Rooftop Rainwater Research Articles

Food Producing Facades Key to a Sustainable Future

The built environment uses substantial and increasing amounts of energy, contributing to Urban Heat Island effect, while population growth and urban development have outpaced food production globally. There is a growing trend to introduce green infrastructure into the built environment via green roofs, green façades, and urban agriculture. Research is limited, however, into the use of food producing plants being grown on a living façade to improve total building performance. The purpose of this research study was to test the assertion that food producing plants can be grown successfully in a vertical greenery system or green wall integrated into an existing commercial building façade. Specifically, this dissertation investigates the role of integrating food producing plants into a living facade to positively impact four outcomes: food production, thermal performance, air quality and rainwater management in a temperate climate. This was a six-year long longitudinal research study. The findings from this study conclusively demonstrate that a maximum average production of 2.64 kilograms of produce per square meter of façade panel can be generated annually (0.54 lbs./ft2). The façade temperatures were reduced between 5.56oC-20.53oC (10oF-36.95oF) with approximately 20% reduction in cooling energy, reducing urban heat island. Airborne small particulates (PM2.5 )were reduced a maximum of 5.6% for the living facade compared to the control. An average of 14.26 litres of rooftop rainwater per square meter of facade per day (0.35 gal/ft2/day) was used for irrigation. In addition, observational studies revealed enhanced access to nature for building occupants, wildlife habitat and biodiversity.

Unmanned aerial vehicles for planning rooftop rainwater harvesting systems: a case study from Gurgaon, India

Abstract Rooftop rainwater harvesting systems (RRWHS) effectively provide water access by storing precipitated water. The amount of water harvestable using these systems is proportional to the availability of rooftop areas in the region. The use of satellite imagery has gained traction in recent times considering the challenges in conducting a manual survey to determine the rooftop area. However, the limitations on spatial resolution impaired stakeholders from conducting similar assessments in areas with small residential units. In this regard, the use of unmanned aerial vehicles (UAVs) providing high-resolution spatial imagery for the delineation of rooftops of all scales has become popular. The present study is an attempt to utilize UAV-generated orthomosaics to estimate the harvestable quantity of rainwater for setting up an RRWHS. A study area in the Gurgaon district, India, is selected, and the steps involved in estimating the quantity of water harvestable using UAVs are demonstrated. In addition to these computations, a suitable site for constructing the storage unit is identified with the aid of a weighted overlay technique implemented using a Geographic Information System. The results from the study show that nearly 11,229 m3 of water can be harvested per year in the study site using the RRWHS.

Study on Potential and Practices of Rooftop Rainwater Harvesting System in Oxford College of Engineering and Management

The objective of this study was to evaluate the possibility of promoting rooftop rainwater harvesting to address future water scarcity in the Oxford College of Engineering and Management Nawalparasi district. AutoCAD software drew accepted plans and maps; manual measurement was done with measuring tape since some parts were missing.
 The results show that the linear forecast 1558.139, 1581.57mm,1548.63mm, 1598.14mm and 1570.64mm. The volume of water is 5135.54, 5028.16, 5188.94, 5099.68 respectively. It also shows the calculation of water demand which is 5,820,000 liters per year, and the water harvested is 5188946.58 liters per year. Finally, with this ratio, we realized we could fulfil 89.15% of water demand through water harvesting. The time series relevant results indicated that the A.R.I.M.A. model of forecasting rainfall was based on (0.1.0), signifying the R Square value is .631 and the p-value is insignificant (p > 250), which is better for this forecasting model.

Estimation of Water and Energy Saving by Rainwater Harvesting: Sulaimani City as a Case Study

