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For a large part of human history, urbanization was focused on two main objectives: defence and resource harvesting. The first objective was always achieved in a broad sense, i.e., defending the population from other humans and from natural events. Focusing on human activities, this defensive approach was also applied to urban drainage, which resulted in a systematic underestimation of the impacts of urbanization on natural systems. Environmental sustainability was introduced in an attempt to mitigate these impacts, as they had the potential to endanger future developments; thus, the possibility that urban floods may be the lesser evil was accepted. Resilience was then introduced to improve not only defence of urban areas but also their ability to recover from negative events, even though physical resilience is not always accompanied by social resilience. This paper attempts to address the philosophy of urban drainage design, introducing the new concept of floodability as an evolution of flood resilience by identifying its requirements and drivers and by using real examples to present the new concept.

The normalized difference water index (NDWI) has been extensively used for different purposes, such as delineating and mapping surface water bodies and monitoring floods. However, the assessment of this index (based on multispectral remote sensing data) is highly affected by the effects of atmospheric aerosol scattering and built-up land, especially when green and near infrared bands are used. In this study, a modified version of the NDWI was developed to improve precision and reliability in the detection of water reservoirs from satellite images. The proposed equation includes eight different parameters. A Bayesian procedure was implemented for the identification of the optimal set of these parameters. The calculation of the index was based on Sentinel-2 satellite images of spectral bands collected over the 2015&ndash, 2019 period. The modified NDWI was tested for the identification of small reservoirs in a subbasin of the Belice catchment in Sicily (southern Italy). To assess the effectiveness of the index, a reference image, representing the actual reservoirs in the study area, was used. The results suggested that the use of the proposed methodology for the parameterization of the modified NDWI improves the identification of water reservoirs with surfaces smaller than 0.1 ha.

The ALADIN project was aimed at contributing to environmental and energy sustainability of the urban water system by means of a decision support tool able to allow an evaluation of the energy impact related to each different macro-sectors of urban water cycle highlighting the main energy flows and to assess the system energy balance and identify the possible energy-efficient solutions. Moreover the tool suggests the most efficient actions in reducing water losses. In the present paper the main features of the developed tool are presented. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

In recent years, the evaluation of water quality in distribution systems has generated enormous interest in the scientific community due to the increasing concentration of population in urban areas and frequent issues connected with supply water quality. Following the wave of bioterrorism subsequent the events of September 11th 2001, a need can be foreseen to seek adequate preventive measures to deal with contamination in water distribution systems that may be related to the accidental contamination and deliberate injection of toxic agents of any origin in the distribution networks. Therefore, it is very important to create a sensor system that detects contamination events in real time, while maintaining the reliability and efficiency of the measurements, limiting the cost of the instrumentation. A reliable monitoring system, for this kind of problems, cannot be deployed without realistic modelling support. The current state-of-the-art in water distribution systems analysis usually adopt a simplified approach to water quality modelling, neglecting dispersion and diffusion and considering simplified reaction kinetics. Even if such simplifications are commonly acceptable in fully turbulent flows, they may take to relevant errors in transition flows with low velocity thus taking to unreliable interpretation of the contamination in complex networks. The present paper aims to compare different modelling approaches to the evaluation of contaminant dispersion in two distribution networks: one laboratory network in which contamination experiments were carried out in a controlled environment (Enna, Italy) and a full-scale real distribution network (Zandvoort, Netherlands).

The pressure sensors positioning is a crucial step for leakages detection. The optimal positioning of monitoring sensors, or simply sampling design, has been previously addressed with respect to several purposes. The proposed methodology aims to select the pressure monitoring nodes for leakages detection by coupling the water distribution network hydraulic simulation model with the identifiability analysis. The nodes selection is done among those which are more sensitive with respect to different leakages positions and uncorrelated from each other to avoid redundant information. The parameter uncertainty effect on the results is also investigated. The method is applied to the benchmark network Apulian.

