Includes bibliographical references.

Missouri River Governance: Collective Action and Basin-Wide Problems -- Decision Trees for Incorporating Hypothesis Tests of Hydrologic Alteration into Hydropower–Ecosystem Tradeoffs -- Modeling Shasta Reservoir Water-Temperature Response to the 2015 Drought and Response under Future Climate Change -- Linking Nelder–Mead Simplex Direct Search Method into Two-Stage Progressive Optimality Algorithm for Optimal Operation of Cascade Hydropower Reservoirs -- Multiobjective Optimization for Water Resource Management in Low-Flow Areas Based on a Coupled Surface Water–Groundwater Model -- Paired-IRF Method for Detecting Leaks in Pipe Networks -- Evaluation of Implementation Strategies of Onsite Water-Conserving Technologies in Three Urban Neighborhoods -- Boosting Genetic Algorithm Performance in Pump Scheduling Problems with a Novel Decision-Variable Representation -- Algorithm Design Based on Derived Operation Rules for a System of Reservoirs in Parallel -- Resolving Emerging Issues with Aging Dams under Climate Change Projections -- Energy Recovery and Leakage-Reduction Optimization of Water Distribution Systems Using Hydro Turbines -- Probability of Water Fixture Use during Peak Hour in Residential Buildings -- Linear Model and Regularization for Transient Wave–Based Pipeline-Condition Assessment -- Assessing the Impacts of Urban Water-Use Restrictions at the District Level: Case Study of California’s Drought Mandate -- Mass, Energy, and Cost Balances in Water Distribution Systems with PATs: The Trondheim Network Case Study -- New Considerations for a Reservoir Capacity Optimizer That Accounts for Failure Risks -- Effects of Demand, Mixing Fraction, and Rate Coefficient Uncertainty on Water Quality Models.

[Article Title: Missouri River Governance: Collective Action and Basin-Wide Problems / Neil S. Grigg, p. 1-6]

Abstract: Forum papers are thought-provoking opinion pieces or essays founded in fact, sometimes containing speculation, on a civil engineering topic of general interest and relevance to the readership of the journal. The views expressed in this Forum article do not necessarily reflect the views of ASCE or the Editorial Board of the journal.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001196

[Article Title: Decision Trees for Incorporating Hypothesis Tests of Hydrologic Alteration into Hydropower–Ecosystem Tradeoffs / Jory S. Hecht, Richard M. Vogel, Ryan A. McManamay, Charles N. Kroll, and J. Michael Reed, p. 1-12]

Abstract: Short streamflow records make it difficult to determine the extent to which discharge changes in excess of ecological thresholds are due to dam operations or natural variability. Unnecessary changes to reservoir operating rules can reduce off-stream benefits, whereas no changes to rules when thresholds are exceeded can degrade downstream riverine ecosystems. We introduce a Bayesian decision tree approach to a hypothetical hydropower–ecosystem decision problem that compares expected in-stream and off-stream losses resulting from incorrect decisions.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001184

[Article Title: Modeling Shasta Reservoir Water-Temperature Response to the 2015 Drought and Response under Future Climate Change / Rachel Hallnan, Laurel Saito, David Busby, and Scott Tyler, p. 1-10]

Abstract: Stress on California’s salmon fisheries drives a need for effective temperature management in California’s Sacramento River. Shasta Dam has a temperature control device that enables managers to provide cold discharge temperatures to the river that are required for downstream Chinook salmon spawning and rearing. An added stress to water temperature management is prolonged drought and associated high air temperatures. California experienced its worst drought in a century from 2012 to 2015, and these conditions may provide insight into future reservoir conditions, as climate change predictions suggest that droughts will be more frequent and intense.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001186

[Article Title: Linking Nelder–Mead Simplex Direct Search Method into Two-Stage Progressive Optimality Algorithm for Optimal Operation of Cascade Hydropower Reservoirs / Zhong-kai Feng, Wen-jing Niu, Jian-zhong Zhou, and Chun-tian Cheng, p. 1-11]

Abstract: To satisfy growing energy demand, the hydropower industry of China is experiencing unprecedented development, and the total power generation and installed capacity of hydropower in China rank first in the world. The system scale and rate of development have posed computational modeling challenges, because the computational burden in hydropower optimization modeling using classical dynamic programming methods grows exponentially as the number of reservoirs increases.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001194

[Article Title: Multiobjective Optimization for Water Resource Management in Low-Flow Areas Based on a Coupled Surface Water–Groundwater Model / Masoomeh Zeinali, Arash Azari, and Mohammad Mehdi Heidari, p. 1-15]

