Arid Environments

Question 1

What are large perennial rivers?

Answer 1

Exogenous rivers (with source outside of arid area) e.g the Nile in the Ethiopian Highlands
- Very important on national and international scales, often controlled by dams etc

Question 2

What are small perennial rivers

Answer 2

Exogenous rivers with limited discharge, often of local or regional importance e.g Yaramuk in Middle East

Question 3

What are shallow aquifers

Answer 3

• Limestone hills / mountains that contain large underground water supplies e.g Atlas Mountains in Morocco

Question 3

What are Wadi’s?

Answer 3

• Dry river beds which only intermittenly carry water, most endogenous
• Some are allogenic, so carry water from outside desert until evaporations exceeds discharge, where they dry up
• Only filled after large and irregular precipitation events

Question 4

What are deep fossil aquifers

Answer 4

• Larger underground supplies that cover over 1,000km^2
• Water comes from pluvial periods, therefore is often non renewable
  e.g Great Artesian basin in Simpson Desert in Australia

Question 5

What is direct interception of coastal mist and fog?

Answer 5

• In hyperarid conditions, can contain 3-600mm of rainfall per year
• If trapped, could increase meteorlogical water available by 500%
• In Atacama, can harvest 200-400L per day

Question 6

What are desalination plants?

Answer 6

• A long term solution in coastal arid regions
• A highly expensive processes means only wealthy countries can do it
• Could be supported by solar energy when technology appears

Question 7

How can snow and ice give water to arid areas?

Answer 7

• In desert areas near high mountain ranges, meltwater provides a key source of water, such as in the Atacama and Gobi
• In Andes, much of the meltwater is evaporated before it reaches mountains.