Grantee Research Project Results
2015 Progress Report: Taking it to the Streets: Green Infrastructure for Sustainable Philadelphia Communities
EPA Grant Number: R835558Title: Taking it to the Streets: Green Infrastructure for Sustainable Philadelphia Communities
Investigators: Ballestero, Thomas P
Institution: University of New Hampshire
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 2013 through September 30, 2017 (Extended to September 30, 2020)
Project Period Covered by this Report: October 1, 2014 through September 30,2015
Project Amount: $992,759
RFA: Performance and Effectiveness of Green Infrastructure Stormwater Management Approaches in the Urban Context: A Philadelphia Case Study (2012) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
This project proposes to build municipal capacity in the greater Philadelphia urban watersheds for green infrastructure (GI) by engaging local and regional stakeholders in a planning and implementation process that is supported by science-based resources and up-to-date relevant technical information. This will be accomplished by: 1) forming and working with multi-sector project advisors who will help guide the implementation of the project goals with the project partners; 2) increasing municipal familiarity with the design, construction, and maintenance of green infrastructure practices through the installation of high impact, high-visibility demonstration projects; 3) increasing municipal capacity to implement GI by identifying existing social/economic/knowledge/technical barriers and prioritization of strategies; 4) developing partnerships within and between government and other stakeholders in the City; 5) clear tracking of green jobs and job opportunities associated with GI implementation; and 6) targeting outreach and dissemination of technical and informational resources through identified and prioritized approaches.
Progress Summary:
During this period UNHSC personnel attended various meetings coordinated by EPA project officers. UNHSC personnel also met in Philadelphia with local project collaborators and PWD personnel. Green infrastructure projects with six Philadelphia elementary schools are in various stages of planning and design.
An EPA certified QAPP was completed and submitted to the EPA in August 2014. In accordance with the tasks listed in the QAPP, the following parts tasks been completed or are underway.
Task 1: Develop QAPP—task is complete.
Task 2: Collaborative Planning Demonstration Project Implementation—task is underway through efforts to develop stormwater management designs for several Philadelphia elementary schools.
Task 3: Land Use, Impervious Cover, and Pollutant Loading Analysis—task is underway.
Task 4: Performance Monitoring—task has begun at the UNH Tree Trench site in Durham, NH, as detailed in this progress report.
Task 5: Resource Framework Development.
Task 6: Green Infrastructure Training and Design and Implementation Capacity Building.
Task 7: K-12 Education.
In the summer of 2014, UNHSC installed a tree trench on the UNH campus. Below is a summary of the design elements followed by corresponding specifications required by PWD.
Watershed Area (ft2) | 25,265 |
Watershed Area (acres) | 0.58 |
Imperviousness (%) | 0.92 |
Rv | 0.878 |
Tc (min) | 6.9 |
System Perimeter (ft) | 334.0 |
Lengh (ft) | 150.0 |
Width (ft) | 17.0 |
Depth between overflow elevtion and outlet | 2.66 |
System area (ft2) | 2,250 |
Hydrologic loading ration | 10:1 |
Total storange volume stone (ft3)* | 2713.2 |
Total storage volume PUD (ft3)** | 13.4 |
Total storage vlume inlet pipe (ft3)** | 13.4 |
Total system storage (ft3) | 2,740 |
* straight vollume calculation in stone ** total storage space using PWD criteria for pipe storange |
Greened Acres | Rainfall (in) | Wd (in) | IC (acres) | Volume runoff treated by PWD II.4 (ft3) |
---|---|---|---|---|
0.79 | 1.49 | 1.49 | 0.53 | 2,740 |
For the UNH A Lot site using the equation above, the water quality volume for this system is WQv = 2,740 ft 3.
Design of a second system currently is being organized and planned (B lot, system 2). UNH researchers will work closely with PWD staff to ensure the design is consistent with PWD standards and research interests.
