Management Of Urban Drainage Systems Research Articles

Optimal sensor placement for the routine monitoring of urban drainage systems: A re-clustering method

The construction of an efficient monitoring network is critical for the effective and safe management of urban drainage systems. This study developed a re-clustering methodology that incorporates additional perspectives beyond node similarity to improve the traditional clustering process for optimal sensor placement. Instead of targeting event-specific water quality or hydraulic monitoring, the method integrates the water hydraulic and quality characteristics of nodes in response to the demand for routine monitoring. The implementation of this method first applies model simulation to generate the attribute datasets required for clustering analysis, and then re-clusters the initial clustering result according to the constructed re-clustering potential indices. And the information theory-based evaluation metrics were introduced to quantitatively assess the sensor deployment scheme obtained by amalgamating the two clustering results. Two networks with different drainage systems and sizes were chosen as case studies to illustrate the application of the framework. The results demonstrate that the clustering process enables to expand the information contained in the monitoring network, and that the re-clustering strategy can generate more comprehensive and practical solutions upon this basis.

Building an urban drainage database (GIS) for urban planning and management: A case study in Cao Bang Province Viet Nam

The management of urban drainage systems faces many shortcomings in many urban areas in developing countries, including Vietnam. This poor management is causing economic and environmental consequences, especially flooding. One of the reasons is that urban areas have not applied technology in management, do not have a database of the status of current urban drainage system, so the management skills is not scientific and there is no forecasting technique. GIS technology is a highly effective management support tool in many cities around the world, and the Vietnamese government has also issued regulations requiring the use of GIS in urban management. This paper studies the process of establishing a GIS database for urban drainage in ArcGIS sofware and a case study in Cao Bang city, Vietnam. The results of this study are a reference for cities that want to use GIS technology in urban management and the database of this study is for Cao Bang City in Vietnam to be used to integrate into the database of city (big data) in Viet Nam government-oriented urban management.

Performance assessment of the operational management of urban drainage systems: a case study of Bejaia City, Algeria.

Over the recent years, managers of the Algerian National Sanitation Office (ONA) have been worrying about the degraded state of their Urban Drainage Systems (UDS). This infrastructure failure is due essentially to the lack of funding and absence of adequate structured methodology for diagnosis and maintenance. As a result, ONA's managers found it very interesting to get a tool that allows them to assess their management of UDS operation. The aim of this paper is therefore to provide an assessment tool to managers for a good network operation. The adopted approach is participative and takes into account the specific local context. Six performance indicators, grouped into two criteria, have been constructed to achieve this objective. These indicators have been chosen for their effectiveness; they are scaled to get their performance scores according to a scaling constructed here based on standards when available and to the ONA expert's recommendations. The developed tool is applied to the UDS of Bejaia City, in north-eastern Algeria. The assessment and the analysis of the performance evolution of these indicators for the period 2017-2021 are carried out. The results highlighted successes that can be maintained as well as weaknesses that need to be improved.

The structure design of integrated urban drainage systems: A view of robust optimization

Rapid urbanization puts a lot of pressure on urban water pollution from point and non-point sources, calling for the practical, specific, and integrated management of urban drainage systems (UDS). The structural design of an integrated UDS is essential for highly complex and uncertain urban water management. In this study, we developed a multi-objective robust optimization model to explore the optimal structures of UDS considering system uncertainty. We applied this model to City B, northern China, to illustrate its effectiveness. The results show that the model can produce optimal designs with a more robust performance in terms of structural uncertainty. When the uncertainty degree ranges from 5% to 20%, a considerable extra cost (increased by 1.10–2.68 times) is required to improve the robustness of UDS. With the increase in structural uncertainty, the fraction of the cost invested in the stormwater subsystem increased from 10.2% to 27.2%. The findings showed that stormwater management is efficient in coping with system uncertainty. The research results promote an understanding of robust urban drainage systems.

