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1020 KiB

Open AccessArticle

Expert Decision Support Technique for Algal Bloom Governance in Urban Lakes Based on Text Analysis

by Yu-Ting Bai, Bai-Hai Zhang, Xiao-Yi Wang, Xue-Bo Jin, Ji-Ping Xu and Zhao-Yang Wang

Water 2017, 9(5), 308; https://doi.org/10.3390/w9050308 - 28 Apr 2017

Cited by 6 | Viewed by 3751

Abstract

As a typical phenomenon of eutrophication pollution, algal bloom threatens public health and water security. The governance of algal bloom is largely affected by administrators’ knowledge and experience, which may lead to a subjective and one-sided decision-making result. Meanwhile, experts in the specific [...] Read more.

As a typical phenomenon of eutrophication pollution, algal bloom threatens public health and water security. The governance of algal bloom is largely affected by administrators’ knowledge and experience, which may lead to a subjective and one-sided decision-making result. Meanwhile, experts in the specific field can provide professional support. How to utilize expert resources adequately and automatically has been a problem. This paper proposes an expert decision support technique for algal bloom governance based on text analysis methods. Firstly, the decision support mechanism is introduced to form a general decision-making framework. Secondly, the expert classification method is proposed to help with choosing suitable experts. Thirdly, a multi-criteria group decision-making method is presented based on the automatic analysis of experts’ decision opinions. Finally, an experiment is conducted to verify the expert decision support technique. The results show the technique’s feasibility and rationality. This paper describes experts’ information and opinions with natural language, which can intuitively reflect the natural meaning. The expert decision support technique based on text analysis broadens the management thought of water pollution in urban lakes. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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189 KiB

Open AccessArticle

Improved or Unimproved Urban Areas Effect on Soil and Water Quality

by Sally D. Logsdon and Patricia Sauer

Water 2017, 9(4), 247; https://doi.org/10.3390/w9040247 - 1 Apr 2017

Cited by 2 | Viewed by 4420

Abstract

Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions [...] Read more.

Construction in urban areas usually results in compacted soil, which restricts plant growth and infiltration. Nutrients may be lost in storm runoff water and sediment. The purpose of this study was to determine if existing lawns benefit from aeration and surface compost additions without the negative impact of nutrient loss in runoff. Four sets of lawns were compared, with or without compost plus aeration, as a paired comparison. Surface bulk density was significantly reduced in the treated lawns (1.32 versus 1.42 Mg·m⁻³). Visual evaluation of soil structure showed improvement in the treated lawns. Of fifteen measurement dates over four years, four dates showed significantly higher surface soil water contents in the treated lawns compared with the untreated lawns. When compared over time, three of the four treated lawns had significantly higher soil water content than the untreated lawns. Nutrient concentrations in rainfall simulator runoff were not significantly different between treated and control lawns, which showed that compost did not negatively impact water quality. Compost and aeration helped restore soil quality for urban soils of recent construction. Full article

(This article belongs to the Special Issue Urban Water Challenges)

3467 KiB

Open AccessArticle

Design and Operation of Decentralized Reservoirs in Urban Drainage Systems

by Eui Hoon Lee and Joong Hoon Kim

Water 2017, 9(4), 246; https://doi.org/10.3390/w9040246 - 31 Mar 2017

Cited by 12 | Viewed by 6858

Abstract

Poor drainage of urban storm water can lead to urban inundation which presents a risk to people and property. Previous research has presented various measures to prevent and reduce urban flooding and these measures can be classified into costly but effective structural measures, [...] Read more.

Poor drainage of urban storm water can lead to urban inundation which presents a risk to people and property. Previous research has presented various measures to prevent and reduce urban flooding and these measures can be classified into costly but effective structural measures, and economical but less effective non-structural measures. This study suggests a new approach to reduce urban flooding by combining structural and non-structural measures in a target watershed in Seoul, South Korea. Inlet design modification in a detention reservoir (Decentralized Reservoir, DR) is examined in conjunction with combined inlet/outlet management for the DR. Monitoring nodes used to control DR inlet/outlet operations are selected by locating the first flooding node, maximum flooding node and DR inlet node. This new approach demonstrates outstanding flood volume reduction for historical flooding events that occurred in Seoul during 2010 and 2011. Flood volumes during the 2010 event using the combined inlet/outlet operation in the DR were between 1656 m³ and 1815 m³ compared to a flood volume of 6617 m³ using current DR operation. Finally, the suggested operating level for the DR based on the best hydraulic section, system resilience index, and local regulations is 1.2 m. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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2629 KiB