Abstract: Optimal operation of water resource systems requires understanding the interaction between the surface water and groundwater in the region of interest. Furthermore, model parameters as well as effective surface and underground factors should be estimated and calculated. This research focuses on linking the nondominated sorting genetic algorithm II with a coupled surface water–groundwater model in an area of southwestern Iran.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001189

[Article Title: Paired-IRF Method for Detecting Leaks in Pipe Networks / Wei Zeng, Jinzhe Gong, Angus R. Simpson, Benjamin S. Cazzolato, Aaron C. Zecchin, and Martin F. Lambert, p. 1-11]

Abstract: Pipeline leak detection is critical for targeted maintenance and water loss reduction within water distribution systems. This paper proposes a hydraulic transient, impulse response function (IRF)–based, signal analysis approach for leak detection in water pipelines and networks. In the proposed approach, continuous pressure signals are sent into the pipeline, where pressure responses are measured by two transducers (separated by a distance) located close to the generator. Given this setup, a signal analysis methodology was theoretically derived to extract the major components of the deconvolution between these two measured pressure traces. The result shows that the deconvolution consists of a pair of IRFs of the pipeline with opposite signs and a time shift associated with the distance between the transducers. Hereon, they are referred to as a paired IRF.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001193

[Article Title: Evaluation of Implementation Strategies of Onsite Water-Conserving Technologies in Three Urban Neighborhoods / Nancey Green Leigh and Heonyeong Lee, p. 1-12]

Abstract: This paper addresses a knowledge gap that exists for citywide or neighborhood-wide applications of onsite water-conserving technologies, such as rainwater and graywater systems. A framework is developed for evaluating policies requiring onsite rainwater and graywater systems in residential units. This framework incorporates housing stock dynamics, fixture retrofitting, and water demand models. It assesses costs and benefits of policy implementation strategies for three urban neighborhoods selected according to their built environment and socioeconomic characteristics.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001185

[Article Title: Boosting Genetic Algorithm Performance in Pump Scheduling Problems with a Novel Decision-Variable Representation / Luigi Cimorelli, Andrea D’Aniello, and Luca Cozzolino, p. 1-11]

Abstract: Pumping stations used in water distribution networks (WDNs) consume a significant portion of the energy required to deliver municipal drinking water. Smart management strategies such as optimal pump scheduling (OPS) have gained the attention of water companies and managing authorities because they help reduce both energy costs and detrimental consequences for the environment. Genetic algorithms (GAs) are frequently used to approximate the solution of OPS problems, although many researchers have resorted to hybrid models to improve computational performance.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001198

[Article Title: Algorithm Design Based on Derived Operation Rules for a System of Reservoirs in Parallel / Qiankun Zhao, Ximing Cai, and Yu Li, p. 1-12]

Abstract: It is challenging to obtain optimal operation rules for a system of reservoirs in parallel. This study derives generic optimal operation rules from a multistage nonlinear programming (NLP) model established for a system of reservoirs in parallel with a single demand. The optimal operation depends on the system’s capability in coordinating individual reservoir storages to regulate inflows to those reservoirs and it is interfered by the full-empty cycles of reservoirs due to the variability of the inflows and/or the limitation of storage capacities. In general, small reservoirs are often made empty to leave space for future inflow or full to reserve water for the future, while large reservoirs are operated within their capacities.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001197

[Article Title: Resolving Emerging Issues with Aging Dams under Climate Change Projections / Ji-Hyeok Choi, Changhyun Jun, Pan Liu, Jong-Suk Kim, and Young-Il Moon, p. 1-11]

Abstract: Concerns about the collapse of dams due to overtopping are increasing owing to heavy rainfall and frequent typhoons associated with climate change. As a result, there has been a spike in anxiety among residents living near the downstream areas of dams. Although the dangers associated with dam safety are increasing, there is still a lack of comprehensive dam rehabilitation and implementation frameworks that consider climate change. A thorough review of existing dam facilities is needed in light of climate change and the deteriorating conditions of aging dams.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001204

[Article Title: Energy Recovery and Leakage-Reduction Optimization of Water Distribution Systems Using Hydro Turbines / Gideon Johannes Bonthuys, Marco van Dijk, and Giovanna Cavazzin, p. 1-12]

