In highly water-poor areas, rooftop rainwater harvesting (RRWH) can be used for a self-sustaining and self-reliant domestic water supply. The designing of an optimal RRWH storage tank is a key parameter to implement a reliable RRWH system. In this study, the optimal size of RRWH storage tanks in the different West Bank governorates was estimated based on monthly (all governorates) and daily (i.e., Nablus) inflow (RRWH) and outflow (domestic water demand, DWD) data. In the estimation of RRWH, five rooftop areas varying between 100 m² and 300 m² were selected. Moreover, the reliability of the adopting RRWH system in the different West Bank governorates was tested. Two-time series scenarios were assumed: Scenario 1, S1 (12 months, annual) and scenario 2, S2 (8 months, rainy). As a result, reliable curves for preliminary estimation of optimal RRWH storage tanks for the different West Bank governorates were obtained. Results show that the required storage tank for S1 (annual) is more than that of the S2 (rainy) one. The required storage tank to fulfill DWD is based on the average rooftop area of 150 m², the average family members of 4.8, and the average DWD of 90 L per capita per day (L/c/d) varies between (75 m³ to 136 m³) and (24 m³ to 84 m³) for S2 for the different West Bank governorates. Further, it is found that the optimal RRWH tank size for the 150 m² rooftop ranges between 20 m³ (in Jericho) to 75 m³ (in Salfit and Nablus) and between 20 m³ (in Jericho) to 51 m³ (in Jerusalem) for S1 and S2 scenarios, respectively. Finally, results show that the implementation of an RRWH system for a rooftop area of 150 m² and family members of 4.8 is reliable for all of the West Bank governorates except Jericho. Whereas, the reliability doesn’t exceed 19% for the two scenarios. However, the reduction of DWDv is highly affecting the reliability of adopting RRWH systems in Jericho (the least rainfall governorate). For instance, a family DWDv of 3.2 m³/month (25% of the average family DWDv in the West Bank) will increase the reliability at a rooftop area of 150 m² to 51% and 76% for S1 and S2, respectively.

中文翻译：

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巴勒斯坦西岸的屋顶雨水收集罐的最佳尺寸，以实现可持续的生活用水

在缺水率很高的地区，屋顶雨水收集装置（RRWH）可用于自给自足和自给自足的家庭供水。最佳的RRWH储罐的设计是实施可靠的RRWH系统的关键参数。在这项研究中，根据每月（所有省份）和每天（即纳布卢斯）流入量（RRWH）和流出量（国内需水量，DWD）数据估算了西岸不同省份的RRWH储罐的最佳尺寸。在RRWH的估算中，五个屋顶面积在100 m ²和300 m ²之间变化被选中。此外，还对在西岸不同省份采用RRWH系统的可靠性进行了测试。假设有两个时间序列方案：方案1，S1（每年12个月），方案2，S2（8个月，多雨）。结果，获得了用于不同西岸省最佳RRWH储罐初步估算的可靠曲线。结果表明，S1（每年）所需的储水箱要多于S2（雨天）所需的储水箱。满足DWD所需的储罐是基于平均屋顶面积150 m ²，平均家庭成员4.8和人均每天90 L人均DWD（L / c / d）之间变化的（75 m ³至136 m ³）和（24 m ³至84 m ³）用于西岸不同省份的S2。此外，发现150 m ²屋顶的最佳RRWH储罐尺寸在20 m ³（在Jericho中）至75 m ³（在Salfit和Nablus中）和20 m ³（在Jericho中）至51 m ³（在耶路撒冷）分别针对S1和S2场景。最后，结果表明，针对150 m ²的屋顶区域实施RRWH系统4.8的家庭成员对除耶利哥以外的所有西岸省来说都是可靠的。而在两种情况下，可靠性不超过19％。但是，DWDv的减少极大地影响了杰里科（降雨量最少的省）采用RRWH系统的可靠性。例如，家庭DWDv为3.2 m ³ /月（西岸平均家庭DWDv的25％）将使屋顶面积为150 m ²的S1和S2的可靠性分别提高到51％和76％。