Step b . Data requirements of the shoreline change model cover a wide 

 range of coastal-process and project-related information, as summarized in 

 Table 2. Within the framework of shoreline change modeling, guidelines are 

 available for collecting, reducing, and analyzing the data in a systematic 

 manner. Most physical data needed for evaluating and interpreting shoreline 

 and beach evolution processes in a wide sense are used in the shoreline change 

 modeling methodology. Certain other data may be lacking in particular appli- 

 cations having unique requirements , so that coastal experience and overall 

 project planning should not be subverted by complete dependence on shoreline 

 change modeling requirements. For example, geological and regional factors 

 may be involved, as through earthquakes, subsidence, or structure of the sea 

 bottom substrata. Environmental factors such as water circulation and quality 

 (temperature, salinity, sediment concentration, etc.), as well as biological 

 factors should be considered. Thus, although a shoreline model such as 

 GENESIS can simulate the movement of beach fill material placed at arbitrary 

 locations and times along the beach, the breeding habits of sea turtles and 

 birds may restrict the season and/or location of the fill. In summary, data 

 requirements of the shoreline change model provide an organized and comprehen- 

 sive first step in assembling the available data for project design. 



Steps c-e . Shoreline change modeling provides a powerful tool for quanti- 

 tative and systematic evaluation of alternatives and optimization of the final 

 plan. As an example, Hanson and Kraus (1986b) simulated beach change for nine 

 hypothetical combinations of plans to mitigate erosion at a recreational 

 beach. The without-project ("do nothing") alternative and general shore 

 protection schemes were evaluated for groins of various sizes and spacings, 

 beach fills of various quantities, and a single, long detached breakwater. 

 Technical criteria for judging the solution involved two factors , protection 

 of the eroding beach and minimization of the quantity of sand transported 

 downcoast which would enter the navigation channel of a fishing harbor. 

 Shoreline change modeling readily allowed a matrix of shoreline change volumes 

 to be compiled for target sections of the coast by which technical solutions 

 could be ranked. Economic criteria were then applied to arrive at the most 

 feasible project plan. In evaluation of Steps c-e, it may become apparent 

 that other methodologies, such as physical modeling (for estimating wave 



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