There are some significant steps that have been taken in the GIS filed that will be useful for the project. All of the data that we need has been sourced (more on this later) and the mapping analysis has commenced. Some highlights:
We used the CDL and the NLCD data to output corn growing areas and all agriculture areas, respectively. These were then clipped to the watersheds, so that the actual size of the growing land could be determined. A map of this type (showing corn production in blue) is below:
All of the pesticide data that we had (unfortunately, only from 2010) was put in a table and the amount of pesticide used in each watershed, on average, was calculated. For instance, the Phosphorus used for corn production equaled about 0.00981 lbs. per square meter over the watersheds.
About the data sources: we have all of the necessary parameters: demographics, the cropland data, pesticide data and water quality data. However, some of our original sites were found, after analysis, to have too little water quality data; therefore we are attempting to find sampling sites that have more data to work with, which will mean running all of the processes again. It is relatively simple to do this, though, with only one or two watersheds.
