Rehabilitation of Urban Drainage Systems Using a Resilience-Based Approach

Highly efficient methods are needed to mitigate negative impacts of urban storms such as flooded roads and damage to properties and infrastructures. A rehabilitation approach based on resiliency is proposed in this paper for urban drainage systems using structural improvement of bottlenecks. The resilience-based approach enhances system capability to act very flexible against exceptional loads such as bridge/culvert blockage during the floods. The approach integrates a multi-objective evolutionary algorithm (MOEA) and EPA-SWMM simulation model to find cost-effective rehabilitation measures under structural failure of critical elements in the network. It is applied to the western part of Tehran Stormwater Drainage System (TSDS) to attain optimal measures by minimizing the costs and flood volumes. The approach outperforms the conventional methods (particularly compared to a previous rehabilitation proposal for the study area) when the system encounters unexpected blockage conditions. Results show that the optimal design obtained by the proposed approach can decrease network flooding from 3.5 × 10⁶ m³ to near zero with at most 23% lower investment costs relative to the traditional design.     

城市小区管网排水及区域排涝水文计算方法初步探讨

城市小区管网排水和城市区域排涝两者概念不同，采用的标准和水文计算方法也有很大差别。从设计暴雨、产流、汇流等方面初步探讨了两种水文计算方法和成果的差异。     

国内外城市排水系统的回顾与展望

从国外城市排水系统各个发展阶段的特点及其最新进展出发，通过对比、分析找出国内外的差距，提出一些初步想法：适当的调整政策，并加大投资，以加快发展；引入城市排水管理的新观念，全面规划，提高效益；选择污水截流加处理作为改造现存直排式合流制的主要方案；积极创造条件，修订设计规范；建立我国的城市暴雨径流过程的计算机方法。     

An Approach for Determination of the Drainage Network Effect on GIUH Using Hesitant Probabilistic Fuzzy Linguistic Sets

Water Resources Management - Digital elevation models (DEMs) enable extraction of stream networks, delineation of watersheds and determination of geomorphological characteristics. A widely used...     

Many-Objective Optimization of Sustainable Drainage Systems in Urban Areas with Different Surface Slopes

Water Resources Management - Sustainable urban drainage systems are multi-functional nature-based solutions that can facilitate flood management in urban catchments while improving stormwater...     

Planning Against Long Term Water Scarcity: A Fuzzy Multicriteria Approach

The study presents a multicriteria method incorporating a fuzzy set approach and the 0/1 programming for selecting the most appropriate actions for facing long term water scarcity in a water system under a set of objectives and constraints. The proposed method includes also the right of veto which can be utilised under certain extreme conditions or for securing commensurate solutions. The proposed method is applied for devising the technical component of a rational preparedness plan against long term water scarcity in the island of Naxos, Cyclades (Greece).     

Investigation of Rainfall Forecast System Characteristics in Real-Time Optimal Operation of Urban Drainage Systems

This study investigates the role of rainfall forecast system characteristics in predictive real-time optimal operation (PRTOP) of urban drainage systems (UDSs). A simulation-optimization model is proposed integrating the stormwater management rainfall-runoff simulator, the harmony search optimization algorithm, and a rainfall forecasting module. This module generates different rainfall forecast scenarios depending on the forecast (time) horizon (FH) and the forecast type (perfect or imperfect). Five adaptive PRTOP models are compared to evaluate the relationships between the FH, forecast type, and the system’s relative regulating capacity (SRRC). The models are tested in a part of UDS of Tehran, capital of Iran. Results indicate that for the studied system, perfect knowledge of future rainfall is more beneficial for a specific range of the SRRC, equal to 80–90% of its upper bound. Besides, the performance of the PRTOP model improves with increasing the FH up to a certain point, and then having no further positive effect. Finally, the PRTOP model equipped with a hypothetical forecasting model where the forecast error is a nonlinear function of the forecast lead time still performs better than both a zero-FH reactive RTOP model and short forecast horizon PRTOP models.

     

Improving Performance Criteria in the Water Resource Systems Based on Fuzzy Approach

Water Resources Management - Reliability, resilience, and vulnerability (RRV) have been widely used as the performance criteria of a water supply system in the studies conducted over the last three...     

