Assessment of Groundwater Abstraction for Irrigation Practices Using FAO-CROPWAT Model and GIS: Case Study of Hajeb Layoun-Jelma Basin (Central Tunisia)

The assessment of groundwater abstraction is an important tool to ensure its sustainability and management. This study aims to assess the groundwater abstraction for irrigation during the hydrological year of 2016–2017, using GIS, and to compare it with the water abstraction estimated by the Tunisian water management authority. This land use map allowed us to extract the different irrigated crops and to calculate the irrigation water requirements (IWR). The results showed that the groundwater pumping volume is approximately 34.29 Mm3. This volume is 2.7 times higher than the one published by the Tunisian water management authority, which is equal to 12.7 Mm3. This significant difference (21.59 Mm3) is caused by the increasing number of illegal wells (digging wells without a permit from the water management authorities).