Impact of Climate Change on Hydraulic Performance in Water Distribution Networks

Author(s):  
James Northwood

The Intergovernmental Panel on Climate Change (IPCC) has forecast higher mean air temperatures for the mid-latitude region of North America. Studies have shown a strong positive correlation between temperature and municipal water demand. Warmer air temperatures in the future have the potential to increase municipal water demand above levels forecast without climate change considerations. The predicted increase in mean temperature and the onset of hotter and dryer summer weather may create challenges for water providers in the future. Without appropriate network upgrades, higher water demands may degrade the hydraulic performance of existing systems. This creates a need to characterize the impact of higher temperatures on peak water demands and on the hydraulic performance in water distribution networks. The aim of the research is to begin to understand the impact of higher temperatures on nodal demands and pressures in water distribution networks. The sensitivity of municipal water demand to an increase in air temperature is established through previous climate adaptation research completed for the geographical region of central Canada. Results indicate that without adaptation, a 2-4 °C temperature increase causes mean pressure head to fall below the acceptable minimum and produces large uncertainties in pressure head under maximum hour demand (MHD) and maximum day demand (MDD) + fire design conditions in the Anytown network. The combination of low mean pressure head and a high coefficient of variation of pressure head increases the probability of hydraulic failure in the Anytown network. Adaptation strategies are presented as ways to hedge the effects of a warming climate in the Anytown network

Entropy ◽  
2018 ◽  
Vol 20 (8) ◽  
pp. 576 ◽  
Author(s):  
Do Yoo ◽  
Dong Chang ◽  
Yang Song ◽  
Jung Lee

This study proposed a pressure driven entropy method (PDEM) that determines a priority order of pressure gauge locations, which enables the impact of abnormal condition (e.g., pipe failures) to be quantitatively identified in water distribution networks (WDNs). The method developed utilizes the entropy method from information theory and pressure driven analysis (PDA), which is the latest hydraulic analysis method. The conventional hydraulic approach has problems in determining the locations of pressure gauges, attributable to unrealistic results under abnormal conditions (e.g., negative pressure). The proposed method was applied to two benchmark pipe networks and one real pipe network. The priority order for optimal locations was produced, and the result was compared to existing approach. The results of the conventional method show that the pressure reduction difference of each node became so excessive, which resulted in a distorted distribution. However, with the method developed, which considers the connectivity of a system and the influence among nodes based on PDA and entropy method results, pressure gauges can be more realistically and reasonably located.


2018 ◽  
Vol 19 (3) ◽  
pp. 846-854 ◽  
Author(s):  
M. A. Pardo ◽  
J. Valdes-Abellan

Abstract Traditional methods for prioritizing the renewal of water are based on heuristic models, such as the number of breaks per length, rule-of-thumb, and records held by the water utility companies. Efficient management of water distribution networks involves factoring in water and energy losses as the key criteria for planning pipe renewal. Prioritizing the replacement of a pipe according to the highest value of unit headloss due to ageing does not consider the impact on water and energy consumption for the whole network. Thus, this paper proposes a methodology to prioritize pipe replacement according to water and energy savings per monetary unit invested – economic prioritization. This renewal plan shows different results if comparing with replacing pipelines with regard to age and it requires calculating water and energy audits of the water distribution networks. Moreover, the required time to recover the investment performed needs to be calculated. The methodology proposed in this work is compared with the unit headloss criterion used in a real water-pressurized network. The results demonstrate that using the unit headloss criterion neither water, energy nor the investment is optimized. Significant water and energy savings are not fully exploited.


2019 ◽  
Vol 63 (4) ◽  
pp. 295-300 ◽  
Author(s):  
Tamás Huzsvár ◽  
Richárd Wéber ◽  
Csaba János Hős

One of the basic infrastructures of every settlement is the water distribution system, which provides clean and potable water for both private houses, industrial consumers and institution establishments. The operational robustness and vulnerabilities of these networks is an essential issue, both for the quality of life and for the preservation of the environment. Even with frequent and careful maintenance, unintentional pipe bursts might occur, and during the reparation time, the damaged section must be isolated hydraulically from the main body of the water distribution network. Due to the size and complexity of these networks, it might not be trivial how to isolate the burst section, especially if one wishes to minimize the impact on the overall system. This paper presents an algorithmic method that is capable of creating isolation plans for real-life networks in a computationally efficient way, based on the graph properties of the network. Besides this segmentation plan, the topological behavior of the structural graph properties was analyzed with the help of the complex network theory to create a method for the quantitative topology based categorization of the water distribution networks.


