Solving for Stormwater Issues in I-95 Project

Dr. Erica McKenzie and Temple Engineering team up with PennDot to address environmental concerns in the massive infrastructure project

You have probably noticed some construction on I-95 recently. It turns out that the project isn’t only about improving the road infrastructure. Environmental Engineering faculty are working with Pennsylvania’s Department of Transportation on a stormwater project as part of the I-95/Girard Avenue Interchange upgrades. PennDOT has partnered with Temple and Villanova Engineers to study the effects of highways on local water quality and to find better management of resources. The PennDOT project to widen I-95 in Northeast Philadelphia, starting around the 676 interchange and running past Cottman Avenue, started in 2009 and will go into next decade. It requires new stormwater management that didn’t exist when the highway was first built. Temple is researching water quality testing and determining what goes back into the environment. This level of involvement with universities is unique and not matched in any other major infrastructure project nationally.

Dr. Erica McKenzie, assistant professor in the Civil and Environmental Engineering Department since 2015, studies the effects of trace metals that exist in water. Some of these enter stormwater from road runoff, such as the copper from brakes and zinc from the tire composite. Anyone who has driven that stretch of 95 knows the amount of brake and tire wear that creates. Dr. McKenzie is working to create better environmental management for the area. “My job is to come along and understand how much (of these metals) is washing off. When we implement some kind of a stormwater management strategy, is that effective?”

i-95 project

Part of the challenge Temple looks to solve is how to treat this water in a dense urban setting over the three-plus miles of highway. "There's not a lot of space to properly treat stormwater runoff," said Mark Rhoads, project manager with AECOM, an engineering firm consulting on the project. "Regulations in place from the EPA, to through the DEP in state and down to the Water Department, we really had to look at the treating the stormwater management in a different way. This information being providing by the universities with their analysis of the maintenance work is really cutting-edge. We are looking at these creative ways to support the maintenance, to find new best practices and new ideas, and to engage new organizations in this area."

Philadelphia has a very old sewage system where residential sewage often combines with the runoff. Big storms can strain this capacity and lead to overflow that returns to local waterways. Philadelphia has attempted to solve these issues with multiple options, from green spaces to storing some of the smaller amounts over time.

A major concern stems from the usage of road salt which may mobilize various metals found on roadways. Dr. McKenzie and her students are trying to figure out how quickly the metals leave the soil and join water, and how the introduction of salt, like that used in deicing, affects that process and in how far the metals might travel. Dr. McKenzie believes these results might require PennDOT to do more regular maintenance, especially in sensitive watershed areas, where these metals may travel downstream.

Freshwater activity has always been a part of Dr. McKenzie's life. She grew up in Montana and spent most of her time outside, exploring nature. A family friend got her interested in environmental engineering. "That sounded like the best job ever," she said. "Combine science with really cool recreation." At Colorado State, she found interest in water quality through various research projects, which included a trip to Benin, in West Africa, to analyze polluted groundwater.

Dr. McKenzie earned her professional degrees at University of California, Davis, where she became an “environmental chemist.” She became very focused on the chemical aspects of environmental engineering, like how the environment and chemistry affect the way contaminants behave. Coming to the East Coast was an adjustment for a self-described “Rocky Mountain Girl”, as she had never worked on the East Coast or in an urban environment. Dr. McKenzie credits her colleagues in helping her adjust. Notably, department chair Dr. Rominder Suri, with getting her started with lab space, which she had the opportunity to design from the ground up, and with proposal writing.

Using her focus on contaminant analysis in a project with the size and comprehensiveness of the I-95 project fascinates Dr. McKenzie. “It’s a really exciting project to be a part of because it’s very multidisciplinary,” she said. “Here at Temple, two faculty members are in Earth and Environmental Science ─ one is working mostly on the groundwater portion, the other is working on LIDAR (light detection and ranging), which is a way to get a better understanding of the topography of an area. We have a plant scientist who’s looking at what plants are thriving versus what plants aren’t doing that well in these stormwater management areas. Beyond the science, we want these things to be pretty. These are in these neighborhoods and we want them to be seen as an aesthetic resource. We have people managing those things as well.”

“There’s three of us in civil engineering, myself, Benoit Van Aiken, and Robert Ryan. Myself and Benoit are more on the contaminant side, to understand if there are nutrients present, are there metals present, are there hydrocarbons present, and what’s happening to them as they move through that management system. Robert is working on the modeling of that, to understand the contaminant dynamics in that system.” So far, Dr. McKenzie's testing has shown buildup of contaminants in the construction areas.

This project has garnered attention from outside the area, as the work was featured in presentation to Beijing Drainage Group in the fall. Throughout the process, the professors have earned high marks from their industry partners. "When we get together for a status meeting, it become more like a workshop," said Rhoads. "All these university ideas get thrown on the table. They're able to relate to the language we speak and we're able to understand what they're saying. We're all communicating towards a common good and we're all headed in the same direction." The research has altered thinking about the maintenance of PennDOT's stormwater collecting devices.

-- Marco Cerino