Rooftop Water Harvesting Research Articles

Rooftop water harvesting for managed aquifer recharge and flood mitigation in tropical cities: Towards a strategy of co-benefit evaluations in João Pessoa, northeast Brazil

Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.

Barriers to implementing poverty alleviation through livelihood strategies: A participatory analysis of farming communities in Ethiopia’s upper Blue Nile basin

Poverty is multi-dimensional global challenge that impedes individual and community capacities to satisfy basic needs. These capacities are shaped by locally configured institutional and biophysical processes that are often hidden from external researchers and practitioners. To explore this worldwide aspect, we adopt participatory rural appraisal (PRA) methods to expose barriers to implementing livelihood strategies to address poverty in Ethiopia’s upper Blue Nile basin, where 85 % of the population are subsistence farmers reliant on local ecosystem services (ES). We identify local barriers to poverty alleviation in three steps. First, we classify major ES-livelihood interrelationships among communities of Debre Mawi catchment in upper Blue Nile. Secondly we assess ongoing struggles in these interrelations using combined biophysical and social assessment criteria to evaluate how poverty relates to current patterns of ES management. The analysis identifies complex interdependencies between livelihoods and regulating (crop pest controls), provisioning (water, land, and feed availability, soil fertility) and cultural (top-down ES management, population growth) ES that create bottlenecks to effectively ‘lock in’ poverty. Thirdly, we identify potential new ES management strategies, focused on dry season water availability. We conduct participatory field experiments on rooftop water harvesting to show this is a promising approach for increasing water availability to enhance agricultural production. Depending on the rooftop area, our modelling suggests that farmers can improve household income by US$136– 14,876 from 5 months beef fattening and US$69–7704 from 4 months sheep fattening. Except these specific livelihood strategies, the findings are replicable to the world’s ES-dependent regions.

All-day fresh water harvesting by microstructured hydrogel membranes

Solar steam water purification and fog collection are two independent processes that could enable abundant fresh water generation. We developed a hydrogel membrane that contains hierarchical three-dimensional microstructures with high surface area that combines both functions and serves as an all-day fresh water harvester. At night, the hydrogel membrane efficiently captures fog droplets and directionally transports them to a storage vessel. During the daytime, it acts as an interfacial solar steam generator and achieves a high evaporation rate of 3.64 kg m−2 h−1 under 1 sun enabled by improved thermal/vapor flow management. With a homemade rooftop water harvesting system, this hydrogel membrane can produce fresh water with a daily yield of ~34 L m−2 in an outdoor test, which demonstrates its potential for global water scarcity relief.

The Effectiveness of Rain Water Harvesting for Sustainable Practices in West Hararghe Zone, Oromia Regional State, Ethiopia

This study was conducted in West Hararghe Zone, Oromia regional state to evaluate rain water harvesting Effectiveness for sustainable practices. The data were collected from a total 336 household selected randomly. The data’s obtained were analyzed qualitatively. The study reviled that Rain water harvesting is one of the most important means to increase agricultural productivity and source of a domestic water supply for drought prone of Western Hararghe Zones. Specifically, in selected kebeles of Miesso district there is no access of perennial spring and river. Ground water also found at very deeper and can’t be extracted by their current economic and educational status. In line with this about 83.6% of the farmers were implemented rain water harvesting practices on their farm land and communal land to minimize the risks associated with scarcity of rainfall. From these value 97.3% were in Miesso district. In agreement with this, 54.8% of the house holders have been using roof top water harvesting system in this study area. Specifically, about 25% of the respondents use roof top water harvesting system in Miesso district. Additionally, about 30.1% of the farmers were constructed family pond on their farm land for vegetable/horticultural crop production, cash crops (chat) and also for livestock. Contour ridges were implemented by 89.3% and 92.4% of the farmers in Miesso and Habro districts, respectively. Similarly, 73.8% of the respondents in the study area were implemented flood water diversion to their farm land. Accordingly, 30.8% and 20.5% of the respondents from Habro and Miesso district state preferred flooding WH system than others techniques.

