Balancing water demand reduction and rainfall runoff minimisation: modelling green roofs, rainwater harvesting and greywater reuse systems

2014 ◽  
Vol 15 (2) ◽  
pp. 248-255 ◽  
Author(s):  
Domniki Stratigea ◽  
Christos Makropoulos
Keyword(s):  
Water Demand ◽  
Potable Water ◽  
Rainwater Harvesting ◽  
Demand Management ◽  
Green Roof ◽  
Green Roofs ◽  
Model Parameters ◽  
Water Storage Tank ◽  
Total Runoff ◽  
Greywater Reuse

Recent years have seen a growing interest in more distributed approaches towards stormwater management, often integrated with other forms of distributed management of urban water such as water demand management technologies. This paper focuses on the role of green roofs (GR), rainwater harvesting (RWH) and greywater reuse and their integration at the building level. A number of models were developed to simulate these systems, and provide design curves able to simultaneously minimise both total runoff volumes and the amount of potable water used in the building (for irrigation and toilet flushing). The models developed were applied to the design of stormwater infrastructure for the building of the National Gallery, in Athens, Greece. A sensitivity analysis of various model parameters was conducted, with results suggesting, inter alia: (i) a significant decrease of total runoff volumes for rainfalls of medium-to-small return periods; (ii) a significant influence of the plant factor on water requirements (with implications for selecting vegetation for GR in a Mediterranean climate); and (iii) a significant impact of latent heat peaking during the months of June and July. The trade-off, on runoff volumes, between percentage of green roof area and the dimensions of the water storage tank was also investigated. The results suggest that the most preferable solution for conserving potable water was RWH combined with greywater recycling, while for runoff minimisation the best option was the combination of green roof and greywater recycling.

scholarly journals Modelling Rainwater Harvesting and Greywater Reuse for Tank Size Optimizations

10.29007/zwnv ◽  
2018 ◽  
Author(s):  
Sara Simona Cipolla ◽  
Marco Maglionico
Keyword(s):  
Potable Water ◽  
Rainwater Harvesting ◽  
Daily Rainfall ◽  
Residential Building ◽  
Green Roofs ◽  
Water Withdrawal ◽  
Water Supply Systems ◽  
Alternative Source ◽  
Climate Conditions ◽  
Greywater Reuse

In the light of water shortages, frequently affecting many regions worldwide, domestic rainwater harvesting and greywater reuse systems represent an alternative source to provide non-potable water in buildings, reducing the water demand from mains water supply systems. This study fits this framework providing a methodology, based on a hydraulic/hydrological model developed by means of the EPA’s Storm Water Management Model, which allow optimizing the system design by giving the opportunity to the user to consider different catchments surfaces (impervious, gravel and green roofs), plant's configurations, user’s habits, water end-uses, and climate conditions. The model has used to model a residential building, located in the city of Bologna (Italy), and equipped with a hybrid greywater/rainwater system. Continuous simulations were performed with 13 years daily rainfall data, and the long-term performance of different system combinations were evaluated. The case study showed a non-potable water saving efficiency of 75.86%, which accounts by 26.71% mains water withdrawal. The final goal of this paper is those of presenting the hydrological/hydraulic model that has been used as engine of a calculator tool for sizing and planning hybrid rainwater/greywater systems.

Designing a rainwater harvesting system for urban green roof irrigation

2014 ◽  
Vol 15 (2) ◽  
pp. 271-277 ◽  
Author(s):  
Liaw Chao-Hsien ◽  
Huang En-Hao ◽  
Chiu Yie-Ru
Keyword(s):  
Potable Water ◽  
Rainwater Harvesting ◽  
Design Method ◽  
Green Roof ◽  
Green Roofs ◽  
Replacement Rate ◽  
Rapid Urbanization ◽  
Simulation Based ◽  
Water Replacement ◽  
Design Factors

Green roof systems have been suggested to ease the growing urban environmental problems resulting from rapid urbanization. However, the irrigation of green roofs heavily depends on using precious potable water and consequently generates negative environmental effects. Rainwater has been recommended to address this dilemma, but the design method has not been well developed. In this study, the major design factors of a rainwater harvesting system for green roof irrigation systems are examined, and a simulation-based mathematical model is established to elucidate the correlation between tank volume and system performance. The optimal system design and probability distribution of the potable water replacement rate are also discussed on the basis of a case study of a university building in Keelung, Northern Taiwan. The results show that the optimal tank volume, potable water replacement rate, and probability of exceedance are 9.41 m3, 92.72%, and 88.76% (±1SD), respectively. In addition, the economic performance is identified to be feasible. Hence, the design method has been verified to be a useful tool to ease the urban environmental issues.

scholarly journals Comparing simulations of green roof hydrological processes by SWMM and HYDRUS-1D

