BEACH EROSION STUDIES 



Beach erosion control studies of specific localities are usually- 

 made by the Corps of Engineers in cooperation with appropriate agencies 

 of the various States by authority of Section 2 of the River and Harbor 

 Act approved 3 July 1930. By executive ruling the costs of these 

 studies are divided equally between the United States and the coopera- 

 ting agencies. Information concerning the initiation of a cooperative 

 study may be obtained from any District or Division Engineer of the 

 Corps of Engineers. After a report on a cooperative study has been 

 transmitted to Congress, a summary thereof is included in the next 

 issue of this Bulletin. Summaries of reports transmitted to Congress 

 since the last issue of the Bulletin and lists of completed and 

 authorized cooperative studies follow. 



SUMMARIES OF REPORTS TRANSMITTED TO CONGRESS 



GRAND ISLE, LOUISIANA 



Grand Isle, located on the Gulf Coast of Louisiana, has a maximum 

 width of about 3 A mile and length of about 7.5 miles extending in a 

 general northeast to southwest direction between Barataria and Caminada 

 Passes. The island is low with an elevation of 3 to 5 feet above mean 

 low water in the central section and a maximum height of 6 feet at dunes 

 along the shore near the western end. The island is located in 

 Jefferson Parish about 60 miles south of New Orleans and $0 miles north- 

 west of Southwest Pass of the Mississippi River. Grand Isle is used as 

 a summer resort, also for seafood and oil production activities. Its 

 permanent population is 1,190, but it is estimated that more than 3,000 

 people visit the beach during summer week ends. Although not highly 

 developed at present, it is increasing in popularity for recreational 

 use. The entire shore is privately owned. 



Tides in the area are semi-diurnal, the mean range being 1.1 feet 

 and the spring range 1.7 feet. In 19^7 the tide reached a height of 

 3.h feet above high water. The Gulf shore of the island is exposed to 

 waves from the southeast, south and southwest. As Southwest Pass 

 limits the fetch to the east and southeast, waves approaching the shore 

 are more likely to have a component tending to cause eastward littoral 

 drift. Predominant drift in that direction is indicated by accretion 

 west of existing groins and erosion of the shore east thereof. 



The Gulf shore of Grand Isle has had a history of intermittent 

 erosion and accretion. In earlier years there was erosion on the west- 

 ern half and accretion on the eastern half of the island. In recent 

 years accretion has occurred at the western end and erosion on the 

 central and eastern sections. In 19£l-5>2 the State built four groins 

 near the western end and ten near the middle of the island for protection 

 of the highway. These structures have caused accretion at the west end 



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