Economical, Efficient and Optimum Design of Storm Water Harvester

In most parts of India, water table is getting lowered. The problem is more predominant in dense cities. Some cities have become dependent on potable water supply. Due to paving of roads and construction of buildings, Infiltration has reduced and run off has increased. Run off increases when the rainfall is intense and with increased road and building infrastructure. Further there is huge withdrawal of water to meet the demand for growing population. Sowing of paddy to increase the returns from farming adds to the problem. Paddy needs 150cm of water from sowing to harvesting. It is not the natural crop of this region. Part of this water demand is met by monsoon and the rest by pumping out of water. There is huge and rapid withdrawal of water from tube wells to keep the crops inundated in water. This causes the drawdown or lowering of water table. In the last two decades water has been receding at the rate of 50-100cm per year. After concerns of water harvesting were raised, the rate of decline has receded. Since we cannot do much about reducing water demand, the solution lies in water harvesting and recycling waste water. Roof top water harvesting is easy and has no challenges. Storm water harvesting is challenging and daunting task. The harvesters get clogged and may not be operational for long time. Optimum solution has been found for filter material to be used, and design of harvester.

Assessing Potential for Rooftop Rainwater Harvesting:An Option for Sustainable Rural Domestic Water Supply in Arid Region of Haryana

Water supply to rural communities on a sustainable basis is an important development objective of India. Rainwater harvesting is one of the promising ways of supplementing the surface and underground scarce water resources in areas where existing water supply system is inadequate to meet the demand. The present study is an attempt to find out the rooftop rainwater harvesting potential at micro level. A primary survey of 763 households in an arid Dhani Mohabbatpur village of Hisar district in Haryana was conducted to assess the rooftop rainwater harvesting potential. Potential of rainwater supply from the rooftops of the village residents was estimated using the runoff coefficients for cemented and non-cemented built-up houses including public buildings namely, bus stand, panchayat ghar, child development centre, primary and high schools of the village. The study revealed that the potential of rooftop water harvesting in the village is encouraging and if harvested, it will supplement the water need of village residents. Moreover, it will also reduce the pressure on village public water supply as well as on surface and groundwater resources in the water scarce region.

Energy-water optimization model incorporating rooftop water harvesting for lawn irrigation

The management of energy and water is increasingly gaining attention among domestic end-users. In developing countries, potable water supply is unreliable leading to alternative strategies such as rooftop water harvesting (RWH), storage and pumping. Since urban garden irrigation is the highest outdoor water consumer, optimal scheduling is important to conserve energy and water over conventional lawn irrigation methods. A model to optimally control the lawn irrigation was developed with the simulation results showing 17.4% potential water savings when using water directly from municipal sources. With RWH of a 1-h event with 1-mm rainfall from a 120-m2 roof, the model can potentially save 23.4% of water and 73.8% in energy costs per day. Such savings are important in reducing the demand for existing water and energy sources as well as greenhouse emissions. Further, this paper looks into two strategies to maximize the pump’s life through minimizing the maintenance cost.

Health Risk Assessment of Domestic Roof Water Harvesting Using Failure Mode and Effects Analysis: Evidence from Nagaur, Rajasthan, India

ABSTRACT This article is crafted around assessment and analysis of health risks associated with domestic rooftop water harvesting in India, with the prime objective of bringing to the forefront the deterrent issues and challenges in rainwater harvesting in general and domestic rooftop water harvesting in particular. This is based on a study on health risk assessment of a domestic rooftop water harvesting project conducted in the Nagaur district of Rajasthan, India, providing a critical reflection and exemplifying the prevalent scenario in the arid regions of the world. The methodology used for deriving the conclusions is failure mode and effects analysis. A set of risks were graded according to their severity based on their risk priority number scores evolved, including various contaminants polluting the harvested rainwater. The findings bear implications for planning of reconstructive changes to be incorporated and thus providing the necessary outlook for effective alleviation of the deterrents and make rainwater harvesting the premium solution for realization of the Millennium Development Goals by providing access to safe drinking water to the populace chiefly in the developing countries where the problem of scarce safe water is grave.