Stormwater Harvesting Systems Research Articles

Toward a water-sensitive precinct with stormwater harvesting: a case study in South Africa

ABSTRACT The study assessed static management, i.e., without planned periodic maintenance of the storage (no sediment dredging) denoted as SC1, or with maintenance denoted as SC2. The second approach was dynamic management based on applying Real-Time Control (RTC) techniques to scenario SC1 and scenario SC2 denoted as RTC-1 and RTC-2, respectively. The dynamic management of the UCT dam with RTC-1 and RTC-2 approaches increase yield by 2.1 and 1.1 ml, respectively. Additionally, RTC-1 and RTC-2 approaches increase volumetric reliability by 5.3 and 2.5%, respectively, while maintaining the required level of service of a stormwater harvesting system. SC1 and SC2 results in water savings of up to 21.15 and 21.45 ZAR/kl, respectively, while RTC-1 and RTC-2 could save up to 19.35 and 19.45 ZAR/kl. Thus, static configurations results in water savings approximately 9% in comparison to RTC. In addition, static configurations harvested stormwater at a relatively lowest unit cost in comparison to RTC configurations. Notwithstanding this finding, the RTC system exhibits a great potential in reshaping the stormwater harvesting system to simultaneously deliver water conservation and stormwater management.

Flood Mitigation Techniques Using Storm Water Harvesting Methods: A Bibliometric Analysis

ABSTRACT This paper tries to breakdown 12 years of research on storm water harvesting systems that can aid in flood mitigation by methodically evaluating the existing literature and identifying relevant research gaps. Bibliometric co-citation meta-analysis is used to understand decentralized storm water harvesting methods that can aid in flood management. 165 articles from multiple disciplines in scopus database are used in this study to identify literature pertaining to flood mitigation techniques using storm water harvesting methods. Further these articles where analyzed for their scientific productivity, relevance and collaboration. Also the VOS viewer software and Bibliometrix R Package software were employed for visualization. The results of this study revealed that most of such studies focus on urban context. Thus, the study offers academics and practitioners a pertinent multidisciplinary platform for research on urban water security and encourages the growth of further knowledge on this subject.

Multi-scale stormwater harvesting to enhance urban resilience to climate change impacts and natural disasters

Abstract Stormwater harvesting systems are a viable option to adapt cities to cope with climate change and reduce pressure on water supply services. This is particularly crucial in the event of natural disasters (e.g., earthquakes, floods), where large parts of cities may become disconnected from a secure water supply for prolonged time periods. We demonstrate how optimum location, density and storage size can be determined using UrbanBEATS, a spatial planning-support system for planning and design of sustainable Blue-Green Infrastructure strategies. We investigate the Ōtākaro/Avon River catchment, Christchurch, New Zealand for the time periods 2011–2020, 2041–2050 and 2091–2100 (for the RCP 8.5 climate change scenario). For targets of 30% of potable water substitution and 70% storage volumetric reliability, we found that stormwater harvesting systems in all climate scenarios required a larger capacity compared to the baseline. Most storages achieved their set targets and were larger than the municipality's recommended 9 m3 for flood inundation, indicating that the identified storages would also reduce minor flooding while ensuring water savings. A shift in the spatial layout of modelled systems from highly distributed to more centralised, however, raises a potential conflict with disaster resilience where more local solutions would be preferable.

Stormwater Harvested from Permeable Pavements as a Means to Save Potable Water in Buildings

