7.2: Down to the Last Drop

Assignment Outcomes

  • Explore the consequences of human actions on water resources.
  • Examine the health impacts of availability to clean water.

Engage: Can human actions alter water resources?

Step 1: Go to the ArcGIS Online map, Down to the Last Drop, and explore the map.

Step 2: Examine the recent view of the Aral Sea in Central Asia.

Step 3: With the Details pan visible, click the button, Show Contents of Map.

Step 4: Click the checkbox to the left of the layer name, Aral Sea, 2000 (image) & 1960 (black outline).

Step 5: The image is from 2000 and the outline shows the 1960 extent of the sea before humans began to alter water flow to the Aral Sea.

  • What physical changes can be seen in the Aral Sea since humans altered the water flow?

Explore: Where are other lakes and rivers that are drying up due to human actions?

Step 6: Click the Bookmarks button. Select one of the other location bookmarks for a closer examination.

Step 7: Click the map marker to view detailed information about human alterations to this water resource.e

  • What human events have caused changes in water resources.
  • What natural events have caused changes in the water resource?

Explain: Why is the water to the Aral Sea decreasing?

Step 8: Select the Bookmark, Aral Sea Region.

  • Do both rivers reach the Aral Sea?

Step 9: Turn on the layers Aral Sea Watershed Dams and Irrigated Land in Aral Watershed.

  • Do dams or canals have the most significant impact? Zoom in to irrigated areas to view canals.
  • What factors could influence the placement of the dams and canals?

Elaborate: How would the Aral Sea drying up affect the surrounding areas?

Step 10: Turn on the layer, Aral Sea Dust Impact. Zoom out to see the impact area.

Step 11: Increased dust and salt storms sometimes send dust 500 km from the Aral Sea.

  • The reason why dust and salt storms occur is that the dry bed of the salty sea has no vegetation.
  • What environmental, economic, and health effects might this have on the surrounding areas? Look closely at the areas within the buffer.

Evaluate: How has human alteration affected the Colorado River?

Step 12: Press the button, Bookmarks. Select the Colorado River bookmark.

Step 13: Turn on the layer, Lower Colorado River Basin Dams and Canals.

Step 14: Zoom in and out to identify human alterations and causes.

  • What are some similarities and differences between the effects of human alterations on the Colorado River?


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