Aspectos económicos y sociales de la desalación de acuíferos continentales a pequeña escala en el se de España (Murcia & Alicante) y Siggiewi, Malta

Resumen

The growing global demand for water, and as a consequence, the reliability of supply of resources, is a global priority, especially in areas with semi-arid climates, such as the Campo de Cartagena area, San Vicente del Raspeig, Alicante (SE , Spain) and Siggiewi, Malta. In order to cope with the growing scarcity of water, desalination (of seawater or brackish aquifers) has emerged as a feasible option to increase the availability of water resources. This technology has become more accessible in many regions of the world, this fact has led to many saline / brackish continental aquifers throughout the Mediterranean coast are currently exploited. The agricultural and urban sector has developed small groundwater desalination plants to guarantee the availability of water, often leaving aside a correct economic evaluation. Information on the cost of desalinated water is limited; Its final cost is very variable and seems to be quite site-specific. Conventional methods of economic analysis of projects, such as cost-benefit analysis (CBA), are currently applied to compare the economic viability associated with the implementation of different project proposals and other environmental and social costs (for example, use for irrigation of gardens), which are generally not taken into account. The CBA and the application of other techniques such as the willingness to pay (WTP) and the contingent valuation method (CVM) have been applied in study areas to carry out an ex-ante and ex-post evaluation of small desalination plants for both agricultural use as urban. In the Campo de Cartagena and Siggiewi, Malta an CBA was carried out for different desalination plants that irrigated citrus crops and vineyards. Within the CBA, the Net Present Value (NPV), the Internal Rate of Return (IRR), cost / benefit ratio and a sensitivity analysis were applied to see the profitability of the projects. The results for the Campo de Cartagena area indicate that, for the cases studied, the current agricultural management is feasible and the costs do not exceed the benefits, with a positive NPV and a cost / benefit ratio greater than 1. The internal rate of return is also positive and higher than 11%. The results show practical and theoretical implications on how to increase water resources in areas where water is scarce, ensuring profitability for farmers and encouraging private sector investments. For Siggiewi, Malta, two irrigation scenarios were evaluated, the current form of irrigation "do-nothing", compared to the "non-conventional water use" of the water mix from a small desalination plant and groundwater. The results indicate a profitable project starting from a minimum area of ¿¿1ha of vineyard crops. For San Vicente del Raspeig, the benefits obtained by the existing green areas, a park and a lagoon were taken into account, where the willingness of citizens to pay (WTP) for their preservation based on the contingent valuation method (CVM) was taken into account. . The results indicated that the final cost of the desalinated water was 0.29 € / m3 and, according to the results of the DAP, the value derived from the social benefits provided by the leisure area was 0.51 € / m3, the cost being end of the water 0.22 € / m3. Consequently, the use of brackish water for irrigation has a high social value that should be considered when evaluating projects related to desalination.