Showing papers in "Urban Water Journal in 2007"
TL;DR: In this paper, the authors describe Mumbai's drainage system, details of the flooding and the measures being taken by the city to mitigate such floods in the future, and the Mumbai experience would be helpful for planning response strategies for other large cities to cope with similar events.
Abstract: Mumbai city, having an area of 437 km2 with a population of 12 million, came to a complete halt owing to the unprecedented rainfall of 994 mm during the 24 hours starting 08:30 on 26 July 2005. At least 419 people (and 16 000 cattle) were killed as a result of the ensuing flash floods and landslides in Mumbai municipal area, and another 216 as a result of flood-related illnesses. Over 100 000 residential and commercial establishments and 30 000 vehicles were damaged. The current paper describes Mumbai's drainage system, the details of the flooding and the measures being taken by the city to mitigate such floods in the future. The Mumbai experience would be helpful for planning response strategies for other large cities to cope with similar events in the future.
136 citations
TL;DR: Scholz et al. as mentioned in this paper present a text book on sustainable urban drainage systems with an emphasis on wetlands for water treatment, which is meant to be a textbook at undergraduate level but is also aimed at practicing engineers.
Abstract: Today very many wetlands are built, as are other elements in sustainable urban drainage systems. The principles of the design are, however, more art than science. At best they are designed from experience. There is a need for guidelines and simple explanations. The book Wetland systems to control urban runoff, by Miklas Scholz, tries to fill that gap with a very engineering approach. The book covers most aspects of sustainable urban drainage systems, but with an emphasis on wetlands for water treatment. The book is meant to be a text book at undergraduate level, but is also aimed at practicing engineers. The book consists of 32 chapters, of which most of them can be read separately. The title of the book is a little misleading, since the first part of the book is basic sanitary engineering, including methods for waste water engineering and treatment of drinking water described from a civil engineering approach. Of the first 23 chapters, only one is directly devoted to wetlands. The basic principles of water treatment are given to make it possible for the reader to see how wetlands function in comparison to conventional waste water treatment plants. This is likely to be appreciated by the undergraduate student, but as an experienced engineer one would probably prefer to have all wetlandspecific processes in the chapters devoted only to wetlands. However, the general review of water in a city environment does not include storm water drainage, which means that those who do not have knowledge of storm water design must read up on this before they can use the information on sustainable urban drainage system given in the last sections of the book. Also basic information about natural wetlands is lacking, such as which types there are, water balance, and interaction with groundwater; and what the hydrological function and resident time in a wetland are when the water level is high as compared to when it is low. The first part of the book, where wetlands is only included to a minor extent, is general. In the second part, wetlands are the focus of eight chapters in which six different ways of using wetlands are given, referring in detail to case studies performed by the author, and showing strategies to choose the most appropriate elements to be used in sustainable urban drainage systems in Glasgow and Edinburgh, and a methodology of how to predict the performance of a wetland. The six cases are: wetlands to improve stream water, control of roof runoff using ponds, wetlands for treating road runoff, wetland upstream belowground detention, infiltration wetland system, and natural riparian peatland for treating diffuse pollution. The experience gained from these studies is of value for the engineer who needs to design a wetland – pond infiltration system. Such studies are not often reported. However, since there is not much attempt at generalization (which maybe is not possible), he or she must still base the design on information from other sources. The text would have benefited if the principles of different constructed wetlands had been shown in figures in a general chapter; nor are different elements of sustainable urban drainage systems shown in figures. Discussions of how the different systems function during very high and very low flows are missing. As a text book in sanitary or ecological engineering the book is well written and easy to read, although it is completely lacking in figures and references. The second part with case studies and many references, is useful for practicing engineers, since there is information not found elsewhere, but it requires that the reader has knowledge from other sources about wetlands and stormwater systems.
127 citations
TL;DR: In the UK, there are currently no regulations in respect to the microbial quality of harvested rainwater for non potable use, although there are generally standards relating to the required plumbing to ensure that potable and nonPotable supplies remain separate.