Rainwater harvesting could be a possible solution to decrease the consequences of water scarcity and energy deficiency in Iraq and the Kurdistan Region of Iraq (KRI). This study aims to calculate the water and energy (electricity) saved by rainwater harvesting for rooftops and green areas in Sulaimani city, KR, Iraq. Various data were acquired from different formal entities in Sulaimani city. Moreover, Google Earth and ArcMap 10.4 software were used for digitizing and calculating the total rooftop and green areas. The results showed that for the used runoff coefficients (0.8 and 0.95), the harvested rainwater volumes were 2901563 and 12197131 m³ during the study period (2005 – 2006) and (2019-2020). Moreover, by comparing the study area's rainwater harvesting volume and water production, the water-saving percentage was 8.21 to 22.68%. Furthermore, the energy-saving percentage recorded was from 7.70 to 22.5% by implementing rooftop rainwater harvesting. On the other hand, using average daily rainfall data for the year (2005-2020), the total water-saving percentage and the total energy-saving rate for both runoff coefficients were very close. Water and energy-saving results were calculated using year-by-year rainfall data, taking more time and effort for its computation. Moreover, the water-saving percentage for the selected green area was not encouraging, and the results were between 0.73 and 11.15%. Additionally, the storage size for three typical buildings was calculated, and the results show the average storage size required for rainwater harvesting using daily rainfall data was 11.2 to 14.68 m³ (house), 291.42 to 422.33 m³ (school), and 10.5 to 11.41 m³ (hotel) for runoff coefficients of 0.8 and 0.95, respectively.

The impact of the regularization on the economic analysis of rooftop rainwater harvesting system

Abstract In this study, the economic feasibility of rooftop rainwater harvesting of residential and public/commercial buildings for all 81 provinces of Türkiye is assessed. The Rippl method (RM) is used for optimal storage tank estimation. The net present value (NPV) and the discounted payback period (DPP) are used for economic analysis. Two scenarios were assessed using RM for (I) residential buildings and (II) public buildings. Optimal storage tanks for scenarios I and II were estimated by the selection of minimum roof areas to supply the demand for toilet flushing water for above 90% volumetric reliability. ArcGIS 10.2 was used to illustrate nationwide results of (1) roof areas and storage tank volumes, and (2) the economic analysis. The average DPP of rainwater harvesting system is 36 years for residential buildings and 23 years for public buildings. Based on NPV analysis, 17 out of 81 provinces are economically feasible for residential buildings. The feasibility status in public buildings is 43 economically feasible and 38 infeasible. More savings in public buildings can be obtained in a relatively shorter DPP. Furthermore, regularization is more effective in public buildings than residential buildings.

Assessing the Feasibility of Rooftop Rainwater Harvesting for Food Production in Northwestern Arizona on the Hualapai Indian Reservation

With the uncertainties of climate change and the persistence of droughts in the Southwestern US, finding additional renewable water resources is crucial to ensure safe drinking water and attain food security in rural and tribal communities. Rainwater harvesting (RWH), the practice of centralizing, collecting, and storing rainwater for later use, has the potential to help alleviate some water stresses in these communities. Although RWH is not a new concept, it has not been widely practiced in arid and semi-arid environments in the United States. This study assessed the feasibility of rooftop RHW at a small scale, in Peach Springs, Arizona, on the Hualapai Indian Reservation. Working alongside the Federally Recognized Tribal Extension Program (FRTEP) agent for the Hualapai Tribe, this study considered RWH from four prospective buildings to supplement irrigation practices for food production. Due to high standard deviation and coefficient of variation values, annual precipitation amounts were classified into normal, dry, and wet years to assess variability over the last 40 water years. An average total of ~29,285 L could be collected from one of the buildings considered for RWH during the growing season of April to September during a classified normal year. The Food and Agriculture Organization’s (FAO) AquaCrop model was used to determine the area that can be cultivated with four staple crops, maize, tomatoes, dry beans, and sunflowers, which are currently being grown in the community garden, solely using the captured rainwater. Cultivable areas range from 8.7 m2 to 71 m2 depending on the catchment size, crop, and classified precipitation year—a wet, dry, or normal precipitation year. A total of 81.2 kg of dry corn could be harvested during a normal precipitation year, solely using the collected rainwater from one of the buildings.

