Remote Sensing-Based Model for Estimating Groundwater Pumping: Case Study of Irrigated Perimeter of the Medjerda Lower Valley, Tunisia

The estimation of groundwater exploitation in arid and semi-arid countries such as Tunisia remains a challenging issue. In the Medjerda lower basin, water resources are overexploited due to Climate Change, anthropogenic pressures, and the intensification of irrigated areas. To address this, estimating spatially distributed crop water consumption is crucial for promoting efficient water management. This study aims to estimate volumes of groundwater pumping for irrigation in a citrus orchard area of the Medjerda Lower Valley basin using earth observation data as input of the SAtellite Monitoring of Irrigation (SAMIR) model based on the FAO-56 dual crop coefficient water balance model. The SAMIR model's simulated irrigation volumes were compared with the actual volumes of water that were supplied by farmers. The results showed significant difference between the simulated required volumes of
$\boldsymbol{1252074 \ \mathrm{m}^{3}}$
and the declared amount of
$663 \ 882 \ \mathrm{m}^{3}$
, indicating an estimated groundwater irrigation pumping of about
$239 \ 813 \ \mathrm{m}^{3}/\text{year}$
. These findings confirm the feasibility of earth observation data for estimating irrigation groundwater pumping in water-scarce areas, and that they can be useful for decision-makers.