The Drainage Basin Water Cycle (Booklet 3)

Question 1

What is the definition of a river drainage basin?

Answer 1

A river’s drainage basin is the area surrounding the river where the rain falling on the land flows into that river and is drained by the river and it’s tributaries.

Question 2

What can drainage basins also be referred to as?

Answer 2

Drainage basins can also be referred to as catchment areas.

Question 3

What is the definition of a river water shed?

Answer 3

A watershed is the boundary between two river basins.

Question 4

What is the definition of a river channel?

Answer 4

The channel is what the river flows in.

Question 5

What is the definition of a river confluence?

Answer 5

The river confluence is where the two main channels meet.

Question 6

What is the definition of a river source?

Answer 6

The river source is the beginning of the river.

Question 7

What is the definition of a river tributary?

Answer 7

The river tributary is a small stream which joins the main channel.

Question 8

What is the definition of a river mouth?

Answer 8

The river mouth is where the river meets the sea.

Question 9

What happens to water which falls outside of the river watershed?

Answer 9

The boundary of a drainage basin is the watershed - any precipitation which falls beyond the watershed enters a different drainage basin.

Question 10

Which type of system is the drainage basin hydrological cycle?

Answer 10

The drainage basin hydrological cycle is an open system as new water (inputs) enters the system and then leaves (outputs).

Question 11

How does water eneter and leave the drainage basin system?

Answer 11

Water comes into the system as precipitation and leaves via evaporation, transpiration and river discharge.

Question 12

What is the input of water into a drainage basin hydrological cycle?

Answer 12

Input of water into the drainage basin hydrological cycle:
- Precipitation

Question 13

What are the 6 stores of water in the drainage basin hydrological cycle?

Answer 13

Stores of water in the drainage basin hydrological cycle:
1) Interception
2) Vegetation storage
3) Surface storage
4) Soil storage
5) Groundwater storage
6) Channel storage

Question 14

What are the 10 flows/transfers in the drainage basin hydrological cycle?

Answer 14

Flows/transfers of water in the drainage basin hydrological cycle:
1) infiltration
2) Overland flow
3) Throughfall
4) Stemflow
5) Throughflow
6) Percolation
7) Groundwater flow
8) Baseflow
9) Interflow
10) Channel flow

Question 15

What are the 4 outputs of water in the drainage basin hydrological cycle?

Answer 15

Outputs of water in the drainage basin hydrological cycle:
1) Evaporation
2) Transpiration
3) Evapotranspiration
4) River discharge, or river flow, is another output

Question 16

What is the definition of precipitation?

Answer 16

Precipitation is an input of water in the drainage basin hydrological cycle and it includes all the ways moisture comes out of the atmosphere. Precipitation is mainly rain, but it also includes other types like snow, hail, dew and frost.

Question 17

What is the definition of interception?

Answer 17

Interception is a store of water in the drainage basin hydrological cycle and is when some precipitation lands on vegetation or other structures, like buildings and concrete or tarmac surfaces, before it reaches the soil. Interception creates a significant store of water in wooded areas.

Question 18

Why is Interception storage only temporary?

Answer 18

Interception storage is only temporary because the collected water may evaporate quickly, or fall from the leaves as throughfall.

Question 19

What is the definition of vegetation storage?

Answer 19

Vegetation storage is a store of water in the drainage basin hydrological cycle and is water that has been taken up by plants. It is all of the water contained in plants at any one time.

Question 20

What is the defintion of surface storage?

Answer 20

Surface storage is a store of water in the drainage basin hydrological cycle and includes water in puddles (depression storage), ponds and lakes.

Question 21

What is the definition of soil storage?

Answer 21

Soil storage is a store of water in the drainage basin hydrological cycle and includes moisture in the soil.

Question 22

What is the definition of groundwater storage?

Answer 22

Groundwater storage is a store of water in the drainage basin hydrological cycle and includes water stored in the ground, either in the soil (soil moisture) or in rocks.

Question 23

What is the definition of a water table?

Answer 23

The water table is a store of water in the drainage basin hydrological cycle and is the top surface of the zone of saturation - the zone of soil or rock where all the pores in the soil or rock are full of water. The water table is used by researchers to assess drought conditions, health of wetland systems and the success of forest restoration programmes etc.

Question 24

What is the defiition of an aquifer in the drainage basin hydrological cycle?

Answer 24

An aquifer is a store of water in the drainage basin hydrological system and includes porous rocks (rocks with lots of holes in them) that hold water.

Question 25

What is the defintion of channel storage?

Answer 25

Channel storage is a store of water in the drainage basin hydrological system and is the water held in a river or stream channel.

Question 26

What is the definition of infiltration?

Answer 26

Infiltration is a flow/transfer in the drainage basin hydrological system and is water soaking into the soil. Infiltration rates are influences by soil type, soil structure and how much water is already in the soil.

Question 27

What is the definition of overland flow?

Answer 27

Overland flow is a flow/transfer in the drainage basin hydrological cycle is also known as runoff and is water flowing over the 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.

Question 28

What is the defintion of throughfall?

Answer 28

Throughfall is a flow/transfer in the drainage basin hydrological cycle and is water dripping from one leaf (or other plant part) to another.

Question 29

What is the definition of stemflow?

Answer 29

Stemflow is flow/transfer in the drainage basin hydrological cycle and is water running down a plant stem or a tree trunk.

Question 30

What is the definition of throughflow?

