scholarly journals Reliability analysis of complex water distribution systems: the role of the network connectivity and tanks

Author(s):  
L. Berardi ◽  
D. Laucelli ◽  
F. Ciliberti ◽  
S. Bruaset ◽  
G. Raspati ◽  
...  

Abstract A reliable water distribution network (WDN) can provide an adequate supply service to customers under both normal and abnormal working conditions. The WDN reliability analysis, therefore, is a keystone to improve the supply service efficiency. Strategies for reliability analysis are usually proved on small WDNs, which do not compare with large real complex systems in terms of number of water tanks, pressure reduction valves, variable speed pumps, controlled devices and possible alternative water supply schemes. The topological changes due to pipeline interruptions impact on emptying–filling of water tanks and network pressure status. This work proposes a two-level procedure for mechanical reliability assessment, suited for large real WDNs. It leverages a path/connectivity-based approach to set up reliability indicators for global-level analysis and local screening of the most critical scenarios. The employed advanced hydraulic model includes the automatic detection of topological changes and the robust modelling of water level in tanks using the generalized global gradient algorithm. The extended period simulation enables the reliability assessment of alternative water supply schemes and the sensitivity of tanks and controlled devices to single failure events. The procedure is demonstrated on a real complex network, being consistent with the ongoing digital transition in the WDN management sector.

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.


Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1493 ◽  
Author(s):  
Susanna Andreasi Bassi ◽  
Iskandar Tange ◽  
Benjamin Holm ◽  
Alessio Boldrin ◽  
Martin Rygaard

Water supply challenges in emergency situations have increased in recent years and there is a need for analyses targeting economic and environmental sustainability. Our study investigated the end-user water demand, the capital and operational costs, the carbon footprint, the freshwater availability and the risks surrounding water quality for several groundwater supply alternatives in Ugandan refugee settlements. We compared hand pumps, motorised pumps (solar, diesel and hybrid) and water trucking. The end-users’ survey highlighted the significant variability of water access. The economic evaluation showed that the breakeven year for solar and diesel pumps was greatly affected by the length of the water distribution systems (e.g., pipes, storage tanks), the chosen timeframe and the daily working hours of the diesel engine. When excluding capital investment, most alternatives were economically viable at the existing water fee (0.8 USD/m3), and solar driven pumps were down to 0.09 USD/m3. Finally, the combustion of diesel caused the highest CO2-eq emissions per m3. Water trucking is the worst option in both the economic and environmental analysis at 7–8 USD/m3 and >1 kg CO2-eq/m3. The methodology and the results of this paper will support decision-makers to build and finance sustainable water provision solutions in refugee settlements.


Author(s):  
Chalchisa Milkecha ◽  
Habtamu Itefa

This study was conducted generally by aiming assessment of the hydraulic performance of water distribution systems of Addis Ababa Science and Technology University (AASTU). In line with the main objective, this study addressed, (1) pinpointing problems of existing water supply versus demand deficit (2) evaluating the hydraulic performance of water distribution system using water GEMS and (3) recommended alternative methods for improving water demand scenarios. The University’s water supply distribution network layout was a looped system and the flow of water derived by both gravity and pressurized system. The gravity flow served for the academic and administrative staffs whereas the pressurized system of the network fed the students dormitories, cafeteria’s etc. The study revealed the existence of unmet minimum pressure requirement around the student dormitories which accounts 25.64% below the country’s building code standard during the peak hour consumption. The result of the water demand projection showed an increment of 2.5 liter per capita demand (LPCD) in every five years. Hence, first, the university’s water demand was projected and then hydraulic parameters such as; pressure, head loss and velocity were modeled for both the existing and the improved water supply distribution. The finding of the study was recommended to the university’s water supply project and institutional development offices for its future modification and rehabilitation works.


1992 ◽  
Vol 8 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Pilar Cereceda ◽  
Robert S. Schemenauer ◽  
Marcela Suit

Resources ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 162 ◽  
Author(s):  
Barbara Tchórzewska-Cieślak ◽  
Katarzyna Pietrucha-Urbanik ◽  
Dorota Papciak

Given that a consequence of a lack of stability of the water in a distribution system is increased susceptibility to secondary contamination and, hence, a threat to consumer health, in the work detailed here we assessed the risk of such a system experiencing quality changes relating to the biological and chemical stability of water intended for drinking. Utilizing real operational data from a water treatment station, the presented analysis of the stability was performed based on the fault tree method. If they are to protect their critical-status water supply infrastructure, water supply companies should redouble their efforts to distribute stable water free of potentially corrosive properties. To that end, suggestions are made on the safeguarding of water distribution systems, with a view to ensuring the safety of operation and the long-term durability of pipes.


2004 ◽  
Vol 2 (3) ◽  
pp. 137-156 ◽  
Author(s):  
M. M. Aral ◽  
J. Guan ◽  
M. L. Maslia ◽  
J. B. Sautner ◽  
R. E. Gillig ◽  
...  

In a recently completed case-control epidemiological study, the New Jersey Department of Health and Senior Services (NJDHSS) with support from the Agency for Toxic Substances and Disease Registry (ATSDR) documented an association between prenatal exposure to a specific contaminated community water source and leukaemia in female children. An important and necessary step in the epidemiological study was the reconstruction of the historical water supply strategy of the water distribution system serving the Dover Township area, New Jersey. The sensitivity of solutions to: (1) pressure and pattern factor constraints, (2) allowable operational extremes of water levels in the storage tanks, and (3) the non-uniqueness of the water supply solution are analysed in detail. The computational results show that the proposed approach yields satisfactory results for the complete set of monthly simulations and sensitivity analyses, providing a consistent approach for identifying the historical water supply strategy of the water distribution system. Sensitivity analyses indicated that the alternative strategy obtained from the revised objective function and the variation of constraints did not yield significantly different water supply characteristics. The overall analysis demonstrates that the progressive optimality genetic algorithm (POGA) developed to solve the optimization problem is an effective and efficient algorithm for the reconstruction of water supply strategies in water distribution systems.


2020 ◽  
Vol 10 (22) ◽  
pp. 8219
Author(s):  
Andrea Menapace ◽  
Ariele Zanfei ◽  
Manuel Felicetti ◽  
Diego Avesani ◽  
Maurizio Righetti ◽  
...  

Developing data-driven models for bursts detection is currently a demanding challenge for efficient and sustainable management of water supply systems. The main limit in the progress of these models lies in the large amount of accurate data required. The aim is to present a methodology for the generation of reliable data, which are fundamental to train anomaly detection models and set alarms. Thus, the results of the proposed methodology is to provide suitable water consumption data. The presented procedure consists of stochastic modelling of water request and hydraulic pipes bursts simulation to yield suitable synthetic time series of flow rates, for instance, inlet flows of district metered areas and small water supply systems. The water request is obtained through the superimposition of different components, such as the daily, the weekly, and the yearly trends jointly with a random normal distributed component based on the consumption mean and variance, and the number of users aggregation. The resulting request is implemented into the hydraulic model of the distribution system, also embedding background leaks and bursts using a pressure-driven approach with both concentrated and distributed demand schemes. This work seeks to close the gap in the field of synthetic generation of drinking water consumption data, by establishing a proper dedicated methodology that aims to support future water smart grids.


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