Developing Intensity-Duration-Frequency (IDF) Curves Based on Rainfall Cumulative Distribution Frequency (CDF) for Can Tho City, Vietnam

Information on the relationship between rainfall intensity, duration and accumulation frequency or return period (IDF) is commonly utilized in the design and management of urban drainage systems. Can Tho City, located in the Vietnamese Mekong Delta, is a city which has recently invested heavily in upgrading its stormwater drainage systems in the hope of preventing reoccurring flood events. Yet, much of these works were designed based on obsolete and outdated IDF rainfall curves. This paper presents an updated IDF curve for design rainfall for Can Tho City. For each duration and designated return period, a cumulative distribution function (CDF) was developed using the Pearson III, Log-Pearson III, and Log-Normal distribution functions. In order to choose the best IDF rainfall curve for Can Tho City, the CDF rainfall curve and empirical formulas used in Vietnam and Asia (Vietnamese standard 7957:2008, Department of Hydrology, Ministry of Transportation, Talbot, Kimijima, and Bermard) were compared. The goodness of fit between the IDF relationship generated by the frequency analysis (CDF curve), and that predicted by the IDF empirical formulas was assessed using the efficiency index (EI), and the root mean squared error (RMSE). The IDF built from Vietnam’s standard TCVN 7957:2008 with new parameters (A = 9594, C = 0.5, b = 26, n = 0.96) showed the best performance, with the highest values of EI (0.84 ≤EI≤ 0.93) and the lowest values of RMSE (2.5 ≤RMSE≤ 3.2), when compared to the other remnants.

Soft sensing of water depth in combined sewers using LSTM neural networks with missing observations

Information and communication technologies combined with in-situ sensors are increasingly being used in the management of urban drainage systems. The large amount of data collected in these systems can be used to train a data-driven soft sensor, which can supplement the physical sensor. Artificial Neural Networks have long been used for time series forecasting given their ability to recognize patterns in the data. Long Short-Term Memory (LSTM) neural networks are equipped with memory gates to help them learn time dependencies in a data series and have been proven to outperform other type of networks in predicting water levels in urban drainage systems. When used for soft sensing, neural networks typically receive antecedent observations as input, as these are good predictors of the current value. However, the antecedent observations may be missing due to transmission errors or deemed anomalous due to errors that are not easily explained. This study quantifies and compares the predictive accuracy of LSTM networks in scenarios of limited or missing antecedent observations. We applied these scenarios to an 11-month observation series from a combined sewer overflow chamber in Copenhagen, Denmark. We observed that i) LSTM predictions generally displayed large variability across training runs, which may be reduced by improving the selection of hyperparameters (non-trainable parameters); ii) when the most recent observations were known, adding information on the past did not improve the prediction accuracy; iii) when gaps were introduced in the antecedent water depth observations, LSTM networks were capable of compensating for the missing information with the other available input features (time of the day and rainfall intensity); iv) LSTM networks trained without antecedent water depth observations yielded larger prediction errors, but still comparable with other scenarios and captured both dry and wet weather behaviors. Therefore, we concluded that LSTM neural network may be trained to act as soft sensors in urban drainage systems even when observations from the physical sensors are missing.

Combined Application of Real-Time Control and Green Technologies to Urban Drainage Systems

The increase in waterproof surfaces, a typical phenomenon of urbanization, on the one hand, reduces the volume of rainwater that naturally infiltrates the subsoil and, on the other, it determines the increase in speeds, flow rates, and outflow volume surface; at the same time, it causes a qualitative deterioration of the water. This study researched the optimal management of urban drainage systems via the combined application of real-time control and green technologies. A hydraulic model of the sewer system of the suburbs of Bologna (Italy) was set up using the Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) to evaluate the reduction in water volume and the masses of pollutants discharged in water bodies. The combined application of these technologies allows significantly reducing both the pollutants released into the receiving water bodies and the overflow volumes, while optimizing the operation of the treatment plants. Green technologies cause an average reduction equal to 45% in volume and 53% of total suspended solids (TSS) sent to the receiver. The modeled cases represent only some of the possible configurations achievable on urban drainage systems; the combined use of different solutions could lead to further improvements in the overall functioning of the drainage system.