Abstract: The current paper examines the reported microbial quality of rainwater supplies. The majority of microbial contamination derives from debris and faecal material deposited on the roof surface, principally from birds. The prevalence and level of contamination varies widely, both in terms of indicator organisms and pathogens. Gastrointestinal pathogens such as Campylobacter spp., Salmonella spp., Cryptosporidium spp. and Giardia spp. have all been isolated from harvested supplies, although these may not always be of types infective to humans. In the UK, there are currently no regulations in respect to the microbial quality of harvested rainwater for non potable use, although there are generally standards relating to the required plumbing to ensure that potable and non potable supplies remain separate.
42 citations
TL;DR: In this paper, the authors focus on urban drainage as a component of urban upgrading and discuss issues related to the integration of drainage systems serving informal settlements into citywide stormwater management systems.
Abstract: Many cities in developing countries are typified by large areas of informal settlements These often do not adhere to official planning guidelines, building regulations and construction standards and, as they are not officially recognised by local authorities, are rarely provided with adequate infrastructure and services The provision of improved systems for drainage of wastewater and stormwater runoff is an important component of urban upgrading initiatives This paper focuses on urban drainage as a component of urban upgrading and discusses issues related to the integration of drainage systems serving informal settlements into citywide stormwater management systems Experiences from urban upgrading schemes in different parts of the world are used to highlight innovative approaches towards planning and design as well as illustrating examples of potential problems that may be encountered during project implementation and subsequent operation
42 citations
TL;DR: In many tropical island settings in the world and as a result of human activities and tropical weather conditions, urban areas have been vulnerable to special kinds of hazards such as tropical cyclones and accompanying storm surges, flash floods and landslides as discussed by the authors.
Abstract: In many tropical island settings in the world and as a result of human activities and tropical weather conditions, urban areas have been vulnerable to special kinds of hazards. The most common and the most widely experienced hazard events for these localities are tropical cyclones and accompanying storm surges, flash floods and landslides. Such events can cause serious damages to the drainage systems, roads, properties, receiving environment and even the loss of human lives. Given the threats of climate change, such natural disasters are likely to strengthen this trend in the coming years. In many situations, it is the population living in low-lying urban areas that are most exposed to these disasters. From this, it follows that the scientific and professional communities have a responsibility to evolve better stormwater management approaches directed to minimizing hazard risks owing to urban flooding, even while addressing different climatic conditions. Although, the physics, chemistry and biology of pro...
41 citations
TL;DR: In this article, the authors summarise the results of research into the control of urban litter in urban catchments, and the cost-effective removal of that portion that makes it way into separated stormwater drainage systems.
Abstract: Urban litter (alternatively called trash, debris, flotsam, jetsam, floatables, gross pollutants, rubbish or solid waste) is a major problem in South Africa. It accumulates in public areas until either someone removes it, or it is transported by the wind and/or stormwater runoff into the drainage system. The current paper summarises the results of research into the control of urban litter in urban catchments, and the cost-effective removal of that portion that makes it way into separated stormwater drainage systems.
33 citations
TL;DR: The results indicate that there was no microbial contamination in 100 random samples collected from 20 selected areas and other quality parameters such as colour, pH, turbidity, hardness, magnesium, sulphate and chloride were within acceptable limits as discussed by the authors.
Abstract: A safe drinking water programme known as The National Drinking Water Quality Surveillance Programme (NDWQSP) was launched by the Ministry of Health, Government of Malaysia in 1983 to ensure safe practices in water treatment and distribution. The aim of this work was to assess the effectiveness of this programme in the improvement of tap water quality in and around Kuala Lumpur. The results indicate that there was no microbial contamination in 100 random samples collected from 20 selected areas. Other quality parameters such as colour, pH, turbidity, hardness, magnesium, sulphate and chloride were within acceptable limits. Heavy metals such as Cu2+, Pb2+, Cr (total), Ni2+, Cd2+, Fe (total) and Mn (total) were also under control. The only exception was Ba2+, which did not comply with the standard and was up to ten times higher than the guideline value. Moreover, there was significant variation in water quality as indicated by the test results.
