Rainwater harvesting for human consumption and livelihood improvement in rural Nepal: benefits and risks

Use of rooftop rainwater as a source of drinking water in developing countries is increasing. However, scepticism about the potential of this source and the associated health risks is still prevalent among water planners. A free listing and a household survey among 120 households was conducted in the hills of Nepal to examine the performance of rainwater harvesting systems. Users perceive few health risks and in contrast, reported a wide range of benefits, including health benefits associated with the consumption of rainwater. Water quality testing results generally demonstrate good water quality but confirm that appropriate operation and maintenance practices are critical to ensure the collection of good quality water. Deficiencies in technical design and construction, lack of awareness, no market for spare parts and the inability of vulnerable households to maintain the system pose a risk to the collection and storage of safe water and to the long‐lasting performance of the systems.     

Spatial and numerical analysis of the parameters influencing potential for potable water savings made using rainwater harvesting: case of the Paris agglomeration

The quantity of Potential for Potable Water Savings (PPWS) made using rainwater harvesting differs between municipalities within the same region. Three main parameters contribute to this difference: roof area, the number of inhabitants and rainwater use scenarios. This article proposes a spatial and numerical analysis of how these parameters influence PPWS across municipalities in the Paris agglomeration. A comparison between the location of the municipalities, the PPWS value and the values for the previous parameters was used to understand the observed difference. The spatial analysis shows that municipalities (districts) in the Paris have the highest PPWS values, on the contrary, the peripheral municipalities in the outer suburbs have the lowest PPWS values and the results for the intermediary municipalities—in the inner suburbs—are contrasting. The numerical analysis demonstrates a strong correlation between the main parameters influencing the PPWS value; where a high value for the “roof area” means a high value for the “number of inhabitants” and a good mix of rainwater “use scenarios,” and vice‐versa. In conclusion, the planning and design of the municipality—building density, types of buildings, number of inhabitants, the city's vocation—are key factors in defining the level of PPWS made using rainwater harvesting.     

Rainwater catchment water quality in Micronesia

Rainwater catchment systems (RWCS) in Micronesia were sampled to assess their bacteriological water quality and to determine which RWCS characteristics had a significant impact on water quality. Total and fecal coliform bacteria tests were used to evaluate 203 catchments on 10 islands. Fifty-seven percent of the RWCS had no fecal coliform bacteria and 61% had fewer than 10 total coliform bacteria per 100 ml. Catchment characteristics were found to have a statistically significant effect on total coliform bacteria levels but they did not affect faecal coliform bacteria concentrations. Rainwater catchment systems were found to provide acceptable water in most cases but disinfection prior to consumption is still highly recommended.     

空调冷凝水与雨水收集联合系统的可行性分析

提出了一种空调冷凝水和雨水收集联合系统,该系统能够收集夏季雨天的雨水,晴天的冷凝水,在一定程度上克服了现有雨水收集系统运行的不连续性。同时,利用溶液热交换器收集了冷凝水的部分冷量,用以降低冷凝负荷,从而降低了空调的功耗。将全部的空调冷凝水回收利用,消除了空调冷凝水对建筑物的腐蚀等危害。能够有效达到节能减排的目的。     

Rainwater harvesting to control stormwater runoff in suburban areas. An experimental case-study

On a 23 ha urban watershed, 10 km East of Paris, rainwater tanks have been installed on 1/3 of the private parcels to prevent stormwater sewer overflows. This paper investigates the macroscopic effect of rainwater harvesting on runoff, and thus the potential of this technique for stormwater source control. The analysis is performed using the SWMM 5 model, calibrated on rainfall- runoff measures from two measurement campaigns, before and after the equipment. The availability of two data-sets allows the authors to point out changes in the catchment's behaviour. The main findings are that: (1) catchment's evolution, mainly caused by individual land-cover modifications, produces non-stationarity of the hydrologic behaviour; (2) the rainwater tanks installed, although they affect the catchment hydrology for usual rain events, are too small and too few to prevent sewer overflows in the case of heavy rain events.     

侨香村雨水收集与利用系统的设计

介绍了侨香村小区工程概况、设计原则，进行了雨量计算，并做了雨水收集与利用系统设计的介绍，最后提到了雨水收集与利用系统对建筑设计的影响。     

The perceived barriers to the inclusion of rainwater harvesting systems by UK house building companies

This work investigates the barriers that exist to deter the implementation of rainwater harvesting into new UK housing. A postal questionnaire was sent to a selection of large, medium and small house-builders distributed across the UK. Questions were asked concerning potential barriers to the inclusion of rainwater harvesting in homes separated into five sections; (1) institutional and regulatory gaps, (2) economic and financial constraints, (3) absence of incentives, (4) lack of information and technical knowledge, and (5) house-builder attitudes. The study concludes that although the knowledge of rainwater systems has increased these barriers are deterring house-builders from installing rainwater harvesting systems in new homes. It is further acknowledged that the implementation of rainwater harvesting will continue to be limited whilst these barriers remain and unless resolved, rainwater harvesting's potential to reduce the consumption of potable water in houses will continue to be limited.     

