbidity, and suspended particulate matter levels; and collection of lake bottom sediments, macrozoobenthos and fish. Analysis of the aerial photographs showed that the beach face profile changed markedly during the study as a result of beach nourishment. Dredging of about 19,000 cubic meters of beach sediment from an accretion area adjacent to the harbor's north breakwater caused the beach face to recede, while deposition of this sediment on a feeder beach south of the harbor caused the beach face there to extend lakeward.
Resumo:
"December 1982."
Resumo:
Bibliography: p.34.
Resumo:
"March 1976."
Resumo:
Issued April 1977.
Resumo:
Cover title.
Resumo:
Contract no.: DACW72-77-M-0639 (v.2).
Resumo:
"May 1980."