Over the past year since installation, UNHSC personnel have been investigating system performance using a variety of instruments and methods. To date no orifice control has yet to be installed due to the low measured infiltration rate of the soil at the bottom of the system. At this writing, the primary outlet for the system is through infiltration (horizontal and vertical) into the surrounding native soils. Monitoring wells were installed in and around the system to record changes in water level in relation to rainfall events and to determine the movement of water through the groundwater system. Soil moisture sensors also have been placed in vertical profiles around the tree pits to determine water movement through the engineered soils due to draining and/or evaporation. Water quality samples of direct runoff into the system and within the perforated underdrain at the bottom of the system have been collected and analyzed for total suspended sediments, heavy metals (copper, zinc), nitrogen species (ammonia, nitrate, nitrite, total Kjeldahl nitrogen), and total phosphorus. Rainfall also is being measured on site.
Although designed for 1.5 inch precipitation, more than 2 inches needs to fall in order for the system to fill—demonstrating the conservativeness of static designs. Over the 1-year monitoring period, the system demonstrates 80% volume reduction.
Figure 1. Continuous wter level history for the Philadelphia Tree Trench (precipitation amount in inches for certain
events are idebtified)
An additional effort being performed addresses computer modeling of green infrastructure systems. UNH is employing the Storm Water Management Model (SWMM) model at the site and watershed scale. The SWMM model, which is very commonly used to calculate stormwater runoff in urban areas, has been updated over the past several years to include low impact development capabilities. This allows planners and regulators to estimate the impact of varying levels of LID implementation, and to model optimal location and type of LID systems. SWMM input assumes certain basic construction (number of layers, flow routing) characterizes for each type of system. The user usually inputs values for hydrodynamic properties (such as soil/media suction head, permeability, drainage coefficient) based on literature values. In most cases, LID systems are not monitored after installation, and the accuracy of individual LID SWMM models may not be known. The UNHSC has over a decade of detailed inflow, outflow, and pollutant removal data on more than two dozen LID systems, including recent data on the Philadelphia Tree Trench installed under this project. UNH is using this extensive database to estimate the potential error propagated by using literature values to develop LID SWMM models, then populating a regional watershed model with these values. Our initial analysis of a porous pavement installation and a gravel wetland, indicate errors on the order of 10-30% in peak flow and total flow volume, respectively (Figure 2).
Figure 2. Flow from a porous pavement installation at UNHSC as modeled (red), and measured
(blue). The model was developed using values that a design engineer would reasonably assume,
and generally underestimates storage in the system, and total outflow.
UNH modified the SWMM model of the Wingohocking watershed to include existing LID installations. Once error estimates are developed for a range of LID installations, we will populate the model with possible LID build out to 40% disconnection, and calculate the potential error across the region (Figure 3).
Figure 3. Tree trench installations near MOrris Leeds Middle School.
Future Activities:
For the period 11/18/2015 through 11/18/2016, monitoring of the A lot Philadelphia tree trench will continue and be augmented with flow and water quality monitoring. In addition, we will design an experiment to study microbiological characteristics and performance. This effort will include water sampling, analysis by plate techniques as well as analysis by Amplicon sequencing to identify and understand which organisms are present at each synoptic event and location.
Water level data from the Philadelphia tree trench will be studied to test the hypothesis of infiltration out the sides of the system.
Hydrograph data from the Philadelphia tree trench will be used to calibrate a SWMM model to represent the actual performance of these systems, and then this method will be used to explore via the SWMM model the Wingohocking watershed, especially how static sizing implications address Combined Sewer Overflows (CSOs) and how much green acreage is necessary to meet CSO reduction targets.
UNH will continue to work with six Philadelphia elementary school GI projects and offer to assist with more potential GI efforts as opportunities arise. UNH also will design and construct another Philadelphia design at a parking lot on the UNH campus.
Villanova University and UNH are planning webinars and focused workshops for professionals and PWD staff.
Journal Articles:
No journal articles submitted with this report: View all 44 publications for this projectProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- Final Report
- 2019 Progress Report
- 2018 Progress Report
- 2017 Progress Report
- 2016 Progress Report
- 2014 Progress Report
- Original Abstract
1 journal articles for this project