3.1.1.2 GD The water cycle (Part 1)

Outline the four major stores of water:

Hydrosphere

Cyrosphere

Lithosphere

Atmosphere

Explain the role of cryospheric change in the water cycle [4 marks]

The cryosphere is a major store of water and is any water that is frozen. This storage accounts for 1.7% of all water on earth.

During cooling periods, such as glacial periods, the cryosphere expands, slowing down the water cycle as ice restricts water from returning to the sea. Conversely, during warming periods, the cryosphere releases water into the cycle as ice melts, leading to increased volumes of water in the oceans. This, coupled with thermal expansion, causes sea levels to rise.

Explain the role of hydrospheric change in the water cycle [4 marks]

The hydrosphere is a major store of water and is any water that is liquid. The hydrosphere acts as a vast reservoir of water, including oceans, rivers, lakes and groundwater. This storage accounts for 96.5% of all water on earth

Processes impacting upon this important store include precipitation inputting water to the store and evaporation moving water from the ocean into the atmospheric store. These changes have minimal impact upon the storage capacity, however long term climatic change events such as ice ages do have the potential to lower the storage capacity significantly

Explain the role of lithospheric change in the water cycle [4 marks]

The lithosphere is a major store of water and is any water that is stored in the crust and the upper mantle. This storage also accounts for 1.7% of all water on earth.

Water can flow through the lithosphere into underground aquifers but this transfer may be relatively slow, often taking many years. Some water is stored within bedding planes, joints and pores in rocks and can remain there for hundreds of years.

Explain the role of atmospheric change in the water cycle [4 marks]

The atmosphere is a major store of water. This storage accounts for approx 0.001% of all water on earth. The atmosphere has water held in the air as gas, clouds, and precipitation.  The Amount of water found in the atmosphere is only 12,900km³, 8% of all easily accessible freshwater

The amount of water vapour that can be held in the air depends on its temperature.  Cold air cannot hold as much vapour as warm air. This results in air over the tropics being humid and air over the  poles being very dry. 

Describe how evaporation acts as a water flow [4 marks]

Evaporation is the process of turning from a liquid to a gas. 

Rates of evaporation depend on:
• Amount of solar energy
• Availability of water
• Humidity of the air - The more humid the air the closer to saturation point the air is so less evaporation will occur
• Temperature of the air – Warmer air can hold more water than cold air.

Outline how condensation occurs in the water cycle [4 marks]

Condensation is the conversion of a vapour or gas in the atmosphere to liquid. As air cools, it can't hold as much moisture, leading to droplet formation. These droplets condense onto particles, forming clouds, which eventually release precipitation, like rain or snow, completing the water cycle.

Outline how clouds form in the water cycle [4 marks]

Clouds form as a result of condensation, which is the conversion of a vapour or gas in the atmosphere to liquid. Tiny water droplets then gather around condensation nuclei like dust or smoke particles, eventually accumulating to form visible clouds. Gravity causes clouds to fall because of their own weight and release precipitation which flows into the hydrosphere. Some common types of clouds include cumulus and cirrus.

Cloud forms as a result of condensation - when water vapour condenses around tiny particles called condensation nuclei, which serves as nuclei for the droplet formation. Gravity causes clouds to fall because of their own weight and release precipitation which flows into the hydrosphere. Some common types of clouds include cumulus and cirrus.

Outline the causes of precipitation in the water cycle [4 marks]

Precipitation is the main input into the drainage basin system.  Precipitation includes rain, drizzle, sleet, snow and hail. Precipitation results from the condensation of water vapour falling due to gravity and this process occurs after evaporation thus completing the water cycle.

How do cryospheric processes impact the drainage basin [4 marks]

Cryospheric processes on hill slopes involve freezing and thawing of water in the soil and rock, causing expansion and contraction. This can lead to mechanical breakdown, creating frost heave and potentially destabilizing the slope. Permafrost, where the ground remains frozen for extended periods, also affects slope stability.

Outline flows within the water cycle operating on a hill slope [4 marks]

Groundwater flow is the movement of water through permeable rock under the force of gravity. This is the slowest flow of water on a hillslope

Overland flow/surface runoff occurs when precipitation runs directly over the ground. It occurs when the amount of precipitation exceeds the soil's capacity to absorb it or when the ground is saturated. Runoff is faster at a hillslope than flatter terrain, as water has less opportunity to infiltrate into the soil and more tendency to flow over the surface.