Human impacts of hydrological cycle

Question 1

Deforestation

Answer 1

The cutting down of trees increases run-off and the potential for soil erosion. Decreases in evapo-transpiration and therefore cloud formation impacts on local rainfall patterns. Changes to vegetation cover can lead to more extreme river flows as water is not intercepted and stored by the trees. For example, Maharashtra, India

Question 2

Irrigation

Answer 2

Taking water from a river or ground water storage can reduce river flow. Lowering water tables and increasing evaporation/evapo-transpiration by placing water in surface stores, eg ditches/canals. Increased farming opportunities provided by irrigating crops removes water from the hydrological cycle as the crops
grow. For example, Bengkulu, Indonesia.

Question 3

Urbanisation

Answer 3

The removal of natural vegetation and replacement with impermeable concrete/hard surfaces and drains can
speed up overland flow and can lead to higher river levels. As more urban land is concreted over the rate of evaporation from these surfaces increases as the rate of percolation through the land surface decreases. It also decreases the amount of water which returns to groundwater storage, possibly reducing the water table.
For example, Hurricane Harvey, Houston, USA.

Question 4

Mining

Answer 4

The silting up of lakes, rivers and reservoirs leads to reduced storage capacity in these areas. Mining may also lead to reduced vegetation cover leading to increased run-off, higher evaporation and cloud
formation altering the rainfall pattern. For example, Kadoma, Zimbabwe.