Abstract

The condition of the water distribution networks in Canada has been deteriorating over the past few decades due to the lack of preventive maintenance and asset management programs. It was reported that 60 percent of the water mains in Canada became unacceptable and inefficient for use. A study conducted by the Canadian Water and Wastewater Association (CWWA) estimates an outlay of $34 billion is needed to replace the existing 112,000 Km of water mains in Canada. Trenchless technology is one of the rapidly developing areas in rehabilitation and replacement of water mains. Selection of the most suitable trenchless method(s) is currently performed manually by a decision-maker, thus other more efficient and new methods may be overlooked. This thesis studies the methods used and the decision-making process involved in the rehabilitation of water mains with a focus on trenchless technology. A decision-support methodology has been developed using information gathered from the literature, a survey questionnaire form, and from a field investigation carried out by the author. The methodology incorporates Multi-Attribute Utility Theory and Analytical Hierarchy Process in its decision support system. The methodology has been implemented in an automated system composed of three modules: interactive flowcharts, Data Files and Query System, and a Decision Support System. The developed system automates the selection of the most suitable trenchless method for the rehabilitation of a specified water main project taking into consideration the project's characteristics and the decision-maker's preference. The system was tested using a case study of a water main rehabilitation project.