Valuating the Receiving Waters of Urban Wastewater Systems through a Stakeholder-based Approach

The valuation of ecological services in European aquatic ecosystems is increasingly deemed to be an essential element for the integrated management concept pursued by the Water Framework Directive (2000/60/EC). However, the assessment methods are often doubted for their objectivity and transparency when based on the elicitation of stated preferences. The current research attempted to explicitly focus on the biases linked with the stakeholders participating in assessing methods operating with stated preferences. The most significant stakeholder groups were classified in three broad teams of Experts, Decision Makers and Affected Professions. The three teams' preferences were in turn assessed in economic and non-economic terms for the accentuation of the high fluctuation among the findings, and the threatening biases emerged in the sourcing of stated preference methods. The wastewater treatment plant in Athens, Greece and Saronikos Bay offered a sound case study.     

Flooding Control and Hydro-Energy Assessment for Urban Stormwater Drainage Systems under Climate Change: Framework Development and Case Study

Flooding issue and energy shortage have become the common concerns impeding the urban development under climate change scenarios. Exploiting potential hydro-energy from urban stormwater drainage system (USDS) has multiple beneficial perspectives for controlling flooding, relieving energy shortage and mitigating the greenhouse gases emission, which has not yet been systematically investigated in previous works. In this paper, a systematical analysis framework is developed to design the flooding risk control measures and to assess the feasibility and capacity of the hydro-energy development in USDS. The GCMs and HBV models, integrated within the SWMM computation platform, are adopted to simulate the hydrological and hydraulic processes during rainfall events, with the results used to manage the flooding situation and evaluate the energy generation capacity under the influences of both historical and future climate changes. The framework is then applied to a practical case in Tung Chung town of Hong Kong. The analysis result shows that, in the studied area, it is significant and worthwhile to develop the hydro-energy in USDS, which is evidenced to be beneficial to the energy generation and the flooding risk control as well as water resources management in the urban drainage system. The developed method and obtained results of this study may provide a new perspective and technical guide for effective USDS management and operation.

     

某城区排涝泵站设计流量计算方法初探

采用平均排除法、最大24 h雨型洪水流量时程分配法和产流汇流法3种方法分别计算了某城区电排站的设计流量,并将3种方法的计算结果进行对比分析,选用合适电排站的设计流量,可为类似工程设计流量的确定提供参考。     

基于概率数学方法与GIS的泥石流敏感性分析及评价——以汶川县为例

以汶川县为研究区,通过对震后的高分辨遥感影像的遥感解译,获得了145条泥石流沟及流域中的崩滑物源的分布图。选择了坡度、坡向、地层岩性、地震峰值加速度、距水系距离、距断层距离作为评价因子,利用概率数学方法与GIS的空间分析功能,获得145条泥石流沟在上述6个评价因子上的分值;再利用层次分析法计算得到各评价因子权重,建立泥石流敏感性评价模型,得到了研究区泥石流沟敏感性分级图。结果表明:研究区145条泥石流沟中,有60条泥石流沟属于高敏感性,43条泥石流沟为中敏感性,其余42条泥石流沟敏感性较低,研究成果对于认识该地区泥石流灾害现状及发展趋势与防灾减灾有一定的参考意义。     

A Dynamic Flow Forecast Model for Urban Drainage Using the Coupled Artificial Neural Network

Water Resources Management - Dynamic flow forecast, which is one of the critical technologies in the field of future Intelligent Drainage, has great potential for mitigating the damages resulting...     

Sustainable Design of Urban Stormwater Drainage Systems by Implementing Detention Tank and LID Measures for Flooding Risk Control and Water Quality Management

Water Resources Management - With the increasing emphasis and application of the flooding control and mitigation measures of detention tank (DT) and low impact development (LID) in urban stormwater...     

