The objective of this paper is to address the problems of inefficiency and inequity in water allocation in the El Angel watershed, located in Ecuador's Sierra region. Water is captured in a high-altitude region of the watershed and distributed downstream to producers in four elevation-defined zones via a system of canals. Upstream and downstream producers face radically different conditions with respect to climate and terrain. A mathematical programming model was created to study the consequences of addressing chronic water scarcity problems in the watershed by shifting water resources between the four zones. The model captures the nature of water use by humans, crops and dual purpose cattle. Its objective function maximizes producer welfare as measured by aggregate gross margin, subject to limited supplies of land, labor and water. Five water allocation scenarios are evaluated with respect to efficiency in land and water use and equity in income distribution. Results reveal that although water is the primary constrained resource downstream, in the upstream zones, land is far more scarce. The current distribution of water rights does not consider these differences and therefore is neither efficient nor equitable. Improvements in efficiency (resource use) and equity (income distribution) are associated with (1) a shift of water to the lower zone, and (2) the use of lower levels of irrigation intensity upstream. Furthermore, the scenarios that result in the most efficient use of resources also bring the greatest degree of equity in income distribution, indicating that these may be complementary, not conflicting, goals.

这篇论文的目的是为了解决位于厄瓜多尔塞拉地区的埃尔安赫尔流域水资源分配的低效和不公平问题。水被收集在分水岭的高海拔地区，然后通过运河系统向下游的四个高海拔区域的生产者分配。上游和下游生产者面临着完全不同的气候和地形条件。通过在四个区域之间转移水资源，建立了一个数学规划模型来研究解决流域长期缺水问题的后果。该模型捕捉了人类、作物和两用牛用水的本质。它的目标函数是在土地、劳动力和水资源有限的情况下，以总毛利润率衡量的生产者福利最大化。从土地和水的利用效率和收入分配的公平性两方面评价了五种水资源分配方案。结果表明，虽然水是下游的主要约束资源，但在上游区域，土地资源更为稀缺。目前水权的分配没有考虑到这些差别，因此既不有效也不公平。效率(资源利用)和公平(收入分配)的提高与(1)水向较低区域的转移以及(2)上游灌溉强度较低水平的使用有关。此外，导致最有效利用资源的情况也带来收入分配方面最大程度的公平，这表明这些目标可能是互补的，而不是相互冲突的。