Paweł Chudziński, S. Cyfert, W. Dyduch, Maciej Zastempowski
Water utilities are an essential service that helps protect public health during crises. The Covid-19 pandemic revealed that crisis preparedness is a crucial capability that water utilities must possess. The purpose of this paper is to identify managerial actions and responses that were undertaken by water utility managers in order to reduce the risk related to the first economic lockdown caused by the unexpected Covid-19 crisis. As water utilities should learn from Covid-19 so as to strengthen their future risk preparedness, the paper offers some theoretical underpinnings on risk management. As a result of literature analysis, we focus on the risk management framework that distinguishes five types of risk. The survey was carried out among 116 waterworks in Poland in April 2020. The results indicate the importance of minimising liquidity risk and supply chain risk, which is relevant to the adopted theoretical framework. The findings also highlight the importance of a category that was not originally included in the research model – that is human resource risk, an area that requires managerial attention in the water utility sector. The results could also provide useful pointers for other water utilities, especially those operating in the same or similar legislative regime.
{"title":"Risk management during the Covid-19 crisis: business responses in the Polish water utilities","authors":"Paweł Chudziński, S. Cyfert, W. Dyduch, Maciej Zastempowski","doi":"10.2166/aqua.2022.090","DOIUrl":"https://doi.org/10.2166/aqua.2022.090","url":null,"abstract":"\u0000 Water utilities are an essential service that helps protect public health during crises. The Covid-19 pandemic revealed that crisis preparedness is a crucial capability that water utilities must possess. The purpose of this paper is to identify managerial actions and responses that were undertaken by water utility managers in order to reduce the risk related to the first economic lockdown caused by the unexpected Covid-19 crisis. As water utilities should learn from Covid-19 so as to strengthen their future risk preparedness, the paper offers some theoretical underpinnings on risk management. As a result of literature analysis, we focus on the risk management framework that distinguishes five types of risk. The survey was carried out among 116 waterworks in Poland in April 2020. The results indicate the importance of minimising liquidity risk and supply chain risk, which is relevant to the adopted theoretical framework. The findings also highlight the importance of a category that was not originally included in the research model – that is human resource risk, an area that requires managerial attention in the water utility sector. The results could also provide useful pointers for other water utilities, especially those operating in the same or similar legislative regime.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72975423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nabeallah Yazdi, S. N. Mousavi, A. Zarei, Abdoulrasool Shirvanian
Since climate change, intermittent droughts with various severities, poor management and uncontrolled abstraction of water resources, and inattention to the balance of these resources have caused the water crisis in recent decades, it is vitally important to study the water scarcity, its changes in the future, and the effect of climate change and drought on the scarcity through appropriate management policies in the agricultural sector. To achieve this goal, the present study selected the Fasa plain in Iran and calculated its water poverty index (WPI) from 2008 to 2018 using parametric and non-parametric statistical tests. Also, the study calculated the correlation coefficient between the WPI and climate change and drought in the study area. It then evaluated the effects of water resources management policies in the agricultural sector on the poverty index. The results showed that water consumption had the greatest weight in calculating the WPI. The WPI has fluctuated between 0.297 and 0.678 in the Fasa plain, and the worst situation of water poverty was experienced in 2014. Despite its insignificance, the downward trend in the WPI showed that water resources management has become more unfavorable over time. Finally, it was concluded that the WPI in the Fasa plain was more dependent on drought than on climate change in the short term. Therefore, managing water resource consumption in this plain is vitally important, especially in drought conditions. The results also showed that reducing water consumption in the agricultural sector can significantly improve the WPI. Therefore, solving the water crisis in this plain, given the drought conditions and its future trend, requires policies improving water-use efficiency in the agricultural sector.
