GIS Based Applications of Sensitivity Analysis for Water Distribution Models

Möderl, M.; Hellbach, C.; Sitzenfrei, Robert; Mair, Michael; Lukas, Alfred Fredrich; Mayr, Ernest; Perfler, Reinhard; Rauch, Wolfgang

doi:10.1061/41173(414)14

Cited by 17 publications

(7 citation statements)

References 7 publications

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“…For example, pipe burst consequences analyses can be supported by systematic failure mode specific discharge rate calculations by the means of an EPANET2 based vulnerability analyses (Möderl et al 2011, Friedl et al 2012. EPANET2 allows to model pressure dependent water "demands" like leakage outflow or irrigation with an emitter equation.…”

Section: Introductionmentioning

confidence: 99%

Impact of Failure Mode, Crack Area, and Pressure on Leakage Outflow

Fuchs-Hanusch¹,

Günther²,

Steffelbauer³

et al. 2014

World Environmental and Water Resources Congress 2014

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The calculation of leakage outflow is of interest for several tasks in water distribution system analysis, e.g. investigation of pipe burst consequences, efficiency estimations of pressure management or model based leakage localisation. Several studies on pressure -leakage dependencies have shown that this dependency can be much higher than defined with the orifice equation of Torricelli. The findings of these studies differ significantly, even for the same pipe material, failure modes and sizes. In this paper, we describe the influence of uncertainties in assumptions of emitter exponents and crack areas on discharge rates for different failure modes. An approach for modelling elastically deforming leaks in water distribution pipes (Cassa et al. 2013, van Zyl et al. 2014) was implemented into systematic discharge rate calculations with EPANET2 by the means of an iterative estimation of the emitter exponent. For a partial pipe network of the city of Vienna, the results of the original EPANET2 and the extended emitter approach were compared. The largest differences in leakage outflow and hence in the amount of pipes with potential high failure consequences were found for longitudinal cracks. For this failure mode material, crack size and dimensions have a significant influence on the emitter exponent. Consequently, it is recommended for systematic discharge rate calculations to gather historic data about typical failure modes and failure dimensions of the investigated system. Further, if failure modes with a high sensitivity on the emitter exponent (like longitudinal crack or spiral crack) are relevant for the investigated system, a detailed calculation of the discharge rate is suggested.

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Section: Introductionmentioning

confidence: 99%

Impact of Failure Mode, Crack Area, and Pressure on Leakage Outflow

Fuchs-Hanusch¹,

Günther²,

Steffelbauer³

et al. 2014

World Environmental and Water Resources Congress 2014

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“…A change according to (10) means that all flow rates and state parameters remain unchanged, except the following:…”

Section: Mathematical Problems In Engineeringmentioning

confidence: 99%

“…There was a computer-based NRSA study of pipe length, diameter, and roughness variation for an Alpine WDS [10]. Specifically, uncertainly in roughness is especially frequently studied [8,15,16,18].…”

Section: Pipe Parameter Scaling Lawsmentioning

confidence: 99%

“…This equation gives the limits of the state parameters (elevations) according to (10). The procedure for a linear sensitivity study is as follows.…”

Section: Linearization: Additivementioning

confidence: 99%

“…For the effect of continuous change of parameters on hydraulic variables, of interest here, this method was applied to calibration, pipe diameter design, and input uncertainty assessment [10], and vulnerability identification [11]. Other recent applications include the sensitivitymatrix method for ranking the relative importance of pipes [9], leakage localisation [19], and studying demands [20].…”

Section: Introductionmentioning

confidence: 99%

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The Sensitivity of a Water Distribution System to Regional State Parameter Variations

Page

2018

Mathematical Problems in Engineering

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The sensitivity of a pressurised water distribution system (WDS) to state parameter variations is studied. A novel local regional sensitivity analysis (LRSA) approach is introduced which applies the same change to a collection of parameters, called a region. For example, sensitivity to suburbs can be studied. General analytical (using algebraic methods) results are derived. They show how sensible conclusions arise from LRSA and state this dependence of the WDS on regions for the first time. For most cases, the WDS is 1.852-2 times more sensitive to pipe roughness coefficients than to pipe lengths. In most cases, when certain pipes do not have minor losses, the WDS is 4.871-5.333 times more sensitive to pipe diameters than to pipe lengths. Hence, the WDS is the most sensitive to pipe diameters, medium sensitive to pipe roughness coefficients, and least sensitive to pipe lengths. For most cases, when all reservoir and tank elevations (and heads) remain the same, changes of other elevations do not change flow rates and change the pressures in a simple additive way. In most cases, when all the reservoir water surface elevations are changed together, the flow rates remain unchanged, and the pressures change in a simple additive way.

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