Wastewater Pipe Condition Rating Model Using Multicriteria Decision Analysis

Abstract

This paper presents a novel wastewater pipe condition rating model that builds on published literature and expands on industry-accepted and used guidelines and practices that currently consider mostly structural and operational defects in estimating pipe condition. A series of pipe internal and external, as well as hydraulic factors and parameters are identified and included in the proposed methodology to obtain a comprehensive rating of the pipe’s current condition. By using the analytic hierarchy process (AHP) multicriteria decision analysis, subject matter expert knowledge and input is used to determine relative importance weights of carefully selected and defined criteria and factors that affect wastewater pipe condition. The level of agreement between subject matter expert opinions is tested by employing statistical analysis. An in-depth sensitivity analysis using clustering is presented to determine the main criteria’s sensitivity to changing relative importance weights. For validation purposes, the proposed model is applied to a small portion of a US wastewater collection system. The results show satisfactory average validity percentage.