{"title":"Investigating the effects of climate change, drought, and agricultural sector policies on the trend of the water poverty index in Iran","authors":"Nabeallah Yazdi, S. N. Mousavi, A. Zarei, Abdoulrasool Shirvanian","doi":"10.2166/aqua.2022.112","DOIUrl":"https://doi.org/10.2166/aqua.2022.112","url":null,"abstract":"\u0000 Since climate change, intermittent droughts with various severities, poor management and uncontrolled abstraction of water resources, and inattention to the balance of these resources have caused the water crisis in recent decades, it is vitally important to study the water scarcity, its changes in the future, and the effect of climate change and drought on the scarcity through appropriate management policies in the agricultural sector. To achieve this goal, the present study selected the Fasa plain in Iran and calculated its water poverty index (WPI) from 2008 to 2018 using parametric and non-parametric statistical tests. Also, the study calculated the correlation coefficient between the WPI and climate change and drought in the study area. It then evaluated the effects of water resources management policies in the agricultural sector on the poverty index. The results showed that water consumption had the greatest weight in calculating the WPI. The WPI has fluctuated between 0.297 and 0.678 in the Fasa plain, and the worst situation of water poverty was experienced in 2014. Despite its insignificance, the downward trend in the WPI showed that water resources management has become more unfavorable over time. Finally, it was concluded that the WPI in the Fasa plain was more dependent on drought than on climate change in the short term. Therefore, managing water resource consumption in this plain is vitally important, especially in drought conditions. The results also showed that reducing water consumption in the agricultural sector can significantly improve the WPI. Therefore, solving the water crisis in this plain, given the drought conditions and its future trend, requires policies improving water-use efficiency in the agricultural sector.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78084372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A water distribution network (WDN) is an essential component of an urban water supply scheme to deliver safe and adequate water to consumers under various operational conditions. This study focuses on the performance evaluation of an urban WDN using fuzzy logic-based aggregation of reliability, resilience, and vulnerability indices. To assess the individual performance indicators, this study advocates the pressure-dependent analysis (PDA) for the hydraulic simulation. Furthermore, it advocates a fuzzy rule-based aggregated performance index (API) that will deliver the outcome in linguistic form and help the decision-maker to prioritize the maintenance of the WDN. The proposed method is illustrated with the help of a real-time WDN for part of Dire Dawa city in Ethiopia. It has been found that the API values for this network are 0.721 and 0.624, respectively, under normal and abnormal conditions, which are just satisfactory. It has been noticed that nodes J4, J44, J47, and J49 are critical from the overall low API. Efforts should be made to improve the hydraulic and residual chlorine conditions at these nodes to increase the API. It is felt that such a methodology will help the decision-makers in improving the performance of an existing urban WDN.
{"title":"Fuzzy logic-based integrated performance evaluation of a water distribution network","authors":"B. Beker, M. Kansal","doi":"10.2166/aqua.2022.004","DOIUrl":"https://doi.org/10.2166/aqua.2022.004","url":null,"abstract":"\u0000 A water distribution network (WDN) is an essential component of an urban water supply scheme to deliver safe and adequate water to consumers under various operational conditions. This study focuses on the performance evaluation of an urban WDN using fuzzy logic-based aggregation of reliability, resilience, and vulnerability indices. To assess the individual performance indicators, this study advocates the pressure-dependent analysis (PDA) for the hydraulic simulation. Furthermore, it advocates a fuzzy rule-based aggregated performance index (API) that will deliver the outcome in linguistic form and help the decision-maker to prioritize the maintenance of the WDN. The proposed method is illustrated with the help of a real-time WDN for part of Dire Dawa city in Ethiopia. It has been found that the API values for this network are 0.721 and 0.624, respectively, under normal and abnormal conditions, which are just satisfactory. It has been noticed that nodes J4, J44, J47, and J49 are critical from the overall low API. Efforts should be made to improve the hydraulic and residual chlorine conditions at these nodes to increase the API. It is felt that such a methodology will help the decision-makers in improving the performance of an existing urban WDN.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77279574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adeline Umugwaneza, X. Chen, Tie Liu, Richard Mind’je, Aline Uwineza, P. M. Kayumba, Solange Uwamahoro, Jeanine Umuhoza, Aboubakar Gasirabo, Albert Poponi Maniraho
The increasing demand of water results in the overexploitation of water resources. This situation calls for more effective water management alternatives including rainwater harvesting (RWH) systems. Due to the lack of biophysical data and infrastructure, the identification of suitable sites for various RWH systems is a challenging issue. However, integrating geospatial analysis and modeling approaches has become a promising tool to identify suitable sites for RWH. Thus, this study aimed at identifying suitable sites for RWH in the Nyabugogo catchment located in Rwanda by integrating a geo-information-based multi-criteria decision-making (MCDM) and SWAT (Soil and Water Assessment Tool) model. Moreover, the sediment yield was compared to the soil erosion evaluated using the Revised Universal Soil Loss Equation (RUSLE) owing to the lack of sediment concentration measured data. The results revealed that about 4.8 and 16.35% of the study area are classified as highly suitable and suitable areas for RWH, respectively. Around 6% of the study area (98.5 km2) was found to be suitable for farm ponds, whereas 1.6% (26.1 km2) suitable for check dams, and 25.9% (423 km2) suitable for bench terraces. Among 50 proposed sites for the RWH structures, 29 are located in the most suitable area for RWH. The results implicated that the surface runoff, sediment yield, and topography are essential factors in identifying the suitability of RWH areas. It is concluded that the integrated geospatial and MCDM techniques provide a useful and efficient method for planning RWH at a basin scale in the study area.
