The potential for a rainwater harvesting (RWH) system to supplement the water supply in Chittagong city, Bangladesh, was assessed. Two years were selected for the analysis (2006 and 2020); the projected rainfall for 2020 was evaluated using the Statistical Downscaling Model. Data on projected runoff, land use changes, population growth and catchment areas were also accumulated. The whole city was divided into 22 sub-basins and 176 354 building rooftops were studied for RWH opportunities. Using the weighted linear combination method in a geographic information system environment, potential rooftops and zones were identified for 2006 and 2020. The results showed that the areas with a high RWH potentiality index could supplement water demand by up to 13.03% and 29.68% in 2006 and 2020, respectively. With proper data, this novel approach for a decision support system can be applied to investigate RWH potential in any urban area.

中文翻译：

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孟加拉国缺水城市的雨水收集潜力

评估了孟加拉国吉大港市雨水收集（RWH）系统补充供水的潜力。选择了两年进行分析（2006年和2020年）；使用统计降尺度模型对2020年的预计降雨量进行了评估。还收集了有关预计径流量，土地利用变化，人口增长和集水区的数据。整个城市被划分为22个子流域，并研究了176354个屋顶建筑以获得RWH机会。在地理信息系统环境中，使用加权线性组合方法，确定了2006年和2020年的潜在屋顶和区域。结果表明，具有较高RWH潜力指数的区域可以在2006年补充高达13.03％和29.68％的需水量和2020年。有了适当的数据，