There is No Farther to Go

There is No Farther to Go

On July 25th, I reached the end of the lake; I reached the 25 ft dam!

The dam edge is the brown concrete that can be seen above the water
My final transect line by the dam

I was very excited as throughout the summer, and even to my third to last week at the park, I did not think I would be able to finish collecting points to map the entirety of the lake. In total, I collected over 4000 points on about 200 different transect lines.

I finished mapping the lake on the morning of July 26th by mapping its outline and then spent the rest of the day and then Thursday processing the data in ArcGIS Pro. (My last day, Friday July 28th, I spent at Manassas National Battlefield Park).

A map of all the points I collected this summer

My final map is to the right. It is a TIN (triangulated irregular network) map. In a TIN map each point (a x, y coordinate pair) is given a z-value (an altitude value) and differently colored triangles are rendered between the points to show elevation, or in my case depth. Overall, the Lake 2 area (in the north) was much more filled-in than the Lake 5 area (in the south). In fact, the Lake 2 area contains two islands that are a result of fill-in. Nevertheless, the maximum lake depth was 15 ft 1 in and the average lake depth was 5 ft 2 in. 

My final TIN map

I made a contour map as well. The lines on a contour map show areas of equal depth.

Contour map with interval labels
Contour map without interval labels

Though my last day was July 28th, I got to present my work via poster presentation at the Department of the Interior headquarters on Wednesday, August 2nd. The poster does not contain my final map though as I had not collected all the data at the time it was due for printing.

My final poster

I really enjoyed working at Prince William Forest Park this summer. And, as a result, it is hard to narrow down my summer to one or even two favorite parts. However, some of my favorite unique moments were seeing bats in person, seeing a baby turtle and other creatures up close, and holding alive fish (they were caught in the macroinvertebrate net) in my hands.

Two of my biggest takeaways (which are related) are that I cannot always go as fast as I want to and that attention to detail is important. The GPS’ precision limited how fast I could go and map the lake as if the GPS could not locate me to a certain radius I would have to wait at each depth collection point even longer. Some things that made the GPS’ precision decrease was the weather being cloudy, the GPS being under thick foliage, its receiver being covered by my hand, or it just deciding to not want to cooperate. Attention to detail is also important as counting macroinvertebrates that move around required focus and not rushing counting.

Finally, part of the reason that I applied and accepted this position (the title of which was Hydrology Assistant) is because I think I want to pursue a career in hydrology. The good news is I am still interested in hydrology! Overall, I enjoyed lake surveying. However, as I mentioned in Blog 4 my favorite parts were doing things that were outside of what I normally did. I confirmed that I do like some variance in my work as a lot of the lake surveying was repetitive. Lake surveying did present a variety of problems (down trees and tree branches in the way, running out of rope, the lake being an odd shape, the bank being inaccessible, a wasp nest being in an inconvenient place, and lots of mud) that I had to overcome that made it especially interesting though. In fact, when there were no problems on the lake the days blurred together. I also like knowing that my work will help to make change as my data will be used to help inform dredging activities. Besides lake surveying, my other two main focuses, macroinvertebrate and E. coli sampling were pleasant. I originally thought I would not like macroinvertebrate sampling, but I was wrong. Admittedly though, after a full day of macroinvertebrate sampling I was ready to be done as I got neck crinks from staring at the pans containing the macroinvertebrates. Nevertheless, it was a great summer!

So long Lakes 2 & 5! So long Prince William Forest Park! Thanks for reading!

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