First Update- Picking Watersheds, Collecting Data

A little over three weeks into my research, and I suppose I’ve embraced my first summer in Virginia. My research fluctuates between days spent in front of a computer and field days spent around James City County, collecting water and data from streams. We began the summer with 7 preliminary watersheds, ranging from forested (Matoaka Woods) to residential to highly impervious (Newtown). However, given that everyone has gated communities and Homeowners’ Associations around here, we had to give up 3 of our watersheds. This was thankfully not an insurmountable problem, as we needed to eliminate some anyways.

During my first two weeks here, 4 out of 5 days were spent here in McGlothlin 207 (the Torture Chamber, as we affectionately call it) with ArcGIS. While we were finalizing our watershed locations, I was constantly moving outlets and calculating corresponding drainage areas. Once I would calculate a watershed boundary, I would have to count impervious surface cover. To do this, I measured the area of every roof, road and sidewalk. These surfaces force water that would normally infiltrate to become surface runoff, often entering storm drains or flowing into streams.

On my days away from Arc, I can usually be found in the woods. Two weeks ago, we collected data from Pogonia Creek and Chisel Run, which are in Matoaka Woods and near Eastern State Hospital, respectively. We allowed cation exchange resin to absorb with the cations in the water, which we are currently shedding with acid in the lab. The concentration of the cations will allow us to determine the age of the water. For our Newtown watershed, by far the most urbanized, we had to collect large amounts of water in order to date it, due to its high conductivity. So, yesterday, my colleague Pat and I went out to the stream with 90L of jugs and carboys. We used a peristaltic pump to collect 90L of streamwater over the course of a few hours, which will then be analyzed for its 22Na concentration.

So far, I have learned a lot about fieldwork. For starters, nothing goes as planned. Our first trip around town ended in much frustration as every stream was above our conductivity threshold. Secondly, there’s a lot of waiting and repetitive actions. Yesterday, we spent 3 hours filling up gallons jugs with water. The pump operated at about .5L/min, so it took approximately 8 minutes for one jug to fill up. In that time we would bring full jugs up the hill, then try some whittling. Once we completed this, we had to measure the discharge of the stream using the salt dilution method. This involves dumping a known mass of dissolved salt into the stream, and measuring the conductivity with an automatic probe as the salt passes through. At 2 out of 3 of our streams however, this process involves about an hour of waiting for the conductivity to rise and fall. While in the scheme of things a few hours is not very long for necessary data, the amount of time true data collection takes cannot be learned in the constructed 3-hour labs that we go through during the school year.


  1. mssmith01 says:

    Wow, measuring all that sounds like a tedious task! Now that you have the water, how will find the 22Na concentration? Also, when you do get this info, what will it tell us? Good luck!