Ecosystem services from rainwater harvesting in India

Availability of a safe and reliable water supply is an issue in developing nations, including India. Rainwater harvesting (RWH) is a site-specific source control used to satisfy human, agricultural, and safety demands for water. This study analyzed the effects of capturing rainwater for a 12.5 year period (Jan 1999–Jun 2011) to provide three ecosystem services: water supplementation for indoor use, water supplementation for food production and groundwater recharge (GWR). A hydrologic analysis was completed using satellite rainfall data and a water balance approach. Two demand scenarios, indoor and outdoor, were considered, with water in excess of demand and storage directed to recharge groundwater. An economic analysis quantified RWH system net present value. The results indicated significant ecosystem services benefits were possible from RWH in India. RWH for the purpose of providing irrigation to a small garden and allowing overflow to a drywell for GWR was concluded to be an approach to maximize benefits. This scenario provided the greatest net present value (21,764–38,851 INR), fastest payback period (0.30–0.98 years), and recharge to groundwater of more than 40% of onsite rainfall. The benefit of the outdoor vegetable irrigation was determined and the results showed that the caloric demands of the typical Indian household (2.75 kg of tomatoes and 1.05 kg of lettuce) could be met with a 20 m² garden, and excess food could be sold to offset the capital cost of the system and later for economic gain.     

小区雨水回收利用系统的经济效益分析

雨水回收利用系统具有很好的环境效益,是缓解城市水资源短缺和浪费问题的重要措施。为分析雨水回收利用系统的经济效益,运用给排水和工程经济的相关理论,研究了其节水效益和全生命周期成本,通过动态投资回收期的方法建立了雨水回收利用系统的成本效益模型。结合广州某小区工程实例,利用时间序列法对水价进行了预测,计算得到雨水回收利用系统的成本效益,求出动态投资回收期,证明了雨水回收利用系统具有较好的经济效益。模型也为类似工程的雨水回收利用系统的经济性研究提供了参考方法     

Physicochemical and microbiological quality of water from a pilot domestic rainwater harvesting facility in Ireland

Dublin Institute of Technology personnel were commissioned in 2005 by the Department of Environment, Heritage and Local Government in Ireland to assess the feasibility of utilizing harvested rainwater to replace treated mains water, for nonpotable uses. A pilot project was set up. The project involved the design, installation, commissioning and monitoring of rainwater harvesting facilities in a rural housing development. A monitoring programme was carried out to examine the physicochemical and microbiological quality of the harvested rainwater. Harvested rainwater was sampled monthly and tested. Analysis of the harvested rainwater quality showed a consistently high quality of raw water in general compliance with the requirements of the European Communities (Quality of Bathing Water) Regulations for 100% of samples and the European Communities (Drinking Water) Regulations, 2007 for 37% of sampling dates.     

Rainwater harvesting for domestic use: A systematic review and outlook from the utility policy and management perspectives

In recent years, water insecurity has been reported as a problem of worldwide concern. Rainwater harvesting (RWH) for some domestic uses is regarded as a path out of this situation. However, in some localities, RWH has been the sole water source for all domestic and non-domestic uses. In recent times, research in RWH has gained more traction from the operationalization and engineering perspectives. However, for direct rainwater usage to become a societal norm and generate significant societal benefits, studies in RWH must assess the alignment of outcomes from policy and management perspectives. Therefore, a comprehensive literature review of 83 collated papers on RWH is conducted in two stages. First, a systematic review of the literature is performed to identify the thematic content (structure of the literature, problem orientation), contextual application (technical and social considerations), and theoretical alignment scope (neo-institutional theory, agency theory, and ecological modernization theory). Second, gaps in the literature are identified, and theoretical alignment of the ideas from policy and management perspectives is proposed to advance RWH research. Key findings are: (1) despite RWH being aimed to provide social benefits, the present literature is constrained in supporting social policy-making and management of rainwater as a public utility system; (2) policy and governance frameworks that include socio-economic and socio-environmental pragmatism are needed to achieve RWH programs realistically; and (3) modeling of RWH systems requires considering spatial variabilities, policy evaluations, and governing theories. RWH has the potential to have a central position in water resource management worldwide.     

