Geography, Answer questions
GEOG 1216 – Autumn 2016 developed by Helen Hazen 1 In-Class Activity 5: Drainage Basin Characteristics Google Earth A. Mississippi Delta Fly to New Orleans 1. Zoom in until you can identify the individual canals and levees that make up the city’s Hurricane Protection System. Look for floodgates at the edge of the city. How does this levee system protect the city from flooding; why is it needed? How might it actually make the effects of flooding worse? 2. Fly to the Lower Ninth Ward. Check the ‘imagery date’ at the bottom of the screen to see whether these pictures are pre- or post-Katrina. What proportion of this neighborhood has been rebuilt? Think of TWO advantages of rebuilding this neighborhood in the same place after the hurricane and TWO disadvantages. 3. Identify the Mississippi river flowing through New Orleans. How do you know that this is the lower course of the Mississippi river? 4. Follow the Mississippi to the coast and look for its distributaries. What is the name of the landform at the mouth of the Mississippi river as it enters the sea? Explain in no more than TWO sentences the processes that form this landform. How has the construction of levees around New Orleans influenced the lower course of the Mississippi drainage basin? 5. See if you can find evidence of the canals built by the petrochemical industry along the Louisiana coast. How do you know that the canals you are looking at are not naturally occurring? GEOG 1216 – Autumn 2016 developed by Helen Hazen 2 B. Amazon Basin Fly to the Amazon River where it meets the Atlantic 1. Look at the complex and extensive system of distributaries at the river’s mouth. Use the “measure” tool in the upper toolbar to measure the length of one of the larger islands in the mouth of the river. Compare this to the length or width of a place you are familiar with to get a sense of the huge scale of the Amazon River. 2. Follow the Amazon upriver towards Manaus. How would you characterize the gradient of the land around Manaus from clues you got from looking at the river (i.e., don’t just look at the elevation figures at the bottom of the screen!)? 3. At Manaus the Rio Negro joins the main Amazon channel. Note the very different colors of these two rivers. How can you explain this difference in color? Provide a hypothesis for why the two rivers do not mix immediately. 4. Fly west along the main course of the river until you reach the Lago do Tomaniqua. What is this feature? Explain in a few sentences how this feature formed. 5. Continue upriver until you reach the Peruvian border and then the town of Iquitos. Look at the characteristics of the river at this point. Does the river appear to be lower, middle, or upper course at this point? What evidence did you use to come to this conclusion? What does this tell us about the gradient of the Amazon drainage basin? GEOG 1216 – Autumn 2016 developed by Helen Hazen 3 6. Keep following a tributary upriver until you notice a change in the landscape that implies that you have reached the upper course of the river. How do you know that you are now in the upper course of the river? 7. Zoom out to identify exactly where you are in South America. What can you now conclude about the location of the continental divide in South America? 8. Try to locate some rivers that flow westwards from the Andes to the Pacific. How are these rivers different from the Amazon? Explain why these rivers differ so significantly in their capacity. C. Nile Valley Fly to the point where the Nile meets the Mediterranean 1. What formation is found at the mouth of the Nile? 2. Egyptologists have had difficulties finding some ancient cities that are described in ancient texts as situated on distributaries in the Nile Delta. One of your Egyptology colleagues explains that he knows that the city of Tanis is supposed to be on the banks of one of the Nile’s distributaries but that he has searched satellite footage and cannot find evidence of this settlement along any of the Nile’s distributaries on the current satellite maps. As a physical geographer, explain to your Egyptology colleague why he may be looking for Tanis in the wrong place. GEOG 1216 – Autumn 2016 developed by Helen Hazen 4 3. Find the Aswan Dam. How do you think the damming of the Nile has affected the characteristics of the river? Think about water and sediment characteristics in your answer. 4. In which two distinct regions does the Nile rise? (Follow the “White Nile” and the “Blue Nile.”) What characteristics of these regions help to explain why they receive more abundant precipitation than most of the course of the Nile? D. Ganges/Brahmaputra River Basin Fly to the Ganges delta in Bangladesh 1. Fly over Bangladesh, keeping an eye on the elevation figures (‘elev’) at the bottom of the screen. Look also at the shape of the coastline and the layout of watercourses in the country. List THREE explanations related to physical geography that may help account for why Bangladesh is one of the most flood-prone countries in the world. 2. Travel upriver from the delta, past Dhaka, to where the Brahmaputra and Indus rivers divide. Follow the eastern branch of the river (the Brahmaputra) to the Indian border. Zoom in until you can see the details of the river channel. What type of river formation is this? What is the key factor that is essential for the creation of this type of riverbed? 3. Follow one or more of the Brahmaputra’s tributaries as far upriver as possible. Where does the Brahmaputra River rise? What sorts of landscape features can you identify in this part of the river’s course? Apart from monsoon rains, what provides a significant additional source of water for the Brahmaputra?