Laboratory analysis of countermeasures against saltwater intrusion

In coastal areas, aquifers are subject to a natural process called saltwater intrusion. This phenomenon concerns the landward movement of salt water inside freshwater aquifers with a movement dictated by the highest density of saltwater. Salt water is considered one of the major pollutants of underground aquifers because, in addition to not being drinkable, if extracted for agricultural purposes can ruin the harvest and the soil. The previous one is a widespread problem all over the world, starting from the Mediterranean coasts, both East and West coasts in the U.S., Gulf of Mexico and Middle East coasts. The seriousness of the situation has worsened in the summer, when, given the scarcity of rain and fresh water recharge also due to climate change, the salt intrusion proceeds for many kilometers inland. In order to have a faithful representation in the laboratory within a channel three different porous media were interspersed obtaining a composition as heterogeneous as possible to simulate the phenomenon that naturally happens in nature. Starting from data previously processed by numerical experiments, the hydraulic conductivity of the medium was extrapolated and the analysis concentrated on the representation of dry periods interspersed with periods of usual recharge in order to study the behavior of intrusion into time. This work aims to provide a better understanding of the salt water intrusion process characteristics in heterogeneous formations and provides a basic evaluation of feasible control measures according to a laboratory analysis; moreover, the results discussed in this thesis will constitute a basis for future laboratory experimental analysis and successive on field studies of countermeasures related to salt water intrusion in porous heterogeneous media.