Scientific Results

This catalogue is obtained by conducting a systematic literature review of scientific studies and reviews related to monitoring, forecasting, and simulating the inland water cycle. The analysis maps scientific expertise across research groups and classifies findings by the type of inland water studied, application focus, and geographical scope. A gap analysis will identify missing research areas and assess their relevance to policymaking.

ID ▲	Type	Year	Authors	Title	Venue/Journal	DOI	Abstract
publications-4221	article	1987	Walski, Thomas M. and Brill, E. Downey and Gessler, Johannes and Goulter, Ian C. and Jeppson, Roland M. and Lansey, Kevin E and Lee, Han Lin and Liebman, Jon C. and Liebman, Jon C. and Liebman, Jon C. and Mays, Larry W. and Morgan, David R. and Ormsbee, Lindell	Battle of the network models: Epilogue	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(1987)113:2(191)	Several models that can be used to optimally size water distribution pipes were applied to a hypothetical system. The results are summarized in this paper. The models produced solutions with costs that were within 10\% of one another, although the solutions were quite different. While the models were helpful in sizing pipes, some manual calculations and a good deal of engineering judgment were required to apply them.
publications-4222	article	1988	Wagner, Janet M. and Wagner, Janet M. and Shamir, Uri and Shamir, Uri and Marks, David H. and Marks, David H.	Water Distribution Reliability: Simulation Methods	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(1988)114:3(276)	Following a companion paper on analytical methods, this paper presents simulation as a complementary method for analyzing the reliability of water distribution networks. For this simulation, the distribution system is modeled as a network whose pipes and pumps are subject to failure. Nodes are targeted to receive a given supply at a given head. If this head is not attainable, supply at the node is reduced. Pumps and pipes fail randomly, according to probability distributions with userβ€specified parameters. Several reliability measures are estimated with this simulation. Confidence intervals are also supplied for some of these reliability measures. Simulation results are presented for a small network (ten nodes) and a larger network (sixteen nodes). Simulation enables computation of a much broader class of reliability measures than do analytical methods, but it requires considerably more computer time and its results are less easy to generalize. It is therefore recommended that analytical and simulation me...
publications-4223	article	1993	Rossman, Lewis A. and Boulos, Paul F. and Altman, Tom	Discrete Volume-Element Method for Network Water-Quality Models	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(1993)119:5(505)	An explicit dynamic water-quality modeling algorithm is developed for tracking dissolved substances in water-distribution networks. The algorithm is based on a mass-balance relation within pipes that considers both advective transport and reaction kinetics. Complete mixing of material is assumed at pipe junctions and storage tanks. The algorithm automatically selects a pipe-segmentation scheme and computational time step that satisfies conservation of mass and seeks to minimize numerical dispersion. In contrast to previous water-quality models, there is no need to first find unique flow paths through the network. The resulting method is both robust and efficient, and can be readily applied to all types of network configurations and dynamic hydraulic conditions. The applicability of the method is demonstrated using an example pipe-distribution network. Enhancement of distribution-system water-quality management is a principal benefit of the methodology.
publications-4224	article	2014	Beal, Cara and Beal, Cara and Stewart, Rodney Anthony and Stewart, Rodney Anthony	Identifying Residential Water End Uses Underpinning Peak Day and Peak Hour Demand	Journal of Water Resources Planning and Management	10.1061/(asce)wr.1943-5452.0000357	AbstractAccurate and up-to-date peak demand data are essential to ensure that future mains water supply networks reflect current usage patterns and are designed efficiently from an engineering, environmental, and economic perspective. The aim of this paper was to identify the water end-uses that drive peak day demand and to examine their associated hourly diurnal demand patterns based on over 18 months of water consumption data obtained from high-resolution smart meters installed in 230 residential properties across South East Queensland, Australia. Peak day (PD) to average day (AD) ratios between 1 and 1.5 were driven by both external and internal end-uses. However, as the PD:AD ratio increased above 1.5, demand was driven largely by external water usage (i.e.,lawn and garden irrigation). Peak hour ratios (i.e.,PHPD:PHAD) ranged from 1.3 to 3.0 for the four peak demand days. At the end-use level, the individual end-use category PHPD:PHAD ratios were in the range of 0.7β€“3.3 for all end-uses, with the ex...
publications-4225	article	2008	Xu, Jianhua and Fischbeck, Paul S. and Small, Mitchell J. and VanBriesen, Jeanne M. and Casman, Elizabeth A.	Identifying Sets of Key Nodes for Placing Sensors in Dynamic Water Distribution Networks	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(2008)134:4(378)	The design of a sensor-placement scheme capable of detecting all possible contamination events for a water distribution system before consumers are put at risk is essentially impossible given current technologies and budgets. It is, however, possible to design sensor-placement schemes that optimize related objectives (e.g., minimize expected volume of contaminated water consumed prior to detection), but this requires the availability of hydraulic and water quality models for the distribution network and significant computational power, which are the main obstacles to the identification of optimal sensor locations. This paper describes a different approach that reduces the problemβ€™s complexity by expressing a water distribution system as different graphs based on the information readily available from most, if not all, water utilities. The approach provides critical policy and decision support for utilities when hydraulic and water quality models are not available and/or when simulation-based techniques ar...