Open AccessArticle

Water Use Efficiency Improvement against a Backdrop of Expanding City Agglomeration in Developing Countries—A Case Study on Industrial and Agricultural Water Use in the Bohai Bay Region of China

by Minghao Bai, Shenbei Zhou, Min Zhao and Jing Yu

Water 2017, 9(2), 89; https://doi.org/10.3390/w9020089 - 2 Feb 2017

Cited by 16 | Viewed by 7569

Abstract

Most city agglomerations of developing countries face water shortages and pollution due to population growth and industrial aggregation. To meet such water security challenges, policy makers need to evaluate water use efficiency at the regional or basin level because the prosperity of city [...] Read more.

Most city agglomerations of developing countries face water shortages and pollution due to population growth and industrial aggregation. To meet such water security challenges, policy makers need to evaluate water use efficiency at the regional or basin level because the prosperity of city agglomerations is indispensable to the sustainable development of the region or basin. To solve the issue, this paper adopts a non-directional distance function within the framework of environmental production technology to measure water use efficiency. Based on the distance between actual water use efficiency and the ideal efficiency, it calculates the potential reduction space of water input and pollutants by slack adjustment. Added to the Malmquist index, it forms a non-radial Malmquist water use performance index, which can be divided into technological change and technical efficiency change, to measure dynamic water use efficiency. Further, water use efficiency change is analyzed from the perspectives of technological improvement and institutional construction. Bohai Bay city agglomeration, a typical water-deficient city agglomeration in China, is taken as a case study, and data on water resource, environment, and economy from 2011 to 2014 have been used. In conclusion, there is much space for water use efficiency improvement on the whole. However, even having considered potential reduction space of water input and pollutant discharge under current environmental production technology, it is still not enough to support the city agglomeration’s sustainable development. To relieve current potential water safety hazards, not only technical improvement but also institution innovation for highly efficient water use should be kept accelerating in Bohai Bay region. In terms of urban water management in developing countries, the research conclusion is of theoretical and practical significance. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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1761 KiB

Open AccessArticle

Experimental and Numerical Analysis of Egg-Shaped Sewer Pipes Flow Performance

by Manuel Regueiro-Picallo, Juan Naves, Jose Anta, Jerónimo Puertas and Joaquín Suárez

Water 2016, 8(12), 587; https://doi.org/10.3390/w8120587 - 9 Dec 2016

Cited by 19 | Viewed by 12576

Abstract

A Computational Fluid Dynamics (CFD) model was developed to analyze the open-channel flow in a new set of egg-shaped pipes for small combined sewer systems. The egg-shaped cross-section was selected after studying several geometries under different flow conditions. Once the egg-shaped cross-section was [...] Read more.

A Computational Fluid Dynamics (CFD) model was developed to analyze the open-channel flow in a new set of egg-shaped pipes for small combined sewer systems. The egg-shaped cross-section was selected after studying several geometries under different flow conditions. Once the egg-shaped cross-section was defined, a real-scale physical model was built and a series of partial-full flow experiments were performed in order to validate the numerical simulations. Furthermore, the numerical velocity distributions were compared with an experimental formulation for analytic geometries, with comparison results indicating a satisfactory concordance. After the hydraulic performance of the egg-shaped pipe was analyzed, the numerical model was used to compare the average velocity and shear stress against an equivalent area circular pipe under low flow conditions. The proposed egg shape showed a better flow performance up to a filling ratio of h/H = 0.25. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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3111 KiB

Open AccessArticle

Coping with Pluvial Floods by Private Households

by Viktor Rözer, Meike Müller, Philip Bubeck, Sarah Kienzler, Annegret Thieken, Ina Pech, Kai Schröter, Oliver Buchholz and Heidi Kreibich

Water 2016, 8(7), 304; https://doi.org/10.3390/w8070304 - 21 Jul 2016

Cited by 67 | Viewed by 27098

Abstract

Pluvial floods have caused severe damage to urban areas in recent years. With a projected increase in extreme precipitation as well as an ongoing urbanization, pluvial flood damage is expected to increase in the future. Therefore, further insights, especially on the adverse consequences [...] Read more.