2019 ◽  
Vol 20 (1) ◽  
pp. 130-139 ◽  
Author(s):  
Xie Haowen ◽  
Wu Yawen ◽  
Wang Luping ◽  
Luo Weilin ◽  
Zhou Wenqi ◽  
...  
Keyword(s):  
Process Model ◽  
Low Impact Development ◽  
Green Roof ◽  
Green Roofs ◽  
Storm Water Management Model ◽  
Total Runoff ◽  
Storage Reservoirs ◽  
Swmm Model ◽  
Hydrus 1D

Abstract Green roofs are a sustainable, low-impact development technique. They can reduce peak stormwater runoff and runoff volume and improve the quality of runoff from individual buildings and developments, which can lower the risk of frequent urban flooding and improve the quality of receiving waters. Few studies have compared different types of green roof models under the same rainfall intensities; thus, in this study, the predictions of a non-linear storage reservoirs model, Storm Water Management Model (SWMM), and a physical process model (HYDRUS-1D) were discussed. Both models were compared against measured data obtained from a series of laboratory experiments, designed to represent different storm categories and rainfall events. It was concluded that the total runoff of the SWMM model is always less than that of HYDRUS-1D. The maximum flowrate of the SWMM model is more than that of HYDRUS-1D during all events.

scholarly journals Reduction of Potable Water Consumption and Sewage Generation on a City Scale: A Case Study in Brazil

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2351 ◽  
Author(s):  
Cureau ◽  
Ghisi
Keyword(s):  
Water Consumption ◽  
Potable Water ◽  
Rainwater Harvesting ◽  
Single Family ◽  
Water Savings ◽  
The Public ◽  
Water Demands ◽  
Harvesting Systems ◽  
The City ◽  
Greywater Reuse

This article aims to estimate the reduction of potable water consumption and sewage generation in the city of Joinville, southern Brazil. Four strategies were considered to promote potable water savings: replacement of conventional toilets with dual-flush ones, greywater reuse, rainwater harvesting, and the combination of these three strategies. Residential, public, and commercial sectors were assessed. The potential for potable water savings ranged from 1.7% to 50.5%, and the potential for sewage generation reduction ranged from 2.1% to 52.1%. The single-family residential sector was the most representative for water savings and sewage generation reduction. The public sector would be the least contributor to such reductions. It was found that in the city of Joinville, for low non-potable water demands, greywater reuse was the most viable strategy to save water. When non-potable demand is high and there is a large catchment area, it is recommended to install rainwater harvesting systems. It was concluded that there is a high potential for potable water savings and reduction of sewage generation if measures were adopted in Joinville, but it is necessary to evaluate which strategy is the most appropriate for each building.

scholarly journals Stormwater Retention and Reuse at the Residential Plot Level—Green Roof Experiment and Water Balance Computations for Long-Term Use in Cyprus

Water ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 1055 ◽  
Author(s):  
Katerina Charalambous ◽  
Adriana Bruggeman ◽  
Marinos Eliades ◽  
Corrado Camera ◽  
Loukia Vassiliou
Keyword(s):  
Water Balance ◽  
Plant Species ◽  
Rainwater Harvesting ◽  
Green Roof ◽  
Irrigation Treatment ◽  
Stormwater Runoff ◽  
Green Roofs ◽  
Roof Experiment ◽  
Stormwater Retention

Green roofs can provide various benefits to urban areas, including stormwater retention. However, semi-arid regions are a challenging environment for green roofs as long dry weather periods are met with short but intense rainfall events. This requires green roofs to retain maximum volumes of stormwater, while being tolerant to minimal irrigation supplies. The objectives of this study are (i) to quantify the stormwater retention of two substrate mixtures with two plant species under natural rainfall; (ii) to assess the performance of two plant species under two levels of deficit irrigation; and (iii) to compute stormwater runoff reduction and reuse by green roofs and rooftop water harvesting systems for three standard residential plot types in urban Nicosia, Cyprus. A rooftop experiment was carried out between February 2016 and April 2017 and results were used to compute long-term performance. Average stormwater retention of the 16 test beds was 77% of the 371-mm rainfall. A survival rate of 88% was recorded for Euphorbia veneris and 20% for Frankenia laevis, for a 30% evapotranspiration irrigation treatment. A combination of a green roof, rainwater harvesting system and 20-m3 tank for irrigation and indoor greywater use reduced stormwater runoff by 47–53%, for the 30-year water balance computations.

