Potential Rainwater Research Articles

A sustainable design approach of a mega hostel: a study based at NIT, Srinagar, Kashmir, India

ABSTRACT In a sustainable building design, energy, water and resource optimization are key considerations, along with minimizing impacts on the ecology and environment. In this case study, water-related issues are considered from a sustainability perspective. The main objective of this study is to provide a sustainable design for a mega-hostel at the National Institute of Technology (NIT) Srinagar, with the aim of achieving an eco-friendly design which minimizes its dependence on external sources of energy. Rainwater harvesting, greywater reuse and the installation of a biogas plant are the three main techniques considered in this project. Rainfall data were collected and water demands for the mega-hostel and greywater produced by the mega-hostel were estimated. Potential rainwater harvesting, dimensions of a storage tank, first flush volume, discharges and dimensions of gutters have been calculated in this study. Greywater quantity has been calculated and a membrane bioreactor (MBR) to treat greywater is suggested, because it is space-optimized. Dimensions of a biogas plant and the quantity of gas released have also been estimated based on the amount of food waste generated by the mega-hostel.

Rainwater Harvesting Site Selection for Drought-Prone Areas in Somali and Borena Zones, Oromia Regional State, Ethiopia: A Geospatial and Multi-Criteria Decision Analysis

Rainwater collection systems play a crucial role in enhancing water availability in regions with low precipitation. This study focused on identifying potential rainwater harvesting (RWH) locations in drought-prone areas, specifically the Borena zone of Oromia and the regional states of Somali. This research leveraged geospatial techniques and a multi-criteria decision analysis (MCDA) to assess feasible RWH sites. The dataset comprises essential factors such as rainfall, drainage density, slope, soil texture type, and land use/land cover. These thematic layers serve as inputs for analysis, with each factor being weighted using the Analytical Hierarchy Process (AHP) method based on its significance. Reclassifying factors into subclasses facilitates suitability analysis. The weighted linear combination (WLC) technique is applied to identify and prioritize potential rainwater harvesting (PRWH) locations based on four suitability classes: highly suitable, moderately suitable, low suitability, and unsuitable. Our findings reveal that 1% of the study area, covering approximately 3288 km2, is highly suitable for RWH. Areas with moderate suitability constitute approximately 12% (37,498 km2), while regions with low suitability, representing the majority, encompass about 75% (242,170 km2). Additionally, 13% (41,000 km2) of the study area is deemed unsuitable for RWH. The proposed technique for identifying suitable RWH sites is adaptable to other low-precipitation regions. However, before implementing RWH structures, further research is imperative. This study proposed the exploration of socioeconomic variables in future research and urged for an in-depth examination of various aspects of environmental sustainability. Our research paves the way for adapting rainwater harvesting systems to align with community needs and life cycles while also exploring the socio-economic and environmental dimensions of sustainability for future study. The insights offer promising solutions to address the urgent issues associated with water scarcity. This should include comprehensive site depictions, an exploration of social and economic activities, and the meticulous preparation of a cost-benefit analysis.

Technical and economic impact of water reuse as an integrated water resource management measure in rural water supply systems

ABSTRACT Water reuse becomes an alternative to reduce the demand in the conventional water supply systems, especially in regions, where non-potable use of drinking water, as for garden and grass irrigation, is predominant. This study evaluates the footprint of reuse on small water supply systems in rural areas, where raw water quality does not meet the drinking water standards and complicated treatment is needed. Individual facilities for reuse of potential rainwater, light gray, gray and domestic wastewater in the households could lead to a decrease in non-potable tap water use up to 60% and a decrease of households' annual expenses for water supply up to 93 €/household. The installation of individual facilities for common reuse of rainwater and gray wastewater requires the highest investment costs, but the option`s operational costs are between 15% and 20% lower than all other options considered. The Drinking Water Treatment Plant capacity reduction due to Integrated Water Resource Management measures implementation enables from 48% up to 58% saving in the total operational costs for drinking water supply in the settlement. The shortest payback period and best economic impact of reuse for small scale water supply systems is observed if rainwater and gray wastewater are reused together.

