Summer research comes to an end!

This is the final post of the summer but definitely not the end of this project! Summer totals leave me with 24 fields completed in GIS and I hope to analyze 40 in total. Also, I have 4 fields in both resolutions to test the 10m DEMs and I would like to have 10 total as the larger the sample size, the more reliable the results. We have ground-truthed only 2 fields, it being a very time consuming process and I would like to have the in-field data for at least 5 more fields. I will work on getting this information in September when the weather is gentler and the forest slightly less vegetated. The past few days have been spent writing up the methods I used this summer to get a head start on my thesis and working with the LIDAR data on James City County fields.

The LIDAR dataset for the Coastal counties was very large and had to be extracted by a GIS shapefile of just James City County. Once the computer had finished the extraction I was able to clip the county file by rectangles drawn around each field of study. When I return to school after a short break I will work on analyzing about 7 more fields in the county and hopefully include a few of them in my ground-truthing data. I also plan to use the LIDAR on Mathews County fields to complete my goal of 40 fields total.

Results thus far show concentration of flow to be occurring on all fields, with varying intensities and frequencies. However, I have seen a great deal of flow entering fields adding to flow accumulations at points which exit the field. This creates points on the field margin which drain an area that is larger than the actual field size! This is very important because high flow means channel formation. When taking only the total drainage into account the top 10 points on each field are responsible for 66%-91% of the drainage! Ground truthing has shown that approximately 90% of these predicted high flow/channel locations are correct and the flow values match well with the evidence of surface flow we have seen. There is still a lot to be done but already we see that our hypothesis is true on the fields we’ve analyzed so far.

 The summer was very productive and I am well on my way to a great thesis! I couldn’t have done it without the support of my professors, my teammates, the Charles Center and the Girton and Bright Families scholarship! I also owe a big thanks to the wonderful farmers and landowners in Charles City County who have agreed to allow me to walk their fields testing my data, the project would not be able to happen without their cooperation.

Comments

  1. It is amazing how much information you can determine about a site using just GIS.