This book describes the general view of seawater intrusion and groundwater problems in coastal aquifer; the Concept of seawater intrusion and saline groundwater, the Seawater intrusion, groundwater and climate change, the Modeling seawater intrusion and groundwater flow pollution, the artificial recharges techniques and the Tunisiäs experience in artificial recharge and the Impact of the coronavirus (covid-19) on the environment and water resources.This book is aimed at students, academics, researchers, engineers and managers who wish to develop an in-depth understanding of various topics relevant to sustainably managing coastal groundwater resources. It discusses a wide variety of topics, including mathematical models, hydrochemistry, groundwater discharge, coastal aquifer management, hydrology and of course climate change and sea level rise. It is assumed that the reader has a basic knowledge of groundwater hydrology. The book is a resource for researchers and engineers working on groundwater-related issues in coastal areas. It serves as an access point to the scientific literature, as it provides ample references to other works to help the reader find additional information.