Integrated Exploitation of Rainwater and Groundwater: A Strategy for Water Self-Sufficiency in Ca Mau Province of the Mekong Delta

Groundwater sources have been exploited excessively for numerous purposes worldwide, leading to increasingly severe depletion. However, the replenishment of groundwater sources has not usually been a focus in economically and socially underdeveloped countries and regions. In coastal provinces of the Vietnamese Mekong Delta (VMD), rural areas are facing difficulties in accessing fresh water due to shortages from the water supply plant and excessive use of groundwater, highlighting an urgent need for sustainable development solutions. Our study first conducted interviews with 200 households in Ca Mau Province of the VMD to identify the current situation and the challenges and obstacles of rainwater harvesting and to find sustainable and proactive solutions. We then analyzed daily rainfall data from 10 meteorological stations to construct four scenarios of the water balance method: (i) potential rainwater harvesting based on existing roof area; (ii) optimal scale of storage tank and catchments for different levels of water usage; (iii) tank scale utilizing rainwater entirely during the rainy season and basic needs during the dry season; and (iv) integrated water supply between rain and groundwater. The results showed that using rainwater entirely for domestic water supply requires large storage tank capacities, making these scenarios difficult to achieve in the near future. Our research introduces a novel integrated water supply approach to storing rain and groundwater that has demonstrated high effectiveness and sustainability. With existing tank capacities (0.8 m3 per person), rainwater could only meet over 48% (14 m3 per year) of the water demand while requiring 14.8 m3 of additional groundwater extraction. With a tank capacity of 2.4 m3 per person, ensuring rainwater harvesting meets basic demand, harvested rainwater could satisfy 64% of the demand, with artificial groundwater supplementation exceeding 1.79 times the required extraction, while excess rainwater discharge into the environment would be minimal. Our research results not only provide potential solutions for rainwater and groundwater collection to supplement sustainable domestic water sources for Ca Mau but also serve as an example for similar regions globally.

Flood Risk Reduction Strategy With Vertical Drainage In Medan City, Indonesia

As the population of a city increases, there will be excessive exploitation of nature, uncontrolled land use change, and a decrease in the environment’s carrying capacity. These impacts cause flood disasters to increase in quantity and quality. Floods are still difficult to predict and avoid. Medan City is still haunted by the same problem as other cities in Indonesia, namely flooding. The government has focused on flood management by building a horizontal drainage network system, normalizing rivers, building embankments, but flooding still occurs frequently. Therefore, vertical drainage is needed for flood management. Vertical drainage drains surface water directly into the soil layer that horizontal drainage cannot accommodate. This research aims to study the ability of vertical drainage in Medan City to reduce flood risk. Based on the test results, vertical drainage has a discharge of 0.812 liters/second. Based on technical calculations, vertical drainage can distribute potential rainwater collected on the surface and with the addition of possible water from other sources at the research site within 9 minutes 1 second until it runs out as much as 440 liters. As a result, one vertical drainage system can effectively accommodate an area of 25 m2.

Selection Frameworks for Potential Rainwater Harvesting Sites in Arid and Semi-Arid Regions: A Systematic Literature Review

Water shortage is a concern in arid and semi-arid regions across the globe due to their lack of precipitation and unpredictable rainfall patterns. In the past few decades, many frameworks, each with their own criteria, have been used to identify and rank sites for rainwater harvesting (RWH), a process which is critical for the improvement and maintenance of water resources, particularly in arid and semi-arid regions. This study reviews the present state of the art in rainwater harvesting site selection for such regions and identifies areas for additional research. The results of a systematic review performed based on two major databases of engineering research, Scopus and Engineering Village, are presented. Sixty-eight relevant studies were found and critically analysed to identify patterns and unique features in the frameworks used. The results of this study show that 41% of the frameworks consider both biophysical and socioeconomic criteria, whereas the remaining 59% of the frameworks depend on biophysical criteria alone. The importance of each criterion is encapsulated through a suitability score, with 21% of the frameworks using a binary (0 or 1) indicator of whether the site matches a criterion or not and the other frameworks using graded scales of differing granularities, with 52% using a low-resolution scale of 1 to 3, 4, or 5, 7% using a medium-resolution scale of 1 to 10, and a further 7% using a high-resolution scale of 1 to 100. The remaining 13% of the frameworks did not specify the scale used. Importantly, this paper concludes that all existing frameworks for selecting RWH sites are solely based on biophysical and/or socioeconomic criteria; ecological impacts, the consideration of which is vital for building RWH systems sustainably, are currently ignored.

GIS based identification of water harvesting potential area in the Bale lowland of south eastern Ethiopia

ABSTRACT Assessment of potential surface runoff harvesting sites is an important undertaking in a country like Ethiopia, where high spatial variability in rainfall, recurrent drought, and flash floods are common. In this study, a geographical information system (GIS)-based multi-criteria evaluation was used to select potential rainwater harvesting sites in Oromia, the Bale lowland, Ethiopia. The Analytic Hierarchy Process (AHP) was used for standardization of the criteria and weight overlay analysis of multicriteria for a combination of multi-layers using ArcGIS 10.8. Six criteria layers, including slope, runoff, soil depth, precipitation, soil texture, and land use land cover, were derived to identify the rainwater-harvesting catchment. The analysis, shows that of the total 500 km2 of the catchment area 29.18% of the area has highly suitable 40.87% of the area has suitable 22.49% of the total area has moderately suitable 6.98% of the area has marginally suitable and 0.5% of the area is not suitable for runoff water harvesting at the study area. Providing accurate and precise spatial representation of the physiology and land use for the analysis of runoff generation potential sites within the study area is an important step in developing an integrated strategy for surface rainwater harvesting plans in the study area.