In water supply systems, a considerable amount of apparent loss is caused by meter under-registration. Water meters are subject to intrinsic systemic error depending on the actual flow rates passing through them. Furthermore, the moving parts of the meter are subject to wear and tear that progressively reduce meter accuracy. The increase in systemic error is especially evident at low flow rates because of growing friction in the rotating mechanism, which requires a higher flow to start the meter (starting flow). The aim of this paper is to experimentally investigate metering error in an attempt to find a direct link between meter age, network pressure and apparent losses caused by the inability of the meter to accurately register the volume passing though it at low flow rates. The study was performed through laboratory experiments in which worn-out water meters were tested using a test bench. The results of the laboratory experiments show that ageing and pressure are both relevant parameters for determining meter starting flow. These results were then applied to assess the effects on apparent losses of the age of the meter, varying pressure values upstream of the meter (the pressure in the network where the meter is installed) and different patterns of flow rates passing through the device (the consumption pattern of the user). The presented results are useful for understanding the effects of operating conditions on water meter under-registration, which can aid water managers in implementing effective replacement campaigns.

Water demand is the driving force behind hydraulic dynamics in water distribution systems. Consequently, it is crucial to accurately estimate the actual water use to develop reliable simulation models. In this study, copula-based multivariate analysis was proposed and used for demand prediction for a given return period. The analysis was applied to water consumption data collected in the water distribution network of Palermo (Italy). The approach produced consistent demand patterns and could be a powerful tool when coupled with water distribution network models for design or analysis problems. The results were compared with those obtained using a classical water demand model, the Poisson rectangular pulse (PRP) model. The multivariate consumption data statistical analysis results were always higher than those of the PRP model but the copula-based method maintained the daily water volume of actual consumptions and provided maximum daily consumption that increased with the return period.

This paper presents the results of experimental tests on the intrusion of contaminant through pipe cracks in water distribution network resulting from low/negative pressures. The tests were carried out on a looped distribution network at the University of Enna and were performed first producing a pressure transient that causes negative pressures then reproducing intermittent supply. A soluble contaminant was added to the water volume in the network through a pipe crack. Sampling of water volume was carried out in two nodes of the network and the contaminant concentrations were measured. It was showed that: the contaminant was drawn in and transported, in the first set of tests; the contaminant was carried through the network to the point-of-use when the pipes become completely full and the distribution system was in steady state conditions, in the second, and that the concentrations was higher than in the first set of tests.

In the last decades, a growing attention on energy saving associated with water resources usage and leakages reduction has been recorded at both national and international level. Scientific research has focused on implementation of several methodologies aimed at the understanding of energy transformation processes occurring in the integrated water system. The main concern is then identifying energy impacts associated to each macro-area of integrated water system, such as collection, treatment and distribution, and analysing the potential interactions between them. Unfortunately, only overall energy consumptions are usually available at national level. The main objective of the paper is to present a decision support tool, developed in the framework of the ALADIN project, able to analysing the water and energy balance in the integrated water service. In order to achieve a sustainable use of water resources, the tool allows an assessment of the energy impact of different macro - areas of integrated water system. Moreover, each macro - area can be treated as an element able to share energy with other elements, aiming to obtain an energy saving on the whole integrated water system. In this way, the decision support tool could suggest efficient solutions, according to the operator objectives,with regard to energy and water losses management. Therefore, the tool could provide guidelines for choosing the best management solutions, depending on the particular analysed system, and allow, at the same time, the energy and water resources saving. The proposed tool was applied to a complex water supply system, the Favara di Burgiosystem (Sicily, Italy) in order to show its reliability.

The optimization and management of an integrated urban wastewater system is a complex problem involving many processes and variables. The possible control options are defined by several management strategies that may differently impact the economic, operational or environmental performance of the system. The present paper aims to contribute to the environmental and energy sustainability of urban wastewater systems by means of a multicriteria performance analysis. The paper begins with a complete analysis of the system performance in several fields of interest (energy, environment, quality of service, operation, economy and financial resources), and it highlights the management strengths and weaknesses in each subsystem. The analysis was carried out by means of a prototype, developed during the ALADIN project, which enables understanding the system, planning effective improvement actions and assessing their possible effects in each part of the urban water cycle. To demonstrate the potential of such an approach, it was tested on an actual integrated urban wastewater system in Sicily.

