The European Commission highlighted that in Spain: “there is a lack of adequate incentives for efficient use of the resource and the adequate contribution to the recovery from different users is not guaranteed” and recommended to “present transparently subsidies and cross-subsidies”. This paper develops a robust hydro-economic methodological approach that provides transparency in the water cost contribution calculations and helps to assess the economic efficiency of the water resources allocation strategy for a particular water system. The Upper Genil River (a sub-basin of the Guadalquivir River Basin in southern Spain) presents an interesting context of study given its intricate multi-source supply system to meet multi-sectorial water demands, along with conflicts (especially during critical drought events) over historical water rights and the priority of water use. The simulation results demonstrated that, despite the additional average annual cost paid by the household water user for having the theoretical priority of water use (€ 6863 per cubic hectometre of water consumed) compared to the agricultural water user, in practice, that extra cost does not translate into a significant increase in the guarantee of water supply. In fact, the priority of water use would only be patent in very extreme drought events (200-year return period) and when all alternative water supply sources are exhausted. Therefore, competent authorities should ensure that a greater emphasis is placed on transparent water cost recovery assessments to achieve sound water pricing policies and efficient water allocation strategies, which can help to successfully address the major challenge of water scarcity.

欧盟委员会在西班牙强调指出：“缺乏有效利用资源的充分激励措施，不能保证对不同用户的回收做出充分贡献”，并建议“透明地提供补贴和交叉补贴”。本文开发了一种鲁棒的水-经济方法论方法，该方法可在水成本贡献计算中提供透明度，并有助于评估特定水系统的水资源分配策略的经济效率。上盖尼尔河（西班牙南部瓜达尔基维尔河盆地的一个流域）提供了有趣的研究背景，因为其复杂的多源供水系统可以满足多部门的用水需求，以及历史水权和用水优先权之间的冲突（尤其是在严重干旱事件中）。模拟结果表明，尽管与农业用水户相比，家庭用水户每年因拥有理论上的用水优先级而付出了额外的平均年度支出（每立方米耗水6863欧元），但实际上，这笔额外费用确实没有转化为对水供应的保证的显着增加。实际上，只有在极端极端干旱事件（200年恢复期）中，并且当所有替代供水源都用尽时，用水才是优先考虑的问题。因此，