Use of remote sensing to determine rainwater harvesting sites for piped micro-irrigation schemes in Chimanimani District, Zimbabwe

The eastern highlands of Zimbabwe, particularly Chimanimani District, are endowed with natural water bodies such as springs, pools, wetlands, puddles and river systems, which are potential sources of water for irrigated farming. Despite this, water challenges continue to exist due to rainfall seasonality and lack of suitable water harvesting sites. This calls for solutions to harness water in long-lasting sources to support the piped micro-irrigation schemes. These schemes are pillars in agricultural interventions such as horticulture, livestock farming, fish farming and beekeeping. This study therefore, determined potential rainwater harvesting (RWH) sites in Chimanimani District using geospatial techniques. Water pixels from Landsat 8 images were extracted using the normalised difference moisture index (NDMI) and normalized difference vegetation index (NDVI). Potential RWH sites were classified into land-based zones, wetlands and natural water bodies. Findings show that land-based zones cover 27.53%, wetlands cover 24.65% and water bodies cover 6.11% of the district. The study also indicates that integrating geographic information systems with remote-sensing tools is a useful approach in identifying RWH sites. Thus, this study provided a spatially explicit approach and presents a suitability map for RWH in Chimanimani District.

Spatial sensitivity of generalised equations to predict rainwater tank outcomes: a case study for Brisbane

Several studies have been conducted to calculate potential rainwater savings through rainwater tanks installed in residential and commercial buildings.

Determination of Rainwater Harvesting Potential: A Case Study from Ege University

Rainwater is a valuable resource that provides numerous benefits. The necessity of collecting and reusing rainwater has increased in cities where the effects of climate change are prominent. With little effort and a relatively high initial construction cost, harvesting rainwater can be a cost-effective benefit. In addition to its economic benefits it is an environmentally friendly process that prevents the rainwater from going to waste. In this research the roofs of 24 buildings in an area around Ege University Central Campus (Izmir, Turkey), which has a Mediterranean climate, were selected for a pilot project. The amount of rainwater to be harvested was calculated to be 16.570,30 m3. This study determined that the potential rainwater to be harvested from the research area throughout the year could provide 11% of the water required for irrigation of the existing green areas throughout the year and 20% of the water required for irrigation from April to October. Therefore, considering the ratio of the potential rainwater that was harvested during the summer season to the potential rainwater amount that could be harvested throughout the year, this experiment showed the potential benefits of storing the harvested rainwater in the rainy spring and winter seasons throughout the year.

Climate Change Impacts on ‘Seasonality Index’ and its Potential Implications on Rainwater Savings

Seasonality Index (SI) is commonly used to define rainfall variability within a year for a locality, which has got significant impact on the water resources planning and management. Both the longer periods of dry and wet conditions are reflected by SI value. As SI is calculated using historical rainfall data, a historical average value is represented for a locality. However, with the emerging impacts of climate change SI values based on historical data are likely to change. This paper presents expected changes in future SI values for the largest city of Australia (Sydney) based on projected future rainfall scenarios for the city. The paper further illustrates potential water savings through rainwater tanks under projected climate change scenarios using an earlier developed daily water balance model, eTank. For the simulations of potential water savings through rainwater tanks, projected daily rainfall data was collected from Australian government data portal for four stations within Sydney. Future potential rainwater savings efficiencies were correlated with the corresponding SI values. It is found that such correlation closely matches with an earlier developed correlation using past historical data, however the future water savings efficiency will be slightly lower than the past water savings efficiency.

