55. Information Use in Dutch Sewer Asset Management

Sewer systems are capital-intensive infrastructures, requiring appropriate asset management to safeguard serviceability. In the Netherlands, effective sewer asset management is described by De Leeuw’s control paradigm. Reliable data and information are key elements in decision making for rehabilitation and renewal of the assets. Rehabilitation is often based on limited asset condition information. Although various sources described procedures for guiding decision making for rehabilitation, it remains unclear which and how information sources are used in this process, and to what extent value trade-offs influence decisions. In order to improve current sewer asset management, this study assesses the availability and use of information in decision making for sewer system renewal in the Netherlands. Eighteen interviews were conducted at seven municipalities, combined with an analysis of their municipal sewerage plans. The interviewees described the decision making process and the information sources they use in this process. Decisions for sewer system renewal are often based on intuition in implicit risk analyses, where risk is defined as ‘feeling times consequence’. Sewer asset management is ineffective, because it relies mostly on intuition, hampering justification, accountability, and repetition of decisions and preventing evaluation. Evaluation procedures and a critical attitude toward relevancy and quality of information are recommended.