GIS

This semester I was enrolled in the Intro to GIS class at Tufts, the first time it was offerred to the undergraduate population. What is GIS, you may ask? GIS stands for Geographical Information System, which allows one to question, interpret, analyze, and understand data and relationships in a visual or spatial manner. More simply, GIS allows one to create maps and analyze trends on a spatial scale. For example it can be as simple as mapping the peaks hiked in New Hampshire (figure 1 in gallery), or as complicated as determining the best location for a hydroelectric dam.

During the semester we were given multiple assignments that were designed to teach us different skills in ArcMap (a GIS program), including using vector and raster data, suitability analysis, interpolation, using census data, and much more. The semester culminated in a self-designed final project that really forced us to consider what problems needed to be solved, how to solve them, and how to work around the different obstacles that arose. While frustrating and sometimes extremely time-consuming, learning to use ArcMap is a skill I am very grateful to have developed.

I’ve included the maps from my assignments below, as well as my final project and poster (Designing a poster is way more difficult than one would think). Below is the introduction to my final project:

Recent developments in the availability of fossil fuels have led researchers and scientists to explore new methods of extracting natural gas from the earth. One of these new techniques is hydraulic fracturing (fracking), where large quantities of water, sand, and chemicals are pumped into horizontal wells to open up cracks in the earth and extract the gas. This technique now allows companies to access gas reserves that were previously inaccessible. Some of the richest resources for fracking exist in the Marcellus Shale formation, which covers most of western Pennsylvania. As of 2010, the Marcellus Shale portion of Pennsylvania had 71,000 active gas wells, with projections of over 60,000 wells being built in the next 30 years. The rapid expansion of fracking has faced strong opposition for multiple reasons, including the possibility of contaminating groundwater or surface water with methane and radioactive wastewater. My goal was to determine areas that would be particularly vulnerable to this type of contamination, specifically places of high human population. I focused on Allegheny County in Pennsylvania because of it’s location within the Marcellus Shale formation andbecause it is the second most populous county in the state.

With this in mind, my project involved a vulnerability analysis, which can also be thought of as a reverse suitability analysis. The objective was to determine areas where fracking sites were most likely to contaminate water sources close to large population centers. To do this, several factors were considered including population, water bodies (lakes and rivers), reservoirs, fracking wells, and public water sources such as groundwater withdrawal. Each variable was given a ranking or score and I used the buffer tool to create and find the areas of overlap between the variables. By calculating which areas had the highest total score based on the score of each variable, I was able to show the most at risk areas for water contamination given these constraints.

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