The main objective of this work is to analyse the potential for potable water savings in university buildings by using stormwater collected from permeable pavements. Six buildings located on the campus of the Federal University of Santa Catarina (UFSC) were selected to obtain monthly water consumption patterns and parking lot areas. The same six buildings were then evaluated considering their location in eight different cities in Brazil, with different rainfall patterns. Simulations using the computer programme Netuno were run to obtain the potential for potable water savings in each building and city combined. The structural design of permeable pavements was also assessed using two methods available in the literature, that is, the American Association of State Highway and Transportation Officials (AASHTO) and Brazilian Portland Cement Association (ABCP). The hydrological-hydraulic design of the permeable pavement was also carried out. The designed thicknesses were compared with the thicknesses obtained using the computer programme Permeable Design Pro. The potential for potable water savings between 18.4% and 84.8% was obtained, depending on the city, building and non-potable water demand considered. For the structural design, the thicknesses obtained by using both methods were similar; however, it was observed that the AASHTO method better represents the pavement model. Regarding the hydrological-hydraulic design, the differences obtained show that the simplification performed for the pavement drainage was in favour of safety. In conclusion, the use of permeable pavements in stormwater harvesting systems is promising, aligning the drainage aid, structural capacity and potential for saving potable water.

Stormwater harvesting in ephemeral streams: how to bypass clogging and unsaturated layers

To cope with water scarcity in drylands, stormwater is often collected in surface basins and subsequently stored in shallow aquifers via infiltration. These stormwater harvesting systems are often accompanied by high evaporation rates and hygiene problems. This is commonly a consequence of low infiltration rates, which are caused by clogging layers that form on top of the soil profile and the presence of a thick vadose zone. The present study aims to develop a conceptual solution to increase groundwater recharge rates in stormwater harvesting systems. The efficiency of vadose-zone wells and infiltration trenches is tested using analytical equations, numerical models, and sensitivity analyses. Dams built in the channel of ephemeral streams (wadis) are selected as a study case to construct the numerical simulations. The modelling demonstrated that vadose-zone wells and infiltration trenches contribute to effective bypassing of the clogging layer. By implementing these solutions, recharge begins 2250–8100% faster than via infiltration from the bed surface of the wadi reservoir. The sensitivity analysis showed that the recharge rates are especially responsive to well length and trench depth. In terms of recharge quantity, the well had the best performance; it can infiltrate up to 1642% more water than the reservoir, and between 336 and 825% more than the trench. Moreover, the well can yield the highest cumulative recharge per dollar and high recharge rates when there are limitations to the available area. The methods investigated here significantly increased recharge rates, providing practical solutions to enhance aquifer water storage in drylands.

Developing Generalised Equation for the Calculation of PayBack Period for Rainwater Harvesting Systems

Many end-users for the stormwater harvesting systems are reluctant in implementing the system due to uncertainties of the potential returns for their investment for such system. A common practice of presenting potential benefit of a certain investment is through calculation of payback period using net annual benefit from the system. Traditional practice of doing such payback period analysis for rainwater tanks was considering individual building/roof, system volume, and specific investment cost. It is not feasible to conduct such analysis for each and every rainwater harvesting system installed in different buildings. To overcome this tedious practice, this study presents development of a generalised equation for the estimation of payback period for rainwater tanks based on roof area, initial cost, and rate of return. Based on an earlier study, several payback periods were calculated for different roof sizes, initial costs, and rate of return. It was found that all these variables can be correlated and embedded into a base equation of power function. Final developed equation results were compared with the payback periods calculated through traditional practice considering net annual savings and net present value of cumulative savings. It is found that the developed equation can estimate payback periods with very good accuracies; for all the selected internal rates of return correlation values ranging from 0.99 to 1.0 were achieved. Corresponding coefficient of determinations varied from 0.988 to 0.993. Furthermore, it is found that for a fixed roof area and rate of return, the payback period is having a power relationship (having an exponent less than 1.0) with the initial cost.

A study on the effectiveness of percolation ponds as a stormwater harvesting alternative for a semi-urban catchment

Abstract One of the challenges in urban stormwater management is to identify a suitable stormwater management method which will be socially, technologically and economically viable. In this paper, a study on the effectiveness of decentralized and interconnected percolation ponds as a stormwater harvesting technology, for a partially urbanized (semi-urban) catchment is presented. When applied to a case study region in Katpadi, Tamil Nadu, the results were encouraging. The investment required for implementing the proposed stormwater harvesting came to be about ₹555 Million for Option I and ₹714 Million for Option II. The annual volume of water that can be added to the groundwater system through infiltration from the ponds was found to be 1.22 Mm3 in the case of Option I and 0.74 Mm3 in the case of Option II. The percentage area under stormwater harvesting for the entire catchment was found to be 6.14% under Option I and 9.36 under Option II. The hydrologic performance of the proposed stormwater harvesting system indicated that for peak runoff values Option II is more efficient (in terms of minimizing runoff volume) compared to Option I; however, for daily rainfall values, Option I is hydrologically more efficient when compared to Option II.

