What role does Hoover Dam play in the Colorado River water supply scheme?

Completed in 1936, it impounds Lake Mead, the largest reservoir by volume in the USA, storing water for irrigation and cities and generating hydroelectric power.

What is the Central Arizona Project?

A canal of about 336 miles (541 km) that lifts Colorado River water from Lake Havasu to Phoenix and Tucson, using large amounts of energy for pumping.

How has the Colorado River water supply scheme affected the river's delta in Mexico?

So much water is extracted that the river rarely reaches the Gulf of California, and the delta's wetlands have shrunk to about a tenth of their former extent.

How do dams on the Colorado River affect sediment and ecosystems downstream?

Reservoirs trap sediment, so releases are clear and cold, eroding sandbars in the Grand Canyon and harming native fish such as the humpback chub.

AQA A-Level Geography 7037

Water and Carbon Cycles

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Resource Security

The Colorado River water supply scheme

3 things to know
Component 2

Overview

The Colorado River water supply scheme as a case study of water resource development, covering Hoover Dam, the aqueducts that carry water to desert cities, the environmental costs downstream, and why the river is over-allocated.

What you need to know

Answer each one before you reveal it.

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Key term

What is the Colorado River Aqueduct?

Process

Why is water lost from reservoirs in the Colorado River scheme?

Process

How many people depend on water from the Colorado River?

Questions from this subtopic

Each one with the model answer underneath.

1
How many people depend on water from the Colorado River?
Model answer
About 40 million people in seven US states and Mexico, including the cities of Los Angeles, Phoenix and Las Vegas.
2
What role does Hoover Dam play in the Colorado River water supply scheme?
Model answer
Completed in 1936, it impounds Lake Mead, the largest reservoir by volume in the USA, storing water for irrigation and cities and generating hydroelectric power.
3
What is the Colorado River Aqueduct?
Model answer
A 242-mile channel completed in 1941 that carries Colorado River water to urban southern California.
4
What is the Central Arizona Project?
Model answer
A canal of about 336 miles (541 km) that lifts Colorado River water from Lake Havasu to Phoenix and Tucson, using large amounts of energy for pumping.
5
How has the Colorado River water supply scheme affected the river's delta in Mexico?
Model answer
So much water is extracted that the river rarely reaches the Gulf of California, and the delta's wetlands have shrunk to about a tenth of their former extent.
6
How do dams on the Colorado River affect sediment and ecosystems downstream?
Model answer
Reservoirs trap sediment, so releases are clear and cold, eroding sandbars in the Grand Canyon and harming native fish such as the humpback chub.

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AThe horns have less sand volume, so they move more quickly.

BSand is transported up the gentle windward slope via saltation.

CSand accumulates at the crest.

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