The effects of water meter age and private tanks on the apparent losses due to metering errors were evaluated by experimental and theoretical analyses. A monitoring campaign on a small district metered area (DMA) was carried out to determine the causes of apparent losses and implement a numerical model. Metering errors are affected by the flow rate passing through the meter, which is dependent on the network pressure and water level of the private tank. A node model that reproduces the effect of private tanks was coupled with EPANET and was applied to the DMA. The proposed modelling approach was used to identify where apparent losses are higher and to schedule maintenance. The model predicted the results of the installation of a device that minimises the effect of private tanks on apparent losses, the unmeasured flow reducer (UFR), the economic impact of losses and substitution programmes.

The actual level of water demand is the driving force behind the hydraulic dynamics in water distribution systems. Consequently, it is crucial to estimate it as accurately as possible in order to result in reliable simulation models. In this paper, a copula-based multivariate analysis has been proposed and used for demand prediction for given return period. The analysis is applied to water consumption data collected in the water distribution network of Palermo (Italy). The approach showed to produce consisted demand patterns and to be a powerful tool to be coupled with water distribution network models for design or analysis problems. (C) 2014 Published by Elsevier Ltd.

In the present paper the effect of private roof tanks and of the float valve characteristics on apparent losses due to water meter errors was investigated via an experimental study. The tests were carried out at the Environmental Hydraulic Laboratory of the University of Enna (Italy), on a high-density polyethylene (HDPE 100 PN16) looped distribution network. The experimental results showed that network pressure plays an important role in the characterisation of the floating ball valve emitter law, but the tank operating condition is the most relevant aspect to be considered mainly for water meter error evaluation. (C) 2014 The Authors. Published by Elsevier Ltd.

Flooding damage appraisal can been obtained by interpolating real damage data caused by historical flooding events or accounting the effects of a flood in terms of the depreciation of assets. Most often, the expected damage is evaluated by means of damage functions describing the relationship occurring between the damage and hydraulic characteristics of flood. The present paper aims to evaluate the uncertainty linked to the choice of the depth-damage function adopted in the flood damage analysis. Several possible depth-damage function formulations were selected in literature and applied to historical flooding events monitored in the "Centro Storico" catchment in Palermo (Italy). (C) 2013 The Authors. Published by Elsevier Ltd.

This paper presents a water meter substitution plan based on a composite "Replacement indicator" which was defined and compared with common substitution strategies based on meter age and on run-to-fail approaches. The methodology was applied to one of the 17 sub-networks in which the Palermo city water distribution network (Italy) is divided. The analysis was carried out considering a substitution budget limitation and the results showed that the use of "Replacement indicator" outperform the classical substitution strategies based on meter age because it takes into account some other variables that may affect meter precision and wearing. (C) 2013 The Authors. Published by Elsevier Ltd.

Apparent losses consist of water volume drawn from the network, consumed by users but not paid for. Those due to water meter under-registration were evaluated by means of a mathematical model able to analyse the complexity of intermittent supply systems with private tanks. This supply scheme is very common in the Mediterranean area where unexpected water shortage often happens and intermittent water supply is a common practice. In order to analyse such complex systems, a demand model, reproducing the effect of private tanks, and an apparent losses module were developed and coupled with an hydraulic network model based on the Global Gradient Algorithm (GGA). In distribution networks pressure reduction valves (PRVs) are often used by water utilities to control the pressure and reduce background losses. These practices could influence the performance of water meters. For this reason, a PRV model was implemented and integrated with the demand and the hydraulic network models to better estimate the effect of pressure management on real and apparent losses. The comprehensive model was applied to a real case study. The proposed modelling approach was used to identify regions of the network with high apparent losses. Furthermore, the model may be used to predict the results of a water meter replacement plan and of the installation of devices that could affect apparent losses. © IWA Publishing 2013.

