Sustainability of irrigated agriculture with overexploited aquifers: The case of Segura basin (SE, Spain)

The structural water deficit suffered by the Segura basin in southern Spain trend toward unsustainability. The imbalance between the resources and the demand has been caused by the expansion of irrigated areas, the emergence of illegal new irrigated lands and pumping wells, the increase in energy cost and the bad management of water use rights by the public water administration. In addition, climate change and frequent drought in this semi-arid region aggravate the situation. As a consequence, many aquifers are overexploited. The region of Murcia has well-developed agri-food sector, which is a key factor in the regional economy. This sector accounts for 21.4% of the regional GDP, and Murcia also has an important tourism sector, so the overexploitation of the aquifers would concern production, exportation and agricultural development as well as the decline in the water level, environmental damage and water quality impairment. On the other hand, the fulfilment of the “good ecological status” objectives set by the Water Framework Directive, with a deadline of 2027, will be a difficult task for water managers. This study proposed a hydroeconomic model to obtain the cost of the overexploited aquifers in the Segura basin in order to decide on the feasibility of using groundwater for agriculture in situations of overexploitation. The results showed that the price paid by farmers for irrigation water in the year 2027 would be 0.53 €/m3 (i.e., annual spending of 180M€), which will involve 10% of the final agricultural crop production in the Region of Murcia. Alternative water sources are proposed to increase water supply security for farmers and to ensure the socio-economic and environmental sustainability of the basin. Finally, the methodology proposed would help to manage water use in other European Mediterranean basins under similar climatic, hydrological and agricultural conditions.