Developing a Reliability Index of Low Impact Development for Urban Areas

A defining characteristic of the urbanization is the transformation of existing pervious areas into impervious areas during development. This leads to numerous hydrologic and environmental problems such as an increase in surface runoff due to excess rainfall, flooding, the deterioration of water quality, and an increase in nonpoint source pollution. Several studies propose supplementary measures on environmental change problems in development areas using the low impact development technique. This study investigated the reduction of nonpoint source pollutant loads and flooding in catchments through urban catchment rainfall–runoff management. For the quantitative assessment of flood disasters and water pollution problems, we propose a reliability evaluation technique. This technique refers to a series of analysis methods that determine the disaster prevention performance of the existing systems. As the two factors involve physical quantities of different dimensions, a reliability evaluation technique was developed using the distance measure method. Using the storm water management model, multiple scenarios based on synthetic rainfall in the catchment of the Daerim 2 rainwater pumping station in Seoul, South Korea, were examined. Our results indicate the need for efficient management of natural disaster risks that may occur in urban catchments. Moreover, this study can be used as a primary reference for setting a significant reduction target and facilitating accurate decision making concerning urban drainage system management.

Development of an assessment tool for infrastructure asset management of urban drainage systems.

The present paper deals with the improvement of infrastructure asset management of urban drainage systems (UDS). A numerical tool for assessing the existing management procedures is proposed. It is based on a participatory methodology for the construction of a set of performance indicators. This methodology consists of two phases. The first concerns the identification of priority objectives, criteria and indicators related to the management of the UDS infrastructure. The second phase concerns the assessment of the global performance for each identified objective. Performance measurement scales are first defined for all the elements of the proposed methodology. Then, the Fuzzy Analytical Hierarchy Process (FAHP) is used for the weighting stage, and the Weighted Sum Method is used for the aggregation of indicators and criteria. To illustrate this methodology, a case study concerning Bejaia City in northern Algeria was carried out. Two priority objectives are identified for this case, they are divided into 6 criteria and 31 indicators. The results of the application of the developed tool highlighted some weaknesses that need improvements in the actual management procedure applied by the local sanitation services.

MITIGASI BANJIR STRUKTURAL DAN NON-STRUKTURAL UNTUK DAERAH ALIRAN SUNGAI RONTU DI KOTA BIMA (Structural and non-structural flood mitigation for Rontu Watershed in Bima City)

Flood is one of natural disasters that often occur in Indonesia. This disaster also occurred in Bima City on December 21, 2016, December 23, 2016, and January 2, 2017 with the affected area were Mpunda, Rasanae Timur, Asakota, Rasanae Barat, and Raba districts. The urban areas become the most affected areas, mainly in the residential areas that located more than 50 meters from the flood plains. The variations of flood heights ranged from 1-4 meters. In addition to the hydrometeorological factors, the flood in Bima was caused by several factors, such as: loss of riparian areas function which turned into settlements nowadays, siltation in the downstream areas, poor management of urban drainage systems, reduced vegetation cover in upstream, and narrowing of river bodies. With the increasing of hydro-meteorological disaster problems and challenges, recommendations of structural and non-structural infrastructure to reduce the risk of flood disaster are needed. Therefore, this research aims to provide recommendations of structural and non-structural as an effort to mitigate flood disaster in Bima City. Analytical methods used in this research were participatory mapping, flood hazards mapping and modeling, and qualitative description. Results showed that the management of Rontu watershed in controlling flood would be effective and efficient by combining the structural and non-structural development. Mapping and modeling the flood-affected areas can become a source in the riparian planning regulation to reduce the risk of flooding .

Flood control in an urban drainage system using a linear controller

Abstract Effective management of floods in densely populated urban areas poses a great challenge. Computer modeling plays an important role in appropriate management of urban drainage systems. In this study an effort has been made to develop an efficient urban drainage model in which hydraulic results obtained from the developed SWMM model have been linked with a Proportional Integral Derivative (PID) controller for controlling floods. The resulting model can optimize flood levels substantially in urban water bodies and hence can be used as an effective tool to mitigate urban flooding.

