Baltimore Ecosystem Study Institute of Ecosystem Studies

2014 BES Annual Meeting Presentation and Poster Abstracts

Development of a framework for assessing the impacts of green infrastructure on groundwater resources in Philadelphia using ParFlow-CLM
Andino-Nolasco, Elvis
Co-Authors: Elvis Andino-Nolasco and Claire Welty

Abstract: In 2012, the City of Philadelphia entered into an agreement with US EPA to reduce the city’s combined sewer overflows by investing $2 billion in stormwater infiltration facilities. The Philadelphia Water Department (PWD) aims to replace up to 40% of the City’s impervious surface area with green infrastructure (GI) to promote stormwater infiltration. As part of an EPA Star grant to analyze the performance of GIs, we are developing ParFlow-CLM model of a 32-sq-km sewershed located within the Wingohocking Creek watershed in northwestern Philadelphia. This area contains 43 planned and implemented GI facilities as of 2014. We are applying our modeling methodology previously developed for the Baltimore metropolitan region to a similar urban hydrogeologic setting, with the important exception that there is no surface expression of streams, and sewage is combined with piped streamflow. The model is gridded at a resolution of 20 m x 20 m x 1 m with ~16.1 M cells comprising the model domain. A GIS layer of sewer pipes provided by PWD is burned into the digital elevation model to represent the stream network draining the domain. Piedmont hydrogeology is represented by a soil-saprolite-fractured bedrock system with literature values of hydraulic conductivity assigned to model layers. Setup of the model framework and details of data assimilation will be presented along with preliminary results. The ultimate goal is to compare subsurface flow regimes with and without implementation of GI, including an analysis of alteration of subsurface flow paths and travel times.