Project Title

Performance and Effectiveness of Urban Green Infrastructure: Maximizing Benefits at the Subwatershed Scale through Measurement, Modeling, and Community-Based Implementation

Project Overview

This project will monitor, model, and evaluate the performance of three Green Infrastructure (GI) sites to control stormwater runoff in Philadelphia, PA. This project will provide valuable results by demonstrating the performance of GI technologies in combined sewer overflow areas, while also taking into account costs and benefits. The research team will engage community partners at each step of the adoption and evaluation process. A couple specific activities include calibrating a subsurface flow model and evaluating landscapes on a subwatershed level, which will inform policy tools that can be used in Philadelphia and other urban areas. People will be able to better protect their local watersheds and ecosystems if they understand the costs, benefits, and performance of GI technology.

Objectives and Plans

Evaluate selected GI demonstration projects in the Philadelphia CSO area to measure and model technical performance. The methodology for developing benefit functions involving environmental benefits such as runoff reduction and water quality restoration requires accurate physical models of the performance of GI practices. Three GI demonstration sites in the Philadelphia CSO area will be used to calibrate and validate mathematical models for calculating benefits. A particularly challenging task will be modeling of subsurface flows in the vadose zone and lateral groundwater mounding in the saturated zone.

Develop methodology for creating zones of green infrastructure (ZGIs) that encompass different combinations of attributes having influence on the performance, benefits, and costs of GI practices, taking into account prospects for successful community-based implementation of appropriate GI practices in each zone in the near-term and successful adaptive management in the long-term.

Develop quantitative GI benefit-investment functions for each zone to enable maximization of benefits and minimization of costs through evaluation of the multiple benefits to neighborhoods resulting from investments in GI. The parameters of benefit functions are expected to demonstrate significant geographic variations within an urban area.

Incorporate benefit functions into tools for use by municipal officials and community stakeholders in evaluation, optimization, and adaptive implementation of GI practices to facilitate transfer of this project’s results to other urban centers. New methodologies will be developed for incorporating benefit function analyses at the ZGI level into evaluations of GI practices in achieving objectives at the subwatershed level and at the scale of the entire CSO area.

Incorporate STEM learning at multiple levels in all phases of the project. Substantial Science, Technology, Engineering, and Mathematics (STEM) education components are included at multiple levels including students at K-12, undergraduate, and graduate levels through the project teams’ academic institutions and project partners at local K-12 schools. Graduate students will be funded through the research team, and methods and results from the projects will be included in future curricula at the university level.

Expected Results


1. Refined methodologies for accurate lifecycle performance assessment of GI practices at the site level.

2. Refined methodologies for evaluation of cost effective, adaptive GI implementation strategies at the subwatershed scale employing multiple benefit metrics including runoff load reductions as well as ancillary benefits affecting community livability.

3. Reports, peer reviewed papers in journals, and transferrable tools. STEM education at the K-12, undergraduate, and graduate levels.


1. Increase national capabilities for assessing and implementing cost-effective and adaptive GI practices for urban stormwater management at the subwatershed level, especially in cities with combined sewers.

2. Community input at all stages will enhance prospects for widespread, successful implementation of green infrastructure.

3. Involvement with the nationally visible Philadelphia’s Green City, Clean Waters program will promote transferability of results, thereby improving the capabilities of other urban centers to evaluate and implement effective strategies for applying GI to the solution of national urban water quality problems.