Identification of resilience factors, variables and indicators for sustainable management of urban drainage systems

La gestión del agua en general y de los sistemas de drenaje urbano (SDU) en particular, debe ser concebida no solo para asegurar la prestación de un servicio público, sino también para garantizar su sostenibilidad y resiliencia. En el presente artículo se presenta un análisis y reflexión que permitió identificar los factores, variables e indicadores de resiliencia para la gestión sostenible de SDU, usando herramientas de gestión de información de temas científicos. Como resultado de este análisis, se identificaron cuatro factores de resiliencia de recursos hídricos: i. Flexibilidad; ii. Recursividad; iii. Redundancia; y iv. Robustez y seis variables de resiliencia de SDU: i. Capacidad de recuperación; ii. Capacidad de respuesta; iii. Amplitud; iv. Capacidad de absorción; v. Capacidad de resistencia; y vi. Curva de respuesta. Para cuantificar estas variables, se proponen sus correspondientes indicadores. Los elementos identificados contribuyen al desarrollo de modelos integrales de evaluación de la resiliencia en SDU.

Study of the drainage properties of pervious concrete

The current trend in the management of urban drainage systems is to return to pre-development conditions that mimic the flow characteristics of natural ecosystems. To do so, cities must implement technologies designed to increase water infiltration and reduce the runoff speed. Pervious concrete is among the new technologies seeking to return paved urban areas to conditions that mirror original soil drainage properties. The prototype described in this study is based on specifications provided by Caderno de Encargos do Departamento de Esgotos Pluviais (DEP) from Porto Alegre, where prototypes of grids similar to those produced by DEP are described, however our prototype was made using pervious concrete. Tests were conducted to compare the mechanical strength of our pervious model and those of DEP, made with conventional concrete. Pervious concrete performed better than conventional concrete in all assessments, suggesting that the application of this technology could be a viable alternative.

SWMM-Based Urban Storm Sewer System Modeling

SWMM modeling plays an important role in the urban drainage system management. The paper depicts several modeling steps, including model parameters, dynamic wave options, CFL condition and equivalent pipe and model evaluation. For dynamic wave options, combination of ignore and both is relatively better than others. Impact of friction equation is very tiny. Especially, Froude No. is recommended not to use, while slope can make a good result. For inertial terms, ignore is considered as the best option. Equivalent pipe is used to deal with SWMM numerical instability, and coefficient of correlation, Nash-Sutcliffe efficiency are used to assess modeling performance.

Advances in LID BMPs research and practice for urban runoff control in China

China is at present experiencing a very rapid urbanization process, which has brought a number of adverse impacts upon the water environment. In particular, urban runoff quantity and quality control have emerged as one of the key concerns for municipal officials. One of the strategies being considered is the use of a Low Impact Development type of Best Management Practices (LID BMPs) for urban storm water runoff quantity and quality control. In this paper, the situation surrounding urban runoff control in China is reviewed first. Then the conventional strategy and technologies for the construction and management of urban drainage systems are discussed, while exploring their inherent dilemmas. The LID BMPs are then introduced to control urban runoff in the context of urban sustainable water systems. After the comprehensive analysis of the various LID BMPs, the advances in LID BMPs research and practice for urban runoff control in China are investigated and summarized. At last, the difficulties of implementing LID BMPs in China are discussed, and a direction for the future is proposed.

Decision support for sustainable urban drainage system management: A case study of Jijel, Algeria

This paper aims to develop a methodology to support the sustainable management of Urban Drainage Systems (UDSs) in Algeria. This research is motivated by the various difficulties that the National Sanitation Office (ONA) has in managing this complex infrastructure. The method mainly consists of two approaches: the top-down approach and the bottom-up approach. The former facilitates the identification of factors related to a sustainable UDS, the development priorities and the criteria available to managers. The latter assesses UDS performance using the weighted sum method to aggregate indicators or criteria weighted using the Analytical Hierarchy Process (AHP). The method is demonstrated through its application to the UDS in the city of Jijel, Algeria.