Stormwater harvesting infrastructure systems design for urban park irrigation: Brimbank Park, Melbourne case study

Abstract Stormwater harvesting for residential and non-residential reuse is an important and crucial aspect to reduce freshwater demand to address climate change, population growth and urbanisation challenges. It is important that freshwater be conserved as much as possible through capturing rainwater and stormwater and using these resources for fit for purpose end uses such as irrigation of public open parks and residential non-potable end uses. The paper describes a methodology for the planning and design of a stormwater harvesting system for park irrigation. The application of suitable models for storage tank capacity and pipe sizing considering peak flows are described. The application of the approach is demonstrated with a local case study for the benefit of wider water professionals engaged in water-sensitive urban design.

Modelling the clogging of a field filtration system used for stormwater harvesting

A model was developed to simulate the clogging of a field-scale stormwater harvesting system with high flow filters over 2.5-year.

Life cycle energy assessment and economic feasibility of stormwater harvested from pervious pavements

Pervious pavements are one of the most used construction techniques among the Sustainable Urban Drainage Systems (SUDS). The objective of this article is to analyse the energy life cycle and the life cycle cost of stormwater harvesting systems using pervious pavements models in order to compare and evaluate the differences and verify what influences the profitability and sustainability. The method proposed started with the definition of pervious pavement models based on literature review. The main characteristic of the models analysed was the use of porous asphalt with different underlying layers, i.e. thickness and material. The hydrological-hydraulic design of the pavements was also assessed. The potential for potable water savings due to harvesting stormwater from a parking lot was estimated for a public building in Florianópolis, southern Brazil. The models were compared to identify what most influences the potable water savings, the profitability and the sustainability of the systems. The maximum potable water savings found were 42%. It was also observed that the overall consumption of the building has been decreasing over the years, and the yearly rainfall has increased, which leads to a higher potential. In the current water consumption pattern, none of the systems evaluated was profitable or presented sustainability, evaluated herein as negative energy balance. However, it was verified that if analysed comparatively with non-pervious pavement, it was profitable to use stormwater harvested from the pervious pavement. Thus, it can be concluded that stormwater harvesting systems in combination with pervious pavements are promising, serving as SUDS and saving money for users. It is also noticeable that the use of porous asphalt is not recommended when aiming for systems with low embedded energy.

Optimization of Pumping Costs and Harvested Volume for a Stormwater Harvesting System

AbstractA harvested stormwater and managed aquifer recharge system has been analyzed through both simulation sensitivity analysis and optimization to reduce operational pumping costs and increase t...

Multiobjective Optimization of Distributed Stormwater Harvesting Systems

AbstractStormwater harvesting (SWH) is an important water-sensitive urban design (WSUD) approach that provides an alternate water supply source and improves runoff quality through integrated system...

Biofiltration for stormwater harvesting: Comparison of Campylobacter spp. and Escherichia coli removal under normal and challenging operational conditions

