scholarly journals Rehabilitation Planning of Water Distribution Network through a Reliability – Based Risk Assessment

Author(s):  
Marianna D'Ercole ◽  
Maurizio Righetti ◽  
Gema Raspati ◽  
Paolo Bertola ◽  
Rita Maria Ugarelli

The management of existing water distribution system (WDS) is challenged by ageing of infrastructure, population growth, increasing of urbanization, climate change impacts and environmental pollution. Therefore, there is a need for integrated solutions that support decision makers to plan today, while taking into account the effect of these factors in the mid and long term. The paper is part of a more comprehensive project, where advanced hydraulic analysis for WDS is coupled with a dynamic resources input-output analysis model. The proposed modeling solution can be used to optimize the performance of a water supply system while considering also the energy consumption and consequently the environmental impacts. Therefore, as a support tool in the management of a water supply system also in the intervention planning. Here a possible application is presented for rehabilitation/replacement planning while maximizing the network mechanical reliability and minimizing risk of unsupplied demand and pressure deficit, under given economic constraints.

Author(s):  
Marianna D'Ercole ◽  
Maurizio Righetti ◽  
Gema Raspati ◽  
Paolo Bertola ◽  
Rita Maria Ugarelli

The management of existing water distribution system (WDS) is challenged by ageing of infrastructure, population growth, increasing of urbanization, climate change impacts and environmental pollution. Therefore, there is a need for integrated solutions that support decision makers to plan today, while taking into account the effect of these factors in the mid and long term. The paper is part of a more comprehensive project, where advanced hydraulic analysis for WDS is coupled with a dynamic resources input-output analysis model. The proposed modeling solution can be used to optimize the performance of a water supply system while considering also the energy consumption and consequently the environmental impacts. Therefore, as a support tool in the management of a water supply system also in the intervention planning. Here a possible application is presented for rehabilitation/replacement planning while maximizing the network mechanical reliability and minimizing risk of unsupplied demand and pressure deficit, under given economic constraints.


2013 ◽  
Vol 438-439 ◽  
pp. 1551-1554
Author(s):  
Shuang Hua He

Conventional demand-driven models of water supply system are formulated under the assumption that nodal demands are statistic constants, which is not suitable for the cases where nodal pressure is not sufficient for supplying the required demand. An efficient approach for pressure-dependent demand analysis was developed to simulate the hydraulic states of the network for low pressure scenarios, and the mean-first-order-second-moment method was introduced to do the functional reliability analysis of post-earthquake water supply system, which can be applied to further study for seismic performance control analysis of water distribution system.


Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6221
Author(s):  
Jedrzej Bylka ◽  
Tomasz Mróz

The water supply system is one of the most important elements in a city. Currently, many cities struggle with a water deficit problem. Water is a commonly available resource and constitutes the majority of land cover; however, its quality, in many cases, makes it impossible to use as drinking water. To treat and distribute water, it is necessary to supply a certain amount of energy to the system. An important goal of water utility operators is to assess the energy efficiency of the processes and components. Energy assessments are usually limited to the calculation of energy dissipation (sometimes called “energy loss”). From a physical point of view, the formulation of “energy loss” is incorrect; energy in water transport systems is not consumed but only transformed (dissipated) into other, less usable forms. In the water supply process, the quality of energy—exergy (ability to convert into another form)—is consumed; hence, a new evaluation approach is needed. The motivation for this study was the fact that there are no tools for exergy evaluation of water distribution systems. A model of the exergy balances for a water distribution system was proposed, which was tested for the selected case studies of a water supply system and a water treatment station. The tool developed allows us to identify the places with the highest exergy destructions. In the analysed case studies, the highest exergy destruction results from excess pressure (3939 kWh in a water supply system and 1082 kWh in a water treatment plant). The exergy analysis is more accurate for assessing the system compared to the commonly used energy-based methods. The result can be used for assessing and planning water supply system modernisation.


