Name ____________________________
Unit 3 Homework
The Mississippi River flows for 3,734 km across the central portion of North America and drains
40% of the continental United States. It is the fourth largest river in the world by volume of
water and the tenth longest. The central United States has not experienced any major mountain
building activity for the past 250 million years. In contrast, the Nooksack River and Rio Puerco
have experienced several episodes of mountain building over the past 10 million years that
continue to this day. Lastly, the Mississippi River only flows across glacial sediment and
sedimentary rocks.
Below is a graph showing the profiles for these three rivers. Their lengths and heights have been
adjusted so all three profiles can fit on one graph. Answer the following questions based on your
observations from Unit 3.
Elevation Above Mouth
Mouth
Headwaters
2000 m
1800 m
1600 m
1400 m
1200 m
1000 m
800 m
600 m
400 m
200 m
0m
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0%
Percentage of River Length
Nooksack
River
Rio
Puerco
Mississippi
River
HW-1. Compare and contrast the profile for the Mississippi River and the profiles for the other
two streams. How are they the same? How are they different?
1
HW-2. What are some reasons why the Mississippi River profile is so different from the other
rivers?
HW-3. The cities of Riverton and Watertown are located on the Running River, which
periodically floods. The riverfront properties for both cities contain numerous attractions,
entertainment venues, recreation facilities, and expensive homes with access to the river.
Based on what you observed in today’s lesson, answer the following questions regarding
these cities.
A) Is one city more vulnerable to erosion or are they equally in danger? Explain your
reasoning.
B) Would the risk to erosion change if this area were in a dry climate instead of a humid
climate? Why or why not?
C) Name one action that either city could take to protect its bank against erosion.
Running
River
5 km
Riverton
Watertown
2
HW-4. Suppose you could travel 1,000,000 years into the future and visit the river you looked at
in detail (either the Nooksack River or Rio Puerco). Assume that all other factors such as
sea level and climate have not changed during that time. What would the river’s profile
look like? Draw that profile on the graph below and explain why this profile would have
that shape.
Elevation Above Mouth
Mouth
Stream Profile of the Nooksack River or the Rio Puerco
1 Million Years in the Future
Headwaters
2000 m
1800 m
1600 m
1400 m
1200 m
1000 m
800 m
600 m
400 m
200 m
0m
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0%
Percentage of River Length
3