1.A.3 The drainage basin, water cycle and soil moisture budget

Inputs into a drainage basin

Precipitation

Solar energy (Inputting energy to drive river)

outputs of a drainage basin

Evapotranspiration of water

Runoff into a river then out to sea

Human use

Water percolating deep into the underground store(leaving the drainage basin)

Transfers/flows in a drainage basin

surface runoff

infiltration

percolation

through flow

groundwater flow

stem flow

through fall

Stores in a drainage basin

Interception store

Vegetation storage

Surface storage

Soil storage

Factors affecting the drainage basin water cycle

climate/weather

amount of water

wind

geology

gradient

permeability of rock

level of saturation

River regime

how the river discharge changes across the year in response to precipitation, temperature, evapotranspiration and drainage basin characteristics

Soil moisture budget

The relationship between precipitation and evapotranspiration over a year

Soil moisture surplus

There is more water in the soil than usual

soil moisture utilisation

precipitation rates lower so the spare water gets used up

soil moisture defecit

the spare water has been used up but precipitation rates are still low

soil moisture reharge

evapotranspiration rates lower and precipitation rates increase so the levels of water in the soil recharge

Soil moisture budgets worldwide

in equatorial countries where seasons aren’t a thing, precipitation rates and temps remain high all year. There are two wet seasons and very short periods of low precipitation meaning there is water for vegetation all years round

In hot countries north of the equator there is 1 wet season so soil moisture is recharged, and surplus doesn’t last long due to the high temps,. There is long dry seasons so water dries up very quickly, long periods of deficits.