Ph.D. Candidate Haley

Graduate Study
Ph.D. Student Spotlight

Haley Lewis

environmental engineering and science


1. Where are you from? 

I am from Miramar, Florida

2. Where did you get your undergrad degree, and what was your major? Do you have an MS? 

I went to the University of Florida and got my BS in Chemical Engineering, Go Gators! I received my MS in Environmental Engineering and Sciences from Northwestern University.

3. What attracted you to engineering?

I have been interested in STEM for as long as can remember. Math was always my favorite subject in school, not because I found it easy, but because I found it challenging. When I took Chemistry and Calculus at my engineering magnet high school, I decided that I wanted to pursue a career in engineering that combined the two subjects.

4. What attracted you to pursue a Ph.D. in your specialty area?

I like to think that I’ve always been a champion for the environment. While studying chemical engineering at UF, I conducted research in the Environmental Engineering Department under Dr. Barron Henderson. I saw many intersections between Chemical and Environmental Engineering and was attracted to the “Big Picture” impact associated with Environmental Engineering research.

5. How do you explain your thesis research to a non-scientist?

More than 80% of the US’s population is concentrated in areas with high percentages of impervious surface cover. Why is this an issue? As you cover natural areas with impervious surfaces like buildings with tar rooftops and concrete streets, you reduce the chances for ground water infiltration and evapotranspiration (evaporation + transpiration). This reduction in natural ground cover increases the chances for runoff which lead to greater flood risks with stormwater that often carries pollutants in it. We are also seeing more intense storms as a result of climate change in the Midwest and along the East Coast. Because of this, many cities are implementing Green Infrastructure (GI) in combination with existing infrastructure (built and grey infrastructure). GI are systems that incorporate nature-based solutions to help alleviate urban storm issues as a result of climatic changes. I study the relationships between the cascading ecological goods and services provided by GI. 

The type of GI that I study are rain gardens, which are like regular gardens except they are swales, or shallow depressions, that are routed to take in stormwater from rooftops and streets. This stormwater is treated by the native vegetation and the microbes within the soil. Unlike regular gardens, rain gardens do not need extra fertilization, they are intended to be self-sustaining. I am studying, to what extent are they self-sustaining. I am also studying the relationships between the quality of vegetation and the impact on the water quality, and the relationships between plant type and pollinator activity and soil moisture. The ultimate goal of this research is to be able to build predictive networks of GI in storm-ridden urban areas that are equipped with sensors that monitor the performance of the GI in relation to their ability to reduce stormwater volume. Additionally, by quantifying the ecological goods and services provided by GI, we hope to give cities ample incentive to install more GI on a larger scale in the near future.

6. What attracted you to NU?

I felt that I would be more than a number at Northwestern. The Civil and Environmental Engineering Department made me feel welcomed and wanted. I felt valued as a student and as a researcher at NU, and I was reassured that I would only have to focus on my classes and research, which was a big plus. Our department is the perfect size for collaboration, and everybody’s work is far-reaching and impactful. I also appreciate the range of backgrounds everyone brings to the department, from Physics to Chemistry, to Material Sciences, I am always learning at NU.

7. What has been the highlight of your time at NU and CEE?

There have been many highlights, but I think the biggest highlight for me has been the opportunity I was given to travel to Buenos Aires, Argentina in 2019 to learn about the work from collaborators at Universidad Nacional de San Martín. It was my first time out of the country, and I was able to experience the Argentinian culture, along with the great research taking place there. It is an experience I will never forget.

8. What has been the most challenging aspect of your graduate school experience?

The most challenging aspect of my graduate school experience has been overcoming imposter syndrome as a researcher and as a scientist. When I first started my thesis work, I was not confident in my abilities to create an experimental design and execute it. Throughout my work, I have learned through trial and error and have developed my own agency in the process. I find that I am now less hesitant to try new methods, or set up new experiments, as I have grown more confident in my abilities. I’ve also learned that failure is inevitable but learning from those failures brings you one step closer to success.

9. Can you tell us about your experience being mentored or mentoring others?

I have had the opportunity to mentor 10 undergraduate and high school research assistants. Because I do a lot of work in the field and lab, having a few extra hands is always helpful. This experience in mentoring students in the field, the lab, and now in data analysis has been as great one as I have learned a lot about myself as a mentor and as a scientist. Having the opportunity to work with young minds that are interested in science is a passion of mine. I have watched my mentees grow into independent researchers, with one of my first mentees completing their Senior thesis on a related topic:  An Integrated Approach to Flood Mitigation: Landscape Analysis, Stormwater Modeling, and Green Infrastructure Design in Markham, IL. I look forward to growing as a mentor, and I hope to inspire others to pursue research in STEM.

10. What are your interests or hobbies outside of your research?

Outside of my research, I am very interested in the arts. I am a painter and I do a little bit of writing as well; I try to tap into my creative side as often as I can. I like to dabble in activities that make me step outside of my comfort zone. I am also a huge basketball fan, watching, not playing.


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