Rachel Rhodes
Basic Queries: Landfills in St. Johns, Florida
For this assignment I used selection tools and calculators to assess Solid Waste Facilities,
particularly landfills, and their proximity to surface water bodies in St. Johns County, Florida. I used data
from April 2011 from the Florida Department of Environmental Protection which included the location
of Solid Waste Management Facilities all across the state. I also I used the 2006 national hydrography
dataset published by U.S. Geological Survey from the Florida clearinghouse to analyze the solid waste
sites proximity to lakes/ponds and swamps/marshes.
First I wanted to locate where landfills were within the county so I
used the select by attribute tool. I selected solid waste facility sites
that were described as Class I, II, or III Landfills. I made sure to use
the correct grammar (I used or instead of and to include all three
types of landfills). I then created a layer from the selection so that I
could clearly see the layer that I was interested in (landfills) by
itself.
Next I wanted to find how many of these landfill sites were
within 500 feet of a water body so I used the select by location
tool to find water bodies including lakes, ponds, rivers, marshes
and swamps from the National Hydrology Layer from the
Florida clearinghouse.
I color coded the two different layers so that red dots represented the landfills that were within 500 feet
of a swamp, marsh, lake or pond and the yellow dots represented landfills that were further away than
500 feet. The picture below shows an example of this. The black lines are roads from the Tiger 2010
Census data that I included as a frame of reference for the layout of the city.
Next I wanted to find out the area (in acres) of water that was in contact or within close proximity to
these landfills. It is important to note that I did not measure the area within 500 feet of the landfill and
then summarize the amount of water in this area. Instead I selected water bodies (using the select by
location tool) that where within 500 feet of a landfill and then I created a new layer. The image below
shows the water bodies in the darker blue that are in contact/within close proximity to a landfill.
Although the entire water body may not be within 500 feet of the landfill, water is not stagnant and I
assumed that pollution from landfills can be moved throughout the water body. After calculating the
area of the water bodies I then statistically analyzed this data to see the sum of acres of water (the sum
of all the dark blue water on the map).
I was also curious what type of water bodies were within close proximity to landfills, so I summarized
the area (acreage) of the water bodies in proximity to landfills by the description of the water body type
(that included lakes/ponds, reservoir, swamp/marsh). See the image below for the summary table.
This map may not accurately assess the impact of landfill proximity on water pollution especially
because I did not take the extra step to exclude landfills that were no longer being used or that were
closed up.