Groundwater development has shown phenomenal progress during past few decades. There has been vast improvement in the perception, outlook and significance of groundwater resource. The unplanned groundwater development may result in fall of water levels, failure of wells, and salinity ingress in coastal areas. The development and over-exploitation of groundwater resources in many parts of the world have raised the concern and need for judicious and scientific resource management and conservation. This book "Groundwater Assessment and Modelling" is intended to provide a comprehensive treatise on assessment and modelling of groundwater. It presents the related aspects on assessment of groundwater potential, groundwater data requirement and analysis, basic concepts and guidelines for groundwater modelling, groundwater modelling software, modelling of unsaturated flow, modelling of sea water intrusion, and impact of climate change on groundwater resources. The book is expected to be quite useful for undergraduate and postgraduate students (water resources engineering), field engineers and researchers working in the area of assessment, development and management of groundwater resources.