316 patterson-simmons. MODEL STUDIES [Ch. 17 



effects on stability of the Atlantic City Beach. Furthermore, the high 

 outer section of the north jetty would afford protection to boats navi- 

 gating the channel and would make dredging operations in the sea- 

 ward portion of the channel considerably less hazardous. 



CONCLUSION 



It has been demonstrated during this discussion that the adjustment 

 and verification of the sedimentation model, and hence the accuracy of 

 results to be obtained therefrom, are based on data obtained from 

 comprehensive prototype investigations. The completeness and ac- 

 curacy of such prototype studies are most essential, as the model study 

 would produce erroneous results if its adjustment and verification were 

 based on inaccurate or incomplete field data. 



In the above connection, model-prototype confirmation studies are 

 of inestimable value to the engineer who works with sedimentation 

 models. After the installation of an improvement plan in the proto- 

 type as a result of a sedimentation model study, the question immedi- 

 ately arises as to how closely the functioning of this plan in nature 

 corresponds to the model predictions. Where inconsistencies are re- 

 vealed through such a confirmation study, model operating techniques 

 may be improved to the end of eliminating such inconsistencies in the 

 future. Model-prototype confirmation studies are believed to be of 

 such importance to the further development of sedimentation model 

 techniques, and thus to the solution of the problems involved, that 

 plans for a confirmation study should be included as part of each com- 

 prehensive improvement plan that has involved study on a sedimenta- 

 tion model. 



It is apparent that the sedimentation model has certain limitations, 

 imposed primarily by the characteristics of the available model bed 

 materials, the adequacy of prototype data, the distortions inherent in 

 small-scale models used for such purposes, and the uncertainties that 

 still exist regarding the mechanics of sediment movements in both 

 model and prototype systems. These limitations are considered to be 

 far outweighed, however, by the many advantages gained through the 

 relatively inexpensive and positive expedient of model analysis as con- 

 trasted with the prohibitive and tremendous cost, effort, and hazard 

 that would otherwise be involved in achieving similar solutions by trial 

 and error in the field. 



Although they do not embrace the entire field of model research, the 

 four examples cited should be enough to demonstrate the broad capa- 

 bilities of hydraulic models for the practical analysis of complex prob- 



