Simulation and optimization of seawater intrusion in coastal aquifers due to climate change and sea level rise

Seawater intrusion, also synonymously referred to in some literature, as saltwater intrusion has become an increasingly dominant constraint on utilization of groundwater in coastal aquifers.; Climate change is a natural factor that has been identified to have serious impacts on the hydrologic regime and water resources. When coupled with extensive freshwater withdrawal through pumping, climate change could pose serious threats to coastal freshwater resources.; The research presented in this dissertation has three basic components; climate change impacts scenario generation, sea level rise sensitive variable density groundwater flow simulation, evolutionary algorithm based groundwater flow optimization for optimal management of coastal aquifers. The climate change scenario generation module was developed using the spatial modeling capabilities of raster based geographical information system (GIS). The module specifically models sea level rise and generates new sea level, shoreline translation and impact maps.; The variable density groundwater flow simulation module simulates the influence of sea level rise in altering the groundwater flow regime. A scenario of climate change was selected and applied. Extensive sensitivity analyses were performed to test the significance of various parameters.; The optimization model is based on the concept of genetic algorithms. The use of evolutionary algorithms to solve optimization problems in water resources is a fairly recent approach. The capability of evolutionary algorithms to handle non-linear problems has instigated interest in the application of these algorithms in the solution of simulation-optimization problems.; The research methodology followed a systematic approach that involved climate change impacts investigation, freshwater-saltwater flow simulation, and optimization of freshwater withdrawal subject to the various constraints considered. A three-dimensional variable density groundwater flow model and a cross-sectional model were developed to simulate seawater intrusion.; The primary objective of the research is to provide an integrated approach to the investigation of seawater intrusion in coastal aquifers and to develop a better understanding of the processes involved. The results obtained from the test cases considered clearly demonstrated the significance of sea level rise as a factor to be considered in the development of a management strategy for coastal aquifers.