Water distribution system model calibration under uncertainty environments

Abstract

The calibration process of water distribution system models allows for accurate and reliable hydraulic analysis results. Thus, calibration is of utmost importance if adequate operation and maintenance model-based procedures are sought. However, in emerging economies, there is a series of factors that make it more difficult to construct accurate models, including very poor information management, unusually high leakages and the presence of a large number of illegal connections. While some of the model variables are assumed to be known under normal circumstances, these factors make it necessary to consider them for calibration as well. This paper presents a calibration methodology flexible enough to address such problems allowing the calibration of pipe diameter, roughness and minor losses, and nodal demands and leakages. A genetic algorithm was implemented as well as a constraint programming algorithm that makes direct use of hydraulic criteria to advance in the solution space. The methodology was tested on a real system in Colombia with a satisfactory outcome. The use of these techniques results in major reduction of calculation time and similar or superior results in comparison to manual methods.

A Graph-Theoretic Framework for Assessing the Resilience of Sectorised Water Distribution Networks

“…Another inherent drawback is the dependence on well calibrated (accurate) hydraulic models for large networks. Beyond the implicit non-linearity, the number of parameters involved in the hydraulic equations and their large number of possible combinations introduce high complexity to the WDN calibration problem (an NP-Hard problem, which cannot be solved in polynomial time Takahashi et al (2010).) For large WDNs, these have an expensive computational cost since, even for moderate size networks, the number of possible failure scenarios grows exponentially and are approached using either some linearising assumptions or the use of heuristics for failure simulations (Berardi et al 2014).…”

Calibration of stormwater management model using flood extent data

“…Barco et al, 2008;Merz et al, 2010b;Takahashi et al, 2010). When a model proves capable of reproducing the response of a drainage system to a specific storm event (or several storm events), then modellers are in a good position to characterise the effects of proposed changes to infrastructure such as new sewer lines, detention basins and pump stations.…”

Model Performance Indicator of Aging Pipes in a Domestic Water Supply Distribution Network

“…In evaluating the performance of a calibrated water distribution network model, most researchers commonly used mean absolute error or relative error (e.g., refs. [16,17]) and correlation coefficient (e.g., ref. [18]) to compare the simulated results and observed data.…”