Multicriteria decision-aid method to evaluate the performance of stormwater infiltration systems over the time

Nowadays, stormwater infiltration systems are frequently used because of their ability to reduce flows and volumes in downstream sewers, decrease overflows in surface waters and make it possible to recharge groundwater. Moreover, they come in various forms with different uses. Despite these advantages the long term sustainability of these systems is questionable and their real performances have to be assessed taking into account various and sometimes conflicting aspects. To address this problem a decision support system is proposed. It is based on a multicriteria method built to help managers to evaluate the performance of an existing infiltration system at different stages of its lifespan and identify whether it performs correctly or not, according to environmental, socio-economic, technical and sanitary aspects. The paper presents successively: the performance indicators and the way they were built, the multicriteria method to identify if the system works properly and a case study.     

Multicriteria evaluation tools to support the conceptual design of activated sludge systems.

During the past decade the pressure of the whole spectrum of stakeholders has increased considerably leading the consideration of different types of objectives, i.e. economical, technical, legal and environmental, into the process design efforts. Thus, the traditional design approaches should turn into more complex assessment methods including different types of objectives in order to conduct integrated assessments. The objective of this paper is to present and discuss the usefulness of three evaluation tools, based on multicriteria decision analysis, to support the conceptual design of activated sludge systems These support tools consist of: i) preliminary multiobjective optimization, where the most promising options (those located near to the optimum) are compared based on the results of dynamic simulation, ii) identification of strong and weak points for each option by means of classification trees and the subsequent extraction of knowledge-based rules, and iii) evaluation of the trade-offs between a certain evaluation criteria and the overall process performance through the integrated application of mathematical modelling and qualitative knowledge extracted during the design process.     

Performance-costs evaluation for urban storm drainage.

The design process of urban stormwater systems incorporating BMPs involves more complexity unlike the design of classic drainage systems for which just the technique of pipes is likely to be used. This paper presents a simple decision aid methodology and an associated software (AvDren) concerning urban stormwater systems, devoted to the evaluation and the comparison of drainage scenarios using BMPs according to different technical, sanitary, social environmental and economical aspects. This kind of tool is particularly interesting so as to help the decision makers to select the appropriate alternative and to plan the investments especially for developing countries, with important sanitary problems and severe budget restrictions.     

Identifying the Criteria Set for Multicriteria Decision Making Based on SWOT/PESTLE Analysis: A Case Study of Reconstructing A Water Intake Structure

This paper proposes an approach for defining the criteria set required for multicriteria decision making. An approach is developed for a specific class of water management problems, and a SWOT/PESTLE analysis is recommended for identifying the internal and external factors that influence a given water system. The factors are grouped into six categories: political, economic/financial, social, technical, legal, and environmental (PESTLE), and separated afterwards according to their positive or negative influence on the system. All factors are filtered by a proposed elimination algorithm to identify the non-inferior factors and declare them as candidates for inclusion into the criteria set. An approach is applied to the real-life problem of how to define the criteria set and enable the selection of the optimal reconstruction solution of a water intake structure within a regional hydro-system in Vojvodina Province, Serbia. To verify the developed approach, an independent expert is invited to asses all factors identified by the SWOT/PESTLE analysis using the analytic hierarchy process (AHP) and to rank factors by order of preference. The outcome is satisfactory because the seven top-ranked factors from AHP completely matched the list of factors derived from the elimination algorithm.     

基于组合决策的黄河流域水量调度方案评价方法

为定量评价黄河流域水量调度方案的优劣,选出水资源综合效益最大的方案,结合黄河流域实际特点,选择可供水量、利津入海水量、龙羊峡水库期末水位等10项指标为评价体系,在模糊优选法、灰色关联分析法、集对分析法等评价方法的基础上建立了组合决策模型,综合考虑各方案在不同评价方法下的优劣顺序,帮助决策者做出准确判断和选择。结果表明,组合决策方法克服了单一决策方法的不足,能够综合考虑各评价指标的重要性,较为科学合理地确定出最优方案。     

Comparison between two methodologies for urban drainage decision aid.