Reliability Analysis Applied on Land Subsidence Effects of Groundwater Remediation: Probabilistic vs. Deterministic Approach

The quantification of soil variability is one of the most important aspects in the geo-engineering context. The uncertainty analysis is the main part of the reliability assessment for which a quantitative evaluation was performed in this study. The Reliability Index and the Probability of Failure using the First-Order Reliability Method (FORM) represents both, an effective method which is easy to implement at the same time. This work analyzes possible effects of compaction induced into the aquifer of the Scarlino Plain, caused by the extension of the hydraulic barrier for groundwater remediation. The currently implemented vertical barrier is composed of 12 wells which reach the depth of 10 m. The improvement of the project involves the construction of a further 40 clusters, each consisting of a doublet which intercepts different depths (10 and 18 m). The models of the subsoil stratigraphy and of the groundwater were built using a numerical model. The groundwater flow and the piezometric surface in the current configuration of the barrier were studied and the project configuration was evaluated. Using the Aquitard drainage model, the land subsidence was estimated to calculate the maximum admissible displacement related to exhibited goods, the so called territorial vulnerability. The evaluation analysis was performed using a traditional deterministic approach, followed by a reliability method based on probabilistic models. Finally, the respective results were reported in a soil mapping with overlapping layers.     

A Non-stationary and Probabilistic Approach for Drought Characterization Using Trivariate and Pairwise Copula Construction (PCC) Model

Under variable climatic conditions, the conventional Standardized Precipitation Index (SPI) and Reconnaissance Drought Index (RDI) are inadequate for predicting extreme drought characteristics. Non-stationary Standardized Precipitation Index (NSPI) and Non-stationary Reconnaissance Drought Index (NRDI) are, therefore, developed by fitting non-stationary distributions. The Generalized Additive Model in Location, Scale and Shape (GAMLSS) framework, with time varying location parameters considering the external covariates, is used to fit the non-stationary distributions. Multivariate ENSO Index (MEI), Southern Oscillation Index (SOI), Sea Surface Temperature (SST), and Indian Ocean Dipole (IOD) are considered as external covariates for the non-stationary drought assessment. The performances of stationary and non-stationary models are compared. The study also concentrated on the trivariate and the Pairwise Copula Construction (PCC) models to estimate the drought return periods. The comparison of two copula models revealed that the PCC model performed better than the trivariate Student’s t copula model. The recurrence intervals arrived at for the drought events are different for trivariate copula model and PCC model. This study showed that non-stationary drought indices will be helpful in the accurate estimate of the drought characteristics under the changing climatic scenario.

     

A Distress-Based Condition Assessment Approach of Urban Water Assets Using Novel Deterioration Indices

Water Resources Management - This paper aims at proposing and demonstrating the application of a novel distress-based condition assessment approach to evaluate the physical condition of inspectable...     

A Fuzzy-Stochastic Modeling Approach for Multiple Criteria Decision Analysis of Coupled Groundwater-Agricultural Systems

The complexity of water resources management increases when decisions about environmental and social issues are considered in addition to economic efficiency. Such complexities are further compounded by multiple uncertainties about the consequences of potential management decisions. In this paper, a new fuzzy-stochastic multiple criteria decision-making approach is proposed for water resources management in which a variety of criteria in terms of economic, environmental and social dimensions are identified and taken into account. The goal is to evaluate multiple conflicting criteria under uncertainties and to rank a set of management alternatives. The methodology uses a simulation-optimization water management model of a strongly interacting groundwater-agriculture system to enumerate criteria based on these bio-physical process interactions. Fuzzy and/or qualitative information regarding the decision-making process for which quantitative data is not available are evaluated in linguistic terms. Afterwards, Monte Carlo simulation is applied to combine these information and to generate a probabilistic decision matrix of management alternatives versus criteria in an uncertain environment. Based on this outcome, total performance values of the management alternatives are calculated using ordered weighted averaging. The proposed approach is applied to a real world example, where excessive groundwater withdrawal from the coastal aquifer for irrigated agriculture has resulted in saltwater intrusion, threatening the economical basis of farmers and associated societal impacts. The analysis has provided potential decision alternatives which can serve as a platform for negotiation and further exploration. Furthermore, sensitivity of different inputs to resulting rankings is investigated. It is found that decision makers’ risk aversion and risk taking attitude may yield different rankings. The presented approach suits to systematically quantify both probabilistic and fuzzy uncertainties associated with complex hydrosystems management.