Drainage Basin Systems Flashcards
What is Condensation?
The process of water vapour changing to liquid water
What are Cryospheric Processes?
Processes that affect the total mass of ice at any scale.
They include accumulation and ablation.
What is accumulation?
The build up of ice mass
What is Ablation?
The loss of ice mass
Define a Drainage Basin
A drainage basin is an area of land drained by a river and its tributaries, including water found on the surface, soil and near-surface geology.
What is evaporation?
Evaporation is where liquid water changes a gas. This requires energy, provided by the sun and aided by the wind.
What is Evapotranspiration?
The total output of water from the drainage basin directly back into the atmosphere.
What is Groundwater flow?
The horizontal flow of water once it has reached the water table.
What is infiltration?
The downward movement of water from the surface into the soil
What is interception storage?
The precipitation that falls on the vegetation or human cover is temporarily stored on these surface.
What happens to water stored in interception storage?
Intercepted water is either evaporated to the atmosphere or absorbed by canopy surfaces and transferred to the ground surface
What is overland flow?
The tendency of water to flow horizontally across land surfaces when rainfall has exceeded the infiltration capacity of the soul and all surface stores are full to overflowing
What is Percolation?
The downward movement of water within the rock under the soil surface. Rates vary depending on the nature of the rock.
What is Run-off?
All the water that enters a river channel and eventually flows out of the drainage basin
What does saturated mean?
This applies to any water store that has reached its maximum capacity
Define Stemflow
Stemflow is the portion of precipitation intercepted by the canopy that reaches the ground by flowing down stems, stalks or tree bole
What is a storm/rainfall event?
An individual storm is defined as a rainfall period separated by dry intervals of at least 24 hours and an individual rainfall event is defined as a rainfall period separated by dry intervals of at least 4 hours.
What is Throughfall?
The portion of the precipitation that reaches the ground directly through gaps in the vegetation canopy and drips from leaves, twigs and stems.
What is ThroughFLOW?
The horizontal flow of water through soil or rock layers.
Movement of water down-slope through the subsoil under the influence of gravity. Particularly effective when underlying permeable rock prevents downward movement.
Define Transpiration
The loss of water from vegetation through pores (stomata) on their surface.
What is the Water Balance?
The balance between inputs and outputs in a drainage basin
When does Transpiration occur?
It occurs mostly when the canopy surface rainwater storage exceeds its storage capacity.
