Available wind and wave data are insufficient to define accurately the 

 characteristics of littoral drift within the study area. Past behavior 

 of the passes between the islands indicates a dominance of southward 

 littoral drift with the net rate of drift being relatively small, par- 

 ticularly in the northern reaches of the study area. Sources of drift 

 material are apparently eroding areas along the Gulf shore and adjacent 

 offshore bottom. 



The major beach changes appear to result from severe storms which 

 occasionally sweep across the Gulf and cause pronounced erosion of the 

 beaches in the study area, the beaches being only partially restored by 

 normal wave action during the periods between storms. Survey infonnation 

 before and after the 19^0 hurricane indicated an average recession result- 

 ing from the storm of about 2$ feet, about 10 feet of which was restored 

 by normal wave action during the next 1 1/2 years. During the 1950 storm 

 the tide reached a level of 5 feet above mean low water. The data indicate 

 that a beach having a 60-foot width above mean high water and maximum ele- 

 vation of 6 feet above mean low water should adequately protect developed 

 property from severe storm damage. The usefulness of groins in the area 

 is probably limited to holding the south end of a fill area near a pass 

 between islands or to preventing erosion of the south end of an island 

 by tidal currents. 



The Division and District Engineer and the Beach Erosion Board con- 

 cluded that the most suitable protective plan consists of providing or 

 restoring, by artificial placement of sand, protective beaches generally 

 60 feet in width above mean high water along portions of the frontage of 

 each of the four islands in the study area, with groins at the southerly 

 ends of the islands. They found that the benefits from prevention of 

 damages, increased value of property, and recreational benefits resulting 

 from the proposed work warrant the adoption of a project for protection 

 and improvement. They recommended that the United States participate in 

 the initial cost of the project to the extent of one-third of the initial 

 cost of protecting the publicly owned portions of the shores of the islands 

 within the limits of the project area, plus the entire cost of protecting 

 the Federally owned frontage on Sand Key, 



The Chief of Engineers concurred generally in the views and recom- 

 mendations of the Beach Erosion Board, 



2.4. 