Suitable sites identification for potential rainwater harvesting (PRWH) using a multi-criteria decision support system (MCDSS)

Suitable sites identification for potential rainwater harvesting (PRWH) using a multi-criteria decision support system (MCDSS)

Assessing Suitable Techniques for Rainwater Harvesting Using Analytical Hierarchy Process (AHP) Methods and GIS Techniques

The objective of this study is to produce suitability maps for potential rainwater harvesting techniques (RWHT) in the West Bank (WB), Palestine. These techniques aim to reduce water scarcity, which is a major problem for the conservation of water resources in the area. Based on literature reviews and expert recommendations, seven RWHts were selected (runoff basin system, contour ridges, cisterns, eyebrow terrace, check dam, on-farm pond, and bench terraces). Analysis methods performed in the Arc GIS environment include spatial analysis and data reclassification. Other calculations include multi-criteria analysis for assigning suitability. Five criteria (rainfall, runoff, land use, slope, and soil texture) for RWHt were analyzed to produce a suitability map for each technique. The results show that runoff basin systems in the northeast and southwest of WB are the most suitable, with about 50% of the area of WB moderately suitable for this technique, while 70% of the area of WB is very suitable for the contour ridge technique. Furthermore, this analysis shows that almost 50% of the WB is very suitable for cisterns. Sixty percent of the area is very suitable for on-farm puddling, especially in the north and southwest of WB. The areas with high suitability for the different techniques comprehensively cover the WB, as shown in the RWHt suitability maps and the integrated map. Nevertheless, this approach can help decision makers in making an initial selection of RWH techniques suitable for their region.

Superiority of water balance modelling for rainwater harvesting analysis and its application in deriving generalised equation for optimum tank size

In an urban setup optimum size of rainwater tank is a critical factor, as the space required for the rainwater tank is limited and expensive. Several methods have been used for the analysis of potential rainwater harvesting. Some authors used Rippl method for rainwater tank sizing. However, through Rippl method, required size often becomes too big and not feasible in an urban space. This paper presents a water balance modelling concept for rainwater harvesting analysis and its application in determining optimum tank size for rainwater harvesting. Results of the daily water balance model were compared with an earlier study results through Rippl method using daily rainfall data for the city of Nablus (Palestine). Daily rainfall data was collected for the city and from the collected data, three years were selected as dry, average and wet years. Using a typical average rainwater demand and the roof sizes used in the published study, and daily rainfall data for the selected years, annual water savings were calculated for varying tank sizes. From the simulated results, it is clear that for tank sizes beyond certain threshold volumes, annual expected water savings remain unchanged. It is found that Rippl method calculated optimum tank sizes are almost double the optimum tank sizes determined through eTank simulations. Finally, several optimum tank sizes were calculated for different roof sizes and demands considering an average weather condition. It is found that the optimum tank sizes can be correlated with the roof size and rainwater demand, which can be incorporated into a single generalised equation for optimum tank size. The equation calculated results are very close to the original optimum tank sizes found through manual calculation.

RANCANGAN SISTEM PEMANENAN AIR HUJAN UNTUK RUMAH TOKO DI KECAMATAN KUTA ALAM KOTA BANDA ACEH

Rainwater harvesting is known as one of solutions for water conservation. Rainwater harvesting decreases stormwater runoff which reduce erosion, conserve water at local level to be used later and so on. Indonesia as tropical country has great water resources, but rainwater harvesting is not common, people only let the rainwater flow to the river without intention to preserve it. This study aims to test the quality of rainwater in the district of Syiah Kuala, Banda Aceh City, then plan the design of a rainwater harvesting system for shop houses that are often found in this area. The study conducted by testing the physical parameters of rainwater quality, collecting common shop house dimension data, and rainfall data, then calculating the potential rainwater that can be harvested by hydrology analysis, and then determine the volume, design, drawing of the rainwater harvesting system. The result shows that pH ranges from 7.8 to 7.9; temperature 28-31; DHL minimum 4u / cm and maximum 20u / cm; TDS ranges from 3-9 ppm, and all of this numbers meet quality standards of PERMENKES NO 32/2017. The highest daily rainfall level was in December 2014 (77.6 mm), and the average monthly rainfall for the last 10 years is 156,321 mm. With a planned rainfall value of 30.8 mm/hour, 2 hours of rain duration, and a return period of rain of 2 years, rainwater has the potential discharge quantity of 0.8 liters/second. The dimension of the system (regarding to SNI 8153:2015) are: (1) horizon pipe 3 inch long, (2) vertical pipe it is 4 inch, and reservoir volume is 0.5 m3

Design of Potential Rainwater Harvesting Structures for Environmental Adoption Measures in India

Design of Potential Rainwater Harvesting Structures for Environmental Adoption Measures in India

PERENCANAAN PEMANFAATAN SISTEM PEMANENAN AIR HUJAN (PAH) DALAM MENDUKUNG PENERAPAN ECODRAIN DI KAMPUS B UNIVERSITAS NEGERI JAKARTA

