the combinations were evident at the lower return periods with the combina- 

 tions of a wide berm revetment and a cap on the existing seawall for the east 

 wall of Roughans Point providing the greatest protection. At higher return 

 periods the protection differential offered by the various structure combina- 

 tions tends to diminish. For still-water levels and wave conditions of an 

 SPN, all structure combinations tested would be ineffective at protecting the 

 interior of Roughans Point. Tests were run to determine a structure height 

 for the north wall. These tests indicated that significant overtopping did 

 not begin until the north wall structure was lowered below 13 ft. Since the 

 existing height of the north wall is above this level at several sections, it 

 is recommended that the revetment height be set at 13 ft with the wall height 

 being set so that there is a transition between the existing wall heights. 

 The only height that would be raised would be that of wall D, which would be 

 raised to match wall C. 



120. For areas where flooding is due to coastal inundation by the 

 still-water level resulting from the combination of storm surge and astronom- 

 ical tide, only the storm surge and probability models were necessary. These 

 areas include both open coast and estuarine locations. For these areas 

 flooded by the still-water level, the results of the modeling indicated that 

 the whole study area floods to approximately the same level. The flood levels 

 are efficiently conveyed through the inlet and throughout the flood plain of 

 the Saugus-Pines River system. Inside the inlet there is a small gradient in 

 the still-water level, rising from north to south, which results from local 

 wind setup caused by north to northeast winds which predominate during storm 

 conditions. This local wind setup results in flood levels inside the inlet 

 which vary by one-half to three-fourths of a foot during the more severe storm 

 events. Outside the river system in Broad Sound a smaller north-south gra- 

 dient exists with differences of only a few tenths of a foot resulting. Data 

 collected after completion of the modeling indicated that losses do occur as 

 the flood levels are conveyed upstream of the Fox Hill Drawbridge on the 

 Saugus River and upstream of the Highway embankment on the Pines River. 

 Stage-frequency curves for these areas were adjusted to accommodate these 

 additional data. The curves were lowered 0.3 and 0.5 ft at the lower return 

 periods for upstream Saugus River and Pines river locations, respectively. 

 These reductions were linearly reduced for higher return periods because 

 higher flood levels would provide greater access to these areas. 



93 



