Incorporating Non-market Benefits of Reclaimed Water into Cost-Benefit Analysis: A Case Study of Irrigated Mandarin Crops in southern Spain

Maintaining a river system's minimum water flow is a pre-condition for achieving the "good ecological status" prescribed by the European Water Framework Directive (WFD). In areas of water scarcity the reuse of treated water for agricultural irrigation is seen as a promising option to reduce the quantitative pressure on the resource. As part of assessing the viability of reclaimed water use in agriculture, and in accordance with the economic principles underpinning the WFD, a comprehensive economic analysis of this irrigation option is needed. This paper contributes to fill this knowledge gap by producing a cost-benefit analysis (CBA) of the use of reclaimed water in agriculture. The costs and benefits of reclaimed water use on an experimental mandarin farm in the south-east of Spain are compared with those of using surface water and a mixture of water sources. The novelty of this study is that non-market benefits are incorporated in the CBA. We thereby account for the increase in welfare that the environmental services of this supply option provide to society at large. These kind of "intangible" benefits are often ignored, but only the combination of market and non-market costs and benefits can produce a balanced assessment of water management options and lead to an efficient and sustainable allocation of the resource. Our results suggest that at the private and social level, when environmental benefits are included, the use of a mixture of water sources, including reclaimed water, seems the best option. However, at low mandarin prices (lower than 0.23 a,not sign/kg) the exclusive use of reclaimed water seems the most beneficial option.