Lessons Learned from Monitoring and Modeling of Philadelphia’s Urban Creeks

Abstract Submission: Philadelphia Water Department (PWD) developed hydrodynamic and water quality models for the non-tidal reaches of Cobbs and Tacony/Frankford creeks situated in highly urbanized areas of Philadelphia, Pennsylvania. These creeks experience issues characteristic of urban areas, such as wet-weather flashiness, and receive pollutant discharges from combined sewer overflows (CSO) and stormwater outfalls. Models were developed as a system integrating US EPA Storm Water Management Model (SWMM) models with US EPA Environmental Fluid Dynamics Code (EFDC) hydrodynamic and water quality models to simulate fecal coliform bacteria and dissolved oxygen. PWD uses these models to understand in-stream water quality dynamics and aid in addressing water quality concerns. Initially developed as requirements for PWD’s Green City, Clean Waters CSO long-term control plan, they are regularly updated based on data from ongoing monitoring programs and continue to be used for regulatory reporting. The models were recently used to simulate water quality conditions of the non-tidal creek CSO receiving waters and evaluate green stormwater infrastructure and CSO control implementation progress in the tenth year of the 25-year program.
The presentation will describe model development and lessons learned from monitoring and modeling urban creeks in CSO-impacted areas. It will highlight tools developed to compare model results against applicable water quality criteria. Monitoring data collected by PWD and other agencies, including bacteria, nutrients, dissolved oxygen, periphyton, and sediment oxygen demand, and how this data informs model development, will also be discussed.

Learning Objectives/Expected Outcome (Optional) : Understanding of the challenges to water quality modeling analyses of urban creeks