A Data Driven Approach for Resilience Analysis of Water Distribution Networks

The water distribution network plays a key role in ensuring and providing a high quality of life for the public, with supply dependability being the most crucial component. A communities thrive is dependent on the availability of safe drinking water for its members. As the population of any community increases, the request for water also increases which imposes additional load to the existing water distribution system. As a result, the present water distribution system may become untrustworthy to meet the demand of the increased population. It is vital to provide an adequate and equitable quantity of water through a well-designed network of pipes in order to meet the ever-increasing water demand of the population. LOOP (Version 4.0) can be used to develop and simulate gravity and pumped water distribution systems that are novel, partially or completely functional. LOOP 4.0 is used to determine the cost of pipe network. EPANET is a computer program that models hydrodynamic behaviour in a pressurised pipe network over a long period of time. The Examination presents the hydraulic analysis of pipe network of Narangi area in Virar city using Loop 4.0 and EPANET 2.0. The results confirmed that the pressure at all junctions and velocities at all pipes are acceptable to deliver appropriate water to the study area’s network, as well as aiding in a better understanding of the study area’s pipeline system. The study also deals with the cost of distribution network.KeywordsLOOP 4.0EPANET 2.0Arc GISElevationNodesPipe networkPressureWater supply

Failures in the water distribution network are some most important factors in water losses, water shortage and dissatisfaction of users and secondary pollutions as well. This research aimed to analyze failure in water distribution networks during 2006-2008, for better water management. Daily failure reports in Ahvaz, Iran distribution network during 2006-2008, were collected from emergency department of Ahvaz water and Wastewater Company; thereafter, they were entered into an Excel database, also failures were defined by pipes type, pipe diameter, and cause of the failure, and finally the data were analyzed. Results indicated that asbestos and polyethylene pipes show maximum failures; maximum failure and fracture has occurred in pipes with 100 and 150 mm diameters. The most important factors affecting on failure were corrosion, traffic load and landslide. In addition, simultaneous influence of type and the diameter of the pipe on the failures were statistically significant. The depth of pipes establishment, corrosion and obsolescence of pipes as well as improper type of pipes were the most important causes of failures in Ahvaz Water Distribution Network. In this regard, upgrading pipe material setting standards and renewing water pipe network are the main strategies for failures minimization.

Gröbner bases for solving ΔQ-equations in water distribution networks

The analysis of a looped water distribution network, operating under pressure and in steady flow conditions, can be accomplished once the topology of the network, the geometry of the pipes, the water demands at the nodes and the head value of at least one node are known. In a water distribution network (WDN), water demands are assigned to the nodes, although in reality they are distributed along the pipes converging at such nodes. This classic assumption represents the total demand along a pipe as two lumped withdrawals at its terminal nodes. This paper demonstrates that the above approximation is wrong because it generates head loss errors which may be significant when network analysis is performed for calibration, system design, real-time operations, rehabilitation strategies, optimal operation studies, reliability analyses, etc. Therefore, an extension of the global gradient algorithm (GGA) for network analysis is proposed which entails a modified GGA permitting the effective introduction of the lumped nodal demands, and without forfeiting a correct physical representation of head losses, by means of a pipe hydraulic resistance correction.

Water distribution systems are regarded as large sparse graphs with complex network characteristics. Topological aspects of system resilience, viewed as the antonym to structural vulnerability, are assessed in connection with the network architecture, robustness and loop redundancy. Deterministic techniques from complex networks and spectral graph theory are utilized to quantify well-connectedness and estimate loop redundancy in the studied benchmark networks. By using graph connectivity and expansion properties, system robustness against node/link failures and isolation of the demand nodes from the source(s) are assessed and network tolerance against random failures and targeted attacks on their bridges and cut sets are analyzed. Among other measurements, two metrics of meshed-ness and algebraic connectivity are proposed as candidates for quantification of redundancy and robustness, respectively, in optimization design models. A brief discussion on the scope and relevance of the provided measurements in the analysis of resilience of water distribution networks is presented.