Abstract: Potential for energy recovery exists at any point within a water distribution system where the mechanical energy of excess water pressure can be converted into electrical energy. Energy conversion decreases the average operating pressure within a system, which in turn reduces water losses from leakages in the system due to the proportionality of leakage and pressure. This paper explores the incorporation of a genetic algorithm (GA) in a procedure to optimize the location and size of energy-recovery turbines (ERT) within a water distribution system based on maximizing recovered energy and reduced water losses evaluated on an economic basis and assigned a differentiated weighted importance.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001203

[Article Title: Probability of Water Fixture Use during Peak Hour in Residential Buildings / Toritseju Omaghomi, Steven Buchberger, Daniel Cole, Jason Hewitt, and Timothy Wolfe, p. 1-10]

Abstract: The standard method for estimating instantaneous peak water use in premise plumbing systems (PPSs) is Hunter’s (1940) design curve, showing water demand versus fixture units. In recent years, federal regulations have mandated efficient water fixtures and, coincidentally, per capita water use has declined dramatically. As a consequence, Hunter’s iconic design curve no longer applies to many contemporary PPSs. In this study, high-resolution indoor water-use data from more than 1,000 single-family homes across the United States were analyzed to estimate the peak hour probability of use (p-values) for efficient water fixtures.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001207

[Article Title: Linear Model and Regularization for Transient Wave–Based Pipeline-Condition Assessment / Xun Wang, Mohamed S. Ghidaoui, and Pedro J. Lee, p. 1-15]

Abstract: Condition assessment or defect detection of a pipeline is a difficult inverse problem. This paper proposes a general linear model framework that can approximately describe a wide range of pipeline condition assessment and defect detection problems. More specifically, the system response is governed by a linear function of a pipe property at discrete locations along a pipe, such that the pipe property can be reconstructed via a least-squares fit to the measured response.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001205

[Article Title: Assessing the Impacts of Urban Water-Use Restrictions at the District Level: Case Study of California’s Drought Mandate / María Pérez-Urdiales and Kenneth A. Baerenklau, p.1-10]

Abstract: This paper estimates feasible water savings for a sample of nine urban water districts in California during the height of the 2012–2016 drought, just prior to the implementation of mandatory water-use reductions, using household production theory and stochastic frontier analysis. Estimates of feasible savings are compared to mandated reductions and actual reductions in each district. Although the mandated reductions were generally feasible, the results reported here show that they had asymmetric impacts across districts and tended to impose larger burdens on some disadvantaged groups.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001169

[Article Title: Mass, Energy, and Cost Balances in Water Distribution Systems with PATs: The Trondheim Network Case Study / Marco Ferrante, Camillo Bosco, Rita Ugarelli, Lorenzo Magenta, and Tomas Eidsmo, p. 1-8]

Abstract: In water distribution systems, the substitution of regulating valves by pumps as turbines (PATs) is sustainable if the energy recovery balances the installation and maintenance costs, with a comparable and efficient reduction of the volume lost by leakage. Hence, the installation feasibility and regulation of a PAT require analysis of the introduced effects on the components of the energy, mass, and cost balances. In this paper these effects are explored by means of a case study, i.e., the water distribution system of Trondheim, Norway.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001201

[Article Title: New Considerations for a Reservoir Capacity Optimizer That Accounts for Failure Risks / Alcigeimes B. Celeste, Ximing Cai, Kumaraswamy Ponnambalam, and Qiankun Zhao, p. 1-5]

Abstract: In this technical note, new considerations and modifications are introduced to a recent design optimization model, developed by the first author, that is able to find the optimal active capacity for a water supply reservoir admitting a predefined minimum number of failure periods, a maximum failure magnitude, or both. It is shown that this model actually finds the best capacity to implement; however, to keep failure indexes within accept limits, the reservoir should also be operated optimally. A simulation-optimization approach is then formulated to find the best capacity even if the reservoir is to be operated by the standard operation policy (SOP), as in typical design procedures that take failure probabilities into account. Applications of both current and modified strategies are carried out and their results compared and commented on.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001199

[Article Title: Effects of Demand, Mixing Fraction, and Rate Coefficient Uncertainty on Water Quality Models / John Gibson, Bryan Karney, and Yiping Guo, p. 1-6]

Abstract: The effects uncertainty on water quality predictions by the free water distribution modeling software created by the US Environment Protection Agency (EPANET2) are assessed using both design of experiments (DOE) and Monte Carlo simulation (MCS). For the test system evaluated, the DOE approach describes the effects of uncertainty with as few as eight model executions and yet shows good agreement with the more computationally demanding MCS approach. Surprisingly, first order disinfectant decay models are less sensitive to uncertainty than water age, even though an additional rate coefficient is required.

https://doi.org/10.1061/(ASCE)WR.1943-5452.0001206