The analysis of landlocked national lowpoints amused me so much that I decided to extend the exercise to individual states within the United States. Once again I found a perfectly matching Wikipedia page so I didn’t have to recreate my own, a List of U.S. states by elevation. Only two states included elevations below sea level, California and Louisiana, and both featured seacoasts. Thus, I only had to search for states with positive elevations, which by process of elimination would have to be landlocked. If the District of Columbia ever became a state it would lead the pack with a single-foot lowpoint at the spot where the Potomac River exited the nation’s capital. However, setting that aside, there were three states with impressive lowpoints all falling beneath a hundred feet (30 metres).
Ouachita River vista by Robert Nunnally on Flickr (cc)
The delta of the Mississippi River drained an incredibly flat plain although it still surprised me that it extended all the way into Arkansas. It had the lowest elevation of all landlocked states. Arkansas was a solid two hundred miles (320 km.) from the nearest seacoast at the Gulf of Mexico. Yet it offered a lowpoint where the Ouachita River crossed from Arkansas into Louisiana at an elevation of only 55 ft. (17 m.). The Ouachita joined the Tensas River, forming the Black River, commingling later with the Atchafalaya River and eventually intertwining with the Mississippi River. The whole mass of bayous, sloughs and waterways formed an immense tangled delta reaching far inland.
Native Americans thrived in the swamplands for hundreds of years during the Pre-Columbian period, building large settlements and ceremonial mounds.
The major Indian tribes that lived along the OUACHITA were the Washita, Caddo, Osage, Tensas, Chickasaw and Choctaw… The Spanish explorer DeSoto recorded in 1540 the existence of an enormous mound built on the banks of the OUACHITA. This site was named "Anilco", and was located at the present site of Jonesville, Louisiana. This mound was tragically destroyed when a bridge was built over the site in the 1930’s. This mound was one of the largest ever recorded in North America.
Priceless cultural artifact or second-rate highway bridge? Apparently priorities differed in the 1930’s.
The actual Arkansas lowpoint (map) occurred at an interesting intersection for followers of modern geography, directly upon a county quadripoint. Four counties (parishes in Louisiana) joined where the Ouachita River left Arkansas and entered Louisiana: Union County, AR; Ashley County, AR; Union Parish., LA and Morehouse Parish., LA. The two entities named Union were referenced previously in "Adjacent Counties, Same Name, Different States."
Arizona also surprised me although maybe it shouldn’t have seemed all that counterintuitive once I considered the situation some more. Arizona was such a large state and it seemed so far away from a seashore. Yet, if one looked at a map it became abundantly clear that its southwestern corner fell pretty close to the Gulf of California. One would have to travel through neighboring México to accomplish that though, and perhaps that was why I tended to overlook it mentally. The quickest path to the Gulf followed the course of the Colorado River, making Arizona’s lowest elevation 72 ft. (22 m.) where it exited the state at San Luis.
Oddly, that hadn’t happened much in the last half century making the lowpoint a dry, empty riverbed instead. A series of state compacts, international treaties and dams strictly parceled the Colorado’s waters to variously prescribed residential and agricultural purposes. The final dam built on the river at a place straddling the U.S / Mexican border between Yuma and San Luis — the Morelos Dam (map) — took what little flow remained and channeled it into croplands in surrounding areas of México. That converted what used to be a wonderfully diversified estuary and turned it into just another patch of Sonoran desert sometime around 1950. Environmentalists on both sides of the border began to wonder what might happen if the Morelos Dam opened periodically and allowed the Colorado River to flow naturally to the sea for limited times. Thus the notion of the "Pulse Flow" came to pass and it actually happened in March 2014:
… officials released an experimental pulse of 105,000 acre-feet of water from the Morelos Dam on the United States-Mexico border, and on May 15 the river once again flowed into the sea. The eight-week water release, though small, was enough to cause a 43 percent increase in green vegetation in the wetted zone and a 23 percent increase along the river’s borders…
Small changes made a big difference.
Lake Champlain, VT by Matt Tillett on Flickr (cc)
Actually all three of the landlocked states with elevations of less than a hundred feet completely fascinated me. Third on the list went to Vermont — literally the Green Mountain — where one would expect higher elevations instead of lower ones. Certainly Vermont included impressive peaks within its boundaries although it also bordered on Lake Champlain (map). Its lowpoint coincided with the lake, a diminutive 95 ft. (29 m.) flowing into the St. Lawrence River and onward towards the Atlantic Ocean.
Lake Champlain served as an important transportation corridor during colonial times and the early days of an independent United States where difficult overland travel took place on muddy, rutted roads. It was a lot easier to navigate a boat inland wherever that was possible instead of turning to horse and wagon. Lake Champlain became Vermont’s access to the outside world. It was no wonder that the lake figured prominently in the Revolutionary War and the War of 1812. Forts such as Ticonderoga and Crown Point appeared along its shorelines. British and American naval forces battled upon its waters. The United States fortified Lake Champlain’s shoreline even after the wars, including the infamous "Fort Blunder" placed on the wrong side of the border by mistake. Canals later connected the lake to the Hudson River watershed and the Erie Canal system, creating a vast superhighway over a large swath of the continental interior.
This was one of the more enjoyable article series I’ve written in awhile. Lowpoints seemed to offer more untold stories waiting to be discovered than highpoints.