Water Cycle Flashcards
What is a drainage basin
An area where precipitation collects and drains into a common river/body of water
is a darinage basin an open or closed system
Open - it has inputs and outputs of energy and matter (water)
Give the input to a drainige basin
Precipitation
Give 7 stores in the drainage basin
- Groundwater storage
- Soil moisture storage
- Chanell storage
- Water table (top layer of ground water storage)
- Sufcare storage
- Interception
- Vegitation storage
Give 7 outputs of the drainage basin
- Stemflow
- Surfecae run off
- Throughflow
- Channell flow
- Groundwater
- Inflitration
- Percolation
What is water balance
The relationship betwen the inputs and outputs of a water system
river discharge = percipitation - evapotranspiration +/- change in stores
What is soil mositure surplus
Percipitation is greater than potential evepotranspiratuon. The soil water store is fullso there is a surplus of soil moisture for plant use and runs off into streams
What is soil moisture utilisation
Potential evapotranspiration is greater than precipitation so plants must rely on water stored which gradually gets used up.
What is soil moisture defiency
Plants must have adpations to survive as there evaportarnspirtaion is greater than precipitation with no remaining water stores
What is soil moisture recharge
Perticiation is now greater than potential evaportation so the soil water store’s will start to fill up again
How do you draw a water ballence graph
y axis = precipitation / evaporation
x axis = months
plot two lines, one for evaportatio and one for percipitation. Lable the ares underneath
What is discharge
The amount of water in a river flowing pasta. paticular point. It is measured in cubic meters per second
Discharge = cross sectional area (m2) x velocity (m/s)
What is a hydrograph + 2 variations
Record of river discharge over time (rainfall always in a bar graph)
Strom hydrograph = shows a change in discharge caused by a period of rainfall
Annual hydrograph = shows variability in discharge over the course of one year - (river regime)
What is overland flow
Volume of water reaching the river from the surface run-off
What is through flow
Volume of water reaching the river through the soil layers
Overland flow + Throgh flow =
Strom flow
How do you draw a hydrograph
y axis = Discarge
x axis = Hours/days/month from start of rain strom
Rainfall bar chart in left cornr (bottom)
basin lag time
What is the rising limb
Rising flood water in a river
Falling limb = opposite
WHat is base flow
Normal discharge of a river, mainly from groundwater flow
Give the 3 types of hydrograph
Flashy
Delayed
Unnusual
Give the charatristics of a flahy hydrograph
- Short lag time
- High, fast peak
- Steep rising limb
WHat causes a flahy hydrograph
- Highly urbinised catchment
- Circular basin
- High drainage density
- Very intense strom with early peak
- Clay/soil with high antedecant moisture
- Small basin
- Steepsided river basin
- Immermable rock type
What causes a delayed hydrograph
- Low antecedent moisture
- Sandy soil with many pores
- Forested catchment area with high interception
- Large basin
- Elongated basin shape
- Low levels of urbanisation
WHat casues an unusual hydrograph
- Clover shaped basin
- Variable rock type/ topography
- Twin peaks relate to storm events in upper part of the basin
Why does a small basin causea flahy hydrograph
short lag time, water arrives all at once
Why does a circular shape causea flahy hydrograph
All tributaies at equal distance from main river -flow of water arrives at same time
The steeper the slop the……..the lage time
Shorter
Permable rock = little………casuing a…………flood
Inflitration
Larger
High drainage density means………over land flow (…….)
Quicker
Flashy
Dranige density = number of rivers ina. basin. Few rivers mean perticipation is lost to inflitartion or intecpetion