TECHNOLOGY AND CULTURE Book Reviews 1033 formulate a plan to tap the Colorado River. In 1952, Freese prepared a groundbreaking document when on behalf of all the state’s engi­ neers he presented a statewide water plan entitled “A Water Policy for Texans.” Always innovative, Freese and Nichols was one of the first organiza­ tions to use computers, preparing an analysis of water distribution networks in 1957. Work in the 1960s reflected a new national aware­ ness of the environment and a heightened understanding of the im­ pact of the engineer’s work on nature and society. During the 1980s modernized operations and broadened services provided archaeolog­ ical research, management plans for fish and wildlife, and architec­ tural and historic surveys. Cited in the success and longevity of the firm is “its ability to govern and assimilate change” (p. 345). But a company does not deal with change, people do that. Much to their credit, those who managed the firm fostered a high degree of professionalism among the engineers they hired and at the same time encouraged them to look on civil engineering foremost as a public service. It is a formula that worked. It is unfortunate that Simon Freese did not live to see the publica­ tion of this book and to enjoy the accolades it will surely receive. Meticulously prepared, objective, and contextual, there is no question that it stands as a landmark in engineering histories. What a pity the founding principals of grand old firms such as Modjeski and Masters, Robinson and Steinman, and Morrison Knudson did not leave similar historical legacies. William Worthington Mr. Worthington specializes in the history of engineering at the National Museum of American History. The Politics ofTechnological Change in Prussia: Out ofthe Shadow ofAntiq­ uity, 1809—1848. By Eric Dorn Brose. Princeton, N.J.: Princeton University Press, 1993. Pp. xiii + 290; notes, bibliography, index. $39.50. While some historians of Prussia have treated the state as an auton­ omous entity (Beamtenstaat) between the Napoleonic Wars and the Revolutions of 1848, others have argued that it was dominated by the aristocracy (Junherstaat). Another major historiographical approach gives state officials credit for promoting Prussia’s early stages of in­ dustrial development. Eric Brose provides a quite different picture. By using technology policy to investigate contending groups of state officials, their visions of past and future, and their relationships with businessmen, Brose develops a new conception of the nature of the Prussian state and its relationship to civil society in the early 1800s. Brose proceeds in a topical manner. He develops a theoretical posi­ 1034 Book Reviews TECHNOLOGY AND CULTURE tion concerning the state made up of contending departments and agencies interconnected with various sections of society, before turn­ ing to discussions of state agencies like the Business Department, the Mining Corps, the army’s technical establishment, and the Overseas Trading Corporation (Seehandlung). The Business Department and the Seehandlung sought to develop a rural industrial base, while the Mining Corps developed its own mines, forges, and foundries, based on techniques from the 1500s and 1600s. Although not significant in terms of overall investment, these strategies produced improvements welcomed by businessmen in the 1810s and 1820s. By the 1830s and 1840s, however, the visions of development promoted by state offi­ cials were no longer seen by businessmen as beneficial. Although initially ambivalent about modern technology, members of the army began supporting the development of railroads in the 1830s against other segments of the state which saw railroads as diverging from their visions of an appropriate future. King Frederick William III allowed competing approaches in the state, but sided with proponents of mercantilist change in the 1810s and 1820s, and supported a law beneficial to railroads in 1838. His son supported railroads also, but increasingly turned to reactionary policies in the 1840s. Thus, seg­ ments of tfie state provided an impetus to technological change until the 1830s and 1840s, when state officials, soldiers, and businessmen, disagreeing about what policies should be followed and who should control production, became increasingly alienated from one another. Brose provides a valuable corrective to visions of a monolithic Prus­ sian state. Competition and even chaos were common. The stress on antiquity was...

Water Distribution Networks are one of the most important infrastructures. The success of a water distribution network depends upon its capability and efficiency to cater water demand and available residual pressures at consumer ends. Conventionally, Demand Driven Approach is used for designing and analyzing a water distribution network. But this approach fails to consider practical situations that can arise in an operational system like valve closure, pipe burst, pump failure, source failure, fire flow, DMA operations and their adverse effects on the network. Practically, residual pressures in the system vary quiet often and so the discharges at consumer ends. As the pressure increases, discharge also increases and vice-versa. Therefore discharges/demands depend upon the available residual pressure. This approach of analyzing a water distribution network is known as Pressure Driven Analysis. The aim of the paper is to study both Demand Driven Approach and Pressure Driven Approach and compare their results.

