The increased demand for water along with limited water supply and climate change has brought about water access challenges globally. Novel and sustainable water management systems are needed for addressing the imbalance between the increasing water demand and limited water resources. Rainwater as a renewable resource presents great potential to help achieve this goal. This study focuses on an important sustainable water management strategy, rainwater harvesting (RWH), and proposes a Geographic Information System (GIS) based method to assess the capability of RWH to meet outdoor irrigation demand at the city scale. High-resolution LiDAR data and orthophotos are used to delineate RWH catchment areas and identify outdoor vegetated sites. Both active and passive RWH are considered in the rainwater supply estimation. Factors including vegetation height, species, density and microclimate variables are incorporated in the outdoor irrigation demand estimation. The approach is applied to study the capacity of RWH in Tucson, Arizona, a semi-arid water stressed city in the Southwestern United States. Results show that the outdoor irrigation in 32% of the Tucson township sections can be met by RWH for more than 8 months of a wet year. The proposed RWH system deployment can lead to an overall savings of 13.8 million U.S. dollars and provides important insights into urban water management and sustainable water planning.

对水的需求增加，加上有限的供水和气候变化，给全球带来了用水挑战。需要新颖和可持续的水管理系统来解决日益增长的用水需求和有限的水资源之间的不平衡。雨水作为一种可再生资源，具有帮助实现这一目标的巨大潜力。本研究侧重于一项重要的可持续水资源管理战略，即雨水收集 (RWH)，并提出了一种基于地理信息系统 (GIS) 的方法来评估 RWH 满足城市规模户外灌溉需求的能力。高分辨率 LiDAR 数据和正射影像用于描绘 RWH 集水区并识别室外植被区。在雨水供应估算中考虑了主动和被动 RWH。包括植被高度、物种、密度和小气候变量在内的因素被纳入室外灌溉需求估算。该方法用于研究美国西南部半干旱缺水城市亚利桑那州图森的 RWH 容量。结果表明，RWH 可以满足 32% 的图森镇路段的室外灌溉在雨季的 8 个月以上。拟议的 RWH 系统部署可带来 1380 万美元的总体节省，并为城市水资源管理和可持续水资源规划提供重要见解。结果表明，RWH 可以满足 32% 的图森镇路段的室外灌溉在雨季的 8 个月以上。拟议的 RWH 系统部署可带来 1380 万美元的总体节省，并为城市水资源管理和可持续水资源规划提供重要见解。结果表明，RWH 可以满足 32% 的图森镇路段的室外灌溉在雨季的 8 个月以上。拟议的 RWH 系统部署可带来 1380 万美元的总体节省，并为城市水资源管理和可持续水资源规划提供重要见解。