2020 ◽  
Vol 20 (8) ◽  
pp. 2964-2970
Author(s):  
D. P. Ayadi ◽  
A. Rai ◽  
A. Pandey

Abstract The effective and efficient supply of drinking water resources are key to its long-term use and access. In recent decades, the population of Kathmandu Valley has exploded owing to several factors. The water supply system here has also undergone remarkable changes and efforts have been made to enhance its equitable distribution. The major effort, of course, is the Melamchi Water Supply Project (MWSP). As the project approaches completion of its first phase, we would like to point out several key issues for the water distribution system here and express our opinions on promoting equitable water distribution. For this we conducted a thorough literature review and found that improvement in the water distribution network and water tariff in the valley, along with promotion of alternative mitigation options, are the focal issues for promoting an equitable water distribution system in Kathmandu Valley.


The study presents the hydraulic design and analysis of Rural Water Distribution System (WDS) for Nava shihora region of zone 1 of the state of Gujarat, India. Water supply distribution system is designed for this study for population estimated for future 30 years. LOOP 4.0 and Water Gems v8i software have been used and the results are compared to determine the economical size of pipes for water distribution system. The economical size of pipes of water supply distribution system is designed by considering the constraints; residual pressure at each node, velocity of flow in pipe, head loos in pipes, material of pipes, elevated service reservoir level, peak factor and available commercial pipe diameters. Further water distribution system has been analyzed for extended period simulation (EPS) for the present population scenario for intermittent water supply using Water Gems v8i. Further water supply system is analyzed the residual chlorine concentration at nodes and in the pipe links and also the total cost of water supply system of rural region is estimated.


Author(s):  
Chiara Arrighi ◽  
Fabio Tarani ◽  
Enrico Vicario ◽  
Fabio Castelli

Abstract. Floods cause damage to people, buildings and infrastructures. Due to their usual location near rivers, water utilities are particularly exposed; in case of flood, the inundation of the facility can damage equipment and cause power outages. Such impact leads to costly repairs, disruptions of service, hazardous situations for personnel and public health advisories. In this work, we present an analysis of direct and indirect damages of a drinking water supply system considering the hazard of a riverine flooding as well as the exposure and vulnerability of the system components (i.e. pipes, junctions, lifting stations etc.). The method is based on the combination of a flood model and an EPANET-based piping network model implementing Pressure-Driven Demand, which is more appropriate when modeling water distribution networks with many off-line nodes. The two models are linked by a semi-automated GIS procedure. The evaluation of flood impact on the aqueduct network is carried out for flood scenarios with assigned recurrence intervals. Vulnerable elements exposed to the flood are identified and analyzed in order to determine their residual functionality and simulate failure scenarios. Impact metrics are defined to measure service outage and potential pipe contamination. The method is applied to the water supply system of the city of Florence (Italy), serving approximately 385 000 inhabitants. Results show that for the worst failure scenario 420 km of pipeworks would require flushing and disinfection with an estimated cost of 21 Mio €, which is about 0.5 % of the direct flood losses evaluated for buildings and contents.


2017 ◽  
Vol 17 (12) ◽  
pp. 2109-2123 ◽  
Author(s):  
Chiara Arrighi ◽  
Fabio Tarani ◽  
Enrico Vicario ◽  
Fabio Castelli

Abstract. Floods cause damage to people, buildings and infrastructures. Water distribution systems are particularly exposed, since water treatment plants are often located next to the rivers. Failure of the system leads to both direct losses, for instance damage to equipment and pipework contamination, and indirect impact, since it may lead to service disruption and thus affect populations far from the event through the functional dependencies of the network. In this work, we present an analysis of direct and indirect damages on a drinking water supply system, considering the hazard of riverine flooding as well as the exposure and vulnerability of active system components. The method is based on interweaving, through a semi-automated GIS procedure, a flood model and an EPANET-based pipe network model with a pressure-driven demand approach, which is needed when modelling water distribution networks in highly off-design conditions. Impact measures are defined and estimated so as to quantify service outage and potential pipe contamination. The method is applied to the water supply system of the city of Florence, Italy, serving approximately 380 000 inhabitants. The evaluation of flood impact on the water distribution network is carried out for different events with assigned recurrence intervals. Vulnerable elements exposed to the flood are identified and analysed in order to estimate their residual functionality and to simulate failure scenarios. Results show that in the worst failure scenario (no residual functionality of the lifting station and a 500-year flood), 420 km of pipework would require disinfection with an estimated cost of EUR 21 million, which is about 0.5 % of the direct flood losses evaluated for buildings and contents. Moreover, if flood impacts on the water distribution network are considered, the population affected by the flood is up to 3 times the population directly flooded.


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