A GIS-based Methodology for Groundwater Potential Recharge Assessment in Sicily (Italy) through Multi Criteria Approach

Abstract

Groundwater resources plays a key role in supporting human well-being, agricultural productivity, and ecological balance. Worldwide, groundwater resource represents a primary source of water supply for drinking purpose, irrigation and for supporting a variety of aquatic ecosystems, including wetlands, springs, and riparian zones. Sicily Island (Italy) relies heavily on groundwater resources, providing drinking water in different cities and water for the main island's agriculturally productive areas. In a context where climate change is expected to affect precipitation patterns and groundwater recharge rates, evaluating potential groundwater recharge areas represents an important issue for sustainable water management and for planning a proper protection of groundwater resources. For the above-mentioned reasons, we propose here a Multi-Criteria Approach (MCA) to assess potential groundwater recharge. The methodology is here implemented through geographic information system (GIS) and uses a large dataset of information for the whole Sicily Island, consisting in spatial distributed data on rainfall, evapotranspiration, aridity index, lithological characteristics of the exposed terrains, density of thrust faults and rock fractures, stream density, land uses and slope.  All the factors are firstly normalized and then used in the MCA for evaluating potential groundwater recharge areas of the entire Sicily Island through the use of different groundwater recharge rates. Results are then validated against a large dataset of wells and boreholes information for the entire region.