Today I attempted to sketch out my watershed. Quickly I realized the map was a little too large to comfortably fit within a paint window, so I settled for mapping the upper section of my watershed.
Behold, my MS paint creation:
I found this exercise a little frustrating, if only because I have access to a professionally created, high-quality watershed map (Available on the county website here). By comparison, my map looks a little rough. With more time, a few ArcGIS courses, and a dual monitor computer, I am confident my end result would be a little more robust.
I did appreciate drawing on my much neglected geometry skills to estimate the average area in this snapshot of the watershed. Since the whole county is only 26.1 square miles, my estimate of less than one square mile for this map seems reasonable.
Additionally, I learned a little bit about Arlington County through this endeavor. In such an urban county, it is easy to overlook our waterways. While I’ve driven over Arlington Boulevard countless times, I did not ever realize a river ran under (through?) the highway.
I also discovered that while Arlington County offers access to a number of free GIS maps, there is no easily accessible online data of our watersheds. It would be easy to map locations of our parking lots, schools, or bus routes. But if you want to check out the watersheds, you’ll have to resort to alternative data sources.
Where The Water Goes 
I appreciate the frustration I felt much the same way. Its hard to match the quality of the data and maps created by Fairfax, Prince William, and Loudoun counties. I think this post would benefit from mentioning where Arlington is because its not clear in your welcome post and this mapping post that its located in VA. Is Arlington a county? Its its own independent city, but I am not sure if its a county. I would really like to know how they decide if a locality is a city and how that differs from counties.
LikeLike
Good question– Arlington is actually a county (not a city) in Virginia, beside Alexandria City, Fairfax, Falls Church, and Washington DC. I’m also a little fuzzy on the difference between counties and cities. It’s definitely worth further investigation!
LikeLike