Cycles Flashcards
Define Input (In a system)
Material or energy moving into the system from outside.
Define Output (In a system)
Material or energy moving from the system to the outside.
Define Energy (In a system)
This is the power or driving force.
Define Stores/Components (In a system)
The individual elements or parts of a system.
Define Flows/Transfers (In a system)
The links or relationships between the components.
Define Positive Feedback (In a system)
A cyclical sequence of events that amplifies or increases change, promoting environmental instability.
Define Negative Feedback (In a system)
A cyclical sequence of events that damps down or neutralises the effects of a system, promoting stability and a state of dynamic equilibrium.
Define Dynamic Equilibrium (In a system)
This represents a state of balance within a constantly changing system.
What is the difference between lithosphere, hydrosphere, cryosphere and atmosphere?
- The lithosphere is the outermost solid layer of the earth, contains the crust and the upper mantle (Land).
- The hydrosphere is all the water on/surrounding the Earth, such as the ocean, rivers and water in the atmosphere (Liquid Water).
- The cryosphere is the frozen parts of Earth’s surface including ice caps, glaciers and snow cover (Frozen Water)
- The atmosphere is the air that surrounds the Earth (Air)
How much of the world’s global water is freshwater?
Only 2.5%
Which two stores of water remains the longest and the shortest?
Longest store = Groundwater (10,000 years)
Shortest store = Soil water (1-2 months)
Define Precipitation (A process in the water cycle)
Transfer of water from the atmosphere to the ground. It can take the form of rain, snow, hail and dew.
Define Evaporation (A process in the water cycle)
Transfer of water from liquid state to gaseous state (Water Vapour). The vast majority occurs from the oceans to the atmosphere.
Define Condensation (A process in the water cycle)
Transfer of water from a gaseous state to a liquid state, for example, the formation of clouds.
Define Sublimation (A process in the water cycle)
Transfer from a solid state (Ice) to a gaseous state (Water Vapour) and vice versa.
Define Interception (A process in the water cycle)
Water intercepted and stored on leaves of plants.
Define Overland Flow (A process in the water cycle)
Transfer of water over the land surface.
Define Infiltration (A process in the water cycle)
Transfer of water from the ground surface into soil where it may then percolate into underlying rocks.
Define Throughflow (A process in the water cycle)
Water flowing through soil towards a river channel.
Define Groundwater Flow (A process in the water cycle)
Transfer of water very slowly through different rocks.
Define Percolation (A process in the water cycle)
Water soaking into rocks.
What are the stores within the water cycle?
- Rivers
- Lakes
- Soil and Groundwater
- Glaciers/Ice
- Trees and Vegetation
- Clouds/atmospheric
What factors can change the magnitudes of stores in the water cycle?
- Deforestation- Prevents interception and infiltration rates, but increases overland flow. (This reduces the vegetation stores and soil stores, but increases river and lakes stores)
- Urbanisation -If slopes are developed, impermeable surfaces will reduce infiltration, however water will travel much quicker through drains and pipes. (This reduces the soil stores, but increases river and lake stores.
- Farming - Ditches drain the land and encourages water to flow quickly to rivers. Irrigation increases the amount of water on the ground as well. (This reduces the vegetation stores , however increases river and lake stores as well as the soil/groundwater stores.
- Storm - Intense rainfall increases the amount of rainfall reaching the ground and increases the magnitude of stores. (This is increasing all stores in this system at the expense of another system)
- Seasonal Change - Winter snowfall and frozen ground interrupts the water transfers and affects the magnitude of stores. (This reduces all the stores besides the glaciers and ice store)
What are the flows within the water cycle?
- Evapotranspiration (Evaporation and Transpiration)
- Precipitation
- Overland flow
- Infiltration
- Percolation
- Groundwaterflow
- Throughflow
- Overland Flow
- Streamflow
What is the main inputs in the water cycle?
Precipitation
What are the main outputs in the water cycle?
Evapotranspiration and Streamflow
What is a drainage basin?
A drainage basin is the area of land that is drained by a river and its tributaries. The edge of a river basin is also marked by a boundary called watershed.
Is the drainage basin system an open or closed system?
It is an open system, with inputs (precipitation) and outputs (runoff and evapotranspiration).
What is the water balance expressed as?
P = O + E + Change in S Where: P = Precipitation O = Total runoff E = Evapotranspiration S = The change in the storage (in soil and rocks)
Why is understanding the water balance a good idea?
Because this helps hydrologists plan for future water supply and flood control by understanding the unique hydrological characteristics of an individual basin.
How do you calculate discharge? (m^3s^-1)
Cross sectional area (m^2) x velocity (ms^-1)
What is a flood hydrograph?
This is a graph showing the discharge of the river over time following a particular stormy event.
What are the characteristics needed for a short lag time and high peak hydrograph? (Using basin size, drainage density, rock type, land use, relief, soil water and rainfall intensity)
Basin size: Small Drainage Density: High density Rock Type: Impermeable Land Use: Urbanised area Relief: Steep slopes Soil Water: Saturated soil Rainfall Intensity: Heavy rainfall > Infiltration rates
What are the characteristics needed for a long lag time and low peak hydrograph? (Using basin size, drainage density, rock type, land use, relief, soil water and rainfall intensity)
Basin size: Large Drainage Density: Low density Rock Type: Permeable Land Use: Forests/green areas Relief: Flat land/gentle slopes Soil Water: Dry soil Rainfall Intensity: Light rainfall < Infiltration rates
What are the human factors that can affect the water cycle?
- Irrigation from Farming.
- Land-Use change (Urbanisation/Deforestation).
- Water Abstraction (Industry, domestic purposes)
What are the natural factors that can affect the water cycle?
- Seasonal Weather
- Drought
- Severe Storms