The objective of the present work is to compare two methodologies based on multicriteria analysis for the evaluation of stormwater systems. The first methodology was developed in Brazil and is based on performance-cost analysis, the second one is ELECTRE III. Both methodologies were applied to a case study. Sensitivity and robustness analyses were then carried out. These analyses demonstrate that both methodologies have equivalent results, and present low sensitivity and high robustness. These results prove that the Brazilian methodology is consistent and can be used safely in order to select a good solution or a small set of good solutions that could be compared with more detailed methods afterwards.     

一体化混凝土热物理参数测定仪的研制

为规范混凝土热物理参数测定仪产品的性能指标和检测方法,经住房和城乡建设部批准,颁布了JG/T329—2011《混凝土热物理参数测定仪》行业标准,为此,同步研制了产品样机。所研制的混凝土热物理参数测定仪通过测试技术和方法上的多项创新,全面实现了新颁标准提出的技术性能要求,整体技术指标达到国际先进水平,部分性能超过国外同类机水平。     

Evaluating the Performance of Agricultural Water Distribution Systems Using FIS,ANN and ANFIS Intelligent Models

Increasing water use efficiency in the agricultural sector requires the use of appropriate methods for intelligent performance evaluation of surface water distribution systems in agriculture. Therefore, in this study a systematic approach was developed for operational performance appraisal of the agricultural water distribution systems. For this purpose, Fuzzy Inference System (FIS), Artificial Neural Network (ANN), and Adaptive Neuro-Fuzzy Inference System (ANFIS) were used to evaluate the technical performance of irrigation network, considering the uncertainties in the water exploitation process. The performance of the developed models was studied on the Roodasht irrigation canal, located in central Iran, which suffers from severe fluctuations in the inflow, by evaluating the adequacy, efficiency, and equity of surface water distribution. Hydraulic simulation of water distribution system, as well as providing the information required for training and validation of the intelligent models, were performed using the HEC-RAS model. The results showed that compared to the FIS model, ANN and ANFIS models similarly predicted the model outputs with lower errors at almost the same level. The adequacy, efficiency, and equity indicators were predicted by ANFIS model with MAPE of 0.16, 0.01 and 0.23, respectively. Also, FIS model was only able to predict the efficiency and could not predict the adequacy and equity with appropriate performance. The findings of this study reveal that since the ANFIS model uses both FIS and ANN models in its structure, it considers the model uncertainty reliably, and it can be used to evaluate the performance of agricultural water systems.

     

Decision support tools for urban water and wastewater systems--focussing on hazardous flows assessment.

The Swedish research programme Urban Water has developed a concept of a multi-criteria basis intended to support decision-making for urban water and wastewater systems. Five criteria groups were established for sustainability assessment of urban water systems: Health and Hygiene, Environment, Economy, Socio-culture, and Technology. Each criterion requires a set of indicators corresponding to quantifiable facts and figures, or qualitative data to comparatively assess the different alternatives in the decision process. The decision support process starts as a baseline study where the existing conditions are addressed. Alternative strategies of the future urban water system are developed and analysed by different tools and methodologies in assessing the five criteria groups. Eventually, the results and conclusions are integrated and synthesised into a basis for decision-making. As an example of a decision support basis for chemical safety, a barrier perspective was introduced to find out if and to what extent hazardous substances can be stopped, diverged, or transformed at various points in the wastewater system. A set of barriers was suggested, i.e. behaviour, systems design, process design, optional recipients, and organisational. The barrier approach was applied to two alternative municipal wastewater system designs--a combined wastewater system vs. a source separated system--analysing the fate of phosphorus, cadmium, and triclosan. The study showed that the combined system caused a higher substance flow to the receiving waterbody than the separated system. The combined system also brought more phosphorus and cadmium to the farmland than the separated system, but only half the amount of triclosan.     

