Tackling Heterogeneity in Groundwater Numerical Modeling: A Comparison of Linear and Inverse Geostatistical Approaches— Example of a Volcanic Aquifer in the East African Rift
Sustainable management of groundwater involves decision making, to achieve goals, under certain constraints. The East African Rift is an active continental rift zone. The volcanic aquifer system is located in Ethiopia. The category of geostatistical models has considerably expanded in hydrogeology. This chapter focuses on two geostatistical methods, for developing forward modeling (kriging) and inverse modeling (pilot points). Inverse modeling has the ability to automatically determine hydraulic parameter values that give the best match between observed and simulated hydraulic heads. The tool to understanding the system and its behavior and to predict its response is modeling. Efficient numerical modeling may constitute a valuable mean to tackle and solve this issue. An important and unavoidable issue in modeling consists of taking into account in numerical models meant to represent real systems, the natural heterogeneity of these underground systems. When dealing with highly heterogeneous media, the nonautomated trial and error approach turns very quickly quite tedious, time-consuming, and approximate.