Compare the length (in miles) of the “boundary course” of the river with the main channel of the present course. (You can measure the distance with a piece of string, or your instructor may show you a more precise method.)

Question

The following questions are based on Map T-5, a portion of the “Jackson, Mississippi-Louisiana” topographic map (scale 1:250,000; contour interval 50 feet; dashed lines are supplementary contours at 25-foot intervals). This map shows the Mississippi River near the town of Vicksburg, Mississippi (32°49'56"N, 91°11'07"W). A color satellite image of this same region is shown in Figure 40-5 (scan the QR code for this exercise or go to the Lab Manual website and Exercise 40). The eastern bluffs of the Mississippi River floodplain can be seen in the southeast corner of the map. The dashed black line along the Mississippi River shows the state boundary between Mississippi and Louisiana. Notice that the “boundary course” of the Mississippi River is quite different from the present course of the river. Some of the changes were natural, others were artificial. There is an extensive set of artificial levees along the course of the river (shown with closely spaced brown tick marks).


(a) Length of present course: __________ miles
(b) Length of “boundary course”: __________ miles
(c) Amount of shortening: __________ miles
(d) The present course length represents what percentage
of the boundary course length? "present" / "boundary" x 1002 __________ %

Answer 1

(a) about 61
(b) about 112
(c) about 51
(d) 54