I-WARP: Individual Water mAin Renewal Planner

Abstract. I-WARP is based upon a nonhomogeneous Poisson approach to model breakage rates in individual water mains. The structural deterioration of water mains and their subsequent failure are affected by many factors, both static (e.g., pipe material, pipe size, age (vintage), soil type) and dynamic (e.g., climate, cathodic protection, pressure zone changes). I-WARP allows for the consideration of both static and dynamic factors in the statistical analysis of historical breakage patterns. This paper describes the mathematical approach and demonstrates its application with the help of a case study. The research project within which I-WARP was developed, was jointly funded by the National Research Council of Canada (NRC), and the Water Research foundation (formerly known as the American Water Works Association Research Foundation – AwwaRF) and supported by water utilities from USA and Canada.

Download Full-text

Planning renewal of water mains while considering deterioration, economies of scale and adjacent infrastructure

Water Science & Technology Water Supply ◽

10.2166/ws.2010.571 ◽

2010 ◽

Vol 10 (6) ◽

pp. 897-906 ◽

Cited By ~ 11

Author(s):

Yehuda Kleiner ◽

Amir Nafi ◽

Balvant Rajani

Keyword(s):

Cathodic Protection ◽

Economies Of Scale ◽

Poisson Model ◽

Pipe Material ◽

Efficient Manner ◽

Structural Deterioration ◽

Dynamic Factors ◽

Water Mains ◽

Subsequent Failure

The structural deterioration of water mains and their subsequent failure are affected by many factors, both static (e.g., pipe material, pipe size, age (vintage), soil type) and dynamic (e.g., climate, cathodic protection, pressure zone changes). This paper describes a non-homogeneous Poisson model developed for the analysis and forecast of breakage patterns in individual water mains, while considering both static and dynamic factors. Subsequently, these forecasted breakage patterns are used to schedule the renewal of water mains in an economically efficient manner, while considering the various associated costs, including economies of scale and scheduled works on adjacent infrastructure. In this paper, he principles of the approach are described briefly and its application is demonstrated with the help of a case study.

Download Full-text

Comparison of four models to rank failure likelihood of individual pipes

Journal of Hydroinformatics ◽

10.2166/hydro.2011.029 ◽

2011 ◽

Vol 14 (3) ◽

pp. 659-681 ◽

Cited By ~ 18

Author(s):

Yehuda Kleiner ◽

Balvant Rajani

Keyword(s):

Water Distribution ◽

Distribution Networks ◽

Classification Model ◽

Pipe Material ◽

Homogeneous Poisson Process ◽

Model Based ◽

Water Mains ◽

Natural Variations ◽

Non Homogeneous Poisson Process ◽

Subsequent Failure

The use of statistical methods to discern patterns of historical breakage rates and use them to predict water main breaks has been widely documented. Particularly challenging is the prediction of breaks in individual pipes, due to the natural variations that exist in all the factors that affect their deterioration and subsequent failure. This paper describes alternative models developed into operational tools that can assist network owners and planners to identify individual mains for renewal in their water distribution networks. Four models were developed and compared: a heuristic model, a naïve Bayesian classification model, a model based on logistic regression and finally a probabilistic model based on the non-homogeneous Poisson process (NHPP). These models rank individual water mains in terms of their anticipated breakage frequency, while considering both static (e.g. pipe material, diameter, vintage, surrounding soil, etc.) and dynamic (e.g. climate, operations, cathodic protection, etc.) effects influencing pipe deterioration rates.

Download Full-text

Copula parameter estimation using Bayesian inference for pipe data analysis

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2017-0084 ◽

2018 ◽

Vol 45 (1) ◽

pp. 61-70 ◽

Cited By ~ 1

Author(s):

Farzana Atique ◽

Nii Attoh-Okine

Keyword(s):

Data Analysis ◽

Soil Condition ◽

Condition Assessment ◽

Pipe Material ◽

Data Set ◽

Copula Modeling ◽

Structural Deterioration ◽

Copula Parameter ◽

Water Mains ◽

Non Gaussian

Water main systems are aging and becoming a growing concern for maintenance. The structural deterioration of water mains is affected by different factors, such as pipe age, pipe material, soil condition, and pipe size, among others. Various methods of modeling have been used to predict the failure of water mains. Since pipe networks are underground and obtaining data on pipe conditions is very costly, statistical modeling has been widely used for pipe condition assessment. An emerging statistical method known as copula modeling is used here for pipe data analysis. The copula method is very useful in cases where marginals belong to different families of distributions. It is also useful for generating a large number of data points when it is difficult to obtain a data set, as is the case for pipe condition assessment, and where data sets have random variables belonging to non-Gaussian family distributions. Different copula families are applied here to model the dependency between the pipe age and repair age of pipes. The paper uses a Bayesian framework to estimate the parameter values in the copula model. This approach offers an additional option for estimating copula parameters for pipe data.

Download Full-text

CT Scans of Asbestos Cement Pipes as a Reference for Condition Assessment of Water Mains

Water ◽

10.3390/w13172391 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2391

Author(s):

Karel van Laarhoven ◽

Jip van Steen ◽

Frank van der Hulst ◽

Hector Hernandez Delgadillo

Keyword(s):

Water Distribution ◽

Poor Performance ◽

Water Distribution Network ◽

Condition Assessment ◽

Water Utilities ◽

Detailed Knowledge ◽

Pipe Material ◽

Detailed Measurement ◽

Asbestos Cement ◽

Water Mains

The water distribution network of The Netherlands contains around 30,000 km of asbestos cement (AC) pipes, which constitutes around 25% of the total network. As a pipe material, AC has a relatively poor performance, and therefore is a high priority for renewal. To help decide an effective order of replacement, the water utilities need condition assessment techniques that help them determine which pipes have the highest risk of failure. In the presented work, X-ray computed tomography (CT) was used to measure the degradation of AC pipes taken out of the field. These scans provide a description of the pipe degradation with unmatched detail. The results are compared with strength tests performed on the same pipes, revealing that detailed knowledge of the complete pipe degradation is more important than previously assumed. Moreover, comparison of the CT results to those of a commercial, non-destructive inspection technique was used as a new avenue for validation of this technique, demonstrating its future usefulness for attaining the detailed measurement of pipe degradation required by water utilities.

Download Full-text