The water balance Flashcards
What is the water balance?
a simple equation to plan for future water supply and for flood control
What is the water balance equation?
Precipitation= total run off + evapotranspiration +/- storage
What causes variations in runoff?
- differences in soil water, rock type and vegetation cover
- type and intensity of precipitation
What is total run off?
the proportion of the total precipitation that makes its way into streams and rivers
How long is the river Wye?
215km
Where is the river Wye located?
Wales
The river Wye is the _____ longest river in the UK?
5th
Where is the river Wyes source?
in the Plynlimon Hills in mid Wales
Which direction does the river Wye flow in before it joins the Severn Estuary in Chepstow?
south-east
Is the river Wye rich with wildlife?
Yes, it has a variety of habitats and is an Area of Outstanding Natural Beauty
Describe the upper part of the River Wye.
- steep slopes, acidic soils and grassland
Why has the upper part of the River Wye got acidic soils?
used to be forested but was cleared for sheep grazing
How does the upper part of the RIver Wye being cleared affect the water balance?
- it has reduced interception and has increased the potential for overland flow
How does ditches being dug in the area surrounding the upper part of the River Wye affect the river?
it increases the speed of water, making the river more prone to flooding
How does the type of rock in the upper part of the River Wye basin affect the river?
the rocks are impermeable mud stones, shales and grits which makes the soil become saturated quickly, which increases overland flow, increasing flooding downstream such as at Hereford
What months is precipitation highest at the River Wye?
October and March
What months is runoff highest at the River Wye?
October and March
What season is evapotranspiration highest at the river Wye?
the summer
Why is runoff highest at the River Wye in October and March?
Because it is when the precipitation is at its highest and as the temperature is low the evapotranspiration rate is at the lowest