A hydraulic model was developed in order to evaluate the potential energy recovery from the use of centrifugal pumps as turbines (PATs) in a water distribution network characterized by the presence of private tanks. The model integrates the Global Gradient Algorithm (GGA), with a pressure-driven model that permits a more realistic representation of the influence on the network behaviour of the private tanks filling and emptying. The model was applied to a real case study: a District Metered Area in Palermo (Italy). Three different scenarios were analysed and compared with a baseline scenario (Scenario 0 – no PAT installed) to identify the system configuration with added PATs that permits the maximal energy recovery without penalizing the hydraulic network performance. In scenarios involving PAT on service connections, the specification of PAT operational parameters was also evaluated by means of Monte Carlo Analysis. The centralized solution with a PAT installed downstream of the inlet node of the analysed district, combined with local PATs on the larger service connections, proves to be the most energy-efficient scenario.

Several studies have been carried out in recent decades to establish a relationship between total head and leaks. In literature, the leakage governing equations have been analysed in light of pipe materials, water head, leak dimension or shape. Most of these contributions questioned the classical Torricelli equation, demonstrating through experimental evidence that the classical orifice law can give unsatisfactory results. Nevertheless, starting from the Torricelli equation, other exponential or linear governing equations have been proposed as mathematical models able to reproduce the leakages in water distribution systems (WDSs). To investigate the validity of the proposed governing equations, an experimental campaign was carried out by means of a water distribution network composed of approximately 500 m of polyethylene pipes. The experiments were designed to investigate the effects of leak area and pipe rigidity on discharge. Furthermore, the effect of leak size enlargement with water head was analysed. Finally, the proposed research contributes to the population of a database for estimating the coefficients of head-discharge relationships.

In water supply management, volumetric water meter are typically used to measure users' consumption. With water meters, utilities can collect useful data for billing, assess the water balance of the system, and identify failures in the network, water theft and anomalous user behaviour. Despite their importance, these instruments are characterised by intrinsic errors that cause so-called apparent losses. The complexity of the physical phenomena associated with metering errors in aging water meters does not allow meter replacement to be guided by single parameters, such as the meter age or the total volume passed through the meter. This paper presents a meter replacement strategy based on a composite 'Replacement Indicator' (RI) that aims to reduce apparent losses. The performance of a meter during its operating life was analysed by means of this indicator, which signals when the meter needs to be replaced. To test the reliability and robustness of the proposed indicator, a Monte Carlo uncertainty analysis was performed. The methodology was applied to a real case study: a district metered area (DMA) in the Palermo city water distribution network (Italy). The analysis showed that ranking based on the composite indicator is better than common ranking procedures based on typical variables (e.g., the meter error curve or the meter age): the proposed indicator can better select the meters to be replaced and favourably affect the associated costs

The present paper describes the analysis of water and energy balance in a complex urban water supply system. The analysis was carried out employing Life Cycle Analysis (LCA) methodologies. The LCA approach was integrated with the analysis of the system energy and water balance. For a real size water supply system, based on the results of the individual LCAs, the current baseline was constructed highlighting the water, energy and environmental (in terms of CO2eq emissions in the atmosphere) costs of supplied water. Then, three different mitigation measures have been evaluated: the first is based on energy production by installation of photovoltaic systems; the second is based on energy recovery by means of hydraulic turbines, exploiting the available pressure potential to produce energy; the third based on energy optimization of pumping stations by installing inverter systems, replacement of rotors with optimized blade profiles and installation of automation systems and self-control. Also the possibility of substituting some of the pipes of the water supply system was considered in the recovery scenario in order to reduce leakages and recovery the energy needed for leakages transport and treatment. The analysis of the results shown that energy recovery scenario is the most reliable solution even without any pipe substitution. Thanks to the recovery of energy and limiting the environmental impact of the system, the CO2eq production per cubic meter of supplied water was reduced from 0.41 to 0.07 kg CO2eq/m3 of supplied water.

The optimal operation of a multi quality network was analysed applying Linear Programming methods. The peculiar service condition of the industrial city of Gela (Italy) was investigated. The network is supplied both from waters derived from a desalination plant and other natural sources. The method aimed to minimise energy cost and find the optimal operation control, while satisfying demand and quality constraints, specifically with regard to water temperature. The method proved to be effective in the selection of the optimal management strategy after the definition of a specific water quality target. (C) 2014 Published by Elsevier Ltd.

