Assessing Performance through the Widespread Monitoring of Philadelphia's GSI

摘要

Philadelphia Water (PWD) has entered its fifth year of the Green City, Clean Waters program, which focuses on implementing green stormwater infrastructure (GSI) to manage runoff. PWD is developing an evaluation and adaptation plan (EAP) to document implementation progress to date. PWD is monitoring constructed GSI systems to assess observed performance compared to design assumptions and expected performance. Due to the large scale of Green City, Clean Waters, the monitoring plan focuses on gathering long term data from many systems, rather than intensive monitoring at a few sites. Each system has two data inputs: a continuous water level logger within the system and gauge-adjusted radar rainfall data. These data are processed with PilotDB, a cloud-hosted data analysis tool developed with the Shiny web application for R. Data are run through a time step-based, mass balance algorithm to develop an estimated water budget for each event at each site. An expected water level time series is developed using knowledge of the design configuration, material properties, and pre-construction geotechnical investigation data. Time series plots for observed and expected water levels are compared in PilotDB, and the interface allows the user to categorize events based on system response. Performance metrics are established for each system, and used to analyze the effect of design parameters on the functionality of each system. Analysis protocols executed in PilotDB and by PWD staff are demonstrated through case studies and summary statistics. Integration of design parameters, as-built conditions, monitoring, and maintenance information into PilotDB analyses is described.