Posts about Geography

The patterns of settlement across the country give reason to the difference. From the brooks of New England and the kills of New Netherland York to the bayous of New France Louisiana and the rios of New Mexico, the variety of names adds flavor to a diverse nation.

The stark differences, especially in the Mid-Atlantic and New England show how varied the histories of those regions are, despite their size.

The map shows creeks and rivers in gray, since those names are so common nationwide. Though sometimes things get mixed up. Consider Philadelphia's Schuylkill River: It's a kill and a river.

Crossposted at The Straight Line.

On a recent WashCycle post, one commenter noted that most planned bike lanes lie in the Northwest quadrant, while others pointed out that the quadrant contains more of the city's land than any other.

I created this map using shapefiles from DC OCTO. The background image is 2008 ortho imagery. The red outline is the city boundary plus the quadrant boundaries. Blue-shaded polygons represent water, bright green shading represents NPS parkland and other while the orange shading represents military bases.

Total area (including water):

• Northwest: 29.21 square miles. 42.6% of the total.
  
• Northeast: 15.52 square miles. 22.7% of the total.
  
• Southwest: 11.02 square miles. 16.1% of the total.
  
• Southeast: 12.73 square miles. 18.6% of the total.

So Northwest is by far the largest quadrant, followed by Northeast. Only about 1/3 of the city is considered "south."

Water area (using OCTO's Water Polygon shapefile and includes the creeks and some ponds):

• Northwest: 1.11 square miles (mostly the Potomac). 15.3% of the city's water total. 3.8% of the quadrant's total area.
  
• Northeast: 0.38 square miles (mostly the Anacostia). 5.2% of the city's water total. 2.4% of the quadrant's total area.
  
• Southwest: 5.26 square miles (Potomac, Channel, Tidal Basin, part of the Anacostia, etc). 72.5% of the city's water total. 47.7% of the quadrant's total area.
  
• Southeast: 0.51 square miles. 7% of the city's water total. 4% of the quadrant's total area.

As you can see, DC's water is predominantly focused in Southwest, due largely to the Potomac, Washington Channel, and the Tidal Basin. Almost three-fourths of the city's "water area" is in Southwest, and almost half of Southwest's total area is covered by water. By comparison, water covers relatively little of Northeast or Southeast, even with the Anacostia River in both.

Subtracting out water area from the total yields Land area:

• Northwest: 28.1 square miles. 45.9% of the city's land total. 96.2% of the quadrant's total area.
  
• Northeast: 15.14 square miles. 24.7% of the city's land total. 97.6% of the quadrant's total area.
  
• Southwest: 5.76 square miles. 9.4% of the city's land total. 52.3% of the quadrant's total area.
  
• Southeast: 12.22 square miles. 20% of the city's land total. 96% of the quadrant's total area.

As can be expected, Northwest has the lion's share of DC's land area, whereas less than 10% of the city's land area is in Southwest.

I didn't stop there, I also ran calculations for both National Park Service land (listed as NPS Map A) and military bases within DC.

NPS-parkland area (using OCTO's Parks Polygon shapefile)

• Northwest: 5.35 square miles. 51.4% of the city's NPS total. 18.3% of the quadrant's total area.
  
• Northeast: 1.52 square miles (mostly Anacostia Park). 14.6% of the city's NPS total. 9.8% of the quadrant's total area.
  
• Southwest: 1.52 square miles. 14.6% of the city's NPS total. 13.8% of the quadrant's total area.
  
• Southeast: 2.01 square miles. 19.3% of the city's NPS total. 15.8% of the quadrant's total area.

This includes circles and triangles maintained by NPS. It also includes some land classified as "parkland" but which contains parking lots (like around RFK stadium, though it doesn't include the stadium itself) or roads (Rock Creek Parkway, Canal Road/Clara Barton Parkway, and others).

Here, Northwest takes the lion's share, with half the city's total. NPS parkland also takes up a larger share of Northwest's total area than the other three quadrants. Roughly half of Northwest's NPS parkland is Rock Creek Park.

Military base/facility area (using OCTO's Military Locations Polygon shapefile)

• Northwest: 0.42 square miles. 17.5% of the city's base total. 1.4% of the quadrant's total area.
  
• Northeast: No military bases/facilities.
  
• Southwest: 1.87 square miles. 77.9% of the city's base total. 17% of the quadrant's total area.
  
• Southeast: 0.11 square miles. 4.6% of the city's base total. 0.9% of the quadrant's total area.

Again, Southwest takes the lion's share, thanks to the joint Anacostia Naval-Bolling AFB base. Note how there are no military bases in Northeast.

Factoring out water area, NPS parkland, and military base area yields this remaining Land area for each quadrant:

• Northwest: 22.33 square miles. 46.1% of the city's land total. 76.4% of the quadrant's total area.
  
• Northeast: 13.62 square miles. 28.1% of the city's land total. 87.8% of the quadrant's total area.
  
• Southwest: 2.37 square miles. 4.9% of the city's land total. 21.5% of the quadrant's total area.
  
• Southeast: 10.1 square miles. 20.9% of the city's land total. 79.3% of the quadrant's total area.

While Northwest has the largest amount of non-NPS/non-military land in the city, both Southeast and Northeast have a higher percentage of their total area as non-NPS/non-military land.

By comparison, Southwest has very little land available, and a large chunk of this is occupied by Federal office buildings near the Capitol and south of the National Mall.

Cross-posted at Just Down the Parkway.

The color coding represents the approximate elevation of different parts of the city. Blue water mains run along roads at the lowest elevations (between zero and 70 feet above sea level). Red water mains are located at the second elevation range (between 70 and 140 feet), green at the third range, orange at the fourth, and brown at the highest elevations. The red and green areas east of the Anacostia River are separate zones than those west of the river, while the lowest zone (blue) spans both sides of the river.

This means that the reservoir that serves your house isn't necessarily the one closest to your house, or even in your quadrant of the city! For example, our house is in Trinidad. While the closest reservoir is at Brentwood Parkway and New York Avenue (just north of Gallaudet University), we are served by reservoirs in Berkley and at the Armed Forces Retirement Home, both across town in the Northwest quadrant of the city.

Meanwhile, the reservoir nearest our house serves locations at the lowest elevations (below 70 feet), from lower Georgetown and Southwest in the west all the way to Rosedale and Deanwood in the east.

Some other examples of reservoirs and the neighborhods they serve:

• The reservoir at Van Ness and 44th NW serves neighborhoods at intermediate elevations across the city like Brookland, Woodridge, and Michigan Park in Northeast; Columbia Heights, Mt. Pleasant, Adams Morgan, and Kalorama in the center of the city; and Foxhall and the Palisades in Northwest.

• Two of the reservoirs at Fort Reno serve higher elevations like Glover Park, Cleveland Park, American University Park, and Forest Hills west of Rock Creek Park; and Petworth, North Portal Estates, Manor Park, and Takoma east of Rock Creek.

• The highest reservoir at Fort Reno serves the highest elevations in the city—neighborhoods like Tenleytown, Chevy Chase, and Shepherd Park.

Neighborhoods east of the Anacostia River have had a persistent problem with lower water pressure. DC Water is looking to rectify that with the construction of the new reservoir and pumping station in Ward 8. The construction of the new Department of Homeland Security headquarters on the campus of Saint Elizabeths will greatly increase demand for water in that part of town, and Mr. Hawkins said it would be a win-win for the neighborhood and DHS to get the new reservoir built as part of the new construction there.

Cross-posted at The District Curmudgeon.