Study on Potential and Practices of Rooftop Rainwater Harvesting System in Oxford College of Engineering and Management

Study on Potential and Practices of Rooftop Rainwater Harvesting System in Oxford College of Engineering and Management

Estimated Water Demand and Rooftop Rain Water Harvesting Potential of Dahiwadi College Campus in Man Tahsil of Satara District (Maharashtra)

Estimated Water Demand and Rooftop Rain Water Harvesting Potential of Dahiwadi College Campus in Man Tahsil of Satara District (Maharashtra)

Rainwater Harvesting for Water Conservation in Sanur’s Tourism Harbour Building: A SWMM Simulation

This study focuses on the implementation of rainwater harvesting as a water conservation alternative in the Sanur International Tourism Harbour Building. The research was conducted to evaluate the effectiveness of this technique in reducing the building’s dependence on freshwater resources and to determine its potential as a sustainable water management solution. The implementation of rooftop rainwater harvesting was considered, and SWMM (Storm Water Management Model) simulation was used to model the hydrological processes, including rainfall, runoff, and infiltration in the study area. The model was calibrated using observed rainfall data collected from the vicinity. The results of the SWMM simulation showed that the rainwater harvesting system was effective in reducing the building’s dependence on freshwater resources and that the system can collect an estimated 41.58 m3 of rainwater. This amount is deemed sufficient to support and overall reduce freshwater consumption and contribute to the conservation of freshwater resources in the area. The study demonstrated the potential of rainwater harvesting as an effective water conservation method for buildings in Sanur, Bali. The implementation of such a system can not only reduce freshwater consumption but also contribute to sustainable water management practices in the region.

Hill Women-led Spring Water Management in Darjeeling Himalayan Region, West Bengal

Water crises is a major problem of Darjeeling, West Bengal, India where rainfall is plentiful. Darjeeling gets only one-third of its daily water requirement through municipal pipelines. The water supply network is mostly town centred so the peripheral areas are deprived of water. Private suppliers also supply water at Rs. 300/- per month per household. Darjeeling Municipality established in 1850 has a centralised water management infrastructure laid down between1910–30. The water supply system originates in Senchel Wildlife Sanctuary, located 15 kilometres upstream of Darjeeling with two lakes and a storage of 33 million gallons of water that is recharged by 26 springs. This centralised system fails to acknowledge the vibrant 90 odd natural springs in the town that people are dependent upon. These urban springs have diverse community-based management systems that have evolved over time and are now facing challenges of rapid urbanisation, market forces, upstream concretisation and contamination and reducing discharges. Due to deforestation which is leading to high runoff resulting to less recharge of groundwater. Women, are worst hit, as they have to travel miles to fetch water in this rugged terrainfor her family while their male counterpart are busy to make both ends meet. Every household maintains a kitchen garden whose water is also being procured by females through irrigation. Rooftop rainwater harvesting is the imperative way to mitigate the water crisis. Moreover, reuse, recycle and reducing wastage will help to mitigate this water crisis.

Rooftop rainwater harvesting by a shallow well – Impacts and potential from a field experiment in the Danube-Tisza Interfluve, Hungary

Groundwater levels have declined significantly in the last decades in many parts of the world, due to anthropogenic activities and climate change. The study focuses on the long-term potential and environmental impacts of rooftop rainwater harvesting coupled with shallow well infiltration, which is a local scale inexpensive solution that could contribute to easing water shortage. The Danube-Tisza Interfluve (Hungary) was used as a study area, where a field experiment was set up, funneling rainwater from the roof of a family house to the shallow dug well in the yard, connected to a porous unconfined aquifer. Changes in groundwater levels, as well as thermal, hydrochemical and isotopic footprints were monitored and evaluated for over 600 days to determine the quantitative and qualitative effects of this method and to identify the long-term physico-chemical impacts of infiltrated water on ambient groundwater. During the monitoring period, 60.616 m3 of precipitation was infiltrated through the shallow well that could achieve significant water quality improvement: Mg2+, Na+, Cl−, SO42−, NO3− concentrations and TDS decreased by 35–88% after the infiltration started and a further 35–96% decrease occurred in these parameters by the end of the monitoring period. Rooftop-collected water was enriched in Zn, Sr, Cu, Mn, Ba and Al, their concentrations being 1.9–48.2 times higher, in roof runoff than in the precipitation. The monitoring of water column changes and infiltration curve analysis after precipitation events helped identifying the clogging process that decreased the hydraulic conductivity of the well bottom by one order of magnitude. The results of this research provide information on the efficiency and environmental impacts of the pilot project and contribute to the extension of the design to town level and to similar settlements in the area. Additionally, general conclusions can be drawn to promote the implementation of similar projects in porous unconfined aquifers worldwide.