Pluvial floods have caused severe damage to urban areas in recent years. With a projected increase in extreme precipitation as well as an ongoing urbanization, pluvial flood damage is expected to increase in the future. Therefore, further insights, especially on the adverse consequences of pluvial floods and their mitigation, are needed. To gain more knowledge, empirical damage data from three different pluvial flood events in Germany were collected through computer-aided telephone interviews. Pluvial flood awareness as well as flood experience were found to be low before the respective flood events. The level of private precaution increased considerably after all events, but is mainly focused on measures that are easy to implement. Lower inundation depths, smaller potential losses as compared with fluvial floods, as well as the fact that pluvial flooding may occur everywhere, are expected to cause a shift in damage mitigation from precaution to emergency response. However, an effective implementation of emergency measures was constrained by a low dissemination of early warnings in the study areas. Further improvements of early warning systems including dissemination as well as a rise in pluvial flood preparedness are important to reduce future pluvial flood damage. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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3626 KiB

Open AccessArticle

Flood Adaptation Measures Applicable in the Design of Urban Public Spaces: Proposal for a Conceptual Framework

by Maria Matos Silva and João Pedro Costa

Water 2016, 8(7), 284; https://doi.org/10.3390/w8070284 - 12 Jul 2016

Cited by 42 | Viewed by 12294

Abstract

Assuming the importance of public space design in the implementation of effective adaptation action towards urban flooding, this paper identifies and systematizes a wide range of flood adaptation measures pertinent to the design of public spaces. It presents findings from both a systematic [...] Read more.

Assuming the importance of public space design in the implementation of effective adaptation action towards urban flooding, this paper identifies and systematizes a wide range of flood adaptation measures pertinent to the design of public spaces. It presents findings from both a systematic literature review and an empirical analysis retrieved from concrete public space design precedents. It concludes with the presentation of a conceptual framework that organizes the identified measures in accordance to their main, and secondary, infrastructural strategies. The intention behind the disclosed framework is to aid a multitude of professionals during the initial exploratory phases of public space projects that incorporate flooding adaptation capacities. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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7498 KiB

Open AccessArticle

Urban Drainage System Improvement for Climate Change Adaptation

by Narae Kang, Soojun Kim, Yonsoo Kim, Huiseong Noh, Seung Jin Hong and Hung Soo Kim

Water 2016, 8(7), 268; https://doi.org/10.3390/w8070268 - 28 Jun 2016

Cited by 42 | Viewed by 11455

Abstract

Recently, urban areas have experienced frequent, large-scale flooding, a situation that has been aggravated by climate change. This study aims to improve the urban drainage system to facilitate climate change adaptation. A methodology and a series of mitigation strategies are presented to efficiently [...] Read more.

Recently, urban areas have experienced frequent, large-scale flooding, a situation that has been aggravated by climate change. This study aims to improve the urban drainage system to facilitate climate change adaptation. A methodology and a series of mitigation strategies are presented to efficiently improve the urban drainage system in light of climate change. In addition, we assess the impact of climate change and predict the scale of potential future flood damage by applying the methodology and mitigation strategies to urban areas. Based on the methodology presented, urban flood prevention measures for Gyeyang-gu (Province), Incheon, Korea, was established. The validity of the proposed alternatives is verified by assessing the economic feasibility of the projects to reduce flood damage. We expect that the methodology presented will aid the decision-making process and assist in the development of reasonable strategies to improve the urban drainage system for adaptation to climate change. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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199 KiB

Open AccessArticle

Groundwater Data Management by Water Service Providers in Peri-Urban Areas of Lusaka

by David Nussbaumer, Ian Sutton and Alison Parker

Water 2016, 8(4), 135; https://doi.org/10.3390/w8040135 - 6 Apr 2016

Cited by 9 | Viewed by 8921

Abstract

Groundwater management by water service providers in Lusaka, Zambia, includes borehole siting, drilling and on-going monitoring. Semi-structured interviews were conducted with Lusaka Water and Sewerage Company (LWSC) and devolved Water Trust managers, in order to assess their needs and collect their suggestions to [...] Read more.

Groundwater management by water service providers in Lusaka, Zambia, includes borehole siting, drilling and on-going monitoring. Semi-structured interviews were conducted with Lusaka Water and Sewerage Company (LWSC) and devolved Water Trust managers, in order to assess their needs and collect their suggestions to improve data management. The research found that both the Water Trusts and LWSC lacked the capacity to fully utilize hydrogeological information. Prior to the research, none of the ten Water Trusts collected water level data. Four have started to collect data recently and another four have plans to, and they would like to share this data more widely. Full article

(This article belongs to the Special Issue Urban Water Challenges)

2001 KiB

Open AccessArticle

Support Vector Regression for Rainfall-Runoff Modeling in Urban Drainage: A Comparison with the EPA’s Storm Water Management Model

by Francesco Granata, Rudy Gargano and Giovanni De Marinis

Water 2016, 8(3), 69; https://doi.org/10.3390/w8030069 - 24 Feb 2016

Cited by 133 | Viewed by 10772

Abstract

Rainfall-runoff models can be classified into three types: physically based models, conceptual models, and empirical models. In this latter class of models, the catchment is considered as a black box, without any reference to the internal processes that control the transformation of rainfall [...] Read more.

