The Great Raft was an enormous log jam or series of "rafts" that covered the Red and Atchafalaya rivers in North America from perhaps the 12th century until its destruction in the 1830s. It was unique in North America in terms of its scale.

Origin

The Great Raft possibly began forming in the 12th century or earlier. It grew from its upper end, while decaying or washing out at the lower end. By the early 1830s, it spanned more than . At one point the raft extended for from Loggy Bayou to Carolina Bluffs.

The Caddo People, 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:

<blockquote>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 anastomosing 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.</blockquote>

thumb|center|500px|Map produced by Red River expedition of 1806 showing Great Raft, smaller rafts, Caddo settlements, and extant trails

Characteristics

At the beginning of the 19th century, the raft extended from Campti, Louisiana, to around Shreveport, Louisiana. The raft blocked the mouth of Twelve Mile Bayou, impeding settlement in the area west of Shreveport. There were many smaller logjams on the Red River.

Consequences

When the log jams were removed, the water level in Caddo Lake and others dropped dramatically, reducing their navigability for riverboats. The ports declined, and riverboats ceased to travel in Caddo Lake.

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.

See also

  • Cane River Lake
  • Los Adaes

Notes

References

Further reading

  • The Great Raft. From Discovering Lewis & Clark , with an undated photograph courtesy Noel Memorial Library Archives, Louisiana State University, Shreveport, and another by photographer R. B. Talfour in 1873.
  • The Attack on the Great Raft by Edith S. McCall, author of Conquering the Rivers: Henry Miller Shreve and the Navigation of America’s Inland Waterways (Louisiana State University, 1984).
  • Great Raft, Parish of Caddo, 2004.
  • Tyson, Carl N. The Red River in Southwestern History. Norman: University of Oklahoma Press, 1981.