32 citations
TL;DR: In this paper, a long-term runoff monitoring was carried out in a highway drainage system in Winterthur, Switzerland, where several runoff quantity simulations were carried out using the distributed model InfoWorks-CS.
Abstract: A long-term runoff monitoring was carried out in a highway drainage system in Winterthur, Switzerland. Several runoff quantity simulations were carried out using the distributed model ‘InfoWorks-CS’. Serial rainfall monitoring data were used for investigation of water runoff behaviour from the highway. The inter-event time definition was calculated from the runoff simulation and applied for better accurate runoff volume determination. Under continuous rainfall condition, the quantity simulation showed a good agreement with the measured hydrograph. However, in some cases where rainfall was not continuous, overestimation of runoff volume and difference in peak height/timing was found after rainfall halting. It was believed that the initial/depression loss on road surface was recovered during the halting period of rainfall and caused the difference in the runoff volume and peak height/timing difference in simulation. The consideration of regenerated depression loss significantly improved runoff simulation re...
27 citations
TL;DR: The performance of the WSP was poor and did not comply with World Health Organization (WHO) and Food and Agricultural Organization (FAO) guidelines for irrigation water in Faisalabad as mentioned in this paper.
Abstract: Faisalabad is one of the few cities in Pakistan that has a waste stabilization pond (WSP) system. Local farmers complained about the high salinity and low nutrient value of the final effluent from the WSP and preferred the use of untreated wastewater. A one-year study showed a strong increase in salinity from untreated wastewater to final effluent with a clear decline in nitrogen concentration, thereby confirming farmer perceptions. The performance of the WSP was poor and did not comply with World Health Organization (WHO) and Food and Agricultural Organization (FAO) guidelines for irrigation water. The poor performance of the WSP could be attributed to a combination of factors: poor design, the extreme climatic conditions and the large quantities of untreated wastewater which were used in agriculture. In countries such as Pakistan where the use of untreated wastewater has a long history, farmer perceptions should play a pivotal role in the selection of suitable wastewater treatment systems.
20 citations
TL;DR: In this article, the authors developed a methodology based on field surveys in the city of Itajuba, located in the valley of the Sapucai River, in Minas Gerais state in the southeast region of Brazil.
Abstract: The present paper describes theoretical aspects and the main results on the development of a methodology for the global evaluation of direct damage caused by floods. This methodology is based on the use of standard flood damage curves versus depth of inundation on dwelling, commerce and service sectors. The research was developed based on field surveys in the city of Itajuba, located in the valley of the Sapucai River, in Minas Gerais state in the southeast region of Brazil. In January 2000, this city suffered severe floods where more of 70% of the urban area was affected; with depths of inundation higher than 3 m in certain areas. The empirical data were obtained through questionnaires applied in the ravaged area in 2002. The questionnaires allowed the characterization of the dwellings and their content, as well as the different categories on commercial and service activities. The generic curves obtained from the data in the survey were used at the same site to evaluate the amount of potential flood dama...
20 citations
TL;DR: In this article, a spatial decision support tool based on soft computing is proposed to assist the optimal siting of wastewater treatment technologies within the context of new urban developments, through the creation of suitability maps.
Abstract: This paper describes the development of a spatial decision-support tool based on soft computing that assists the optimal siting of wastewater treatment technologies within the context of new urban developments, through the creation of suitability maps. The tool is based on multi-criteria decision analysis and fuzzy logic, allowing the inclusion of both uncertainty and of the decision-makers' attitude towards risk in the decision-making process. The paper describes the attributes influencing the siting of wastewater treatment infrastructure and presents a method for using these to generate composite siting suitability maps for a given development site and propose specific locations maximizing the combined suitability index. Extensive sensitivity analysis has been undertaken and the results discussed. The proposed system architecture integrates three widely used software platforms (ArcView GIS, Matlab and MS Excel) into a flexible and user-friendly decision-support tool that can easily be adapted to differe...
