Rooftop Rainwater Research Articles

Modelling scenarios for water supply and sanitation technologies in Jordan

The influx of refugees, population growth and current agricultural practices have led to an increase in water demand in Jordan, placing pressure on existing water provision. Climate change further exacerbates declining water availability. Against this backdrop, the techno-economic feasibility of four water supply and sanitation alternatives for small and medium scale cities in Jordan were explored, using local unit costs and Al-Mafraq as a case study. City level piped network combined with household rooftop rainwater harvesting and surface runoff collection into local ponds and piped networks with treatment using the nature-based solution of root-zone for sanitation were demonstrated to provide the highest benefits in terms of cost, convenience and water conservation. Our work highlights the need to invest in long-term urban infrastructure networks to promote sustainable future growth of cities. This is vital to address severe water scarcity challenges that ultimately impact those at the urban fringes most.

Feasibility of Rooftop Rain Water Harvesting at Grey Iron Foundry, Jabalpur, Madhya Pradesh, India

Feasibility of Rooftop Rain Water Harvesting at Grey Iron Foundry, Jabalpur, Madhya Pradesh, India

Assessment of rainwater harvesting potential from rooftops in Jordan's Twelve Governorates.

Rooftop rainwater harvesting (RRWH) offers a potential solution to Jordan's pressing water scarcity problems. Yet, its feasibility and benefits necessitate a thorough assessment, particularly as existing studies on the subject are outdated and often constrained by limited scope or small data sets. To this end, our study assessed the potential of RRWH in Jordan's 12 governorates, utilizing historical rainfall data from 1987 to 2018 and official statistics on population and rooftop areas. The analyses used the Ripple Method and Water Balance Model to determine potential harvestable water volumes, potential water-saving percentages, and optimal tank sizes under different scenarios (i.e., using rainwater to meet the total consumption or only for toilet flushing). The findings reveal that Jordan has a total potential for rooftop rainwater harvesting amounting to 23.74 Mm3/year, corresponding to 4.54% of the total water demand. Should RRWH be implemented across all rooftops, the projected financial savings for Jordan could range from $170 million to $678 million. Among the governorates, Irbid and Amman have the highest potential, with estimated yields of 7.754 Mm3 and 8.453 Mm3 per year, respectively. Based on the best results for the scenario where harvested rainwater is only used to flush toilets, the optimal tank sizes for storing rainwater were estimated to be 2.7 m3 and 2 m3 per household in Ajlun and Irbid, respectively. For a regularized case (October-May), a payback period of 12.5-24 years based on desalination cost was found for an RRWH system capable of meeting thrice the flushing needs of a household. RRWH was showcased as a sustainable solution to Jordan's water scarcity, emphasizing the necessity for broader implementation.

Evaluating rooftop rainwater harvesting potential to satisfy urban water demand in Hosaena City, South Central Ethiopia

ABSTRACT The assessment of the rainwater harvesting (RWH) potential in Hosaena City from medium to large public buildings is the main objective of the study. ArcGIS with Google Earth Pro was used to calculate the rooftop area of the selected building, and RWH from each category of public buildings was evaluated by considering rooftop areas, monthly rainfall, and runoff coefficient. The result shows that the highest amount of rainwater was harvested from the City Administration building in August (197.1 m3), whereas the lowest was collected from the Health Center building in December (1.8 m3). Additionally, the contribution of RWH from individual public buildings for each month was evaluated, and its values ranged from 0.073 to 1.8%. The comparison shows that Wachemo University, Nigist Eleni Comprehensive Hospital, a technical and vocational institute, and teacher training center buildings, could have a significant potential for rainwater storage, ranging from 1.56 to 28.41%. This implies that, besides saving a noteworthy volume of potable water, the excess rainwater can be stored and utilized for the later dry months. As a result, it is recommended that rooftop RWH in Hosaena be the best source of the city's water supply system to reduce the current water supply shortage.

