Rainwater harvesting from rooftop catchments represents a climate change adaptation measure that is especially significant in areas affected by water scarcity. This article develops a Geographic Information Systems-based methodology to evaluate the spatial distribution of rainwater catchment potential to identify the most favorable urban areas for the installation of these infrastructures. Since performance and water saving potential of rainwater harvesting systems greatly depends on population density and roof size, this assessment was performed for each residential plot on a per capita basis, based on cadastral data and a method of demographic disaggregation. Furthermore, to evaluate spatial variation of runoff coefficient per building, a supervised classification was carried out to consider the influence of roof types on the rainwater catchment potential. After calculating rainwater catchment potential per capita for each residential plot, the spatial clustering of high (hot spots) and low values (cold spots) was assessed through the Getis-Ord General G statistic. Results indicate a spatial pattern of high rainwater catchment potential values in low-density urban areas, where rainwater catchment systems are expected to offer a better performance and a shorter amortization period. These results may be useful for the enactment of local legislation that regulates the obligation to install these infrastructures or offers subsidies for their implementation.

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通过聚类分析评估屋顶集水区的雨水收集潜力

从屋顶集水区收集雨水是一种气候变化适应措施，在受缺水影响的地区尤为重要。本文开发了一种基于地理信息系统的方法来评估雨水集水潜力的空间分布，以确定最有利于安装这些基础设施的城市地区。由于雨水收集系统的性能和节水潜力在很大程度上取决于人口密度和屋顶大小，因此根据地籍数据和人口分类方法，对每个住宅地块进行了人均评估。此外，为了评估每个建筑物的径流系数的空间变化，进行了监督分类，以考虑屋顶类型对雨水集水潜力的影响。在计算每个住宅地块的人均雨水集水潜力后，通过 Getis-Ord General G 统计评估高值（热点）和低值（冷点）的空间聚类。结果表明，在低密度城市地区，雨水集水潜力值高的空间格局，预计雨水集水系统将提供更好的性能和更短的摊销期。这些结果可能有助于制定地方立法，规范安装这些基础设施的义务或为其实施提供补贴。高值（热点）和低值（冷点）的空间聚类通过 Getis-Ord General G 统计量进行评估。结果表明，在低密度城市地区，雨水集水潜力值高的空间格局，预计雨水集水系统将提供更好的性能和更短的摊销期。这些结果可能有助于制定地方立法，规范安装这些基础设施的义务或为其实施提供补贴。高值（热点）和低值（冷点）的空间聚类通过 Getis-Ord General G 统计量进行评估。结果表明，在低密度城市地区，雨水集水潜力值高的空间格局，预计雨水集水系统将提供更好的性能和更短的摊销期。这些结果可能有助于制定地方立法，规范安装这些基础设施的义务或为其实施提供补贴。