GIS-BASED DECISION SUPPORT SYSTEM FOR EVALUATING COSTS AND BENEFITS OF SEWER RENEWAL TECHNOLOGIES

摘要

Sewer renewal technologies are advancing rapidly, and becoming more efficient and cost-effective. Different technologies exhibit different capabilities, limitations, costs, and benefits, which collectively serve as the main criteria for evaluating alternative options. This paper describes the development of a prototype GIS-based decision support system (DSS) for evaluating alternative sewer renewal technologies, including open-cut/trenchless replacement and structural/semi-structuralon-structural lining. The software quantitatively evaluates the applicability, costs, and benefits of alternative renewal technologies. Applicability is evaluated based on a set of criteria that include sewer characteristics (e.g., existing defects, diameter, material, depth, age, etc.), site conditions (e.g., soil type, groundwater level, work area requirements, traffic volume, etc.), along with other social and environmental factors. The expected cost and benefit of each applicable renewal technology are then estimated, and used to optimize the selection of the technologies with the best cost/benefit ratio. Costs are calculated in terms of direct and indirect cost. Benefits are calculated in terms of sewer service life prolongation. The paper also presents an example application of the prototype DSS using data sets from the City of Regina.