Assessment and prioritization of eco‐revetment projects in urban rivers

Ecological revetment for slope protection in urban rivers requires consideration of economic and ecological aspects and also of social aspects including recreation. Taking the Hunhe River as an example, our study established an evaluation system and a decision‐making method for evaluating and prioritizing the eco‐revetment projects. The Delphi method was used for collecting the opinions of experts, which include the relative importance of the indicators and the relative preference of the alternatives. The former was surveyed by pair comparison and processed applied analytic hierarchy process (AHP). The latter was described via linguistic variables, which need to be changed into the quantitative values for TOPSIS analysis. For that reason, we introduced the fuzzy set theory and established a fuzzy multi‐attribute decision‐making method based on TOPSIS to assess and prioritize the projects. The evaluation system includes economic, social, environment and ecological several aspects totalling eight indicators. The evaluating and prioritizing result of the projects shows that the three‐dimensional vegetation net is the best slope protection measures in the study area. The sensitivity analyses of indicator weights and different calculation methods were performed to demonstrate the reliability of the results. The sensitivity analyses indicate that construction cost and maintenance cost are dominant factors during the alternatives prioritization. The distance calculation method and normalization technique are insensitive to the prioritization results. The methodology proposed by this paper offers an effective and feasible tool for managers to evaluate and choose the optimal engineering measures of riverbank protection. Copyright © 2008 John Wiley & Sons, Ltd.     

Tariff Suitability Framework for Water Supply Services

Water supply (WS) tariffs have evolved significantly in the past decades, although in a varying fashion around the world. Indeed, this development is linked to increasingly demanding requirements, or objectives that have to be achieved by water utilities (e.g., stricter quality standards and infrastructure maintenance levels, cost recovery, social concerns and environmental protection demands). The perception of WS tariffs as a powerful management tool, subject to context dependent objectives, raises the concern on how utilities prioritize them. This hierarchy is desirable due to the possible conflicting nature of objectives. From that point of view, and on the basis of protecting the public interest, the fitness between objectives set by the utilities and actual needs may require a broader institutional approach. The need for regulatory activity may be required in the context of too much arbitrariness in tariff setting procedures. For this objective, a regulatory tool is set, based on multicriteria decision analysis (MCDA) modeling methods, to provide a requisite framework capable of considering the multiple dimensions of WS tariffs and the assessment of specialists, practitioners and other legitimate stakeholders in the ‘tariff setting’ decision making process. The specified tariff suitability framework (TSF) will work as a regulatory tool, taking into account the utilities’ particular context and background factors. The outcomes allow to determine the tariff suitability and to build tailored policy recommendations, which are critical aspects for a sound regulation.     

Decision strategies for handling the uncertainty of future extreme rainfall under the influence of climate change

Several extraordinary rainfall events have occurred in Denmark within the last few years. For each event, problems in urban areas occurred as the capacity of the existing drainage systems were exceeded. Adaptation to climate change is necessary but also very challenging as urban drainage systems are characterized by long technical lifetimes and high, unrecoverable construction costs. One of the most important barriers for the initiation and implementation of the adaptation strategies is therefore the uncertainty when predicting the magnitude of the extreme rainfall in the future. This challenge is explored through the application and discussion of three different theoretical decision support strategies: the precautionary principle, the minimax strategy and Bayesian decision support. The reviewed decision support strategies all proved valuable for addressing the identified uncertainties, at best applied together as they all yield information that improved decision making and thus enabled more robust decisions.     

Using decision analysis to determine optimal experimental design for monitoring sewer exfiltration with tracers.

The tracer methods developed to assess exfiltration from sewers in the European project APUSS (assessment of the performance of sewer systems) have a high degree of freedom with regard to the choice of tracer and the dosing strategy. These can lead to very different degrees of uncertainty in the measured exfiltration ratio. In this study, we demonstrate how to select an optimal experimental design using decision analysis, which accounts for this uncertainty and its associated costs. Although the results are site-specific, we can conclude generally that, when NaCl is used as the tracer, the accuracy of the exfiltration estimate is most sensitive to the amount of tracer used and the starting time of the experiment.     

Indicators of Land and Water Productivity in Irrigated Agriculture

A set of four comparative performance indicators is defined, which relates outputs from irrigated agriculture to the major inputs of water and land. These indicators are presented with the objective of providing a means of comparing performance across and within irrigation systems. They require a limited amount of data that are generally available and readily analysed. Four typical applications of these indicators are illustrated: cross-system comparison; temporal variations in performance at one system; spatial variations within one system; and comparing performance by system type. Results of application of the indicators at 40 irrigation systems show large differences in performance among and within systems. In spite of uncertainties in estimation of indicators, the large differences discerned by the indicators justify the approach taken.     