Rainfall-runoff models can be classified into three types: physically based models, conceptual models, and empirical models. In this latter class of models, the catchment is considered as a black box, without any reference to the internal processes that control the transformation of rainfall to runoff. In recent years, some models derived from studies on artificial intelligence have found increasing use. Among these, particular attention should be paid to Support Vector Machines (SVMs). This paper shows a comparative study of rainfall-runoff modeling between a SVM-based approach and the EPA’s Storm Water Management Model (SWMM). The SVM is applied in the variant called Support Vector regression (SVR). Two different experimental basins located in the north of Italy have been considered as case studies. Two criteria have been chosen to assess the consistency between the recorded and predicted flow rates: the root-mean square error (RMSE) and the coefficient of determination. The two models showed comparable performance. In particular, both models can properly model the hydrograph shape, the time to peak and the total runoff. The SVR algorithm tends to underestimate the peak discharge, while SWMM tends to overestimate it. SVR shows great potential for applications in the field of urban hydrology, but currently it also has significant limitations regarding the model calibration. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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5621 KiB

Open AccessArticle

Establishment of a Practical Approach for Characterizing the Source of Particulates in Water Distribution Systems

by Seon-Ha Chae, Do-Hwan Kim, Doo Yong Choi and Cheol-Ho Bae

Water 2016, 8(2), 49; https://doi.org/10.3390/w8020049 - 3 Feb 2016

Cited by 4 | Viewed by 5013

Abstract

Water quality complaints related to particulate matter and discolored water can be troublesome for water utilities in terms of follow-up investigations and implementation of appropriate actions because particulate matter can enter from a variety of sources; moreover, physicochemical processes can affect the water [...] Read more.

Water quality complaints related to particulate matter and discolored water can be troublesome for water utilities in terms of follow-up investigations and implementation of appropriate actions because particulate matter can enter from a variety of sources; moreover, physicochemical processes can affect the water quality during the purification and transportation processes. The origin of particulates can be attributed to sources such as background organic/inorganic materials from water sources, water treatment plants, water distribution pipelines that have deteriorated, and rehabilitation activities in the water distribution systems. In this study, a practical method is proposed for tracing particulate sources. The method entails collecting information related to hydraulic, water quality, and structural conditions, employing a network flow-path model, and establishing a database of physicochemical properties for tubercles and slimes. The proposed method was implemented within two city water distribution systems that were located in Korea. These applications were conducted to demonstrate the practical applicability of the method for providing solutions to customer complaints. The results of the field studies indicated that the proposed method would be feasible for investigating the sources of particulates and for preparing appropriate action plans for complaints related to particulate matter. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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1391 KiB

Open AccessArticle

Analysis of Sources and Sinks of Mercury in the Urban Water Cycle of Frankfurt am Main, Germany

by Imke Fricke, Rolf Götz, Ruprecht Schleyer and Wilhelm Püttmann

Water 2015, 7(11), 6097-6116; https://doi.org/10.3390/w7116097 - 4 Nov 2015

Cited by 13 | Viewed by 7374

Abstract

Mercury (Hg) is still a focus of environmental research, since its levels in fish frequently exceed the Environmental Quality Standard (EQS) of 20 µg/kg for biota defined by the European Water Framework Directive (Directive 2008/105/EC). Current Hg levels in Abramis brama from German [...] Read more.

