Hydrological Characteristics | Geography for GCSE/IGCSE - Year 11 PDF Download

The Characteristics & Processes of Rivers

Water on Earth

• Only 2.5% of Earth's water is freshwater.
• Glaciers and ice sheets hold 68.7% of freshwater, while groundwater constitutes 30%.
• The remaining 1.3% of freshwater is distributed among rivers, soil moisture, lakes, and the atmosphere.
• All water participates in the hydrological cycle.

The Hydrological Cycle

• The hydrological cycle operates as a closed system.
• Water undergoes continuous recycling within this system.
• Within the hydrological cycle, there are reservoirs and movements (transfers).

Stores of Water

Stores refer to places where water is held for a period of time. They encompass:

• Water in the atmosphere, either as water vapor or water droplets in clouds.
• Surface stores like puddles, lakes, rivers, and reservoirs.
• Interception, which occurs when precipitation is hindered from reaching the ground, often by getting caught on leaves or branches.
• Aquifers, which are permeable rocks such as limestone and sandstone capable of holding water.
• Ice, snow, seas, and oceans.

Flows of Water

Flows represent the ways in which water moves through the hydrological cycle. These include:

• Evaporation: The process where water transforms from liquid to vapor due to heat.
• Condensation: The change of water vapor into liquid water, forming clouds.
• Transpiration: The release of water vapor by plants through their leaves.
• Evapotranspiration: The combined process of evaporation and transpiration from the Earth's surface.
• Precipitation: The release of water from clouds in the form of rain, snow, sleet, or hail.
• Overland flow: The movement of water over the land surface due to excess rainfall or snowmelt.
• Infiltration: The process by which water soaks into the ground surface.
• Percolation: The movement of water through soil and porous rock layers.
• Through flow: The lateral movement of water through the soil layer.
• Groundwater flow: The movement of water through underground aquifers and permeable rocks.