Knowledge of pathogen removal in stormwater biofilters (also known as stormwater bioretention systems or rain gardens) has predominately been determined using bacterial indicators, and the removal of reference pathogens in these systems has rarely been investigated. Furthermore, current understanding of indicator bacteria removal in these systems is largely built upon laboratory-scale work. This paper examines whether indicator organism removal from urban stormwater using biofilters in laboratory settings are representative of the removal of pathogens in field conditions, by studying the removal of Escherichia coli (a typical indicator microorganism) and Campylobacter spp. (a typical reference pathogen) from urban stormwater by two established field-scale biofilters. It was found that E. coli log reduction was higher than that of Campylobacter spp. in both biofilters, and that there was no correlation between E. coli and Campylobacter spp. log removal performance. This confirms that E. coli behaves significantly differently to this reference pathogen, reinforcing that single organisms should not be employed to understand faecal microorganism removal in urban stormwater treatment systems. The average reduction in E. coli from only one of the tested biofilters was able to meet the log reduction targets suggested in the current Australian stormwater harvesting guidelines for irrigating sports fields and golf courses. The difference in the performance of the two biofilters is likely a result of a number of design and operational factors; the most important being that the biofilter that did not meet the guidelines was tested using extremely high influent volumes and microbial concentrations, and long antecedent dry weather periods. As such, the E. coli removal performances identified in this study confirmed laboratory findings that inflow concentration and antecedent dry period impact overall microbial removal. In general, this paper emphasizes the need for the validation of stormwater harvesting systems, namely, the testing of treatment systems under challenging operational conditions using multiple indicators and reference pathogens.

Evaluation of three full-scale stormwater treatment systems with respect to water yield, pathogen removal efficacy and human health risk from faecal pathogens

In this study, three full-scale, operational stormwater harvesting systems located in Melbourne, Australia were evaluated with respect to water yields; pathogen removal performance by analysis of native surrogate data (Escherichia coli, somatic coliphages and Clostridium perfringens); and potential human health risk associated with exposures to faecal pathogens using Quantitative Microbial Risk Assessment (QMRA). The water yield assessment confirmed variation between design and measured yields. Faecal contamination of urban stormwater was site specific and variable. Different treatment removal performance was observed between each of the microbial surrogates and varied between event and baseline conditions, with negligible removal of viruses during event conditions. Open storages that provide a habitat for waterfowl may lead to elevated risk due to the potential for zoonotic transmission. Nevertheless, in the Australian urban setting studied, the potential for human faecal contamination of the separated stormwater system was a critical driver of risk. If the integrity of the sewerage system can be ensured, then predicted health risks are dramatically reduced.

Microbiological risks of recycling urban stormwater via aquifers for various uses in Adelaide, Australia

This study investigates the potential for an aquifer to provide treatment of stormwater in addition to engineered treatment for the safe use of recovered water for drinking and non-drinking supplies. A brackish limestone aquifer was investigated as a treatment barrier when assessing microbial health-based targets of stormwater harvesting systems. Aquifer treatment was assessed based on pathogen inactivation and attachment to the aquifer sediments. The results showed that the health-based targets for different end uses including open space irrigation, domestic and industrial non-potable uses and drinking water could be met with additional treatment. The aquifer was estimated to have potential for ~4 log10 removal based on inactivation studies and attachment to the aquifer.

Removal of E. coli from urban stormwater using antimicrobial-modified filter media

Stormwater filters featuring traditional sand filter media cannot reliably treat indicator bacteria for stormwater harvesting. In this work, copper-modified zeolite and granular activated carbon (GAC) were prepared through Cu2+ impregnation and in situ Cu(OH)2 precipitation. Their antibacterial properties and stability in natural stormwater were studied in gravity-fed columns for 24 weeks, under typical stormwater operational conditions. 11 types of other filter media, prepared using zinc, iron, titanium and quaternary ammonium salts as antibacterial agents, were tested in parallel by way of comparison. Cu2+-immobilised zeolite and Cu(OH)2-coated GAC yielded an estimated 2-log reduction of E. coli within 40min with the presence of other native microbial communities in natural stormwater. Even at high flow velocity (effective contact time of 4.5min), both media demonstrated 0.8 log removal. Both media and Cu2+-treated GAC showed effective inactivation of the removed E. coli during dry periods. Copper leaching from Cu(OH)2-coated GAC was found to be below the NHMRC specified drinking water standard, while that from Cu2+-immobilised zeolite varied with the salinity in stormwater. These findings could provide useful information for further development of passive stormwater harvesting systems.

