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Title: Effects of entrance channel dredging at Morro Bay, California
Authors: United States. Army. Corps of Engineers. Los Angeles District.
Kaihatu, James M.
Lillycrop, Linda S.
Thompson, Edward F.
Keywords: Harbors--California--Morro Bay--Hydrodynamics
Channels (Hydraulic engineering)--California--Morro Bay- Evaluation. Morro Bay (CA) .
Publisher: Coastal Engineering Research Center (U.S.)
Engineer Research and Development Center (U.S.)
Series/Report no.: Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; CERC-89-13.
Description: Miscellaneous paper
Abstract: The US Army Engineer Waterways Experiment Station's Coastal Engineering Research Center was requested by the US Army Engineer District, Los Angeles (CESPL), to provide technical assistance in engineering analysis and evaluation of the proposed channel enlargement plans for Morro Bay, California. These plans were developed to alleviate the hazardous conditions present at the entrance. This report details the study and provides final results to CESPL. Significant wave heights, periods, and directions taken from the Have Information Studies' (WIS) hindcast data base were input into the Regional Coastal Processes Wave finite difference model and transformed to breaking conditions along Estero Bay, Southern swell data were taken from an offshore directional buoy moored near Los Angeles, California, during 1984-85 and similarly transformed. The resulting breaking wave heights, periods, and directions, were used to calculate longshore flux factors for use in sediment transport computations. A set of 42 representative waves were input into the Harbor Have Transformation finite element model to ascertain the increase in the level of wave action inside the harbor with improved conditions. The results were then used to compute the number of days of breaking which would occur at various locations throughout the harbor. Existing conditions were also calculated as a check on the procedure; the agreement with Morro Bay Harbor Patrol record was found to be adequate. Current-induced breaking was also analyzed by calculating the maximum entrance channel current during falling tide and then computing the amount of steepness-limited breaking at the entrance for existing and improved conditions. The potential longshore sediment transport rate was calculated using the previously calculated longshore flux factors and techniques found in the Shore Protection Manual. The rate of transport toward the harbor was calculated and compared favorably with results of a prior study. The final results of the study indicated that the frequency of wave breaking would decrease at the entrance after either improvement was implemented. However, the hazardous breaking wave conditions previously at the entrance would be present further inside the harbor. Additionally, these breaking waves would tend to be higher than those presently at the entrance, since increasing channel depth allows more wave energy to enter the harbor.
Rights: Approved for public release; distribution is unlimited.
Appears in Collections:Miscellaneous Paper

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