The potential of rainwater harvesting and greywater recycling as an alternative domestic water resource in Bahnstadt-Heidelberg, Germany

ABSTRACT The use of high-quality potable water for non-essential activities results in substantial water waste. Therefore, treating and utilizing rainwater and greywater which contain low concentrations of organic substances and microbes as alternative domestic water resources can enhance the resilience and sustainability of water in urban areas. However, it encounters several challenges. This study was conducted in Banhstadt-Heidelberg, Germany, to estimate domestic water consumption patterns, evaluate the potential of rainwater harvesting from green roofs, and assess the public acceptability of greywater recycling. The primary data were collected from 361 Bahnstadt residents through the questionnaire to estimate water consumption. The non-potable water demand in Bahnstadt was estimated at 228 m3/day for 5,700 Bahnstadt residents. The harvestable rainfall volume was 16,017.58 m3/year. When rainwater supply was compared to water demand, the potential for rooftop rainwater harvesting was 19.25%. This value indicates that the amount of rainwater collected is less than that of non-potable water required per year. To meet the demand, rainwater harvesting will need to be supplemented with treated greywater. However, only 20.78% of respondents are willing to install a greywater recycling system, mostly because of public health concerns. Overall, this study shows the tendencies toward having green roofs with integrated rainwater harvesting and greywater recycling for the possible account of water saving.

Application of GIS & RS in Rainwater Harvesting for an Arid Region

In dry areas with variable rainfall, water shortages severely affect the livelihoods of local populations. Rainwater harvesting from land sites and roof-tops is a readily available solution to this problem. This study presents a GIS & RS-based methodology to identify potential land sites and roof-top rainwater harvesting potential using easily obtainable and freely available data. Slope, land cover, soil, and drainage maps were used to identify suitable rainwater harvesting land sites, which were further analyzed for surface runoff using the curve number method. This research also incorporated obtainable socio-economic factors in identifying the suitable locations of dams considering the implementation stage. Based on the proposed criteria, 44 suitable locations for dams were identified and validated using a validation map and Google Earth images. CROPWAT model analysis revealed that paddy water demand in Batticaloa would increase threefold if all available land for paddy cultivation was utilized. Therefore, abandoned lands can be utilized by erecting dams at those identified locations. Analysis of Google Earth images also revealed that roof rainwater harvesting would be sufficient to meet the basic water demand in the area. This study demonstrates that rainwater harvesting can be an effective strategy for addressing water scarcity in dry areas.

Necessity and Design of Roof Top Rain Water Harvesting System

Necessity and Design of Roof Top Rain Water Harvesting System

Assessment of Rooftop Rainwater Harvesting Potential: A Case Study for Nagaland

Abstract: Water scarcity has become a serious global threat due to hazardous population growth frequent droughts and changing climate pattern (Carolina B. Mendez et. al). Water is scarce natural resource, even though 71% of land is covered by water out of total water on the earth near about 25% are fresh which is being utilized for various purposes viz. domestic, irrigation and industrial are common. Nowadays the need of commercial water is magnifying tremendously in a developing country like India which has long tradition of rural culture. Here in this study, an attempt was made to estimate the potential of rooftop rainwater harvesting in the state of Nagaland, India. The results showed that the total domestic water demand of Nagaland was estimated at 62,012,868,550 liters and domestic supply potential only from rooftop rainwater harvesting was estimated to fulfill about 64.70% of total water demand and the shortage which is about 35.3% can be through state governments water supply scheme, from the private sector and also other sources like pond, river, spring water, etc

Health Burden of the Consumption of Rooftop Rainwater Harvesting Systems in Buea Sub–Division, Cameroon

Health Burden of the Consumption of Rooftop Rainwater Harvesting Systems in Buea Sub–Division, Cameroon

Assessment of Low-Cost Filter Material for Rooftop Rainwater Harvesting Structure

Assessment of Low-Cost Filter Material for Rooftop Rainwater Harvesting Structure

Rainwater Harvesting System Analysis for Semi-Arid Climate: A Daily Linear Programming Model

