Head of Passes
Head of Passesis where the main stem of theMississippi Riverbranches off into three distinct directions at its mouth in theGulf of Mexico:Southwest Pass (west),Pass A Loutre (east) and South Pass (centre). They are part of the "Bird's Foot Delta", the youngest lobe of the evolvingMississippi River Delta.
29°09′25″N89°15′14″W/ 29.157°N 89.254°W
TheHead of Passesis considered to be the location of the mouth of the Mississippi River.
TheUS Army Corps of Engineersmaintains a 45-foot (13.7 m) shipping channel from the mouth of Southwest Pass—20 miles (32 km) downriver from the Head—up toBaton Rouge,the US's farthest inland deep-water port.[1]
TheMouth of Passesis the aggregate of the individual mouths of the passes connected to the Head of Passes, including the Southwest, South, North Passes and Pass a Loutre.[2]While the majority of the discharge of the Mississippi River flows through these mouths, a portion of the river flows out of theAtchafalaya Rivermouth, and a small portion continues to seep out of the 200 miles (300 km) of the Delta shoreline.[3]
During theAmerican Civil War,Head of Passes was the site of several naval battles. TheAnaconda Plancalled for a largeUnion blockadeof the Confederacy, and included plans to control the Mississippi River. This began in 1861 with a Union blockade stationed at the Head of Passes. This occupation resulted in theBattle of the Head of Passes,where the blockading forces were temporarily driven from the area. Ships involved in the ensuing conflict at the location include theCSSManassas,theUSSVincennes,and theUSSRichmond.
Port Eadsis located at the southern tip of South Pass.
AHP datum
[edit]The Head of Passes is the datum from whichmileageson the Lower Mississippi River are measured.[4]Algiers Point,for instance, is at mile 94.6 AHP (above Head of Passes).Cairo,Illinois,is at mile 953.8 AHP. Mileages downstream from Head of Passes are labelled BHP (below Head of Passes).[5]
Notes
[edit]- ^Navigation Data Center (December 2003)."The US Waterway System—Transportation Facts"(PDF).Retrieved2006-03-11.
- ^"Watershed Assessment, Tracking & Environmental Results System".Environmental Protection Agency.Retrieved2006-03-11.[dead link]
- ^"Mississippi Delta".Visible Earth.Archived fromthe originalon 2006-03-31.Retrieved2006-03-11.
- ^Sole, Robert L.; et al. (November 1999)."Lower Mississippi River Ports and Waterways Safety System (PAWSS) RF Coverage Test Results"(PDF).Retrieved2006-03-11.
- ^Bragg, Marion (1977).Historic Names and Places on the Mississippi River.Vicksburg: Mississippi River Commission. Archived fromthe originalon 2006-01-28.