METHODS TO REDUCE WAVE RUNUP AND OVERTOPPING 

 OF EXISTING STRUCTURES 



PART I: INTRODUCTION 



1. Repair, Evaluation, Maintenance, and Rehabilitation (REMR) field 

 visits conducted by the Wave Research Branch have yielded an enormous amount 

 of information about the status of US Army Corps of Engineers (Corps) coastal 

 structures. Summarizing this information into a coherent account requires a 

 series of nine case history reports, one for each Corps division having ocean 

 or Great Lakes coastline. This effort has identified approximately four 

 hundred structures as having problems of varying type and severity caused by 

 wave action. Over 20 percent of the structures have problems caused by wave 

 runup and overtopping. 



2. These problems can be divided roughly into three general problem 

 areas: 



a. Wave runup and overtopping of breakwaters and sometimes jetties 

 generating excessive wave action on the lee side. Generally, 

 this problem is compounded by additional wave transmission 

 through rubble mounds. 



b. Wave runup and overtopping of seawalls, bulkheads, and sea dikes 

 causing flooding and/or erosion on the backside. 



c. Wave runup and overtopping of revetments causing backside sub- 

 sidence, erosion, and sometimes collapse of the revetment. On 

 reservoirs overtopping of a revetment may cause damage to the 

 upstream dam face or to an embankment . 



3. There is no single comprehensive source of information evaluating 

 methods to calculate wave runup or effectiveness of various strategies to 

 reduce runup and overtopping. The most definitive single reference on runup 

 (Battjes 1974) was prepared for the Technical Advisory Committee on Protection 

 Against Inundation of the Dutch Government. Allsop, Franco, and Hawkes (1985) 

 provide an excellent literature review on wave runup and steep slopes. Some 

 methods used to reduce wave overtopping of seawalls in Japan are discussed by 

 Goda (1985). Douglass (1986) compares four relatively common methods to cal- 

 culate irregular wave overtopping rates. References given above, along with 

 the Shore Protection Manual (SPM) (1984), provide a broad background of infor- 

 mation on how to compute wave runup and overtopping. 