Rainwater harvesting, quality assessment and utilization in Kefalonia Island, Greece

The quality of harvested rainwater which is used for domestic and drinking purposes in the northern area of Kefalonia Island in SW Greece and the factors affecting it were assessed through 3-year surveillance. In 12 seasonal samplings, 156 rainwater and 144 ground- or mixed water samples were collected from ferroconcrete storage tanks (300-1000 m3 capacity), which are adjacent to cement-paved catchment areas (600-3000 m2). Common anions and major cations as well as the metals Fe, Mn, Cd, Pb, Cu, Cr, Ni and Zn were tested. The presence of three major groups of organic compounds, polycyclic aromatic hydrocarbons (PAHs), organochloride pesticides (OCPs) and volatile organic compounds (VOCs), was screened by common analytical techniques. All of the rainwater samples were within the guidelines for chemical parameters established by the 98/93/EU directive. As far as microbiological quality is concerned, total coliforms, Escherichia coli and enterococci were detected in 80.3%, 40.9% and 28.8% of the rainwater samples, respectively, although they were found in low concentrations. Chemical and microbiological parameters showed seasonal fluctuations. Principal component analysis revealed that microbiological parameters were affected mainly by the cleanness level of catchment areas, while chemical parameters were influenced by the sea proximity and human activities. Disinfection should be applied into the tanker trucks which distribute the water to the consumers and not into the big storage tanks in order to avoid by-products formation. Due to the lack of fluoride in rainwater samples, the consumers must become aware of the fact that the supplementation of this element is needed.     

Whole life cost performance of domestic rainwater harvesting systems in the United Kingdom

Rainwater harvesting (RWH) can be used to reduce the demand for potable mains water. At the single‐building scale, previous research has focused on water‐saving potential, while financial assessment has either been omitted or considered in an ad hoc manner. This paper reports on the application of a more rigorous financial analysis of domestic RWH systems than had been conducted previously. Whole life costing was selected as the most appropriate financial assessment technique. A total of 3840 domestic system configurations were assessed at a daily time step, taking into account various stakeholder perspectives and future cost scenarios. In each case, it was found that harvesting rainwater was significantly less cost effective than relying solely on mains‐only water. The domestic RWH systems generally resulted in financial losses approximately equal to their capital costs. Without significant financial support, domestic RWH is unlikely to be cost effective for all reasonably foreseeable scenarios.     

城市小区绿地雨水下渗后收集利用技术研究

针对地下有构筑物的城市小区绿地在排水方面面临的问题,研究了在绿地的土壤层中铺设渗透材料(渗透管材、渗透片材)收集下渗雨水的方法,同时考察了采用不同渗透材料铺设方式时的雨水收集、积水消退效果。试验结果表明,使用渗透管材、渗透片材等渗透材料可以对绿地的下渗雨水起到较好的收集利用效果,其中使用渗透管材和间隔铺设方式对下渗雨水的收集效果最好。     

基于城市雨水利用收集技术的节能减排浅析

本文分析了泉州某商圈拟建雨水收集系统,明确了雨水收集系统技术应用的造价成本以及影响因素,以便读者可以根据实际条件和使用要求选择适宜的方法和配套技术指导类似节水系统工程的实践。     

分析城市景观设计中的雨水生态化利用

本文对雨水生态化利用的各个方面进行了详细地分析,希望这些分析能够更全面的实现雨水的生态化利用,能对未来的城市环境保护和环境发展做出一些贡献。     

城市雨水综合利用系统研究

城市的快速发展带来城市水灾害日益严重和水资源严重匮乏的问题。根据各国开发新型的给排水系统的经验,从增加地面渗透能力和建立蓄水设施,提高城市对雨、洪的调节能力入手,提出适合我国国情的雨水综合利用系统,实现提高渗透能力以补充地下水,实现蓄水—中水利用设施相结合,从而改善城市生态环境,有力保证城市可持续发展。     

基于日水量平衡设计城市小区雨水利用调蓄容量

结合厦门市集美区某新建小区雨水利用工程,阐述了日水量平衡分析在城市小区雨水利用调蓄容量设计中的应用,建立了相应的水量平衡方程式,提出了水量平衡中各要素(径流雨水收集量、用水量、蒸发量、渗透量及其他水源补水量)的计算方法.通过以年为周期的日水量平衡分析方法,结合该区域每日用水状况及过去10年的日降雨量、蒸发量资料,研究了城市小区雨水利用调蓄容量的设计、区域的外排水及补水状况;分析了径流雨水利用率、节水率等经济性指标;制订了旱季、雨季补水计划.     

我国西南地区的雨水集蓄与利用

结合我国西南地区水资源现状，阐述了雨水集蓄利用的必要性，对雨水利用的可行性进行了研究，对当前雨水利用中存在的问题进行了探讨，并针对性地提出了解决问题的措施，以推广雨水集蓄利用技术。     

住宅小区雨水回收利用方法探讨

随着可利用水资源的日趋紧张,雨水以其处理成本低廉,处理方法简单等优点,而成为一种新的可利用水资源。文章从建筑小区雨水利用系统的概念入手,简单介绍了目前国内外几种主要的雨水利用系统,并指出加大建筑小区雨水利用对我国具有重大意义。