CASE HISTORIES OF CORPS BREAKWATER AND JETTY STRUCTURES 

 LOWER MISSISSIPPI VALLEY DIVISION 



PART I: INTRODUCTION 



Background 



1. The US Army Corps of Engineers (Corps) is responsible for a wide 

 variety of coastal structures located on the Atlantic, Pacific, and gulf 

 coasts, the Great Lakes, the Hawaiian Islands, other islands, and inland 

 waterways. Coastal improvements such as breakwaters or Jetties are necessary 

 to provide harbor protection and the safe passage of vessels. These structures 

 are subjected continuously to wave and current forces and usually are con- 

 structed on top of movable-bed materials. Under these conditions structural 

 deterioration may occur and, at some point, maintenance, repair, or rehabil- 

 itation may be required when the structure deteriorates and/or fails to serve 

 the existing needs of the project. Some projects have been maintained for 



150 years or more. Methods of construction and repair have varied signi- 

 ficantly during this time, due principally to a better understanding of 

 coastal processes, availability of construction materials, existing wave 

 climates, regional construction practices, and economic considerations. 



Purpose 



2. The purposes of this report are to provide insight into the scope, 

 magnitude, and history of coastal breakwaters and jetties under Corps Juris- 

 diction; to determine their maintenance and repair history; to determine their 

 methods of construction; and to make this information available to Corps 

 personnel. To accomplish these objectives, case histories of Corps breakwater 

 and Jetty structures have been developed to quantify past and present problem 

 areas (if any), to take steps to rectify these problems, and to subsequently 

 evaluate the remedial measures. General design guidance can be obtained from 

 the solutions that have been most successful during selection of repair tech- 

 niques for other structures. Information in this report should be of parti- 

 cular value to Corps personnel in the US Army Lower Mississippi Valley 

 Division (LMVD) and its coastal districts, and possibly to non-Corps 