Hydrologically Enhanced Distributed Urban Drainage Model and Its Application in Beijing City

Heavy rainfall-induced inundation is becoming more serious in urban areas making it necessary to urgently appraise and redesign the infrastructure system to drain the storm water more efficiently. For the complex urban drainage systems that include street, sewer, and ditch/river networks, a sophisticated urban drainage model is required to facilitate optimal planning and management. Although most existing models simulate the runoff generation process in a simpler manner and treat the drainage connections between runoff generation cells and the corresponding drainage links in a rigid/static manner, this study proposes a new hydrologically enhanced distributed urban drainage model. In the new model, the urban area is discretized into a four-layer network, i.e., two-dimensional (2D) grid network, 1D street network, 1D sewer network, and 1D ditch/river network. Physically based equations are utilized to describe water movement along the four networks, i.e., the 1D Richards equation is used to simulate the infiltration process along the vertical direction in the grid network, the 2D Saint-Venant equation is used to simulate the overland flow process along the planar direction in the grid network, and the 1D Saint-Venant equation is used to simulate the street, sewer, and river flows in the remaining networks. The new model incorporates the state-of-the-art physical descriptions about hydraulic and hydrological processes during the urban storm inundation period, which allows a more realistic depiction of the runoff generation processes, automatic alteration of overland flow routing path, direct and easier usage of gridded radar rainfall data readily available recently, and real-time hydrodynamic flux exchanges between surface and sewer pipes. The model is validated in a hypothetical application by comparing with the published literature results. Also, a real urban watershed application shows the capacity of the model to provide reasonable predictions of the outlet hydrograph, which indicates its potential for planning and real-time management of urban drainage systems.

Studies on the Integration of Geographic Information System (GIS) and Drainage Pipe Network Model

With the development of the simulative theory and calculation method of drainage pipe network, urban drainage pipe network model gradually become an indispensable part of the urban drainage system management. The characteristics of modern drainage pipelines,the content of drainage pipelines system model, the problems of combining GIS with drainage pipelines and how to solve them are briefly described in this paper.

Performance and sensitivity analysis of stormwater models using a Bayesian approach and long-term high resolution data

Stormwater models are important tools in the design and management of urban drainage systems. Understanding the sources of uncertainty in these models and their consequences on the model outputs is essential so that subsequent decisions are based on reliable information. Model calibration and sensitivity analysis of such models are critical to evaluate model performance. The aim of this paper is to present the performance and parameter sensitivity of stormwater models with different levels of complexities, using the formal Bayesian approach. The rather complex MUSIC and simple KAREN models were compared in terms of predicting catchment runoff, while an empirical regression model was compared to a process-based build-up/wash-off model for stormwater pollutant prediction. A large dataset was collected at five catchments of different land-uses in Melbourne, Australia. In general, results suggested that, once calibrated, the rainfall/runoff models performed similarly and were both able to reproduce the measured data. It was found that the effective impervious fraction is the most important parameter in both models while both were insensitive to dry weather related parameters. The tested water quality models poorly represented the observed data, and both resulted in high levels of parameter uncertainty.

The Hull floods of 2007: implications for the governance and management of urban drainage systems

AbstractOn 25 June, the City of Hull suffered from extensive pluvial flooding, causing damage to over 8600 homes and 1300 businesses. Over 100 mm of rain fell over a 24‐h period, rapidly overwhelming the city's drainage system. Hull is especially vulnerable to flooding as it is largely below sea level and relies on a pumped drainage system with no natural ways of drainage. The causes of the flooding can be locally attributed to blocked roadside gulleys but in the main were due to issues with the conveyance of drained water in sewers and the performance of the three pumping stations. In particular, an extensive redesign of the system in 2001 increased flood storage and reduced the pumping capacity. In 2004, remodelling of the 2001 system indicated that it may be underpredicting flood volumes by 100% and decommissioned pumping stations were re‐activated to rectify matters. Subsequent modelling showed that the performance of the drainage system in 2007 was slightly worse than its 2001 configuration. The floods also revealed a series of key weaknesses in how urban drainage systems are managed. There is no system of warning from surface water flooding in the United Kingdom, despite there being an extensive warning system for coastal and fluvial flooding. Urban drainage is largely designed to accommodate 1 in 30‐year events, but this level is not appropriate in all areas, especially low‐lying regions with little or no natural drainage such as Hull. Finally, the structure of the UK water industry postprivatisation, with Local Authority, the Environment Agency and the Water Utility all having control over separate parts of the system, left no single agency with lead control or responsibility for urban surface water flooding.