GENESIS: GENERALIZED MODEL FOR SIMULATING SHORELINE CHANGE 

 TECHNICAL REFERENCE 



PART I: INTRODUCTION 



GENESIS 



1. This report documents a numerical modeling system called GENESIS, 

 which is designed to simulate long-term shoreline change at coastal engin- 

 eering projects. The name GENESIS is an acronym that stands for GENEralized 

 Model for Simulating Shoreline Change. The longshore extent of a typical 

 modeled reach can be in the range of 1 to 100 km, and the time frame of a 

 simulation can be in the range of 1 to 100 months. GENESIS contains what is 

 believed to be a reasonable balance between present capabilities to effi- 

 ciently and accurately calculate coastal sediment processes from engineering 

 data and the limitations in both the data and knowledge of sediment transport 

 and beach change. The modeling system and methodology for its use have 

 matured through application to numerous types of projects, yet the framework 

 of the system permits enhancements and capabilities to be added in the future. 



2. GENESIS simulates shoreline change produced by spatial and temporal 

 differences in longshore sand transport. Shoreline movement such as that 

 produced by beach fills and river sediment discharges can also be represented. 

 The main utility of the modeling system lies in simulating the response of the 

 shoreline to structures sited in the nearshore. Shoreline change produced by 

 cross-shore sediment transport as associated with storms and seasonal varia- 

 tions in wave climate cannot be simulated; such cross -shore processes are 

 assumed to average out over a sufficiently long simulation interval or, in the 

 case of a new project, be dominated by rapid changes in shoreline position 

 from a nonequilibrium to an equilibrium configuration. 



3. The modeling system is generalized in that it allows simulation of a 

 wide variety of user-specified offshore wave inputs, initial beach configura- 

 tions, coastal structures, and beach fills by means of an interface, as 

 depicted in Figure 1. To run the system, the user need only become familiar 

 with its capabilities and the rules of operation of the interface; details of 