TL;DR: In this paper, a methodology for evaluating leakage or physical "unaccounted for water" (UFW) owing to high pressure in water networks is developed, considering the crisis of water supply issues in large cities owing to increases in population.
Abstract: A methodology for evaluating leakage or physical ‘unaccounted for water’ (UFW) owing to high pressure in water networks is developed. Considering the crisis of water supply issues in large cities owing to increases in population, quantifying the UFW in terms of both physical and non-physical losses of water in the network to improve the system efficiency represents an important issue that managers need to consider. A pilot site is used to demonstrate the methodology, including the spectrum of network data for spatial and attributed data stored in a GIS database. Via use of an interface extension tool, the data were transformed into the EPANET model. After hydraulic simulation using mathematical formulae, leakage discharges from the network are quantified and the results provide estimates of the percentage of physical UFW, allowing comparison with the modelling and the measurements of total UFW in the network Physical losses in the pilot site area are determined to be 13% and the non-physical losses (e.g. ...
TL;DR: The finite volume Darcy's flow (FVD) model is based on physical characteristics, which represents flow through gravel material as discussed by the authors, and an excellent model fit was achieved when compared with monitoring data.
Abstract: Today's standardized computer models for simulating flow through in-ground sustainable urban drainage systems (SUDS) require substantial monitoring data in order to allow for a realistic representation of system behaviour, as they are based on predefined or user-specific head-discharge relationships. Darcy's law in combination with the finite volume method was applied to compute the flow through filter material and validated against monitored data. The finite volume Darcy's flow (FVD) model is based on physical characteristics, which represents flow through gravel material. Flow characteristics are dependent on the dimensions and materials used and an excellent model fit was achieved when compared with monitoring data.
TL;DR: This investigation highlights the necessity for constant monitoring of the final effluent and sludge from these treatment facilities, and finds the highest resistance rates were found in E. coli strains isolated from the district capitals sampled.
Abstract: Antimicrobial resistance is a phenomenon of increasing importance. Sewage treatment processes are a vehicle for dissemination of resistant bacteria in both aquatic and terrestrial environments. To assess the number of antimicrobial resistant E. coli present in the wastewater inflow, effluent and sludge from urban sewage treatment plants in Portugal, 42 samples of crude inflow, treated effluent and sludge were collected in 14 municipal sewage treatment plants in Portugal. A total of 940 E. coli strains were recovered and tested, using the diffusion agar method, regarding their sensitivity to 12 different antimicrobial drugs. Resistance to tetracycline, ampicillin, trimethoprime/sulfamethoxazole, streptomycin and ciprofloxacin was found in 42.2, 32.6, 23.3, 26.4 and 11.9% of the isolates, respectively. No correlation was found with regards to medical antimicrobial use in Portugal. The highest resistance rates were found in E. coli strains isolated from the district capitals sampled. Wastewater treatment res...
TL;DR: In this paper, the pollutant transport process operated by stormwater runoff on urban paved surfaces and the relationship between the parameters of the washoff function and the controlling hydrologic variables are investigated.
Abstract: The pollutant transport process operated by stormwater runoff on urban paved surfaces and the relationship between the parameters of the wash-off function and the controlling hydrologic variables are investigated in the present work. Data collected during two monitoring campaigns carried out at the plot scale within a residential area and an auto dismantler site are used to this aim. The observed runoff events are classified into different mass delivery processes and the occurrence of the first flush phenomenon is also investigated. The maximum flow discharge obtained as the average value over the time of concentration of the drainage network is proposed as the controlling factor for the total mass of pollutant that is made available for wash-off during each runoff event.
