Question

How do humans play a role in the water cycle?

Answer 1

Answer:

We are becoming increasingly aware of or impacts on nature. There is considerable evidence that humans are responsible for disruptions and changes to local and global water cycles.

Earth’s water distribution

A number of human activities can impact on the water cycle: damming rivers for hydroelectricity, using water for farming, deforestation and the burning of fossil fuels.

Different countries use different amounts of water, but we all tend to use them in the same ways, and some of these actions can impact on the water cycle – generating hydroelectricity, irrigation, deforestation and the greenhouse effect, as well as motor vehicle use and animal farming.

Hydroelectricity

Most of New Zealand’s electricity is generated using hydro dams. This involves changing the stored gravitational energy of water held behind the dam into electrical energy that can be used. While this is a non-polluting renewable way to generate electricity, it does have environmental impacts – especially when mismanaged.

Rights: The University of Waikato

Clyde hydro dam

The Clyde dam in the South Island uses water to generate electricity. It is New Zealand’s third largest hydro dam.

Rivers must be dammed, which can affect the function of the river both upstream and downstream – lakes are usually formed from the water accumulating above the dam and a build-up of silt can occur, while the amount of water is reduced further downstream. This can be problematic for any plants and animals that may find themselves with too much or too little water, and migrating fish cannot get through the dams.

Seriously mismanaged dams can result in droughts downstream, with smaller streams completely drying up, leaving areas of unwatered land. People then have to look at ways of getting more water into these dry areas