Quality Control and Assessment of the Calibration of a Model of the City of Pittsburgh Sewer System

The Pittsburgh Water and Sewer Authority (PWSA) has completed the development of a hydrologic/hydraulic model of the City of Pittsburgh's sewer system. This H&H model will be an important tool that will be used by PWSA to comply with the requirements of its National Pollutant Discharge Elimination System (NPDES) permit and implement the requirements of its consent order and agreement (COA) with the Pennsylvania Department of Environmental Protection and the Allegheny County Health Department. Because of the significance of the H&H model, PWSA emphasized the importance of defining, achieving, and demonstrating acceptable model calibration, PWSA required the application of a multi-tiered approach for evaluating the calibration of the computer model.This paper describes a process employed by the Pittsburgh Water and Sewer Authority to imbed model calibration assessment and quality control elements within the model calibration activities. The process facilitated a smooth progression of calibration, established a basis for confidence in the calibration results, and facilitated final acceptance of the model by PWSA.