Effects of Data Uncertainty on Multi-species Qualitative Modeling and Pressure Dependent Analysis of Water Distribution Networks Using the Elementary Effect Method

The fixed demand hydraulics engine of EPANET software in its original form is not suitable for analysis of water distribution networks with low operating pressures. A modification of EPANET desktop for pressure driven demand analysis, employing emitter modeling of demands, is presented. The introduced version is able to work in a fully transparent way with standard EPANET network files and could be developed into other EPANET-toolkit based applications following the exact procedure as with standard EPANET. A simple network example used to demonstrate the operation of the system. Finally an illustrative case study of the model application is presented.

An analysis that considers a relationship between nodal demand and available nodal pressure to determine the outflow at that node is carried out and mostly referred as pressure-dependent analysis (PDA). Further, not only the outflow but some demand itself such as leakage losses and water demand at sprinklers, faucets etc., are also considered dependent on pressure. Several node head-flow relationships (NHFRs) have been suggested along with the methodologies for their solution in the last three decades. Further, efforts have been also made to carry out PDA by using an efficient DDA based hydraulic network solver, EPANET. The PDA has been used in tackling a variety of problems on water distribution systems such as: assessing reliability, reliability-based design, parameter calibration, vulnerability analysis, placement of isolation valves, water quality analysis, flushing of contaminated water, leakage modelling, and multi-objective evolutionary optimization. This paper provides a complete development in PDA along with future research need.

This paper describes a rational method of circuit selection for water distribution network analysis. This method reduces the number of systematic corrections necessary for the determination of the distribution of flows by the Hardy Cross method of network analysis.

This paper presents a simple approach for load flow analysis of a radial distribution network with embedded generation. The proposed approach utilizes forward and backward sweep algorithm based on Kirchoff's current law (KCL) and Kirchoff's voltage law (KVL) for evaluating the node voltages iteratively. In this approach, computation of branch current depends only on the current injected at the neighbouring node and the current in the adjacent branch. This approach starts from the end nodes of sub lateral line, lateral line and main line and moves towards the root node during branch current computation. The node voltage evaluation begins from the root node and moves towards the nodes located at the far end of the main, lateral and sub lateral lines. The proposed approach has been tested using three radial distribution systems of different size and configuration and is found to be computationally efficient. The effectiveness of the proposed approach is further demonstrated by integrating the embedded generation into the load flow analysis of the radial distribution network.

A practical way of assessing the impact of various pipe failure conditions on water distribution networks is described. The method avoids the need to undertake a full network analysis or simulation for each particular component failure. The method assesses the vulnerability of the network to the loss of any particular pipe element, and provides a quantitative estimate of the impact on each nodal demand, and the postfailure utilization of nodal sources and pipe elements. Implementation of the method requires only knowledge of the network configuration and a set of typical operating conditions, such as might already be available from a routine network analysis of the intact distribution network. Detailed non‐linear network analysis covering all possible failure conditions is thus avoided. In cases of networks supplied by a number of sources of differing quality, the same overall technique can also be used to determine the chemical/biochemical quality of supply at any point in the network. The results of the method can be combined with pipe failure probabilities to provide measures of network reliability.

The traditional power flow and fault analysis methods fail to meet the requirements in both performance and accuracy aspects in the distribution network applications. This is due to the unbalanced multiphase nature of the distribution network and also due to the emerging penetration of renewable generation at the distribution level. This paper proposes a comprehensive method for power flow solution and fault analysis of multiphase unbalanced distribution networks with high penetration of inverter-interfaced DERs. Also, the self-protection scheme employed for the inverter of the DERs is also formulated in the proposed method. Performance of the proposed method has been assessed by simulations on a sample distribution network.

Scope of this paper is to investigate the effect of different load and distributed generation (photovoltaic systems and wind generators) modelling approaches for the steady-state analysis of distribution networks and the development of ancillary services by system operators. Specifically, five different modelling approaches are considered, based on different assumptions. The power flow problem is solved by applying the examined models to the 33-bus benchmark distribution network and the derived results are statistically analyzed. The accuracy, reliability and performance of the models is evaluated in terms of the calculated voltages, power losses and computational burden.