Defining Likelihood and Consequence of Failure Parameters Specific to Storm Drainage Systems

As part of the Fairfax County, Virginia Department of Public Works and Environmental Services, Maintenance and Stormwater Management Division’s (MSMD) infrastructure reinvestment efforts for the storm drainage system, projects are prioritized based on citizen service requests and physical condition assessments, primarily using the National Association of Sewer Service Companies (NASSCO) Pipeline Assessment Certification Program (PACP) Quick Ratings. As the storm pipe service life renewal program matures, MSMD desires to employ a financially sustainable, asset management approach to maintenance and reinvestment planning. The risk-based prioritization of infrastructure reinvestment projects will consider both Likelihood of Failure (LoF) and Consequence of Failure (CoF). MSMD initiated a project to identify and define the LoF and CoF parameters unique to storm drainage infrastructure that will be used to support risk-based reinvestment planning and prioritization. This manuscript describes the methodology and results associated with the development of Fairfax County’s stormwater specific risk-based parameters.