IRREGULAR WAVE OVERTOPPING OF SEAWALL/REVETMENT CONFIGURATIONS, 

 ROUGHANS POINT, MASSACHUSETTS 



Experimental Model Investigation 



PART I: INTRODUCTION 



Background 

 1 . This report discusses laboratory model tests of irregular wave over- 

 topping for seawall and revetment configurations being considered for use at 

 Roughans Point, Massachusetts (Figure 1). The tests were initiated by US Army 

 Engineer Division, New England (NED), because of a lack of confidence in their 

 wave overtopping estimates made by using the Shore Protection Manual (SPM) 

 (1984). Roughans Point is a 55-acre* residential area which is partially pro- 

 tected from coastal flooding by seawalls on both its northern and eastern 

 boundaries. The Roughans Point interior suffers damage from frequent flooding 

 caused by the overtopping of seawalls. Laboratory tests discussed in this re- 

 port were part of a more comprehensive study which included extensive use of 

 computer models to calculate the frequency of occurrence of flood water levels 

 for the interior of Roughans Point, along the open coast to the north, and for 

 estuarine areas along the Saugus-Pines River system. The physical model tests 

 provided wave overtopping coefficients only for the various seawall/revetment 

 configurations used in the numerical flood routing model for the interior of 

 Roughans Point. Water level calculations for the coastline north of Roughans 

 Point and the estuarine areas did not include consideration of wave over- 

 topping. For further information about the computer models and the organi- 

 zation of the entire study see Hardy and Crawford (in preparation). The model 

 tests described in this report were conducted primarily to develop methods to 

 reduce wave overtopping of the eastern seawall (Figure 2, Reach E), to deter- 

 mine objective criteria for judging the effectiveness of the methods to reduce 

 overtopping, and to provide wave overtopping coefficients to the numerical 

 flood routing model. 



A table of factors for converting non-SI to SI (metric) units is presented 

 on page 3. 



