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Source: https://erdc-library.erdc.dren.mil/jspui/ Three numerical hydrodynamic models with progressively finer grid resolutions, utilizing the finite difference code WIFM, were developed for the purpose of evaluating the influence of proposed structures under storm conditions and providing elevation and velocity data for concurrent numerical sediment transport studies at Oregon Inlet, North Carolina. The offshore model encompassed the entire Carolina coast over the continental shelf and was used to propagate storm effects from deep water to the finer resolution models. The nearshore model extended from Cape Henry to Cape Lookout, and provided finer detail along the Outer Banks, within Pamlico and Albemarle Sounds, and at Oregon Inlet. This model was used for both tide and surge simulations and was the primary tool for establishing structural effects under storm conditions in the Oregon Inlet vicinity. It also was used to provide boundary conditions for the most detailed model of the study known as the shore process model. The shore process model emcompassed less than 85 square miles centered about Oregon Inlet and provided high resolution at the inlet and in the surf zone. It provided more realistic circulation patterns of the inlet, the effects of jetties on inlet flow, and hydrodynamic data for concurrent numerical sediment transport studies. Data collected for previous physical model studies were supplemented by additional data from NOAA and unpublished SAW letter reports for satisfactory calibration and verification of the models under existing tidal conditions and for two severe storms of record: the March 1962 northeaster and Hurricane Donna (1960). Two structural alternatives (involving parallel jetties with 2,500- and 5,000- ft- wide spacings) were studied, and their effects were determined to be limited to the inlet under tidal conditions and to the immediate inlet vicinity under circumstances approximating Hurricane Donna. The maximum possible influence attributable to inlet restriction was determined by simulations with complete inlet closure (this was not under consideration as an improvement plan) under Hurricane Donna conditions, and no changes were noted beyond a 12- mile radius of the inlet. Within that distance, elevation increases of 2.4 ft and 1.4 ft were indicated at the Pea Island Coast Guard Station and Oregon Inlet Marina, respectively, with total inlet closure under Donna- like conditions. For 2,500- and 5,000- ft- wide jetty alternatives, no significant changes were noted during Donna simulations, the 2,500- ft case producing water-elevation increases of 0.6 ft and 0.3 ft, respectively, for the above stations. Tidal simulations with structural alternatives indicated local variations to be limited to the inlet. Simulations at very fine grid resolution were made using the shore process model to provide hydrodynamic data for numerical sediment transport studies covering the normal range of tides with no jetties, four structural alternatives with a mean tide, and the historical March 1962 northeaster with no jetties. NOTE: This file is large. Allow your browser several minutes to download the file. |
