continued until shoaling and scouring histories of the prototype are re- 

 produced in the model. 



t. Block 27 . Movable-bed tests repeating the fixed-bed testing will 

 establish the effect of a plan on material movement. If necessary, addi- 

 tional tests are conducted until an effective plan of movement is defined. 

 It may then be necessary to convert the model back to fixed-bed conditions 

 to determine the hydraulic conditions for the best plan using the inlet 

 hydrography predicted by the movable-bed tests. 



u. Block 28 . Test results are transmitted to and discussed with the 

 sponsor as the results become available. When the final recommended plan 

 is defined, this information is also immediately transmitted to the spon- 

 sor. At this time the sponsor is aware of all significant results from 

 the investigation. 



V. Block 29. A final report is published including all significant 

 results of the investigation. 



Figures 7-1 and 7-2 show that (depending on requirements imposed on 

 the inlet study) the total time to complete the model study cannot be 

 determined without considering the time to accomplish tasks by both the 

 laboratory conducting the model study and the sponsoring organization 

 (field office). Figure 7-1 shows that if the movable-bed verification 

 is based on a 2-year (minimum) prototype history, assuming that a major 

 change in hydrography has occurred, the only effort the sponsor must 

 complete as scheduled without delaying the overall study is the review 

 of the fixed-bed results. If the study is based on a 3-year prototype 

 history, however, the prototype hydrographic survey becomes more criti- 

 cal to the overall schedule than the fixed-bed model testing (Fig. 7-2). 

 If the laboratory completes specific tasks in the estimated times after 

 start of the project without delays between tasks, the verification of 

 the movable-bed model could not be efficiently initiated until the pro- 

 totype hydrographic information is available and analysis completed. 

 Because of these possible differences, proper advanced planning must be 

 based on a full definition of prototype data available, prototype data 

 required (with proper consideration of accuracy of the model results 

 required), and extent of testing required in the model. 



3. Physical Modeling of Tidal Inlets . 



Because the fluid-flow problems associated with tidal inlet studies 

 usually involve a large number of variables, many of the problems are 

 not readily amenable to mathematical analysis. Therefore, recourse is 

 often taken to the operation of physical hydraulic models to determine 

 the significant kinematic and dynamic features of the prototype. 



In any hydraulic model study, the physical phenomena observed in the 

 model should represent those phenomena occurring in the prototype, so 

 that the prototype action can be predicted by operating the model. A 

 model is then, by definition, a device which is so related to a physical 



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