publications-4226	article	2008	Preis, Ami and Ostfeld, Avi	Multiobjective Contaminant Sensor Network Design for Water Distribution Systems	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(2008)134:4(366)	A contaminant intentional intrusion into a water distribution system is one of the most difficult threats to address. This is because of the uncertainty of the type of the injected contaminant and its consequences, and the uncertainty of the location and intrusion time. An online contaminant sensor network is the main constituent to enhance the security of a water distribution system against such a threat. In this study a multiobjective model for water distribution system optimal sensor placement using the nondominated sorted genetic algorithm II is developed and demonstrated using two water distribution systems of increasing complexity. Tradeoffs between three objectives are explored: (1) sensor detection likelihood; (2) sensor detection redundancy; and (3) sensor expected detection time. Pareto fronts are plotted for pairs of conflicting objectives, and simultaneously for all three. A contamination event heuristic sampling methodology is developed for overcoming the problem of contamination event sampling.
publications-4227	article	2009	Davis, Michael J. and Janke, Robert	Development of a probabilistic timing model for the ingestion of tap water.	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(2009)135:5(397)	A contamination event in a water distribution system can result in adverse health impacts to individuals consuming contaminated water from the system. Assessing impacts to such consumers requires accounting for the timing of exposures of individuals to tap-water contaminants that have time-varying concentrations. Here we present a probabilistic model for the timing of ingestion of tap water that we developed for use in the U.S. Environmental Protection Agencyβ€™s Threat Ensemble Vulnerability Assessment and Sensor Placement Tool, which is designed to perform consequence assessments for contamination events in water distribution systems. We also present a statistical analysis of the timing of ingestion activity using data collected by the American Time Use Survey. The results of the analysis provide the basis for our model, which accounts for individual variability in ingestion timing and provides a series of potential ingestion times for tap water. It can be combined with a model for ingestion volume to per...
publications-4228	article	2019	Tao, Fei and Tao, Fei and Zhang, He and Zhang, He and Zhang, He and Liu, Ang and Liu, Ang and Nee, A. Y. C. and Nee, Andrew Y. C. and Nee, A. Y. C.	Digital Twin in Industry: State-of-the-Art	IEEE Transactions on Industrial Informatics	10.1109/tii.2018.2873186	Digital twin (DT) is one of the most promising enabling technologies for realizing smart manufacturing and Industry 4.0. DTs are characterized by the seamless integration between the cyber and physical spaces. The importance of DTs is increasingly recognized by both academia and industry. It has been almost 15 years since the concept of the DT was initially proposed. To date, many DT applications have been successfully implemented in different industries, including product design, production, prognostics and health management, and some other fields. However, at present, no paper has focused on the review of DT applications in industry. In an effort to understand the development and application of DTs in industry, this paper thoroughly reviews the state-of-the-art of the DT research concerning the key components of DTs, the current development of DTs, and the major DT applications in industry. This paper also outlines the current challenges and some possible directions for future work.
publications-4229	article	1993	Clark, Robert M. and Grayman, Walter M. and Males, Richard M. and Hess, Alan F.	Modeling contaminant propagation in drinking-water distribution systems	Journal of Environmental Engineering	10.1061/(asce)0733-9372(1993)119:2(349)	The Safe Drinking Water Act and its Amendments (SDWAA) will pose a massive challenge for the drinking-water industry in the United States. As the SDWAA regulations reach implementation, increasing effort will be devoted to understanding the factors causing deterioration of water quality between treatment and consumption. A cooperative study involving the U.S. EPA, the University of Michigan, and the South Central Connecticut Regional Water Authority (RWA) demonstrated and validated the use of modeling techniques in the RWA distribution system. Models are used to predict the propagation of chlorine residual in one portion of the RWA system. It is found that residuals varied widely both spatially and temporally. Long residence times in storage tanks caused residual disinfection concentrations to be low or nonexistent during discharge cycles. It was found that system operation has a significant effect on the distribution and concentration of chlorine residuals in the system.
publications-4230	article	1996	Buchberger, Steven G. and Buchberger, Steven G. and Wells, Greg D. and Wells, Greg J. and Wells, Greg J.	Intensity, Duration, and Frequency of Residential Water Demands	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(1996)122:1(11)	Water demands at four single-family residences were monitored for a 1-yr period. About 8,000 demands per capita were recorded and converted to single equivalent rectangular pulses. Each pulse was classified by type (deterministic or random), location (indoor or outdoor) and day (weekday or weekend). Basic exploratory data analyses were performed to estimate sample statistics, cumulative distributions, and hourly occurrences of the intensity, duration, and volumes of the rectangular pulses according to type, location, and day. In addition, the hypothesis that residential water demands occur as a nonhomogeneous Poisson rectangular pulse process was examined. Results show that the simple rectangular pulse provided a very reasonable approximation of indoor water demands. However, the variance of the daily pulse count appears to be too high for Poisson process. Potential causes of the high variance in the daily pulse count are discussed. Findings and data from this study can be used to develop and verify fine-resolution network models designed to predict the fate and travel time distribution of substances moving to remote points of consumption in the water distribution system.