Evaluating the Transport and Fate of Nutrients in Large Scale River Basins Using an Integrated Modeling System - Landscape Ecology for Sustainable Environment and Culture - page 182

of watershed management scenarios implemented to address problems in the
downstream.

10.2 Upper Mississippi River Basin

The Upper Mississippi River Basin (UMRB) is located in the Midwest United
States and is one of the seven major basins contributing to the Mississippi River
(Fig. 10.1 ). The Mississippi River is the seventh largest in the world, based on
discharge (580 km 3 year -1 ); whereas the MRB is the third largest in the world
based on area (3,225,000 km 2 ). The Mississippi river flows some 3,770 km
downstream from Lake Itasca, Minnesota, through ten states and eventually dis-
charges to the Gulf of Mexico. The UMRB includes more than 2,011 km of the
Mississippi River extends from the Mississippi River head water at Lake Itasca in
Minnesota to the confluence of Mississippi and Ohio Rivers at Cairo in Illinois.
The Mississippi River is divided into the upper and lower basin at Cairo, Illinois
where the Missouri River enters as the last major tributary. UMRB has the greatest
amount of artificially drained soil, the highest percentage of total land in agri-
culture (corn and soybean) and the highest use of nitrogen fertilizers in the nation.
The Upper Mississippi River (UMR) has been defined by the U.S. Congress as
active commercial navigation routes within the UMRB. The UMRB has a total
drainage area of approximately 490,000 km 2 , about 15 % of the entire MRB,
including large parts of the states of Illinois, Iowa, Minnesota, Missouri, and
Wisconsin. Small portions of Indiana and South Dakota are also within the basin.

Fig. 10.1 Geographic locations of Mississippi River sub-basins