Mercury (Hg) is still a focus of environmental research, since its levels in fish frequently exceed the Environmental Quality Standard (EQS) of 20 µg/kg for biota defined by the European Water Framework Directive (Directive 2008/105/EC). Current Hg levels in Abramis brama from German rivers are in the range of 73–346 µg/kg wet weight (2009) and exceed the EQS by a factor of 3.7–17.3. Therefore, it is important to identify the sources of Hg pollution in the aquatic environment and to develop effective strategies for reducing the input into associated river systems. The aim of the present study was to analyze Hg in the urban water cycle of the city of Frankfurt am Main, Germany. Samples were taken from the river Main crosscutting the city and its tributaries. In addition, precipitation, stormwater runoff, effluents of two municipal WWTPs, and stormwater management structures such as combined sewer overflows and stormwater retention basins have been analyzed. Loads of Hg have been determined based on the measured concentrations and a Hg mass balance for the aquatic system was created. A total of 160 water samples were analyzed by cold vapor atomic fluorescence spectroscopy (CVAFS) according to US EPA Method 1631. Results from the mass balance have shown that approximately 5 kg Hg/a enter and 15 kg Hg/a leave the study area of Frankfurt am Main via the river Main. The largest amount of Hg (24.58 kg/a) throughout the urban water cycle of Frankfurt am Main is transported via wastewater. However, municipal WWTPs in Frankfurt am Main have been identified as the largest Hg sink, since 99.7% (24.5 kg/a) of the Hg is shifted from the sewage water and stormwater during treatment into the sewage sludge. Thus, the increase of the Hg load in the river Main from 5 to 15 kg/a has to be attributed to other sources such as 3 industrial WWTPs, groundwater and non-treated stormwater runoff during heavy rain events. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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Review

Jump to: Research, Other

3081 KiB

Open AccessReview

Re-Thinking Urban Flood Management—Time for a Regime Shift

by Johanna Sörensen, Andreas Persson, Catharina Sternudd, Henrik Aspegren, Jerry Nilsson, Jonas Nordström, Karin Jönsson, Misagh Mottaghi, Per Becker, Petter Pilesjö, Rolf Larsson, Ronny Berndtsson and Shifteh Mobini

Water 2016, 8(8), 332; https://doi.org/10.3390/w8080332 - 4 Aug 2016

Cited by 111 | Viewed by 21888

Abstract

Urban flooding is of growing concern due to increasing densification of urban areas, changes in land use, and climate change. The traditional engineering approach to flooding is designing single-purpose drainage systems, dams, and levees. These methods, however, are known to increase the long-term [...] Read more.

Urban flooding is of growing concern due to increasing densification of urban areas, changes in land use, and climate change. The traditional engineering approach to flooding is designing single-purpose drainage systems, dams, and levees. These methods, however, are known to increase the long-term flood risk and harm the riverine ecosystems in urban as well as rural areas. In the present paper, we depart from resilience theory and suggest a concept to improve urban flood resilience. We identify areas where contemporary challenges call for improved collaborative urban flood management. The concept emphasizes resiliency and achieved synergy between increased capacity to handle stormwater runoff and improved experiential and functional quality of the urban environments. We identify research needs as well as experiments for improved sustainable and resilient stormwater management namely, flexibility of stormwater systems, energy use reduction, efficient land use, priority of transport and socioeconomic nexus, climate change impact, securing critical infrastructure, and resolving questions regarding responsibilities. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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966 KiB

Open AccessReview

Intermittent Domestic Water Supply: A Critical Review and Analysis of Causal-Consequential Pathways

by S. E. Galaitsi, Robert Russell, Amahl Bishara, John L. Durant, Jennifer Bogle and Annette Huber-Lee

Water 2016, 8(7), 274; https://doi.org/10.3390/w8070274 - 30 Jun 2016

Cited by 122 | Viewed by 15105

Abstract

Communities in many parts of the world, especially in developing countries, face obstacles in supplying continuous water to household consumers. Authorities often cite water scarcity as the cause, but we demonstrate that environmental constraints constitute only one aspect of a multi-dimensional problem. By [...] Read more.

Communities in many parts of the world, especially in developing countries, face obstacles in supplying continuous water to household consumers. Authorities often cite water scarcity as the cause, but we demonstrate that environmental constraints constitute only one aspect of a multi-dimensional problem. By asking what causes intermittent domestic water supply, this literature review (129 articles) identifies 47 conditions of intermittent systems and the causal-consequential pathways between them that can reinforce intermittency. These pathways span several disciplines including engineering, government administration and anthropology, and when viewed together they (1) emphasize the human drivers of intermittency; (2) suggest generalized interventions; and (3) reveal a gap in the literature in terms of meaningful categorizations of the reliability of intermittent supplies. Based on the reliability of consumers’ water access, we propose three categories of intermittency—predictable, irregular, and unreliable—to facilitate comparisons between case studies and transfers of solutions. Full article

(This article belongs to the Special Issue Urban Water Challenges)

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