POST-PRINT VERSION AbstractThe hypothesis of a rebound effect as a consequence of water saving investments is taken analogically from the Jevons paradox models in energy economics. The European Commission (EC) alert about the consequences in water stressed regions that are investing heavily in modernization of irrigation networks and systems. This paper reviews the literature, linking water savings with water diversion and water depletion, both from theoretical models and empirical evidence from the published research. In order to increase knowledge of this phenomenon, a new empirical case study is presented based on a survey of 36,000 ha of recently modernized irrigated areas in the Guadalquivir basin (southern Spain). The results of the case study illustrates the conditions that may avoid rebound effect, although the results of the available empirical evidence and the published theoretical research are diverse and lead to contradictory results. Further research is therefore needed to determine the causes and solutions of water saving investment impacts and the possible speculative rebound effect.Keywords: Water conservation; Jevons paradox; Rebound effect; Water pricing; Water use; Water consumption; Spain Highlights The present study analyzes the theoretical and empirical evidence that water saving investments may lead to increased water use and/or consumption. Some authors suggest that if irrigated land expansion is not constrained, increased water abstractions are likely to occur. When land expansion is constrained and water rights are controlled, water depletion does not increase. The results of published research are diverse and have yielded contradictory results regarding the rebound effect as a consequence of water saving investments.

Abstract:In recent decades, the use of economic instruments has been promoted as a way to improve water demand management, required due to the difficulty of further supply increases. Against this backdrop, this paper analyses the potential of water banks as a type of water market that can provide institutional flexibility in the allocation of water resources among different users. Research has involved an extensive review of the literature, which has allowed us to identify different types of water banks that operate around the world, as well as an analysis of the experiences of water banks implemented to date, in order to assess the performance of this economic instrument in improving water management. This has provided evidence that water banks, if properly implemented, can be a useful tool for improving governance of water resources. Finally, the analysis has enabled us to propose a number of guidelines on how to improve the implementation of water banks in different countries around the world.

No abstract

The present study analyzes the empirical evidence of impacts of water saving investments (irrigation modernization) in Spain in the period 1995-2015 resuting in XXX milllion ha modernized with a public subsidy around 50% and an average cost of 6000 EUR/ha. The negative effect of the measure have been an increase of energy consumptio and the water cost. The positive effects have been: increase in productivity of land, labour and water, generallized volumetric billing, substitution of commodity for high value crops, improved working conditions, improved water quality as return flows decrease chemical and salt exported trough retun flows and increased water supply guarantee. Consumption rebound effect has been hetereogeneous as the result of three factors: ex-post limitation to irrigated area expansion, ex.post water allocation cutback and ex-ante existence of deficit irrigation. Finally the positive effects mentioned seems to pay off the invetsment with negative outcome of increased energy and the obligation to maintain an strict policy controlling irrigated are expansion and reducing water rights to avoid a possible rebound effect.

This paper proposes a methodology to compute a cost recovery ratio directly from the System of Environmental-Economic Accounting for Water (SEEA-Water) standard tables. The methodology is applied to the Guadalquivir River Basin in southern Spain. Results illustrate that it allows cost recovery analysis in line with Water Framework Directive Article 9. Wider adoption of the methodology would enhance comparability and knowledge sharing between regions, countries and sectors both in the European Union and worldwide.

This paper develops a general preference model to explain farmers' decisions. Contrary to better known and most commonly used simulation models, the one presented in this paper allows to calibrate, simulate and explain farmers' decisions without assuming linear preferences (as in many multi criteria decision models) or unobservable implicit cost functions (as in positive mathematical programming models). The model is calibrated for crop decisions in the Genil Cabra irrigated area in the Guadalquivir valley (South Spain) as the resulting empirical model is used to study how farmers react by adjusting these decisions when efficiency in the use of water is improved under different scenarios regarding water use rights. The main conclusion of the paper is that the potential water savings from enhancing irrigation technique (636 m 3 ha -1 ) are overcome by increasing water demand due to higher per drop water productivity when sunflower is replaced by maize. For that reason water price increases and/or reduction of water use rights is a necessary condition to convert water savings through improved efficiency into lower water use and better conserved water sources.Additional key words: agricultural policy; mathematical programming; water demand for irrigation. ResumenEvaluación de la mejora de la eficiencia del regadío utilizando un modelo de revelación de preferencias El artículo presenta un modelo de revelación de preferencias que permite explicar las decisiones de cultivo de los regantes. Al contrario de los modelos de simulación más conocidos y utilizados, el que se presenta en este trabajo no exige asumir preferencias lineales (como en el caso de las técnicas multicriterio) ni acude a funciones inobservables de costes implícitos (como en los modelos de programación matemática positiva). El modelo propuesto se calibra para la comarca agraria del Genil Cabra en el valle del Guadalquivir (sur de España) y el modelo empírico resultante se utiliza para estudiar las reacciones de los agricultores a las mejoras en la técnica de riego bajo distintos contextos de derechos de propiedad. La principal conclusión del trabajo es que los ahorros potenciales de agua que se consiguen con la mejora técnica del sistema de riego (636 m 3 ha -1 ) son compensados por los aumentos de la demanda derivados de la mayor productividad del agua cuando el girasol es sustituido por maíz. Por este motivo, para conseguir una reducción efectiva del uso del agua y, por tanto, una mejora en las fuentes del recurso, es necesario aumentar los precios y/o reducir la cantidad de derechos de propiedad.Palabras clave adicionales: demanda de agua

This article proposes a new mathematical programming model for the simulation of farmers' decision-making. We have developed a model based on a multi-attribute utility approach that takes into consideration the most relevant attributes of farmers within a positive framework.This approach overcomes the limitations found in some mathematical models used in the literature to simulate farmers' behavior. A five-step procedure is presented in order to elicit the utility function that reproduces farmers' current decision-making. We illustrate this positive multi-attribute approach using a sample of farmers in an irrigated area in southern Spain, where our simulations demonstrate the accurateness of the model in reproducing actual farmers' decision-making. We also find evidence that the model is able to explain the heterogeneous behavior of farmers within a homogeneous agricultural system.

No abstract