Social and private costs of water for irrigation: The small desalination plant in San Vicente del Raspeig, Spain

Among non-conventional water resources, desalination (from seawater or brackish aquifers) has emerged as a feasible option to deal with water shortage in arid and semi-arid areas. At the University of Alicante (UA, SE Spain), water availability is lacking and groundwater quality is poor. To ensure water availability, the UA built a small reverse osmose (RO) desalination plant (450 m3/day) to water the green areas and an urban park on the campus. The costs of a small private desalination plant, landscape irrigation, and the full cost of water, were assessed. This assessment considered the benefits made by new green areas existing in an urban space and citizens' willingness to pay (WTP) for its preservation based on the contingent valuation method (CVM). The results indicated that the final desalinated brackish water cost was 0.29 €/m3 and, according to the WTP results, the value that derived from the social benefits provided by the leisure area was 0.51 €/m3, being the final cost of water 0.22 €/m3. Consequently, the use of brackish water for irrigation has a high social value that should be considered when evaluating desalination-related projects.