Answer 30

Throughflow is a flow/transfer in the drainage basin hydrological cycle and is water moving slowly downhill through the soil. Throughflow is faster through 'pipes' which includes things like cracks in the soil or animal burrows.

Question 31

What is the definition of percolation?

Answer 31

Percolation is a flow/transfer in the drainage basin hydrological cycle and is water seeping down through soil into the water table.

Question 32

What is the defintion of groundwater flow?

Answer 32

Groundwater flow is a flow/transfer in the drainage basin hydrological cycle and is 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 (gaps that water can get through) can have faster groundwater flow, e.g. limestone.

Question 33

What is the defintion of baseflow?

Answer 33

Baseflow is a flow/transfer in the drainage basin hydrological cycle and is groundwater flow that feeds into rivers through banks and river beds.

Question 34

What is the defintion of interflow?

Answer 34

Interflow is a flow/transfer in the drainage basin hydrological cycle and is water flowing downhill through permeable rock above the water table.

Question 35

What is the defintion of channel flow?

Answer 35

Channel flow is a flow/trsanfer in the drainage basin hydrological cycle and is the water flowing in the river or stream itself. This is also called the river's discharge.

Question 36

What is the defintion of evaporation?

Answer 36

Evaporation is an output in the drainage basin hydrological cycle and is water turning into water vapour.

Question 37

What is the definition of transpiration?

Answer 37

Transpiration is an output in the drainage basin hydrological cycle and is evaporation from within leaves. Plants and trees take up water through their roots and transport it to their leaves where it evaporates into the atmosphere.

Question 38

What is the definition of evapotranspiration?

Answer 38

Evapotranspiration is an output in the drainage basin hydrological cycle and is the process of evaporation and transpiration together.

Question 39

What is the definition potential and actual evapotranspiration?

Answer 39

Potential evapotranspiration (PET) is the amount of water that could be lost be evapotranspiration. Actual evapotranspiration is what actually happens. For example, in a desert potential evapotranspiration is high (because heat increases evaporation) but actual transpiration is low (because there isn't much moisture).

Question 40

What is the definition of river discharge/flow?

Answer 40

River discharge/flow is an output in the drainage basin hydrological system

Question 41

What are the 6 factors which affect infiltration?

Answer 41

1) Type of vegetation 2) Land compaction 3) Gradient of land 4) Heaviness of rainfall 5) Soil depth 6) Type of soil

Question 42

How does the type of vegetation affect the rate of infiltration?

Answer 42

The type of vegetation affects the rate of infiltration for example, there is lots of infiltration in forests as there are lots of root systems. There is lots of infiltration in forests because the root systems provide pathways for water to infiltrate into the soil.

Question 43

How does land compaction impact the rate of infiltration?

Answer 43

Land compaction in livestock grazing areas can decrease the rate of infiltration. Grazing areas are primarily areas of grassland which means that they have small root systems and so there are less roots meaning there are less pathways for water to infiltrate into the ground. Additionally, cattle and other livestock animals can compact the ground which leads to there being less infiltration and instead more surface runoff.

Question 44

How can the gradient of the land impact the rate of infiltration?

Answer 44

The gradient of the land can have an impact on infiltraton rates as steeper slopes have less infiltration as there is more surface run off and overland flow and ultimately less time for the water to infiltrate into the ground compared to on a more gentle slope where the water has more time to infiltrate into the soil.

Question 45

How can the heaviness of the rainfall impact the rate of infiltration?

Answer 45

The intensity of the rainfall can have an impact on the rate of infiltration. For example, lighter rainfall has more time to infiltrate into the ground whereas heavy rainfall leads to surface runoff and therefore less infiltration as the ground mayhave become waterlogged.

Question 46

How can the depth of the soil impact the rate of infiltration?

Answer 46

Typically the deeper the soil the more infiltration as there is more pores within the soil that the water can seep and infiltrate through compared to shallower soil.

Question 47

How can the type of soil impact the rate of infiltration?

Answer 47

The type od soil impacts the rate of infiltration. For example, in sand soils there are high rates of infiltration due to there being lots of pores (pores) for water to seep through. Whereas in clay soils there are low levels of infiltration as there aren't as many pores. Soil moisture content also affects infiltration as if a soil already lots of water in it infiltration will be low whereas in a soil where there isn't already lots of water in it infiltration rates will be higher.

Question 48

What is the water balance worked out from?

Answer 48

The water balance is worked out from inputs (precipitation) and outputs (channel discharge and evapotranspiration). The water balance affects how much water is stored in the basin.

Question 49

Whatis the equation for water budgets?

Answer 49

The water budget equation: P= Q +E +/- S P= Precipitation Q = Discharge E = Evaporation S = Storage

Question 50

What does the water balance in the UK show?

Answer 50

The general water balance in the UK shows seasonal patterns.

Question 51

What is the water balance like in wet seasons in the UK?

Answer 51

In wet seasons, precipitation exceeds evaporation. This creates a watersurplus. The ground stores fill with water so there's more surface runoff and higher discharge, so river levels rise.

Question 52

What is the water balance like in drier seasons in the UK?

Answer 52

In drier seasons, precipitation is lower than evapotranspiration. Ground stores are depleted as some water is used (e.g. by plants and humans) and some flows into the river channel, but isn't replaced by precipitation.

Question 53

How does the cycle for water balance work?

Answer 53

At the end of a dry season, there's a deficit (shortage) of water in the ground. The ground stores are recharged in the next wet season (i.e. autumn).