How does groundwater depletion contribute to unequal access to the resource among classes of farmers? evidences from case studies in the center of Tunisia

Abstract

Groundwater is considered as common pool resources. Managed under open access, this leads to overexploitation and generating of negative externalities that result in a decrease in water availability and increasing its pumping cost. Very often, the impact of these externalities is analyzed mainly in economic and environmental terms. At our knowledge, the studies concerned with social equity and equity access to resources through farmers' classes is limited in Tunisia. In the center of the country, where surface water is both scarce and random, groundwater is the only source of irrigation. Groundwater has transformed rural economies and therefore they can be considered as an example of success in achieving social welfare and economic growth policy objectives in these regions. However, such rapid growth has lead to serious overexploitation and piezometric level falls at the rate of 1 to 1.5meter per year, threading thus the access to groundwater and the livelihood security for several tens thousands of small farmers. This study was undertaken in this context. Through using an economic optimization model, it seeks to analyze the distribution of the cost of externalities of overexploitation of aquifers and economic access to this resource through categories of farmers. The results show that unsustainable water results in significant economic losses to the farmer level, materialized by additional investments in irrigation, increased pumping costs and reduced income. However, the cost of these externalities is unevenly distributed. Indeed, it is at the level of small farmers that attends higher costs. As a result, this category is rapidly losing access to groundwater, further amplifying the existing inequalities in Tunisian rural society. Since regulatory instruments adopted so far (save areas, prohibition etc.) have shown their limitations, this work suggests the involvement of local users in the management of groundwater to ensure effective control of levies to preserve the groundwater and ensure the fairness of its operations. Significant agricultural policy reform is therefore necessary if we are to prevent further degradation of our groundwater. This study suggests the involvement of local users, with the assistance of CRDA, to ensure effective control on groundwater withdrawal. In addition to this policy, the Government should work to create another economic opportunities, in these regions, in order to alleviate pressure on groundwater resources exclusively caused by the horizontal and vertical extension of irrigated agriculture. Currently this sector constitutes the main source of revenue and jobs for the local population.