{"title":"Integrating a GIS-based approach and a SWAT model to identify potential suitable sites for rainwater harvesting in Rwanda","authors":"Adeline Umugwaneza, X. Chen, Tie Liu, Richard Mind’je, Aline Uwineza, P. M. Kayumba, Solange Uwamahoro, Jeanine Umuhoza, Aboubakar Gasirabo, Albert Poponi Maniraho","doi":"10.2166/aqua.2022.111","DOIUrl":"https://doi.org/10.2166/aqua.2022.111","url":null,"abstract":"\u0000 The increasing demand of water results in the overexploitation of water resources. This situation calls for more effective water management alternatives including rainwater harvesting (RWH) systems. Due to the lack of biophysical data and infrastructure, the identification of suitable sites for various RWH systems is a challenging issue. However, integrating geospatial analysis and modeling approaches has become a promising tool to identify suitable sites for RWH. Thus, this study aimed at identifying suitable sites for RWH in the Nyabugogo catchment located in Rwanda by integrating a geo-information-based multi-criteria decision-making (MCDM) and SWAT (Soil and Water Assessment Tool) model. Moreover, the sediment yield was compared to the soil erosion evaluated using the Revised Universal Soil Loss Equation (RUSLE) owing to the lack of sediment concentration measured data. The results revealed that about 4.8 and 16.35% of the study area are classified as highly suitable and suitable areas for RWH, respectively. Around 6% of the study area (98.5 km2) was found to be suitable for farm ponds, whereas 1.6% (26.1 km2) suitable for check dams, and 25.9% (423 km2) suitable for bench terraces. Among 50 proposed sites for the RWH structures, 29 are located in the most suitable area for RWH. The results implicated that the surface runoff, sediment yield, and topography are essential factors in identifying the suitability of RWH areas. It is concluded that the integrated geospatial and MCDM techniques provide a useful and efficient method for planning RWH at a basin scale in the study area.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75434577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Udume Bethel Uchenna, Ota Henry Obiahu, Zhifeng Yan, Onyewuchi Chidi Chikeziri
This study was carried out to evaluate the effect of ammonia toxicity on the growth and hematology of Clarias gariepinus. The mean weight gain of fish 1.52 ± 0.3 g was investigated under laboratory conditions at static bioassay for 96 h and 14 days, respectively. Five treatments of 96 h median lethal concentration LC50 were used, namely, T0 (0.00 g·l−1), T1 (0.40 g·l−1), T2 (0.60 g·l−1), T3 (0.80 g·l−1) and T4 (1.00 g·l−1), and each of these treatment concentrations was replicated three times for both toxicity exposures. The results clearly revealed that 96 h median lethal concentration (LC50) at treatments T4 (4.00), T3 (3.00), T2 (2.00) and T0 (0.00) g·l−1 gave an average mean value of 3.02 ± 0.02 g·l−1 with upper and lower limits of 6.28 and 1.42 g·l−1, respectively. The overall percentage mortality showed more than 71% of fish mortality at T4. Values for the 14 -day sub-acute exposures to ammonia concentrations of T4 (1.00), T3 (0.80), T2 (0.60) and control (0.00) g·l−1 were also obtained. Growth indices indicated significant decreases (P<0.05) in the total feed intake (TFI), specific growth rate (SGR), mean weight gain and food conversion ratio (FCR) compared with the control.