Assessing the Rainfall Water Harvesting Potential Using Geographical Information Systems (GIS)

Water scarcity is a major issue for developing countries due to the continuous increase in population every year, the major environmental challenges faced by developing countries such as Pakistan being the scarcity of water. One proposed solution to meet the requirements is to conserve water from rainfall. The process consists of the collection, storage, and use of rainwater. The rooftop rainwater harvesting systems (RWH) and rainfall harvesting system for artificially recharged water by recharge wells have received increased attention in the recent past as an efficient means of water conservation. In this study, both the systems have been analyzed for the University of Engineering and Technology Taxila (UET Taxila), Pakistan. The objective of this study is to propose a system to harvest water from the rooftops of all of the buildings on the campus and also to propose the most optimum locations of recharge wells for the artificial recharge of groundwater development. Numerous field visits were conducted after every rainfall over the past few months to identify lower elevation areas, which were further validated by the results obtained by Arc GIS. The total area of catchments available for rainwater harvesting in UET Taxila and the amount of water that could be harvested or used for replenishing groundwater reserves were also assessed in the current study. The results show that the harvestable rooftop water per month is 59% of the currently available source for watering trees and plants, and the harvestable water by recharge wells is 761,400 ft3 per year.

Water Security in South Asian Cities: A Review of Challenges and Opportunities

Achieving water security in South Asian cities will require a realistic and holistic understanding of the challenges that are growing in extent and severity. These challenges include the rapid rise in urban household water demand due to both overall population growth and increasing urbanization rate. Additionally, surface water supply in closed river basins is fully utilized, and there is little opportunity in these regions to increase the extraction of surface water to meet rising demands. Furthermore, groundwater extraction in most regions exceeds natural recharge rates, leading to rapidly falling annual water tables and seasonal depletion in hard rock regions and to gradually declining water tables requiring deeper wells and increased pumping effort in alluvial regions. Additionally, even in cities with abundant water resources, poorer segments of the population often face economic water scarcity and lack the means to access it. Nevertheless, there are important potential engineering opportunities for achieving water security in South Asian cities. Much withdrawn water is lost due to urban water distribution inefficiency, and a range of proven techniques exist to improve distribution. Metering of urban water can lead to structural improvements of management and billing, though the water needs of the poorest city residents must be ensured. Industrial water-use efficiency can be significantly improved in manufacturing and electricity generation. The quantities of wastewater generated in South Asia are large, thus treating and reusing this water for other purposes is a strong lever in enhancing local water security. There is limited potential for rooftop rainwater harvesting and storage, though capture-enhanced groundwater recharge can be important in some areas. Some individual inter-basin transfer projects may prove worthwhile, but very-large-scale projects are unlikely to contribute practically to urban water security. Overall, the water challenges facing South Asian cities are complex, and although no single intervention can definitively solve growing problems, numerous actions can be taken on many fronts to improve water security.

Geospatial Assessment of The Potentials of Rooftop Rainwater Harvest at The Federal University of Technology, Akure, Nigeria

Recent reports reveal water shortage at the Federal University of Technology, Akure, (FUTA), Nigeria, with possibilities to worsen if adequate measures are not taken. This research focuses on the assessment of the potential of an alternative source of water supply the Roof Top Rainwater Harvest (RTRWH) at FUTA. This study goes beyond the determination of the potential volume of RTRWH by proposing a storage plan for the RTRWH based on geospatial analysis. Data collected for the study are rainfall data covering 19 years (2000-2018), High-Resolution Satellite Image (HRSI), Ground Control Point (GCP), attribute data, Landsat 8 and Shuttle Radar Topographic Mission (SRTM) Digital Elevation Model (DEM). The rooftop areas were extracted by processing HRSI using ArcGIS software. The volumes of the RTRWH for each building were computed with the rooftop area, precipitation amount and roof's runoff coefficient of the rooftop material as variables. Suitable locations for siting the storage tanks were proposed based on Multi-Criteria Decision Making (MCDM) and geospatial analysis. Result obtained from the study reveals that the total area of rooftop catchment for all buildings considered is 164,246 m2. The study suggests 9 locations suitable for collecting and storing the harvested RTRW. The potential average daily, average monthly and total annual volumes of RTRWH are approximately 607 m3, 18,473 m3 and 221,681 m3 respectively, and thereby could potentially provide ~ 41% of water demand in addition to the existing water supply sources in FUTA. The RTRWH is therefore recommended as an alternative water source at FUTA.

