By Alexandra Johnson
Charlotte Shade knew from a young age that her career would involve the environment. She just wasn’t sure how. So she eventually earned her Bachelor of Science in Biology and a graduate certificate in Geographic Information Systems from the University of Dayton.
Throughout her schooling and later work with the Philadelphia Water Department, Shade came to believe that novel technology could offer new insights into environmental changes.
“I love asking spatial questions,” Shade said. “I think that they are the most compelling.”
At the Philadelphia Water Department, Shade studied Philadelphia’s green infrastructure system, work that involved using models to predict how the city’s current and future water systems will be affected by climate change and population growth.
Shade, who now works as an environmental planner for Point Fort Associates, is one of many scientists studying urban infrastructure, and how it will need to adapt in the near future in the face of a rapidly changing planet.
The Rice Kinder Institute for Urban Research cites rapid heating, increased flooding, increased power failures, and economic hardship as the four most pressing things cities will experience as a direct result of climate change.
The EPA also mentions storm water runoff as a major cause of pollution in urban areas. They explain that this is because flooding sewers will flow directly into local sources of water, such as rivers and lakes without permeable surfaces to filter runoff.
Many cities struggle with this reality, and experts state that most original urban infrastructure was never designed to handle current population levels or densities.
Maps of Philadelphia’s sewer system show that all sewage flows to a single large pipe that runs under the city. The city’s water department warns that as the population grows and more sewage flows to this main pipe, the prospect of flooding increases.
Combine this fact with multiple climate studies predicting more frequent precipitation events in the future, and experts say government officials have a pressing issue to solve.
Most cities across the entire globe face this problem, and there is no easy solution. City infrastructure experts state that ripping out and replacing the piping system requires essentially ripping up and replacing the entire city.
Green infrastructure has been introduced as a possible solution to this issue, and the Rice Kinder Institute also lists it as an invaluable tool for fighting climate change in urban areas.
This type of infrastructure is often associated with the Clean Water Act, and is defined in that piece of legislation as “The range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates…to store, infiltrate, or evapotranspirate storm water and reduce flows to sewer systems or to surface waters.”
The EPA defines it at the city scale as “a patchwork of natural areas that provides habitat, flood protection, cleaner air, and cleaner water.”
The most recognizable form of this infrastructure in cities is parks, rain gardens, and other natural spaces. Research shows that planting trees, shrubs, and grasses have numerous environmental benefits in cities, and filtering contaminated storm water runoff is a significantly important one.
According to the New Jersey Green Building Manual, specific manmade materials, such as pervious concrete, are absorbent and hold rainwater much better than impervious surfaces like traditional asphalt. Therefore, these types of manmade materials are also considered green infrastructure.
Placing all of these natural surfaces and structures in the cityscape creates something called “green acres,” which experts define as acres of land that are able to effectively filter one inch of rain water.
In fact, multiple models have shown that the more green acres a city has, the more resilient it will be in the face of severe weather that may cause flooding. Other land use studies also demonstrate that it can help effectively filtrate the inevitable sewage runoff that comes with large populations densities and dated pipe infrastructure.
Today, Shade’s model predicts that the city of Philadelphia will need to have approximately 10,000 green acres by the year 2036, in order to have acceptable sewage mitigation and runoff levels.
\Shade’s model also shows that the current green infrastructure program that the city has in place is projected to meet this goal, if current policies stand into the future.
“We can always do more,” she added. “Green acres are used as a measuring tool to meet storm water infrastructure goals for the EPA, but they are not yet used as a direct tool to mitigate climate change.”
Shade said she hopes that the city will act as a pioneer and positive example when it comes to green infrastructure.
“It is always easier to promote change at smaller governmental levels like cities, compared to states and countries,” she said.
However, Shade also hopes that her work will spur even bigger changes that need to happen in the uncertain face of climate change.
“We’re going to have to make additional changes,” Shade emphasized, “and we’re not going to have a choice at some point.”
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