historic shoreline configuration; (b) inputting a time series of wave height, 

 period, and direction at the model's seaward boundary; (c) running the model 

 for a specified length of time; and (d) comparing the simulated changes to 

 known historic shoreline changes. Depending on the quality of the comparison, 

 the model can be adjusted by modification of two coefficients, and the cali- 

 bration repeated until satisfactory reproduction is achieved. 



After calibrating the model it is desirable to verify it by reproducing 

 the shoreline change observed at the same site, but for a different time 

 period than used for model calibration. No coefficient adjustment is made 

 during the verification run. After verification, the model can be used to 

 provide reasonable engineering estimates of future changes associated with 

 suggested projects at the site. 



Preliminary Shoreline Response Modeling . The following is a short over- 

 view of the preliminary shoreline modeling task. A complete description of 

 this task and study results is given by Gravens (1988). The scope of work for 

 this task included the following: 



a. Collection and review of existing wave and shoreline processes 

 data along the project reach. 



b. Preparation and calibration of a shoreline response prediction 

 model to estimate the adjacent shoreline impacts of the proposed 

 navigable and non-navigable entrances. 



c. Identification and comparison of available wave data sources, 

 selection of the most appropriate data source, and performing a 

 nearshore wave transformation analysis. 



d. Calibration and verification of the shoreline response model 

 using known quantities of beach evolution from surveyed shoreline 

 positions . 



e. Application of the calibrated model to predict future shoreline 

 changes resulting from construction of the navigable ocean 

 entrance channel . 



Shoreline change simulations covering a ten-year period over the reach of 

 coast from Anaheim Entrance southward to the Santa Ana River were compared 



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