TL;DR: In this paper, the background concentration of suspended solids and nutrients in a constructed stormwater treatment wetland in Brisbane, Australia has been investigated and the study has identified that design issues such as the characteristics of the inlet have a significant impact on these processes.
Abstract: Urban stormwater wetlands have been widely embraced by the community as a beneficial part of the stormwater infrastructure. Although a reasonably large body of research has been undertaken into the treatment efficiency of wetlands during storm events, relatively little is known about inter-event processes. Environmental effects such as wind direction and speed, wildlife and other anthropogenic activities have a significant impact on these processes. The development of a suitable model of these processes is limited by a lack of fundamental data on the movement of contaminants within a stormwater wetland during these inter-event periods. This paper describes a study that has been undertaken to determine the background concentration of suspended solids and nutrients in a constructed stormwater treatment wetland. The study has included an intensive monitoring programme of a recently constructed wetland in Brisbane, Australia. The study has identified that design issues such as the characteristics of the inlet...
TL;DR: The study suggests that exposure to wastewater is a risk factor for skin problems, and contact with wastewater was an important factor associated with self-reported skin problems.
Abstract: To obtain essential information for the planning of epidemiological studies on health risks of exposure to wastewater in aquaculture, a total of 3089 people from 606 households involved in aquaculture in Phnom Penh, Hanoi and Ho Chi Minh City were interviewed in a cross-sectional survey in May 2004. In this study household members were asked about health problems that they had experienced. Our results indicate that the most important health problem associated with wastewater exposure was skin problems, reported by 4% of all people surveyed. Contact with wastewater was an important factor associated with self-reported skin problems. The study suggests that exposure to wastewater is a risk factor for skin problems.
TL;DR: In this paper, the authors proposed a method to separate urine from the wastewater stream, store it at the household and release it in a controlled manner into the drainage system, where all process steps from urine production, separation, harvesting and controlled release of urine have been modelled on a micro-level where all toilets in the system are balanced separately.
Abstract: Considering wastewater from household sources, urine accounts for approximately 80% of the ammonia loads but for only 1% of the hydraulic load. Where classical urine separation deals with the separation and subsequent removal of urine from the wastewater stream, the method promoted here (urine separation for waste design) aims to (1) separate urine from the wastewater stream, (2) store it at the household and (3) release it in a controlled manner into the drainage system. The ultimate goal is on the one hand to average the daily dynamics in the ammonia load to the wastewater treatment plant (WWTP) and on the other hand to reduce ammonia emissions towards receiving waters. All process steps from urine production, separation, harvesting and controlled release of urine have been modelled on a micro-level where all toilets in the system are balanced separately. As a case study the integrated urban drainage system of Vils/Reutte in Tyrol was used where a total of 11 different control strategies – ranging from ...
TL;DR: In this paper, the concentration of pollutants in stormwater runoff from different areas for sorting, recycling, storage and treatment of municipal and industrial waste was investigated at one landfill site in southern Sweden.
Abstract: The concentration of pollutants in stormwater runoff from different areas for sorting, recycling, storage and treatment of municipal and industrial waste was investigated at one landfill site in southern Sweden. Field measurements and calculation based on historical series of precipitation were used to estimate stormwater volumes and pollutant loads generated from asphalt, gravel and steep slopes of landfill cells. The concentration ranges (min – max) of pollutants in stormwater from composting, roads and sorting/storage of recyclables in the studies site were compared. Composting areas presented the widest ranges and the highest values for COD, BOD, TOC, N – tot, N – NH4, P – tot reflecting different composting phases. The composting area for contaminated soils was responsible for the highest concentration values of Cl, Ca, Fe and Cd. Although stormwater from sorting/storage areas for recyclables had the highest concentrations for Zn, Cu, Pb, Ni, Cr, Co and Hg, stormwater runoff from garden waste compost...
TL;DR: In this paper, the authors report on the part of the project dealing with benchmarking of sewerage systems, with a focus on the analysis of investment costs of 34 sewerage system projects.