Climate change and modification of the urban environment increase the frequency and the negative effects of flooding, increasing the interest of researchers and practitioners in this topic. Usually, flood frequency analysis in urban areas is indirectly carried out by adopting advanced hydraulic models to simulate long historical rainfall series or design storms. However, their results are affected by a level of uncertainty which has been extensively investigated in recent years. A major source of uncertainty inherent to hydraulic model results is linked to the imperfect knowledge of the rainfall input data both in time and space. Several studies show that hydrological modelling in urban areas requires rainfall data with fine resolution in time and space. The present paper analyses the effect of rainfall knowledge on urban flood modelling results. A mathematical model of urban flooding propagation was applied to a real case study and the maximum efficiency conditions for the model and the uncertainty affecting the results were evaluated by means of generalised likelihood uncertainty estimation (GLUE) analysis. The added value provided by the adoption of finer temporal and spatial resolution of the rainfall was assessed.

This paper tries to describe the main developments of urban flood forecasting and modelling. Currently, several new technologies are available for flood monitoring, modelling and mitigation and several paradigms suggest the adoption of greener approaches to urban storm water management. These tools and new approaches can be easily adaptable to new developments where the entire urban drainage system can be suited to follow a more sustainable way to drain storm water. The challenge for the future is instead aimed to apply this new philosophy to existing urban areas where the application of new tools and technologies requires high costs and such approaches have to be prepared by constructing a flood resilient society by means of education and capillary information.

This study presents a methodology based on Linear Programming for determining the optimal pump schedule on a 24-hour basis, considering as decision variables the continuous pump flow rates which are subsequently transformed into a discrete schedule. The methodology was applied on a case study derived from the benchmark Anytown network. To evaluate the LP reliability, a comparison was made with solutions generated by a Hybrid Discrete Dynamically Dimensioned Search (HD-DDS) algorithm. The cost associated with the result derived from the LP initial solution was shown to be lower than that obtained with repeated HD-DDS runs with differing random seeds. (C) 2013 The Authors. Published by Elsevier Ltd.

The Porous Shallow water Equations are widely used in the context of urban flooding simulation. In these equations, the solid obstacles are implicitly taken into account by averaging the classic Shallow water Equations on a control volume containing the fluid phase and the obstacles. Numerical models for the approximate solution of these equations are usually based on the approximate calculation of the Riemann fluxes at the interface between cells. In the present paper, it is presented the exact solution of the one-dimensional Riemann problem over the dry bed, and it is shown that the solution always exists, but there are initial conditions for which it is not unique. The non-uniqueness of the Riemann problem solution opens interesting questions about which is the physically congruent wave configuration in the case of solution multiplicity.

Water distribution systems play a fundamental role due to their impact on public health, food, agriculture and energy and consequently, they are identified as critical infrastructures. Integrated urban water management is affected by critical issues that may interfere with the achievement of the best management practice. The work shows a methodology for the identification of interventions priorities in a region where several water distribution systems, with different criticalities, coexist. As metric for critical issues, IWA PIs has been chosen. Multi-criteria Decision Analysis (MCDA) is applied to obtain a sorting of critical issues and thus to define the priorities in the investment planning. The aim is to provide a tool that supports the consistency check between criticalities and interventions planning. The methodology has been applied to 15 management areas within an homogeneous region in the North of Italy.

HIC 2018. 13th International Conference on Hydroinformatics, Palermo, ITA, 01-/07/2018 - 05/07/2018; International audience; In this paper, we present two R packages, airGR and airGRteaching, which are aimed at hydrological modeling. These two open-source packages allow for undertaking simplified simulations of surface flows on river catchments, based on lumped rainfall-runoff models that require few input data. airGR can be used for engineering, research and education purposes and is well indicated for experiments on large sample datasets. airGRteaching is an add-on to airGR and is especially dedicated to education, since one of its functionalities provides an interface on which parameters and models fluxes can be easily understood through an interactive visualization. airGRteaching also contains simplified functions that require less programming from users but do not allow for some more advanced experiments.

