 There are no lock and dams on the lower Missouri River , but there are plenty of wing dams that jettie out into the river and make it harder for barges to navigate . In contrast , the upper Mississippi has 29 locks and dams and averaged 61 @.@ 3 million tons of cargo annually from 2008 to 2011 , and its locks are closed in the winter . 
 <a href='dey_it' title='1'><mark>There</mark></a> are no lock and dams on the lower Missouri River , but <a href='dey_it' title='2'><mark>there</mark></a> are plenty of wing dams <a href='null_relcl' title='3'><mark>that</mark></a>jettie out into the river and make it harder for barges to navigate . In contrast , the upper Mississippi <a href='got' title='4'><mark>has</mark></a> 29 locks and dams and averaged 61 @.@ 3 million tons of cargo annually from 2008 to 2011 , and its locks are closed in the winter . 
It ain't no lock and dams on da lower Missouri River , but it is plenty of wing dams jettie out into the river and make it harder fa barges to navigate . In contrast , tdaupper Mississippi got 29 locks and dams and averaged 61 @.@ 3 million tons of cargo annually from 2008 to 2011 , and its locks r closed in thdainter .