Transition to a water-cycle city: sociodemographic influences on Australian urban water practitioners' risk perceptions towards alternative water systems

Transition to a sustainable water future such as the water-cycle city will necessitate shared, diversified risk management, which acknowledges the subjective risk perceptions of all stakeholders, including water practitioners. Such risk perceptions might vary with personal and professional characteristics. This study explores the influence of these characteristics on Australian urban water practitioners' risk perceptions of four alternative water systems, varying in scale of operation and water source, i.e. seawater desalination, indirect potable reuse, sewer mining and stormwater harvesting systems. Analysis of sociodemographic and risk perception data (N = 620) collected from a national online survey revealed that risk perceptions can vary with age or number of years' experience, educational qualification, stakeholder group and area of work within the water sector, reflecting different communities of practice. To facilitate adoption of a suite of sustainable urban water systems, these different risk perceptions must be identified, acknowledged and managed. Targeted social learning through experimentation is a useful approach to achieve this.

Are green building features safe for preventive maintenance workers? Examining the evidence

Many newly constructed green buildings (GB) are certified using the United States Green Building Council (USGBC) Leadership in Energy and Environmental Design (LEED) rating system for new construction and major renovation which focuses on architectural and mechanical design to conserve energy, reduce environmental harm, and enhance indoor quality for occupants. This study evaluated the preventive maintenance (PM) worker occupational safety and health (OSH) risks related to the design of GB. PM job hazard analyses (JHA) were performed on the tasks required to operate and maintain five GB features selected from 13 LEED certified GB. A 22-item JHA and OSH risk scoring system were developed. Potentially serious OSH hazards included: green roofs made of slippery material without fall protection; energy recovery wheels and storm water harvesting systems in confined spaces; skylights without guard rails; and tight geothermal well mechanical rooms constraining safe preventive practices. GB can present PM OSH risks and these should be eliminated in the building design phase.

Analysis of stormwater harvesting potential: A shift in paradigm is necessary

With increasing population and changing climate regime, water supply systems in many cities of the world are under stress. Water demand is increasing day by day but resources of fresh water are limited. To tackle the situation many water authorities around the world have been promoting the use of water conservation and recycling options through various campaigns and offering incentives/grants for such water saving ideas and innovations. Even with several educational and awareness campaigns and financial incentives, there is a general reluctance to adopt any potential stormwater harvesting measure. The main reasons behind this are that people are not aware of the payback period for their initial investment and the optimum size of the storage required satisfying their performance requirements. Among all the alternative water sources, stormwater harvesting perhaps has received the most attention. One of several water conserving techniques is on-site stormwater harvesting for non-drinking purposes. However there is a lack of knowledge on the actual cost-effectiveness and performance optimisation of any stormwater harvesting system, in particular the proposed design storage volume could be overestimated or underestimated. At present stormwater harvesting systems are proposed and installed without any in-depth analysis of its effectiveness in various climate conditions.

Risk perceptions and receptivity of Australian urban water practitioners to stormwater harvesting and treatment systems

Stormwater harvesting and treatment will be critical systems within water-sensitive cities. Although water practitioners acknowledge the importance of developing stormwater as a water source, their risk perceptions might be barriers. Risk perceptions can be understood within a receptivity framework, with awareness, association, acquisition and application components. In this study, water practitioners' risk perceptions of stormwater harvesting and treatment in Australian cities were examined within this framework, to identify where to focus reform efforts within the water industry to improve their adoption. Analysis of data from an online survey exploring water practitioners' (N = 620) perceptions of risk of alternative water systems revealed that three-quarters of respondents thought stormwater harvesting and treatment yielded at least moderate benefits, supporting fit-for-purpose use of treated stormwater and installation of the infrastructure in different contexts. Perceived general risk of each was slight, although stormwater harvesting was perceived as more risky than treatment, and this difference persisted for specific risks, e.g. public health, environmental. In terms of the receptivity framework, perceived specific risks of stormwater harvesting and treatment systems challenge, to different extents, the practitioners' association, acquisition and application of the systems in Australian cities. In particular, reform efforts should be targeted to perceived management and cost-related risks.