This research is done to plan rainwater harvesting so that it can be used as an alternative water source on the campus B UNJ so it is expected to reduce groundwater use that can cause a puddle. The method used in the PAH development plan is a water balance method. This method compares the level of demand with water volume that can be accommodated or the availability of water (supply). Based on the results of the analysis, it was found that the potential for rainwater in the FIO office building A was 1773.95 m3 , FMIPA building B was 1904.62 m3 , the FIO lecture building C was 1613.21 m3 and the Ulul Albab mosque was 512.16 m3 . Potential rainwater obtained cistern PAH capacity of 200 m3 by saving water needs by 30% in building A FIO, building B FMIPA, and building C FIO. The capacity of the PAH cistern is 80 m3 by saving the water needs of the Ulul Albab mosque by 13.3%. Placement of the PAH cistern under the ground with a ground water system. Ecodrainage application by utilizing the PAH system can reduce drainage load by 0.158 m3 /second or 13.9% from rainwater runoff.

Potential rainwater harvesting suitable land selection and management by using GIS with MCDA in Ebenat District, Northwestern Ethiopia

Rainwater harvesting (RWH) is the way to reduce the effects of mid-season dry spells and drought, which often reduce crop yields. Geographic information system (GIS) with multi-criteria decision making (MCDA) is a powerful tool to identify and solve spatial problems like the identification of the suitable site of RWH. Sentinel image, soil, metrological row data, geological data, and digital elevation model (DEM) data were the source of a dataset to undertake the preprocessing, manipulation, and analysis the suitable site identification by using GIS and remote sensing spatial analysis. More than seven parameters where identified based on an extensive literature review which is land use/land-cover, soil textural, rainfall, lineament, slope, runoff density and curve number, distance from settlement and road. The multi-criteria decision-making method was used for weight value estimation of each criterion and finally, the rainwater harvesting suitability map was generated. The potentially suitable site was grouped into four levels of suitability, which accounts in hectare 3,620, 16,0618, 69,867, and 14,010 ha of highly suitable, moderately suitable, less suitable, and restricted respectively from the total area coverage of 248,115 ha respectively.

Assessment of the potential of rainwater harvesting for maize production in the Lubombo plateau

Eswatini has persistently experienced below average and dwindling maize production chiefly due to low rainfall characterized by erratic patterns. The objective of the study was to assess the potential of rainwater harvesting for rain-fed maize production in the Lubombo plateau. Rainy season characterization, determination of maize crop net irrigation requirements, and assessment of runoff potential and identification of suitable rainwater harvesting sites were carried out to achieve the objective of the study. Rainy season characterization was carried out in INSTAT Plus Statistical software. The net crop irrigation requirement was calculated using CROPWAT 8.0 while the ArcCN-Runoff tool was used to estimate the potential runoff volume generated in the study area. Multi-layer merging of rainfall, slope, soil texture and land use layers was performed in GIS environment to locate potential rainwater harvesting sites. The study revealed that the probabilities of prolonged dry spells are relatively higher during the maize growing season. Nearly 60% of the catchment's area was found to be suitable for rain water harvesting. Through harvesting runoff generated in croplands, the study established that 45% of the crop water requirement deficit could be met. This shows that there is high potential for rainwater harvesting and subsequent use of harvested water to stabilize maize yield in the Lubombo Plateau. These findings can facilitate better planning for rain-fed agriculture in Eswatini while minimizing related climate risks. This study also managed to bridge the literature gap in viability of rainwater harvesting for rain-fed agriculture in the country.

A GIS-Based Multicriteria Analysis in Modeling Optimum Sites for Rainwater Harvesting

In order to select suitable rainwater harvesting sites within the study area, rainwater harvesting criteria needed to be determined, defined, and structured. Several criteria played an important role in selecting the most suitable rainwater harvesting sites. A multicriteria analysis (MCA) approach, which is widely used to classify potential rainwater harvesting sites, was chosen to help select potential sites in the Wadi Horan region of Iraq. An MCA approach offered a systematic methodology focused on mathematics as well as professional expertise to organize and evaluate complex decisions. Unfortunately, there is no method for choosing among them the most appropriate for a given decision problem, as the choice remains a subjective task. This study used a geographic information system (GIS)-based approach with remote sensing to identify the optimal sites for rainwater harvesting. Four indices: evaporation, cost–benefit, sediment, and hydrology were selected in order to compare the potential sites. The analytic hierarchy process (AHP), fuzzy AHP, and rank order method (ROM) were used to assign weight to the study criteria. The results were then compared using a statistical (variance inverse (VI)) method. A sensitivity analysis was done to test the uncertainties and robustness of the results for each method. The results showed that the ROM and VI methods affected the ranking priority and considered all of the criteria that were sensitive to impact in the ranking process at the different levels compared to the methods of AHP and fuzzy AHP.