{"title":"Evaluating the effect of acute ammonia toxicity in a freshwater ecological environment on the growth and hematological functioning of Clarias gariepinus","authors":"Udume Bethel Uchenna, Ota Henry Obiahu, Zhifeng Yan, Onyewuchi Chidi Chikeziri","doi":"10.2166/aqua.2022.138","DOIUrl":"https://doi.org/10.2166/aqua.2022.138","url":null,"abstract":"\u0000 This study was carried out to evaluate the effect of ammonia toxicity on the growth and hematology of Clarias gariepinus. The mean weight gain of fish 1.52 ± 0.3 g was investigated under laboratory conditions at static bioassay for 96 h and 14 days, respectively. Five treatments of 96 h median lethal concentration LC50 were used, namely, T0 (0.00 g·l−1), T1 (0.40 g·l−1), T2 (0.60 g·l−1), T3 (0.80 g·l−1) and T4 (1.00 g·l−1), and each of these treatment concentrations was replicated three times for both toxicity exposures. The results clearly revealed that 96 h median lethal concentration (LC50) at treatments T4 (4.00), T3 (3.00), T2 (2.00) and T0 (0.00) g·l−1 gave an average mean value of 3.02 ± 0.02 g·l−1 with upper and lower limits of 6.28 and 1.42 g·l−1, respectively. The overall percentage mortality showed more than 71% of fish mortality at T4. Values for the 14 -day sub-acute exposures to ammonia concentrations of T4 (1.00), T3 (0.80), T2 (0.60) and control (0.00) g·l−1 were also obtained. Growth indices indicated significant decreases (P<0.05) in the total feed intake (TFI), specific growth rate (SGR), mean weight gain and food conversion ratio (FCR) compared with the control.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89316777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ana Fernandes, Margarida Figueiredo, Jorge Ribeiro, J. Neves, H. Vicente
The internal audits carried out in the first half of 2019 in water laboratories as part of quality accreditation in accordance with ISO/IEC 17025:2017 showed a high frequency of adverse events in connection with sampling. These faults can be a consequence of a wide range of causes, and in some cases, the information about them can be insufficient or unclear. Considering that sampling has a major influence on the quality of the analytical results provided by water laboratories, this work presents a system for reporting and learning adverse events. Its aim is to record nonconformities, errors, and adverse events, making possible automatic data analysis aiming to ensure continuous improvement in operational sampling. The system is based on the Eindhoven Classification Model and enables automatic data analysis and reporting to identify the main causes of failure. Logic programming is used to represent knowledge and support the reasoning mechanisms to model the universe of discourse in scenarios of incomplete, contradicting, or even unknown information. In addition to suggesting solutions to the problem, the system provides formal evidence of the solutions presented, which will help to continuously improve drinking water quality and promote public health.
{"title":"Avoidance of operational sampling errors in drinking water analysis","authors":"Ana Fernandes, Margarida Figueiredo, Jorge Ribeiro, J. Neves, H. Vicente","doi":"10.2166/aqua.2022.074","DOIUrl":"https://doi.org/10.2166/aqua.2022.074","url":null,"abstract":"\u0000 The internal audits carried out in the first half of 2019 in water laboratories as part of quality accreditation in accordance with ISO/IEC 17025:2017 showed a high frequency of adverse events in connection with sampling. These faults can be a consequence of a wide range of causes, and in some cases, the information about them can be insufficient or unclear. Considering that sampling has a major influence on the quality of the analytical results provided by water laboratories, this work presents a system for reporting and learning adverse events. Its aim is to record nonconformities, errors, and adverse events, making possible automatic data analysis aiming to ensure continuous improvement in operational sampling. The system is based on the Eindhoven Classification Model and enables automatic data analysis and reporting to identify the main causes of failure. Logic programming is used to represent knowledge and support the reasoning mechanisms to model the universe of discourse in scenarios of incomplete, contradicting, or even unknown information. In addition to suggesting solutions to the problem, the system provides formal evidence of the solutions presented, which will help to continuously improve drinking water quality and promote public health.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84567640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An appropriate water hammer protective scheme is a significant concern in the operation of water supply projects. According to the special terrain in the water supply project, which forms a siphon breaking structure at the end of the pipeline, three protective schemes were proposed and compared: single vacuum breaking valve (VBV) scheme, VBV and air valve scheme, and VBV and one-way surge tower scheme. Based on the control standards of pipe pressure, three protective schemes were assessed in terms of suppressing the negative pressure caused by a pump trip accident. The results show that the siphon breaking structure with the VBV can achieve good effect protection only in a limited range of pipelines. In the VBV and air valve scheme, the pressure oscillations were obviously caused by repeated inlet and exhaust of the air valves. To avoid supplementing too much gas in the pipe by air valves, which will result in a gas column bridging phenomenon, the VBV and one-way surge tower scheme is proposed and can better meet the requirement of the pressure control standard.
