Product Code Database
The Great Raft was an enormous log jam or series of "floating island" that clogged the Red and Atchafalaya rivers in North America from perhaps the 12th century until its removal in the 1830s. It was unique in North America in terms of its scale.
The Caddo, regional inhabitants for millennia, incorporated the Great Raft into their mythology as protector from competing tribes, and recognized the contribution of associated intermittent flooding to soil fertility and agriculture.
Harrelson et al. describe the origins of the raft:
This ecosystem of entangled logs, vegetation and sediments remained in place for almost two millennia, altering the flow regime of the Red River and causing a complete change in its geomorphic character from a single channel to a series of Anastomosis channels. It is believed that the initial formation of the Great Raft was triggered by catastrophic flooding as the Red River was going through some major geomorphic threshold, such as a major avulsion. The main contributors to the development of the Great Raft are believed to be the shifting geomorphic conditions in conjunction with extensive precipitation, river bank rotational slips and slab failure, rapid lateral migration, copious, rapidly growing riparian vegetation, exceeding a geomorphic threshold, a flashy hydrograph and a very heavy sediment load.
The raft raised the banks of the river, creating and several lakes. Called the Great Raft Lakes, these included Caddo Lake and Cross Lakes, along the lower reaches of the Red River's tributaries. Ports developed along these lakes, and Jefferson, Texas, on Caddo Lake became the second-largest inland port in the United States during this period. The city thrived and was considered a major gateway to East Texas. It was important for shipping out area commodity crops, such as cotton.
Captain Shreve was a steamboat entrepreneur who had successfully invested in the new steam-power technology by developing the snagboat, a steam-powered boat used for raft removal. He had already used this technology to clear navigational paths in the Ohio and Mississippi rivers in 1827. Captain Shreve arrived at the toe of the Great Raft in April 1833 with four snag boats and a force of 159 men. His group began clearing a navigational path through 115 km of the Great Raft and, finally, by the spring of 1838, a path had been cleared; however, the remnants of the Great Raft along the river banks were not cleared and the Great Raft immediately began to reform
When Shreve began work, the raft blocked a distance from directly below to directly above Shreveport. By April 1835, Shreve had removed the raft up to the mouth of Twelvemile Bayou. He concluded this work in 1838, having removed the last impediment to navigation on the Red River. This task was continued by others until the latter part of the 19th century. For his efforts, the city of Shreveport was named after him.
The removal of the massive log jams hastened the capture of the Mississippi River's waters in lower Louisiana by the Atchafalaya River, a major distributary emptying separately into the Gulf of Mexico. In the 20th century, to maintain the Mississippi, the US Army Corps of Engineers built the multibillion-dollar Old River Control Structure.
|
|
