Last week, I took a hurried road trip across the USA from Arizona to Alabama. I documented a few of North America’s hydrologic features with photographs taken from the car window. As this was not a sight seeing trip, please excuse the blurry photos taken through the side window of a moving car. Also, please excuse the paucity of photos, as many interesting features were missed due to darkness.
This is the continental divide where it crosses I-40 in New Mexico, at about 7,200 feet above sea level. A hydrologic divide is a line that separates two drainage basins. On either side of a hydrologic divide, water flows towards different bodies of water. In the case of the continental divide, water west of the divide flows to the Pacific Ocean, and water east of the divide flows to the Atlantic Ocean. Note that the terrain in this photo is rather flat and unimposing. The continental divide is not a line that connects the highest mountain peaks through the Rocky Mountains. In fact, many places along the divide are rather inconspicuous, as steeper and higher mountains often exist on both sides of the divide.
The Rio Grande River in Albuquerque is the most significant river I crossed between Phoenix and the Texas/Oklahoma border (a.k.a. the 100th meridian). Actually, this is the only perennial stream (has flowing water year-round) I-40 crosses between Flagstaff, Arizona and the Texas/Oklahoma border. All other streams crossed by this stretch of I-40 are either intermittent (flow only for part of the year, dry at other times) or are ephemeral (flow only after rainfall).
These three photos document the progression of vegetation as one approaches the 100th meridian from west to east. The first photo is taken about 30 miles west of the meridian, and shows a rather dry and grassy landscape. The second photo shows the landscape right at the meridian. The third photo, taken about 20 miles east of the meridian shows larger hardwood trees and forested areas. Within 30 miles east of the Texas/Oklahoma border, I-40 crosses about a half-dozen perennial streams, whereas in the 600 miles west of the border, the highway crosses only one.
My lousy photo of the Mississippi River taken from the bridge west of Memphis. Most of the rainfall between the Rocky and Appalachian Mountain Ranges flows into the Mississippi River and into the Gulf of Mexico.
This small stream runs across my grandfather’s property, and is typical of small streams found every few miles across much of eastern North America. In the western United States, it would be very unlikely for a private individual to own property crossed by a perennial stream.
This man-made lake east of Dallas, Texas serves as part of the municipal water supply. The Dallas area has many reservoirs like this within and immediately adjacent to the metro area. Many western cities are also fed by reservoirs, but in most cases the reservoirs are outside of town and the water is fed into the city via canal or pipeline.
That’s all for now.