Ecological Conditions of Luetshokha Lake and its Recharge Potential using Rooftop Rainwater Harvesting, Samtengang, Wangdue Bhutan

Luetshokha lake is noted to harbour invasive aquatic plants and experience reduction in water level. This research assessed the floristic and macroinvertebrate composition of Luetshokha lake in Samtengang, Wangdue and its potential to increase water level using rooftop rainwater harvesting (RWH). Presence of aquatic plants such as Brasenia schreberi, Schnoeplectus pungens and Potamogeton distinctus indicate organic pollution of water in the lake. Coenagrionidae and Baetidae families were the most dominant macroinvertebrate communities present in the lake. There was a positive relationship between aquatic plants and macroinvertebrate diversity indices (rs = 0.20, p = 0.25), richness (rs = 0.24, p = 0.16) and evenness (rs = 0.29, p = 0.04). The relationships between aquatic plants and physico-chemical variables were negative; pH (rs = -0.02, p = 0.90), conductivity (rs = -0.45, p = 0.00), Total Dissolved Solids (TDS) (rs = -0.43, p = 0.01) and salinity (rs = -0.34, p = 0.56). However, temperature was positively correlated (rs = 0.25, p = 0.14) with aquatic plants. Similarly, macroinvertebrate diversity was negatively correlated with pH (rs = -0.31, p = 0.07), temperature (rs = -0.11, p = 0.54), conductivity (rs = -0.24, p = 0.17), TDS (rs = -0.24, p = 0.16) and salinity (rs = -0.27, p = 0.12). Family Biotic Index (FBI) indicated good physical condition of lake water with some organic pollution. The lake water level was estimated to rise by 0.05 m through a potential RWH of 1,784.37 m3 from the roof catchment area of 2,221.01 m2.

Performance of rooftop rainwater harvesting system as a source of drinking water

Rainwater Harvesting Systems (RWHSs) are increasingly being used as an alternative or supplementary source of water to curb the water supply deficit in the Kathmandu valley. The harvested rainwater is primarily used for non-potable purposes like flushing toilets and irrigation, but the knowledge on the use of rainwater for potable purpose is remarkably sparse. This study assesses the suitability of rainwater in terms of quantity and quality in a public school that adopts Rooftop RWHS as the source of drinking water. In this study, we observed that the volume of rainwater being harvested is sufficient to address the current demand of drinking water, with a mean rainfall of 1664 mm on a catchment area of 372 m2. Storage capacity needs to be expanded if the demand increases. Physico-chemical and microbial analyses of water samples (before and after a series of treatments) were carried out for the winter, monsoon, and post-monsoon seasons. The values of physico-chemical parameters of the water samples, in all the seasons, were well within both the National Drinking Water Quality Standards (NDWQS, 2005) and the World Health Organisation (WHO, 2017) guidelines for drinking water, while fecal coliforms were detected in the storage tank, but were absent in tap water after the treatments. Based on the findings, we suggest that the harvested rainwater could be used for drinking purposes if properly treated. RWHS use at the institutional level, like in schools, on the one hand, curbs the increasing demand for water in water-deficit locations like Kathmandu, and on the other, encourages the adoption of such sustainable technologies for the water supply.

The Potency of Obtained Clean Water from Rainwater Harvesting in Sikka District

Sikka District is one of the areas experiencing a clean water crisis because only 5.23 % of people have access to clean water in 2020. Therefore, rainwater management will be carried out to obtain clean water using roof top rainwater harvesting technology. This study aims to calculate the potency of clean water that can be obtained from rainwater harvesting. Comparative descriptive analysis method was used to compare the data of clean water potency that can be obtained from rainwater harvesting with the data of clean water needs from the people in Sikka District in 2020. The results show that the potency of clean water that can be obtained from rainwater harvesting is 3,593961.6 m3/year or 3,593,961,600 liters/year and clean water needs of all the people is 17,626,927 m3/year or 17,626,927,000 liters/year. The people that gets clean water from rainwater harvesting is 20.38 % or as many as 65,615 people from the total population in Sikka District. This shows that the use of rainwater cannot meet the clean water needs of all people in Sikka Distric. There is a need for other sources of clean water that are bigger and can be used to meet the needs of all people.