Abstract: In February 2002 an Austrian benchmarking project was completed. The present paper reports on the part of the project dealing with benchmarking of sewerage systems, with a focus on the analysis of investment costs of 34 sewerage system projects. The paper explains the methodology used to make the investment costs of the projects comparable. This was based on an analysis of the final accounts of the finished projects. The paper further delineates the results of the project and considers in detail the important influence of unquantifiable factors, such as economic fluctuations and tendering strategies of the successful contractors, on the calculation of the construction costs.
TL;DR: In this article, a new approach is proposed to determine relevant temporal stratifications through an examination of historical performance, which represents a novel alternative to current practice where stratification regimes are identified using a priori knowledge of criteria deemed relevant.
Abstract: The need for proactive replacement schedules in the management of water supply infrastructure is highlighted by the ever-increasing cost of reactive repairs. Proactive replacement schedules require models of asset performance, and, in turn, these models require appropriate stratifications of the data in order to produce subgroups that are expected to behave uniformly over time. This paper outlines a new approach to determine relevant temporal stratifications through an examination of historical performance. This represents a novel alternative to current practice where stratification regimes are identified using a priori knowledge of criteria deemed relevant. A key advantage of using the actual break histories to identify appropriate stratifications lies in the ability to identify changes in behaviour that may not be reflected in a priori criteria. In an example using Hunter Water Corporation break data a significant change is discovered and found not to correlate with previously hypothesised partition cri...
TL;DR: A review of the existing criteria to evaluate such a hazard is made in this paper, where two new criteria based on theoretical analysis of the water's force acting on a static pedestrian are presented: no slipping criterion and stability to tilt criterion.
Abstract: The current paper focusses on the hazard assessment associated with urban runoff on streets. A review of the existing criteria to evaluate such a hazard is made. Two new criteria based on theoretical analysis of the water's force acting on a static pedestrian are presented: no slipping criterion and stability to tilt criterion. According to these criteria, either a maximum depth, or a maximum velocity or some relation between depths and velocities should be fulfilled in order to guarantee the pedestrian's and driver's safety in the case of medium to large storms. A one-dimensional numerical model is used to solve the urban storm runoff within a street network. This model is applied to an urban watershed of the city of Mendoza (Argentina), obtaining the runoff values belonging to return periods of 5, 10 and 25 years. The results are evaluated bearing in mind four hazard criteria. In conclusion, the numerical model is shown to be a useful tool in relation to the application of the hazards criteria. It is al...
TL;DR: In this article, the authors present the main results of a research project that deals with consumers' perception of water issues in the industrial sector, and examines and analyses water use patterns, water conservation methods and water pricing issues.
Abstract: The present paper presents the main results of a research project. It deals with consumers' perception of water issues in the industrial sector, and examines and analyses water use patterns, water conservation methods and water pricing issues. Issues presented are the contribution of water to production processes, water consumption levels, water conservation options, the possibility of construction of a dual water supply system, the evaluation of different pricing policies, the willingness to pay (WTP) and the potential impact of a price increase. The study has shown that there is limited use of recycling methods, few pollution control practices and small effect of industrial water price on water consumption levels. As far as industrial consumers are concerned, they present inaccurate perception of water consumption levels and low willingness to pay for the improvement of water services.
TL;DR: In this paper, the authors compared the allocation of water demand to nodes with uniformly distributed demand along a pipeline, and showed that the nodal approach produces an upper bound or unsafe solution for pressures in the distribution network.
Abstract: The allocation of water demand to nodes is compared with uniformly distributed demand along a pipeline, and it is shown that the nodal approach produces an upper bound or unsafe solution for pressures in the distribution network. Although the differences are likely to be minor for computer models with many nodes, the simplest examples show differences of up to 25% in head loss between the two approaches. Terminology and concepts from structural engineering are useful in this comparison. The results are particularly significant to simplified models using independently derived values of pipe friction factor.