STORM SURGE ON THE OPEN COAST: FUNDAMENTALS 

 AND SIMPLIFIED PREDICTION 



by 



B. R. BODINE 



Section I. INTRODUCTION 



-Goastal engineers concerned with design problems frequently are 

 required to estimate the storm surge - the rise of water levels on the 

 open coast caused by high winds acting over the Continental Shelf; On 

 the East and Gulf coasts of the United States the most significant rise 

 at the shore is generally associated with the fully developed hurricanes. 

 Here we shall be concerned principally with those hurricanes, although 

 any lesser storm is equally applicable, and surge can readily be estimated 

 by the same methods. The total rise at the shore is dependent on the 

 interactions of the meteorological storm with the sea and the state of 

 the sea during the passage of the storm. Estimating the response of the 

 sea from forces induced by the moving hurricane is complex; practical 

 results are only obtained by accepting approximations . Several open- 

 coast, storm-surge prediction schemes have evolved, particularly in the 

 past three decades, based on various approaches, such as empirical re- 

 lations, method of characteristics, statistical and numerical schemes. 

 Quantitative agreement between any of the methods and observations is not 

 yet completely satisfactory from the standpoint of coastal engineering 

 design. In the past decade, numerical schemes have generally been used 

 exclusively for predicting storm surge. 



High-speed data processing has brought more sophisticated numerical 

 methods to the forefront in many scientific fields. Such methods yield a 

 solution for the more complete and more complex non- linear partial differ- 

 ential equations appropriate to the particular problem. Such techniques 

 have accelerated the study of long-wave motion, and in particular tidal 

 computations. Various schemes, using the method of finite differences, 

 have evolved for resolving the governing hydrodynamic equations in two- 

 dimensions and some in quasi-three dimensions. The open-coast surge 

 problem has been treated among others by Miyazaki (1963) , Leendertse 

 (1967), and Jelesnianski (1966, 1967, and 1970). On a smaller scale, 

 Platzman (1958) has used such a method to compute the surge on Lake 

 Michigan resulting from a moving pressure front, and Reid and Bodine 

 (1968) have treated the hurricane-surge problem in Galveston Bay. Such 

 methods describe the storm generation processes in a much more satisfac- 

 tory manner than those more frequently used by coastal engineers. Such 

 numerical schemes are mentioned here to emphasize their importance, and 

 it is anticipated that in the near future they will replace the less 

 descriptive schemes such as the one which will be discussed here. 



The numerical method covered here is based on the theory developed by 

 Freeman, Baer and Jung (1957) which was referred to as the Bathystrophic 



