FREQUENCY OF COASTAL FLOODING AT ROUGHANS POINT, BROAD SOUND, 

 LYNN HARBOR, AND THE SAUGUS-PINES RIVER SYSTEM 



PART I: INTRODUCTION 



1. The study area was located in the cities of Revere, Lynn, and 

 Saugus, Massachusetts, which are immediately north of Boston. Roughans Point 

 (Figure 1 ) is a 55-acre* residential area which is below the elevation of a 

 spring tide at many locations. Seawalls along both the northern and eastern 

 boundaries offer some protection against coastal flooding. However, damage 

 resulting from flooding caused when waves overtop the seawalls is a frequent 

 occurrence. The Saugus and Pines Rivers join just before passing under the 

 General Edwards Bridge and out into Broad Sound. The lower 2,500 acres of the 

 drainage area just behind Revere Beach are mostly river channel and marsh. 

 This area borders residential, commercial, and industrial areas, many of which 

 are at an elevation only a few feet greater than the elevation of the maximum 

 astronomical tide. Flooding is caused by the inundation of low lying areas by 

 the combination of astronomical tide and storm surge. The Revere Beach-Point 

 of Pines-Lynn Harbor region is made up of recreational beaches, residential 

 and industrial land protected by seawalls, and harbor areas. Flooding results 

 from overtopping of seawalls and dunes by storm waves. Figure 2 is a map of 

 the study area vicinity showing the above locations. 



2. The desired products of this project are stage-frequency curves 

 which relate the elevation of floodwaters to the average waiting time between 

 floods of equal or greater severity. The ordinate of these curves is stage, 

 measured in feet above the National Geodetic Vertical Datum (NGVD), and the 

 abscissa is return period expressed in years. The primary goal of this study 

 initially was to provide flood frequencies at Roughans Point where flooding is 

 caused by the overtopping of seawalls by storm waves. The numerical model 

 efforts needed to predict waves and water levels at Roughans Point could also 

 predict these quantities at nearby locations. Therefore, the scope of the 

 project was expanded to provide flood frequencies for the Saugus-Pines River 



* A table of factors for converting non-SI units of measurement to SI 

 (metric) units is presented on page 3. 