{"title":"Study on water hammer protection of the siphon breaking structure in the water supply system","authors":"Jiawen Lyu, Jian Zhang, Teng-gan Wang","doi":"10.2166/aqua.2022.162","DOIUrl":"https://doi.org/10.2166/aqua.2022.162","url":null,"abstract":"\u0000 An appropriate water hammer protective scheme is a significant concern in the operation of water supply projects. According to the special terrain in the water supply project, which forms a siphon breaking structure at the end of the pipeline, three protective schemes were proposed and compared: single vacuum breaking valve (VBV) scheme, VBV and air valve scheme, and VBV and one-way surge tower scheme. Based on the control standards of pipe pressure, three protective schemes were assessed in terms of suppressing the negative pressure caused by a pump trip accident. The results show that the siphon breaking structure with the VBV can achieve good effect protection only in a limited range of pipelines. In the VBV and air valve scheme, the pressure oscillations were obviously caused by repeated inlet and exhaust of the air valves. To avoid supplementing too much gas in the pipe by air valves, which will result in a gas column bridging phenomenon, the VBV and one-way surge tower scheme is proposed and can better meet the requirement of the pressure control standard.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86264045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Discrete multiple-cavity models coupled with quasi-two-dimensional (quasi-2D) friction models are effective solutions to simulating transient cavitation pipe flows. The simulation accuracy of such models hinges upon the understanding of key parameters of the models, which remains elusive so far. To address such an open issue, this paper employs the discrete vapor cavity model (DVCM) and the discrete gas cavity model (DGCM), combined with the quasi-2D friction model, with a particular focus on revealing the sensitivity of these models to the key parameters such as grid number and weighting parameters. Based on the quantitative analysis and pressure fluctuation history, a method is developed to evaluate the accuracy of numerical results. Results show that the inclusion of the quasi-2D friction model improves the accuracy of predicting time of cavity formation and collapse; however, it does not affect the selection of grid number. Meanwhile, numerical results are sensitive to the weighting parameter of the viscous term in the quasi-2D friction model except for the case of low-intensity cavitation and its value of 1 is suggested for all cases. From the practical point of view, our finding is helpful to understand the feature of discrete multiple-cavity models and improve the simulating accuracy of transient cavitation pipe flows.
{"title":"Parametric analysis of discrete multiple-cavity models with the quasi-two-dimensional friction model for transient cavitating pipe flows","authors":"Q. Sun, Y. Hao, Pei-Yuan Cheng","doi":"10.2166/aqua.2022.159","DOIUrl":"https://doi.org/10.2166/aqua.2022.159","url":null,"abstract":"\u0000 Discrete multiple-cavity models coupled with quasi-two-dimensional (quasi-2D) friction models are effective solutions to simulating transient cavitation pipe flows. The simulation accuracy of such models hinges upon the understanding of key parameters of the models, which remains elusive so far. To address such an open issue, this paper employs the discrete vapor cavity model (DVCM) and the discrete gas cavity model (DGCM), combined with the quasi-2D friction model, with a particular focus on revealing the sensitivity of these models to the key parameters such as grid number and weighting parameters. Based on the quantitative analysis and pressure fluctuation history, a method is developed to evaluate the accuracy of numerical results. Results show that the inclusion of the quasi-2D friction model improves the accuracy of predicting time of cavity formation and collapse; however, it does not affect the selection of grid number. Meanwhile, numerical results are sensitive to the weighting parameter of the viscous term in the quasi-2D friction model except for the case of low-intensity cavitation and its value of 1 is suggested for all cases. From the practical point of view, our finding is helpful to understand the feature of discrete multiple-cavity models and improve the simulating accuracy of transient cavitation pipe flows.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79744563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rainwater harvesting (RWH) is emerging as a promising alternative source of water in sub-Saharan Africa. It can be an alternative source of good-quality water to substitute other freshwater sources, to enable crop production beyond the growing season through supplemental irrigation as well as to improve the environment by minimizing the effect of drought and floods. The Rachuonyo North Sub-County of Kenya experiences low rainfall coupled with high population with limited access to reliable water sources. The study assessed the RWH potential of the Rachuonyo North Sub-Catchment with the aim of providing information on alternative water resources to meet the water demands for agriculture as well as domestic use in the region. The Australian water balance model (AWBM) was used to simulate the RWH potential of the Rachuonyo North Sub-Catchment using the area rainfall, evapotranspiration and river flow data. The calibration and validation of the model were performed with calibration and validation results yielding Nash–Sutcliffe efficiency (NSE) values of 0.503 and 1.00, respectively. Research findings indicated that the area has a potential for RWH with runoff harvest of between 104,496 and 43,646,142 m3/month, which can significantly support the residential and irrigation water demands for the area. Policymakers and development agencies in the region should pro-actively put in place measures to promote RWH interventions as a tool for increasing access to water. The methodology in the study is suitable for adaption for rainfall–runoff simulation in other sub-Saharan African regions where data are limiting.
