INTRODUCTION 1 



METHODS AND PROCEDURES 2 



RESULTS 6 



Small Void — Coarse Sand 7 



Large Void — Coarse Sand 9 



Small Void — Fine Sand 9 



Large Void — Fine Sand 13 



DISCUSSION 14 



APPLICATION 16 



CONCLUSIONS 19 



LITERATURE CITED 20 



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 reader. Such use does not constitute an official endorse- 

 ment or approval by the U.S. Department of Agriculture 

 of any product or service to the exclusion of others 

 which may be suitable. 



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