Stretching from the upper reaches of Minnesota to the Gulf of Mexico and droppingfrom an elevation of 1475 feet above sea level, the Mississippi is the second longest river inNorth America (only the Missouri is longer). As part of a navigable waterway system, it beginsin Minneapolis and flows for over 1800 miles as it joins other waterway arteries. Specifically,south of Minneapolis, the navigable portion of the Mississippi later couples with both theMissouri and Illinois rivers near St. Louis. Flowing further southward, in proximity to Cairo,Illinois, it is wedded with another major waterway discussed above, namely that of the Ohio andits adjoining tributaries. On its pathway to the Gulf, the enlarged Mississippi additionallyincorporates the Arkansas and Ouachita rivers as it approaches the end of its journey. Thus, theMississippi River itself is one of many interconnected waterways which are part of a largerembodiment, designated the Mississippi River Main Stem.Considering the Mississippi River itself, the river is often divided into two sections: theUpper Mississippi River and the Lower Mississippi River. The Upper Mississippi Riverstretches from Cairo, IL to Minneapolis, MN while the Lower Mississippi River is consideredthe portion of river between New Orleans, LA and Cairo, IL. The division of the river into theseparticular sections is due to the differences in river attributes along each section. The UpperMississippi River uses a series of locks to allow transportation on the northern part of the
Mississippi River, transportation that would not occur in the absence of the locks. South of
Cairo, IL. no locks are present due to the depth of this portion of the river. Because the locks
slow traffic along the river as barges must pass through one at a time, the Upper Mississippi is
usually considered a separate waterway. Not surprisingly, the amount of traffic on the river
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system increases as one moves down river as shown in Table 3-1. Note that this table has the
Mississippi River divided into three not two sections. In Table 3-1 the Upper Mississippi is the
section of the river between Minneapolis, MN and the mouth of the Missouri River. The
Middle Mississippi is the section of river between the mouth of the Missouri River and the
mouth of the Ohio River. Finally, the Lower Mississippi is below the mouth of the Ohio River.
Notice that traffic on the Lower Mississippi is more than double that on the Upper Mississippi,
with traffic in the Middle Mississippi being approximately 50% larger than that on the Upper
Mississippi.
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