This article presents a methodology that combines a process-based lifecycle assessment (LCA) with an economic input-output LCA (EIO-LCA) model to quantify the net present value (NPV) lifecycle costs (LCC), energy consumption, and greenhouse gas (GHG) emissions associated with a water distribution system (WDS) pump. The methodology considers the manufacturing, use, and end-of-life (EOL) disposal lifecycle stages, as well as processes that are not typically considered, including discharge valve throttling, pump testing, deterioration, refurbishment, and variable-speed pumping. A case study is used to demonstrate the methodology, assess the implications of different operating scenarios, and determine the relative importance of different processes. Results show that a combination of refurbishment and variable-speed pumping is the most effective means of improving sustainability for the case. Analysis of the results shows similar composition profiles for energy consumption and GHG emissions with pump operation representing over 80% of each, whereas manufacturing and pump operation together represent the majority of the NPV LCC. Sensitivity analyses indicate that the planning period, reference target volume, electricity cost, and discount rate are the most influential parameters.

A global energy-auditing approach is used to describe the complex transient flow associated with sudden pressurization of a confined pipe system containing entrapped air pockets. The key concept is that the greatest pressures following pressurization are directly related to the amount of energy absorbed by the air pockets. The energy approach leads to an insightful understanding of the transient pressurization event, one that clarifies the underlying physics and that better explains several previously published observations. Moreover, the energy formulation leads to analytical algebraic expressions that can be numerically confirmed. individual papers. This paper is part of the Journal of Hydraulic Engineering, © ASCE, ISSN 0733-9429/04015044 (11)/$25.00. © ASCE 04015044-1 J. Hydraul. Eng. J. Hydraul. Eng. Downloaded from ascelibrary.org by UNIVERSITY OF TORONTO on 08/14/15. Copyright ASCE. For personal use only; all rights reserved. © ASCE 04015044-4 J. Hydraul. Eng. J. Hydraul. Eng. Downloaded from ascelibrary.org by UNIVERSITY OF TORONTO on 08/14/15. Copyright ASCE. For personal use only; all rights reserved. © ASCE 04015044-8 J. Hydraul. Eng. J. Hydraul. Eng. Downloaded from ascelibrary.org by UNIVERSITY OF TORONTO on 08/14/15.

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Characteristic solution methods, namely the method of characteristics (MOC) and wave characteristics method (WCM), are widely used for simulating transient pipe network flows. Because the MOC computes solutions at interior nodes, it features higher spatial resolution, whereas the WCM makes simplifications that yield more efficient computations. Practical analyses require numerical methods that are both accurate and computationally efficient. To benefit from the advantages of the two approaches, a generalized characteristic method (GCM) is developed in this paper by combining a flexible friction approximation with a variable reach scheme. Significantly, computational savings are realized by selectively providing greater accuracy and higher resolution solutions only where needed via more interior reaches and higher order solutions; further, the new method reduces to either of the MOC and WCM, thereby showing their intrinsic similarities. Multiple examples compare and contrast the numerical methods. From these, unsteady friction effects and, more importantly, spatial resolution are shown to be directly affected by the interior reach treatment, thus exposing a limitation for solution methods with too few interior reaches. Overall, the key contribution of this work is a methodology featuring a similar degree of accuracy to the MOC, but with a computational cost better than that of the WCM.