Rainwater harvesting has proven to be an alternative water supply scheme for sustainable water management of regions with limited water resources. In this paper, a linear programming (LP) model with daily time steps, which minimizes a rooftop rainwater harvesting system (RWHS) cost, is developed and used to calculate the optimum RWH tank size. The developed LP model is applied to the semi-arid Northern Cyprus in the Eastern Mediterranean. The analysis is carried out for 33 sites which receive average annual rainfall ranging from 292 mm to 548 mm to evaluate the spatial effect of rainfall characteristic and the water cost on the financial feasibility and performance of the RWHS. At 29 out of 33 sites, RWHS investments are found to be financially feasible with discounted payback periods ranging from 12 to 28 years. The optimum RWH tank sizes are determined to be between 2 m3 and 6 m3 resulting in up to 20 % reliability with more than 50 m3 of average annual water savings per house. It is observed that the cost of water is a critical factor that affects the financial feasibility and water savings of a RWHS, especially in regions with limited rainfall. The comparison of the developed daily LP model with an LP model with monthly time steps demonstrates that the financial feasibility and the optimum tank size can only be assessed realistically when daily time steps are used. Finally, the sensitivity analysis shows that the discounted payback period is highly sensitive to the collector area.

Estimation of Roof Top Rain Water Harvesting Potential: A Proposed Solution to Water Scarcity in Shrigonda Town, Maharashtra, India

The burning issue in cities will be water scarcity in the coming years. The world population in cities has increased from 29.6 percent to 56.2 percent and is predicted to reach 68.4 percent by 2050. Therefore, this study has attempted to find a solution to tackle the urban water scarcity issue. Recently, rainwater harvesting has emerged as a sustainable and effective system for water conservation in urban areas. Hence, the ward-wise rooftop area was calculated and the rooftop rainwater harvesting potential was estimated by applying the Gould & Nissen, formula for Shrigonda Town. The result reveals that the total water demand in the water stress period was 41,34,41,010 litres while the total rainwater harvesting potential was 39,07,42,128 litres, which means about 94.51 % of the total demand will be met after the rooftop rainwater harvesting system is installed. The study concludes that rooftop rainwater harvesting is considered a sustainable and best alternative tool to tackle urban water scarcity.

Rooftop rainwater harvesting potential for kitchen gardening in the Rawal watershed, Pakistan

Rooftop rainwater harvesting potential for kitchen gardening in the Rawal watershed, Pakistan

Dilution of Salinity Using Rainwater Harvesting System - An Innovative Approach

In view of the increasing water demand, this paper recognizes rainwater harvesting as an innovative approach to the dilution of salinity. It proposes dilution of salinity to reduce both the direct and indirect effects of salinity on human health and well-being. This paper focuses on the saline regions of the Union Territory of Delhi. It identifies possibilities for salinity dilution by proposing an innovative approach to implement rainwater harvesting. For this purpose, this paper evaluates the rooftop rainwater harvesting potential for roof area including 100, 200, 300, 400 and 500 square meter area, in the identified saline regions of National Capital Territory (NCT) Delhi. To assess the impact of the rainwater harvesting system on salinity dilution, different maps and data were analysed. These maps include a salinity map of Delhi, a depth-to-water level map of Delhi, water level fluctuation map of Delhi, isohytal map of Delhi, etc.

Contribution of rooftop rainwater harvesting to climate adaptation in the city of Hannover: Water quality and health issues of rainwater storage in cisterns and ponds

Rooftop rainwater harvesting systems and blue-green infrastructure are becoming important resilience alternatives for urban climate adaptation. This study sheds light on the largely unreported physicochemical and microbiological quality of private roof-harvested rainwater (RHRW). We aimed to identify the physicochemical and microbiological characteristics of RHRW, explore potential correlations between them and assess probable health risks associated with recreational interactions of children with the water. RHRW was collected from cisterns and ponds located in an inner courtyard in Hanover, Germany. Physicochemical parameters were measured on site and samples were collected once a month in two campaigns in 2020 and 2021. Escherichia coli concentrations ranged from 1 × 10° to 24.1 × 102 MPN/100 mL, Enterococci from 1 × 10° to 19.7 × 102 MPN/100 mL, Salmonella from 1 × 102 to 39 × 103 CFU/100 mL and Pseudomonas aeruginosa from 1 × 10° to 3 × 103 MPN/100 mL. Correlation analysis indicated potential relationships between bacteria, oxygen, and water temperature. The results of the health risk assessment indicated a potential risk of gastrointestinal illnesses due to exposure to Enterococci and Salmonella spp. present in the cisterns and ponds, highlighting the need for appropriate regulations and guidelines for RHRW aimed for non-potable uses. Blue-green infrastructure, when effectively managed and maintained, can offer benefits both by enhancing urban climate resilience and promoting citizens well-being.

