Geophysical techniques involve the use of ground-based and airborne geophysical devices to measure physical properties of the earth. They can assist in the planning and management of irrigation developments by identifying the size and depth of aquifers, the connectivity between surface and ground water, the salinity of aquifers, the mineral composition and depth of the soil and the chances of successful water boring. Most geophysics applied to irrigation is in the form of imaging conducted by moving various devices over the ground, or by insertion and monitoring of sensors within the ground. This book provides an introduction to various geophysical techniques for water managers, including irrigators, engineers and staff of water and catchment authorities and all those involved in various aspects of the irrigation industry from design through to implementation and monitoring.