The study of the relationship between extreme rainfall events and surface temperature represents an important issue in hydrology and meteorology and it could be of capital importance for evaluating the effect of global warming on future precipitation. Various approaches have been tested across different parts of the world, and, in many cases, it has been observed an intensification of precipitation with increasing temperature consistently with the thermodynamic Clausius-Clapeyron relation (CC-rate of 6-7% °C-1), according to which a warmer atmosphere is capable of holding more moisture. Nevertheless, in different locations, the scaling rate between temperature and extreme precipitation has resulted significantly different with respect to the CC-rate, in some cases sensibly higher (super-CC) and in other relevantly lower (sub-CC). In this work, an analysis of the scaling relationship between sub-daily extreme rainfall events and surface temperature is carried out, using data from a large number of rain and temperature gauges across Sicily (Italy). Results highlight the relevant importance of some modeling choices and, particularly, of rainfall duration, for this type of analysis in semi-arid region. An overall sub-CC scaling rate has been detected for most part of the region.

Smart cities are getting essential to drive economic growth, increase social prospects and improve high-quality lifestyle for citizens. To meet the goal of smart cities, Information and Communications Technology (ICT) have a key role. The application of smart solutions will allow the cities to use ICT and big data to improve infrastructure and services (i.e. network efficiency, protection from contamination, etc.). In the water sector, the integration of smart meters and sensors coupled with cloud computing and the paradigm of “divide and conquer” introduces a novel and smart management of the water network allowing an efficient online monitoring and transforming the traditional water networks into modern Smart WAter Networks (SWAN). The Ctrl+SWAN (Cloud Technologies & ReaL time monitoring+Smart WAter Network) Action Group (AG) was created within the European Innovation Partnership on Water, in order to promote innovation in the water sector by advancing existing smart solutions. The paper presents an update of a previous work on the state of the art on the best On-line Measuring Sensors (OMS) already available on the market and innovative technologies in the Research and Development (R&D) phases.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU [ADD1_IRSTEA]Hydrosystèmes et risques naturelsHIC 2018. 13th International Conference on Hydroinformatics, Palermo, ITA, 01-/07/2018 - 05/07/2018; International audience; In this paper, we present two R packages, airGR and airGRteaching, which are aimed at hydrological modeling. These two open-source packages allow for undertaking simplified simulations of surface flows on river catchments, based on lumped rainfall-runoff models that require few input data. airGR can be used for engineering, research and education purposes and is well indicated for experiments on large sample datasets. airGRteaching is an add-on to airGR and is especially dedicated to education, since one of its functionalities provides an interface on which parameters and models fluxes can be easily understood through an interactive visualization. airGRteaching also contains simplified functions that require less programming from users but do not allow for some more advanced experiments.

The identifiability analysis is investigated as sampling design method aimed to the leakage detection in looped water distribution networks. The preliminary ranking of the candidate nodes for the pressure sensors positioning is performed by running several hydraulic simulations and calculating sensitivity functions. The reduced subset of nodes and their sensitivities are then used to perform the identifiability analysis by calculating the collinearity index which provides the maximum number of sensors and their location into the network. The index selects the nodes according to their sensitivities to several leakages scenarios, simulated in EPANET by changing the emitter coefficient of the leakages function both with a One-At-Time and Monte Carlo approach. The collinearity index also identifies the subset of the pressure monitoring nodes with the lowest correlation (redundancy) between the measurements. The method is applied to the benchmark network Apulian.

In the water distribution networks, a deliberate or accidental contamination causes loss of water quality; the implementation of a real-time sensor network is essential to promptly detect the event of contamination. To achieve the optimum positioning of the probes, to reduce the cost of the instrumentation and maintenance, and obtaining, at the same time, a reliable monitoring of the system, optimization techniques are widely applied. In the present study, a numerical optimisation approach was compared with the results of an experimental campaign. The optimization problem is formulated in accordance with literature stateof- the-art, using the genetic algorithm NSGA-II coupled with a hydraulic simulator. The results were tested and verified using a looped laboratory distribution network, equipped with a real-time monitoring water quality system, which allows to run contamination experiments in a controlled environment.