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).     

An Extension of the Sustainability Index Definition in Water Resources Planning and Management

The sustainability index (SI) is a relatively new concept for measuring the performance of water resource systems over long time periods. Its definition is aimed at providing an indication of the integral behaviour of the system with regards to possible undesired consequences if misbalance of available and required waters occurs. SI is initially defined as a product and later reformulated as a geometric mean of performance indicators: reliability, resilience and vulnerability. As an extension of a recently published methodology to compute and use SI, in this paper we propose introducing two more indicators of system performance: (1) reliability of annual firm (safe) water as a system yield and (2) deviation of reservoir levels from corresponding rule curves. The last indicator is of particular importance if there are multi-purpose reservoirs in the system because reservoirs are the most important and sensitive regulators of the water regime within the system. We also propose a framework for assessing system performance in a systematic manner to compute SI at various locations within the system if different operating strategies are applied and, finally, how to evaluate strategies according to the resulting SI by using multi-criteria methods. A case study example from Serbia is used to illustrate the results of measuring sustainability under alternative operating scenarios for a system with three reservoirs and two diversion structures.     

Performance indicators for the efficiency analysis of urban drainage systems.

Performance indicators implemented in a decision support system (DSS) for the technical, managerial and economic evaluation of urban drainage systems (UDS), called MOMA FD, are presented. Several kinds of information are collected and processed by MOMA FD to evaluate both present situation and future scenarios of development and enhancement. Particular interest is focused on the evaluation of the environmental impact, which is considered a very relevant factor in the decision making process to identify the priorities for UDS improvements.     

Technical and Environmental Sustainability Assessment of Water Distribution Systems

An environmental and technical sustainability assessment methodology is developed for both centralized and dual water distribution systems (WDSs) with and without fire flow scenarios. Technical sustainability of potable and reclaimed water networks is measured by a sustainability index (SI) assessment using reliability, resiliency, and vulnerability performance criteria. The U.S. Environmental Protection Agency EPANET software is used to simulate hydraulic (i.e. nodal pressure) and water quality (i.e. water age) analysis in a WDS. Total fresh water use and total energy intensity are considered as environmental sustainability criteria. The procedure considers two separate alternatives for meeting fire flows: (1) adding pumping to a system or (2) adding a non-potable WDS. The reclaimed system is designed using linear programming (LP) optimization. For each alternative, multi-criteria decision analysis (MCDA) is used to combine technical and environmental sustainability criteria for an urban WDS.     

Multicriteria Evaluation of Flood Control Measures: The Case of Ribeira do Livramento

This paper describes the multicriteria process used to evaluate flood control options for the catchment of Livramento creek in the peninsula of Setúbal, in Portugal. In the structuring phase, the environmental, social, and technical dimensions were identified. The MACBETH approach – Measuring Attractiveness by a Categorical Based Evaluation Technique – was then used to construct a quantitative evaluation model based on qualitative value judgments formulated by a group of experts from different technical and scientific fields. The model enabled the overall benefit associated with each option to be appraised, and extensive sensitivity analyses to be performed.     

Model-based knowledge acquisition in environmental decision support system for wastewater integrated management

The main goal of the Water Framework Directive is to achieve good chemical and ecological status of water bodies by 2015. The implementation of integrated river basin management, including sewer systems, wastewater treatment plants and receiving water bodies, is essential to accomplishing this objective. Integrated management is complex and therefore the implementation of control systems and the development of decision support systems are needed to facilitate the work of urban wastewater system (UWS) managers. Within this context, the objective of this paper is to apply integrated modelling of an UWS to simulate and analyse the behaviour of the 'Congost' UWS in Spain, and to optimize its performance against different types of perturbations. This analysis results in optimal operating set-points for each perturbation, improves river water quality, minimizes combined sewer overflows and optimizes flow lamination from storm water tanks. This is achieved by running Monte Carlo simulations and applying global sensitivity analysis. The set-points will become part of the knowledge base composed of a set of IF-THEN rules of the environmental decision support system being developed for this case study.