CASE HISTORIES OF CORPS BREAKWATER AMD JETTY STRUCTURES 

 NORTH PACIFIC 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, Hawaiian Islands, other islands, and inland water- 

 ways. Coastal improvements such as Jetties or breakwaters are frequently 

 required to provide a safe harbor or navigation. These structures are con- 

 tinuously subjected to wave and current forces and are usually constructed on 

 top of movable-bed materials. Under these conditions, structural deteriora- 

 tion may occur to the point where maintenance, repair, or rehabilitation is 

 required for the structure to continue to meet the needs of the project. Some 

 of the projects have been maintained for over 150 years. Methods of repair 

 and construction have varied significantly during this time, due principally 

 to a better understanding of coastal processes, availability of construction 

 materials, regional construction practices, and economic considerations. 



Purpose 



2. The purpose of this report is to lend insight into the scope, 

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

 diction; determine their maintenance and repair history; determine their 

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

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

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

 areas, to take steps to rectify these problems, and to subsequently evaluate 

 remedial measures. General design guidance can be obtained from those 

 solutions that have been most successful. Information in this report should 

 be of particular value to Corps personnel in the US Army Engineer Division, 

 North Pacific (NPD), and its coastal districts and possibly to non-Corps 

 personnel. 