Designing of rooftop rainwater harvesting system by using soft computing technique

Designing of rooftop rainwater harvesting system by using soft computing technique

Sustainable Management of Aquaculture and Water Footprint Analysis in Sunderban

India is the world’s second-largest producer of fish, where the state of West Bengal is leading in fish production. The Sundarbans, located in the southern part of India’s West Bengal state, is a UNESCO-designated world heritage site. The Indian Sundarbans is a tide-dominated region in the southern part of deltaic West Bengal, and is home to 4.43 million people. Even though it is traversed by numerous creeks and rivulets and receives a significant amount of precipitation during the monsoon season, freshwater is a scarce resource in the Sundarbans. During the dry season, there is a lack of fresh water above and below the ground, increasing siltation results in shallower channels, high salinity of the water and soil, and congestion in drainage making it difficult for people to make a living. During the dry season, most blocks experience water scarcity as a result of the ever-increasing population’s demand for water. According to this study, Sundarbans’ current annual domestic and drinking water demands are 105.1 mcm and 8.08 mcm, respectively. By combining the area under various crops and their lifecycle water requirements, the water demand for agriculture has been calculated to be 2782.83 mcm. The rainfall-runoff modelling aims to get a general idea of how much fresh water is available each year through surface runoff. It has also been estimated how much water is available from different sources in each block. It is estimated that deep and shallow bore wells contribute approximately 400 mcm, whereas surface water sources like tanks and canals contribute approximately 50 mcm. The communities that live in the Sundarbans eco-region benefit greatly from aquaculture’s contribution to their socio-economic development. For the sustainable development of aquaculture in the Sundarbans Delta, strong technical, financial and extension services from government organisations and research institutions are urgently required to meet these obstacles. Additionally, this study emphasises that roof-top rainwater harvesting in this region has the potential to supply 45 mcm more water, which could be used to partially satisfy the region’s domestic water demand. Future major policy options for meeting the Sundarbans ecoregion’s water demand include large-scale rainwater harvesting, rejuvenation and reconnection of disconnected river channels, artificial recharge of shallow aquifers to lower their salinity, and de-salination of shallow groundwater.

Evaluation of the effect of different conventional roof types and industrial activity on harvested rainwater in Southern Nigeria

Harvested rainwater is still the only source of acceptable drinking water for rural communities in Nigeria and in some countries, where there are no water networks and it is the rooftop rainwater harvesting that is being exercised for the potable and non-potable usages. This study was aimed at evaluating the effect of roof types and industrial activity on rainwater quality by analysing the physico-chemical/bacteriological characteristics, heavy metals and investigating the metal composition of the roof types. Rainwater was harvested from long-span aluminium, asbestos, corrugated iron, Cameroon zinc, stone-coated tiles roof run-offs and directly from the sky in the urban and rural areas of Imo State between the months of April-July, 2017. The results were compared with water quality standards (NAFDAC, USEPA, WHO and NSDWQ) for drinking water and Water Quality Index (WQI) ratings since there is no standard for rainwater quality. Roofs ages from < 5, 5–10, 15–20, and > 25 years in use were considered. Heavy metals were analysed using Flame-AAS; other parameters were analysed using standard methods. The WQI ratings were calculated using the weighted arithmetic method. Results show mean values ranging from 5.70 to 6.60 for pH, E.coli (not detected) and heavy metals (mg/L) burden of 0.00–0.09 for Pb, Cr (0.00–0.79), Zn (0.00–0.06), Fe (0.00–0.50) and Al (0.00–0.63). The WQI ratings gave excellent water to unfit for drinking water quality in both urban and rural areas. Since the harvested rainwater was not free of contamination, a few helpful recommendations were suggested for positive impacts in Nigeria as a whole.

Rooftop Rainwater Harvesting System at MPCOE Campus

Rooftop Rainwater Harvesting System at MPCOE Campus

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.