{"title":"Assessment of rainwater harvesting potential of Rachuonyo North Sub-Catchment in Kenya using the Australian water balance model","authors":"Kevin O. Odhiambo, B. Ong'or, E. K. Kanda","doi":"10.2166/aqua.2022.153","DOIUrl":"https://doi.org/10.2166/aqua.2022.153","url":null,"abstract":"\u0000 Rainwater harvesting (RWH) is emerging as a promising alternative source of water in sub-Saharan Africa. It can be an alternative source of good-quality water to substitute other freshwater sources, to enable crop production beyond the growing season through supplemental irrigation as well as to improve the environment by minimizing the effect of drought and floods. The Rachuonyo North Sub-County of Kenya experiences low rainfall coupled with high population with limited access to reliable water sources. The study assessed the RWH potential of the Rachuonyo North Sub-Catchment with the aim of providing information on alternative water resources to meet the water demands for agriculture as well as domestic use in the region. The Australian water balance model (AWBM) was used to simulate the RWH potential of the Rachuonyo North Sub-Catchment using the area rainfall, evapotranspiration and river flow data. The calibration and validation of the model were performed with calibration and validation results yielding Nash–Sutcliffe efficiency (NSE) values of 0.503 and 1.00, respectively. Research findings indicated that the area has a potential for RWH with runoff harvest of between 104,496 and 43,646,142 m3/month, which can significantly support the residential and irrigation water demands for the area. Policymakers and development agencies in the region should pro-actively put in place measures to promote RWH interventions as a tool for increasing access to water. The methodology in the study is suitable for adaption for rainfall–runoff simulation in other sub-Saharan African regions where data are limiting.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77167137","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to increasing population, uncontrolled water consumption, and abnormal climatic conditions, the potential of usable water is running out. Water has become one of the most valuable resources for the countries; therefore, rainwater harvesting systems for water recovery gain importance to implement in buildings. Thus, authorities have begun to search for fast and accurate decision tools before taking any action. In the present study, a semi-analytical method for determining the rainwater harvesting potential of the given location is implemented in the Java programming language. Three major districts of Izmir, Turkey are chosen for the study site, namely Cigli, Bayrakli, and Karsiyaka. The result shows that implementing rainwater harvesting systems only in public buildings recovers less than 1% of the population's water needs. On the contrary, encouraging the free zones, which has large rooftop area such as airports and malls, for implementing and using rainwater increases the water recovery to 13% of that district's water needs. It is still a small portion of the public's water needs; therefore, spreading rainwater harvesting in the communities is necessary. It is believed that more accurate and user-friendly rainwater harvesting simulators would encourage the communities to harvest rainwater.
{"title":"Determining rainwater harvesting potentials in municipalities by a semi-analytical method","authors":"E. Ulker, Hadya Tasci","doi":"10.2166/aqua.2022.106","DOIUrl":"https://doi.org/10.2166/aqua.2022.106","url":null,"abstract":"\u0000 Due to increasing population, uncontrolled water consumption, and abnormal climatic conditions, the potential of usable water is running out. Water has become one of the most valuable resources for the countries; therefore, rainwater harvesting systems for water recovery gain importance to implement in buildings. Thus, authorities have begun to search for fast and accurate decision tools before taking any action. In the present study, a semi-analytical method for determining the rainwater harvesting potential of the given location is implemented in the Java programming language. Three major districts of Izmir, Turkey are chosen for the study site, namely Cigli, Bayrakli, and Karsiyaka. The result shows that implementing rainwater harvesting systems only in public buildings recovers less than 1% of the population's water needs. On the contrary, encouraging the free zones, which has large rooftop area such as airports and malls, for implementing and using rainwater increases the water recovery to 13% of that district's water needs. It is still a small portion of the public's water needs; therefore, spreading rainwater harvesting in the communities is necessary. It is believed that more accurate and user-friendly rainwater harvesting simulators would encourage the communities to harvest rainwater.","PeriodicalId":17666,"journal":{"name":"Journal of Water Supply: Research and Technology-Aqua","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89447057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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