The 2005 ASCE Infrastructure Report Card recently graded the condition of sewer infrastructure in the United States as a D-. Eventually, many sewer utilities will need to thoroughly assess their infrastructure to meet regulatory requirements (draft EPA Sanitary Sewer Overflow Policy and Government Accounting Standards Board Statement 34). Traditionally approaches that use size, age, and material as the only factors in prioritizing inspections are insufficient, as they do not take into account a deeper understanding of the variables leading to structural or operational failure, or of the impact of failures on the community and the environment. All utilities face budget constraints that limit the ability to inspect and repair or replace sewer infrastructure. A method is needed to prioritize the acquisition of information with which the criticality of sewers can be assessed and appropriate rehabilitation budgets developed. The Water Environment Research Foundation (WERF) contracted with Brown and Caldwell to develop a tool to help utilities prioritize inspection of sewers to overcome these constraints. The Sewer Cataloguing Retrieval And Prioritization System (SCRAPS) tool is based on an expert system developed by the University of Washington authors. The SCRAPS tool’s knowledge base was assembled from a group of national experts. Input from these experts was used to develop the tools logic assessing the need to inspect specific lines based on available information. In validation exercises using case studies supplied by the experts, the tool was shown to outperform a group of experts in quantifying the need to inspect.
SCRAPS: AN EXPERT SYSTEM FOR PRIORITIZING SEWER INSPECTIONS
Authors: Andy Lukas, Steve Merrill
2006 No Dig Conference