Rooftop rainwater harvesting for sustainable water usage in residential buildings for climate resilient city building: case study of Rajshahi, Bangladesh

PurposeThe effects of population growth in the developing world and climate change have increased the stress on available water resources. The majority of Rajshahi city, Bangladesh, is facilitated with groundwater withdrawal. As Bangladesh is a country of monsoon climate, reserved rainwater can be contributed as an alternative to extracted groundwater. This study aims to develop a framework for rooftop rainwater harvesting (RRWH) for domestic purposes and estimate the appropriate size of the storage tanks and their costs required to fulfill the annual drinking and cooking water demands through RRWH in Rajshahi city of Bangladesh.Design/methodology/approachA total of 100 single-story residential dwellings with varying rooftop areas were surveyed for the projection of RRWH potential. The relationship between the size and cost of a water tank and the rooftop areas of different houses is expressed using a general mathematical equation. Cost estimates for the proposed RRWH system for all houses have been completed, and a cost model illustrating the relationship between rooftop or catchment area and associated cost of RRWH system has been developed.FindingsThis study reveals that a maximum of 110.75 m3/year rainwater can be collected from a 100 m2 rooftop area of Rajshahi city. Moreover, this study finds that such harvesting of rainwater can reduce municipal water supply to the extent of almost 75%. Water samples collected from rooftops also revealed that if germs were removed through bacteria treatment, the collected rainwater potentially can be used for drinking and cooking purposes.Originality/valueThe novelty of this study is that it focused mainly on how significant RRWH can be to meet people’s daily required amount of water for household purpose and ascertain the cost reduction using the RWH method. This paper also is unique as it assessed the volume of the storage tank that is sufficient to distribute the necessary amount of water for drinking and cooking purpose as a sustainable alternative source in the dry season.

A Review on Recent Trends in Rooftop Rainwater Harvesting Technologies

Abstract: Water is one of the world's most valuable resources. Water is required for a variety of tasks in our daily lives. The traditional method of damming rivers and transferring water to urban areas has its own set of social and political difficulties. In order to preserve water and satisfy our daily demands, we must consider alternative cost-effective and relatively simple technical techniques of water conservation. Rooftop rainwater collecting is one of the most effective ways to meet these needs. To begin, the necessary data, such as catchment regions and hydrological rainfall data, are gathered. The collected water must be analysed physically, chemically, and biologically in a laboratory setting. The rooftop's water collecting potential must be calculated. In this review paper methods of analyzing rooftop materials, basic rooftop designing for rainwater harvesting and new technological updates in identification and evaluation of a potential rooftop for rainwater harvesting are reviewed. Keywords: Rwh , Gis , Materials , Remote Sensing

Review on Design of Rooftop Rainwater Harvesting in Gandhi Institute for Technology (GIFT), BBSR

Abstract: Water is the main asset on the earth. Which requires water for different exercises in our everyday life at the rate at which India's general population is growing, it is said that India will undoubtedly replace China from its fundamental place as the most thickly populated country in the world. This will provoke a high pace of use of most huge trademark resource "Water" achieving development of loads on the permitted freshwater resources and supply of it is diminishing at a quickly protected on this planet. Remembering the ultimate objective to proportion and deal with our step by step interest in water essential, we need to think of elective adroit and respectably easier mechanical methodologies of preserving water. The specialized part of this venture is water harvesting gathered from GIFT main building rooftop. Above all else, a little piece of the rooftop is taken where a steep slant is available where water overflows streams and the point of this venture is to gather and store that water and use the water by giving a legitimate method for filtration. The task begins by gathering some significant investigations on water Harvesting and concentrating on them. A legitimate arranging work led to GIFT for an appropriate picture of what is going on at GIFT College and to quantify the elements of the rooftop catchment area. Then other required information is gathered for example hydrological precipitation information and temperature. The volume of water will ascertain thereafter. Water collecting potential for the school will ascertain, and an appropriate plan will be considered. The vital variable of this undertaking is the channel unit which will be planned productive and prudent and possible to carry out in the school. In conclusion, this venture is taken on for preserving the main normal source on the earth. It is a drive to safeguard the water source. "Save Water, automatically Water will save us". Keywords: Rooftop harvesting, channel configuration, rooftop catchment area.