Although simplistic in nature, the beach-fill models must be used in 

 the practical environment of real and unique engineering problems. Some 

 of these problems are: Should a fill factor apply to all of the fill 

 placed? Which sedimentary data should be selected to compute a specific 

 composite? Would the placement of fill on different parts of a beach 

 require different fill factor calculations to assure project specifications? 

 How should a borrow site composite distribution be modified to reflect the 

 effects of different kinds of equipment and techniques? Each of these 

 questions is project specific, but the compilation of information regarding 

 actual decisions made and the performance of completed projects will even- 

 tually provide the kinds of data needed to establish guidelines for future 

 projects. 



Economic considerations for a project must, in part, reflect practical 

 aspects such as the equipment available for use, or practices of local con- 

 tractors. Project expenses should also be based on the engineer's decisions 

 to use solutions that seem most suited to a problem. For example, a volume 

 of fill sediments could be determined by the size of the "hole" dredged, 

 the number of barges hauled, or perhaps the amount of sediment actually 

 ending up on an active beach as determined by prefill and postfill surveys. 

 Payment should be made for that volume estimate which best reflects the 

 original calculations or models used to set up the project. In a situation 

 where periodic renourishment is appropriate, renourishment factors calcu- 

 lated for several potential fill materials should be used to select the 

 cheapest material for the life of the project. Perhaps, a standard for 

 fill should be used to assure, through rigorous sampling during placement, 

 that the materials paid for were of the expected quality. The point made 

 here is that many aspects of the topics discussed can be used to help 

 define and control expenses. 



Many of these comments suggest that the models and methods discussed 

 can serve the engineer as tools to help solve beach-fill problems as well 

 as provide the criteria to evaluate the progress and success of a project. 

 This second appraisal capacity can give the engineer additional control 

 over a project. For example, he can be more active in specifying how and 

 what sample data should be collected, the best placement method to be used 

 for a specific fill, and how payment for a fill should be determined. All 

 of these aspects place more responsibility for a project on the engineer. 

 This is probably reasonable, but if he is more responsible, he should 

 include in his designs the collection of enough information to adequately 

 monitor the performance of each project. Thus, the final recommendation 

 is that long-term monitoring should be one aspect of all beach-fill pro- 

 jects, and that data obtained from such monitoring will improve existing 

 beach-fill schemes and also provide the basis for predicting the success 

 of future works. 



VI. SUMMARY AND RECOMMENDATIONS 



1. Two beach-fill models are recommended. 



a. The adjusted SPM method (R^) enables calculation of a fill 

 factor to determine how much overage may be required when the textures of 

 borrow and native beach sediments are dissimilar. 



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