Water ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 2445
Author(s):  
Mohsen Hajibabaei ◽  
Sara Nazif ◽  
Robert Sitzenfrei

This study proposes an algorithm for the improvement of water distribution networks (WDNs) performance using system dynamics. In the first part, the hydraulic and environmental performance of WDNs is investigated. The hydraulic performance is assessed based on the pressure of nodes and the flow velocity in pipes. Furthermore, using life cycle assessment, an environmental performance index is proposed to examine the environmental impacts of WDNs. Moreover, in order to evaluate the overall performance in regards to the costs, a value index in the system dynamics framework is proposed. Then, based on the developed framework, improvement strategies for a WDN are assessed by applying scenarios according to constraints and requirements of the network. The considered scenarios are as follows: (1) reducing per capita water demand of the WDN; (2) decreasing the average pressure in the WDN; (3) reducing the mean age of the system by its renewing; and (4) a combination of reducing the per capita water demand and average pressure in the WDN. The results indicate that the best solutions for increasing the value index in this network are: (a) to reduce the pressure of the pressure reducing valves (PRV) from 30 to 28 m; (b) to reduce the per capita water demand by the annual rate of 0.5% and 1% and decreasing the pressure of the PRV valves together. Therefore, it is shown how the developed algorithm is a purposeful approach for evaluating and improving the performance of WDNs based on the value index.


Author(s):  
Dionysios Nikolopoulos ◽  
Georgios Moraitis ◽  
Dimitrios Bouziotas ◽  
Archontia Lykou ◽  
George Karavokiros ◽  
...  

<p>Emergent threats in the water sector have the form of cyber-physical attacks that target SCADA systems of water utilities. Examples of attacks include chemical/biological contamination, disruption of communications between network elements and manipulating sensor data. RISKNOUGHT is an innovative cyber-physical stress testing platform, capable of modelling water distribution networks as cyber-physical systems. The platform simulates information flow of the cyber layer’s networking and computational elements and the feedback interactions with the physical processes under control. RISKNOUGHT utilizes an EPANET-based solver with pressure-driven analysis functionality for the physical process and a customizable network model for the SCADA system representation, which is capable of implementing complex control logic schemes within a simulation. The platform enables the development of composite cyber-physical attacks on various elements of the SCADA including sensors, actuators and PLCs, assessing the impact they have on the hydraulic response of the distribution network, the quality of supplied water and the level of service to consumers. It is envisaged that this platform could help water utilities navigate the ever-changing risk landscape of the digital era and help address some of the modern challenges due to the ongoing transformation of water infrastructure into cyber-physical systems.</p>


2013 ◽  
Vol 13 (5) ◽  
pp. 1281-1288 ◽  
Author(s):  
A. Mani ◽  
M. Tabesh ◽  
M. R. Zolfaghari

Water distribution networks are one of the most important infrastructures in urban areas. Evaluating their real hydraulic performance after being damaged by earthquake loadings is crucial for future planning. In this study, pipeline damage caused by seismic wave propagation is modelled using relationships obtained from 1994 Northridge earthquake. Damaged network is hydraulically analysed using the head driven simulation method (HDSM). This analysis helps to obtain actual performance of the water distribution network damaged by seismic waves, without the usual need to handle negative nodal pressures generated from demand driven simulation method. Pressure performance indicator and the total leakage of the network are used as indicators to show the hydraulic performance of the system. Comparison of the damages from different seismic scenarios and the hydraulic indicators of the network, illustrate the probable condition of the water distribution network after the earthquake. The proposed methodology is applied on a reservoir zone of the Tehran water distribution network. The results indicate the degree of damage in terms of pipe burst and leak points in this network.


Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2617
Author(s):  
Thapelo C. Mosetlhe ◽  
Yskandar Hamam ◽  
Shengzhi Du ◽  
Eric Monacelli

Water losses in Water Distribution Networks (WDNs) are inevitable. This is due to joints interconnections, ageing infrastructure and excessive pressure at lower demand. Pressure control has been showing promising results as a means of minimising water loss. Furthermore, it has been shown that pressure information at critical nodes is often adequate to ensure effective control in the system. In this work, a greedy algorithm for the identification of critical nodes is presented. An emulator for the WDN solution is put forward and used to simulate the dynamics of the WDN. A model-free control scheme based on reinforcement learning is used to interact with the proposed emulator to determine optimal pressure reducing valve settings based on the pressure information from the critical node. Results show that flows through the pipes and nodal pressure heads can be reduced using this scheme. The reduction in flows and nodal pressure leads to reduced leakage flows from the system. Moreover, the control scheme used in this work relies on the current operation of the system, unlike traditional machine learning methods that require prior knowledge about the system.


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