Assessment of real losses in potable water distribution systems: some recent developments

2005 ◽  
Vol 5 (1) ◽  
pp. 33-40 ◽  
Author(s):  
R. McKenzie ◽  
C. Seago
Keyword(s):  
Water Demand ◽  
Distribution Systems ◽  
Water Distribution ◽  
Potable Water ◽  
Demand Management ◽  
Water Distribution Systems ◽  
Water Demand Management ◽  
Local Conditions ◽  
The World ◽  
Real Losses

Considerable progress has been made over the past 10 years in the assessment and benchmarking of real losses in potable water distribution systems. Most of the advances have been based on the burst and background estimate (BABE) methodology, which was first developed in the mid-1990s by the UK water industry and has since been widely accepted and used in many parts of the world. Since the original BABE methodology was developed, several other key concepts have been added to the evergrowing list of water demand management tools. In particular, the infrastructure leakage index (ILI) and unavoidable annual real losses (UARL) introduced by A. Lambert, and the fixed area variable area discharge (FAVAD) theory by J. May, are now recognised as key “tools of the trade” in any water demand management assessment. One of the first main developments where the above-mentioned concepts were applied in practice to benchmark leakage was in South Africa, where the local Water Research Commission supported the production of the BENCHLEAK Model. This was basically the first comprehensive model to assess real losses in potable water distribution systems using the UARL and ILI concepts. The model was developed by one of the authors together with A. Lambert, and was soon followed by similar developments in Australia (BENCHLOSS) and New Zealand (BENCHLOSSNZ). Both models incorporated additions and enhancements to the original South African model, and were tailored to suit the local conditions in line with the clients' requirements. Similar developments took place in parallel by various leakage specialists, most notably in Brazil, Malaysia and Cyprus, to mention just a few of the similar initiatives. Each time a new model was developed, certain improvements were made and the “science” of leakage management and benchmarking was enhanced. Through the use of the different models and from discussions with various researchers from around the world, it has become clear that there is a genuine need for such models, and they are being readily accepted by clients in most areas. The discussions have also raised many questions concerning the derivation of the terms used to calculate the UARL and the ILI, and, to address these concerns a specialist group was created through the IWA to investigate the various issues. This paper will highlight the progress that has been made to date with regard to the key issues that have been raised by the task-team members, and recommendations based on the feedback that has been received from around the world. The paper will also present some of the results that have been obtained from different parts of the world to highlight both the progress and the problems associated with the assessment of real losses. The paper will conclude with a short description of several new models that have been developed and are in use, which demonstrate the latest improvements to an ongoing process to assess and benchmark real losses in water distribution systems.

scholarly journals Urban Stormwater Management, a Tool for Adapting to Climate Change: From Risk to Resource

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2616
Author(s):  
María Hernández-Hernández ◽  
Jorge Olcina ◽  
Álvaro-Francisco Morote
Keyword(s):  
Climate Change ◽  
Green Infrastructure ◽  
Water Demand ◽  
Urban Areas ◽  
Rainwater Harvesting ◽  
Flood Hazard ◽  
Demand Management ◽  
Urban Water Management ◽  
The Mediterranean ◽  
The City

The effects of climate change on rainfall in the Mediterranean region are manifested in an overall decreasing trend, and greater irregularity in annual volumes and the city of Alicante is no exception. In addition, there has also been a spread of the urbanised area, which has led to an increase in the flood risk in urban areas (due to a greater runoff and the occupation of flood hazard areas) and drought events due to an increase in the water demand. In light of these new scenarios, the Mediterranean cities should design adaptation systems based on rainwater harvesting within the framework of a circular economy. This study analyses the integration of rainwater in flood and water demand management in the city of Alicante (Southern Spain). In recent years, this city has developed infrastructures in order to use these resources. To do this, different databases have been analysed (rainfall and volume of water collected in the green infrastructure systems). The results reveal that stormwater has become highly important in urban water management in Alicante as the city is now using a resource that previously went to waste and created problems (flooding and pollution). By way of conclusion, it is worth mentioning that the incorporation of rainwater for urban use in Alicante has reduced the pressure on traditional resources in satisfying water demand and has also acted as a measure for adapting to climate change.

scholarly journals Decentralized Water Management: Rainwater Harvesting, Greywater Reuse and Green Roofs within the GST4Water Project

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 673 ◽  
Author(s):  
Sara Simona Cipolla ◽  
Margherita Altobelli ◽  
Marco Maglionico
Keyword(s):  
Hydrological Model ◽  
Rainwater Harvesting ◽  
Green Roofs ◽  
Optimal Size ◽  
Green Technologies ◽  
Research Activity ◽  
Development Fund ◽  
European Regional Development Fund ◽  
European Regional ◽  
Greywater Reuse

this study proposes the results of a research activity devoted to the analysis and development of methodologies, models and strategies, which allow integrating decentralized solutions such as rainwater harvesting, greywater reuse systems, and green technologies in buildings. A methodology based on a hydraulic/hydrological model developed by means of SWMM is presented. It allows estimating the optimal size of the storage tanks, considering the overall efficiency of the system, and calculating the wastewater overflows reduction. This study is carried out within the Work Package three (WP3) of the GST4Water project funded by the Emilia-Romagna Regional Council (Italy) through the European Regional Development Fund 2014–2020 ERDF—ROP.

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