Water and carbon cycles 3 - Drainage Basin Flashcards
What type of systems are drainage basins?
Natural systems viewed as open hydrological cycles
What is a drainage basin?
The area surrounding the river where the rain falling on the land falls into that river
What is the watershed?
The boundary of a drainage basin
What is this area also known as?
Catchment
What happens to precipitation falling beyond the water shed?
Enters a different basin
What kind of system is a drainage basin
Open - receives inputs and outputs
How does water come into the system
Precipitation
How does water leave the system
Evaporation, transpiration and river discharge
What is an input
Water coming into the system
How does this happen
Through Precipitation
How is precipitation an input
Includes all the ways moisture comes out of the atmosphere. Precipitation is mainly rain, but also includes snow, hail, dew and frost
What is a store?
Water stored in the system
What are the 6 stores of a drainage basin
- Interception
- Vegetation storage
- surface storage
- Soil storage
- Groundwater storage
- Channel storage
What is interception
When some precipitation lands on vegetation or other structures, like buildings or surface or in wooded areas. It is only temporary because the water collected may evaporate quickly or fall from the leaves as through fall
What is vegetation storage
Water that’s been taken up by plants. All the water contained in plants at one time
What is surface storage
Includes water in puddles (depression storage), ponds and lakes
What is soil storage
Includes moisture in soil
What is groundwater storage
Water stored in the ground, either in the soil or rocks. The water table is the top surface of the zone of saturation .
What is the zone of saturation?
the zone of soil or rock where all the pores in the soil or rock are full of water
What are p0orous rocks that hold water called
aquifers
What is channel storage
Te water held in a river or stream channel
What are flows
Water moving from one place to another
What are the 10 flows in the basin
- Infiltration
- overland flow / runoff
- Throughfall
- Stemflow
- Throughflow
- Percolation
- Groundwater flow
- Baseflow
- Interflow
- Channel flow / river discharge
What is infiltration
Water soaking in the soil. Infiltration rates are influenced by soil type, structure and how much water is already in the soil
What is overland flow / runoff
Water flowing over land. It can flow over the whole surface or in little channels. It happens because rain is falling on the ground faster than infiltration can occur
What is through fall
Water dripping from 1 leaf to another
What is stem flow
Water running down a plant stem or tree trunk
What is through flow
Water moving slowly downhill through soil. It’s faster through pipes - things like cracks in the soil or animal burrows
What is percolation
The water seeping down through soil into the water table
What is groundwater flow
The water flowing slowly below the water table through permeable rock. Water flows slowly through most rocks, but rocks that are highly permeable with lots of joints have faster groundwater growth
What is base flow
Groundwater flow that feeds into rivers through riverbanks and river beds
What is interflow
Water flowing downhill through permeable rock above the water table
What is channel flow / river discharge
Water flowing in the river or stream itself
What is an output
Water leaving the system
What are the 4 outputs
- Evaporation
- Transpiration
- Evapotranspiration
- River discharge / flow
What is evaporation
Water turning into water vapour
What is transpiration
Evaporation in leaves - plants and trees take up water through their roots and transport it to their leaves where it evaporates to the atmosphere
What is evapotranspiration
Evaporation and transpiration together
What is potential evapotranspiration (PET) in comparison to actual evapotranspiration
The amount of water that could be lost by evapotranspiration, where as in actual it happens
What is river discharge / flow
The discharge of a river is the volume of water that flows through at a given time. Normally measured in cubic metres per second
What is evapotranspiration like in the dessert
PET is high as heat increases evaporation, but actual transpiration is low as there isn’t much moisture
What does the water balance show
The balance between inputs and outputs
What does the water balance affect
How much water is stored in the basin
What does the general water balance in the UK show
Seasonal patterns
What happens in wet seasons
Precipitation exceeds evapotranspiration
What does this create
A water surplus
Why does this create a surplus
The ground stores fill with water so there more surface run off and higher discharge so river levels rise
What happens in drier seasons
Precipitation is lower than evapotranspiration
What happens to the groundwater stores
They’re depleted as some water is used by plants or humans and some flows into the river channel but isn’t replaced by precipitation
What happens at the end of the dry season
There’s a deficit of water in the ground. The ground stores are recharged in the next season
