Goals and Objective:
In our final lab of GIS 2 I was put to work to determine an area within Trempealeau County, which is located in western Wisconsin, for a new frac sand mine. To do this I had to create a suitability model of the land, and I had to create an impact on the environment model as well. I used the DEM from Lab 5 as well as using the land cover and geology of the region. In this lab we utilized the Reclassify, Euclidean Distance, Feature to Raster, Slope, Block Statistics, Map Algebra, and the Project tool. I then combined using Map Algebra the suitability and the impact analysis to determine the best location overall for a potential sand mine.
Methods:
Sustainability Model:
Site Criteria for Sand Mining Suitability:
• Geology
• Land Use Land Cover: agricultural (herbaceous planted/cultivated) land use
• Distance to railroads
• Slope
• Water table criteria
These variables came in all different types, and some need more work than others. The end goal was to transform these into raster to be combined together to determine the sustainability model. For most we needed to determine a rank on a scale of 1-3 with 3 being the most suitable and 1 being the least suitable (Figure 1).
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| Figure 1: Shows the ranks I used in my model along with my reasoning. |
In Figure 2 below there are many different sets of tools each variable had to go through to get to its final stage. In the Geology Class I selected the Jordan and the Wonewoc sandstone formations which are frac sand mines target layers while giving these a 1 while the others get a 0 as they are not targeted by the sand mines.
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| Figure 2: This is my model builder for my Suitability Model. It included many reclassify tools, euclidean distance, and for the first time the slope tool. |
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| Figure 3: This figure shows the outputs of the 6 variables that were taken into consideration. The darker colors are the most suitable, whereas the lighter yellow is the least suitable areas. The red is the most suitable area whereas the yellow will be the least suitable area. |
Impact Model:
Next I made an impact model that areas that would be impacted the most if a mine was placed within the area, and we had 4 variables plus one of my choice which I used wilderness areas.
• Proximity to streams
• Prime farmland
• Proximity to residential areas (noise shed and dust shed)
• Proximity to schools (noise shed and dust shed)
• Wilderness areas
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| Figure 4: This is my model that I created for the Impact Model. It includes may reclassify, euclidean distance, and finally ends up with a Raster Calculator tool. |
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| Figure 5: This Table Shows the five variables I used in my model and the way I reclassified each. I also gave my reasoning on why these variables are important when picking a location for a frac sand mine. |
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| Figure 6: This is the results from my model builder (Figure 3). It shows Residential Areas. Schools, Wildlife areas, Farmland, and Streams. These are all variables that have the potential to have an impact from a frac sand mine. The yellow areas have the highest impacts and the red has the least impacts. |
We were then able to take the models we used and combine them together to create an Optimal Sand Mine location.
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| Figure 7: Showing the final raster calculator giving the Optimal Sand Mine Location. |
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| Figure 8: This is the Optimal Frac Sand mine location in Trempealea County, Wisconsin. The Green areas are the least suitable, whereas the areas in the red-white range are the most suitable. |
Conclusion:
In Figure 8, we are finally able to tie everything together on one view of Trempealeau County. The red-white areas are the most suitable and optimal place for a sand mine. Being able to use all of the different tools really puts in perspective how many objects really go into making a model and deciding on a location to put something new. I know that if this was a real model there would be even more variables to consider than just the few that we used. I also see now how easy it is for someone to mess around with the reclassify tool and get a completely different map than what I currently have.
Sources:
Land Records. Trempealeau County Land Records. Geodatabase http://www.tremplocounty.com/tchome/landrecords/
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