Throughflow - GCSE Geography Definition

Throughflow is the movement of water through the soil layer when rainwater infiltrates the ground from above and then travels horizontally through the soil to reach rivers or streams. This process occurs in the zone above the water table, where the soil is not completely saturated. Throughflow is an important part of the water cycle because it helps to transport nutrients and sustains river flows between rainfall events. Factors like soil type, vegetation, and land slope can affect the speed and amount of throughflow. For example, sandy soils allow water to pass through more quickly than clay soils.