First thermographic survey within the Euganean thermal district (Italy) with an unmanned aerial vehicle

The territory of the Euganean Hills is known worldwide for the occurrence of thermal springs known since ancient times. Currently, local authorities greatly enhance the natural capital of the Hills, including the thermal waters. Despite all this, remote thermal sensing has never been performed before and the present work aims to fill this gap. For this purpose, an UAV survey was conducted in a selected area, accompanied by ground measurements of water temperature and conductivity. The thermographic survey identified known and unknown thermal springs, as well as water leaks from greenhouses and abandoned wells. Since the thermal water is both hot and salty, the UAV system is able to detect the points where salt water is introduced into the fresh water network used for irrigation purposes. Ground controls have made it possible to trace the mixing process between these two types of water, salty (of thermal origin) and fresh (suitable for agriculture) over wider distances and with greater precision. Climate changes and the variable exploitation of water resources cause the continuous change in the balance between salt thermal and fresh water. Therefore, a strong salinization of the water in the surface network can occur as has been documented within the area under examination, also causing severe damage to agriculture. The thermographic survey, accompanied by in situ measurements, proved to be a very effective system for the management of a highly vulnerable territory as observed in the Euganean Hills.