Drainage Basin - Human Impacts

• Urbanisation impacts the drainage basin as trees and grass are removed and replaced with impermeable surfaces, increasing surface run-off
• As more land is concreted over, infiltration will decrease. This makes water gather on the surface in puddles which increases evaporation
• Water will flow through gutters and drains fast, so river levels will increase quickly.
• Deforestation impacts the drainage basin as trees are cut down so less water is intercepted. This increases infiltration as more water is hitting the ground, this leads to soil saturation.
• Saturated soil increases surface run-off, making the water return to the river faster.
• A lack of trees decreases transpiration, altering cloud formation which can impact local rainfall.
• Irrigation takes water from a river or groundwater storage, reducing river flow or the water table.
• By moving water from the ground to the surface, evaporation will increase.
• As crops grow, their roots take water from the soil. This increases transpiration.
• Water can be stored in dams, this increases evaporation
• Surface run off will be reduced as the water cannot move.
• As water is stored in one location, this allows it to begin to percolate into the rock below, increasing the water table.