Parts of a river and its functions + Hydrological Cycle

Question 1

What is a Drainage Basin?

Answer 1

• The drainage basin or catchment area is an area of land drained by a river and its tributaries. It is seen an open system comprising inputs, flows/ transfers, outputs and storage. The amount of water in the system in the basin varies over time, since water can be added in the form of precipitation and lost in the form of evapotranspiration.
• The drainage basin can be divided into three courses: upper, middle and lower.

Question 2

What can the drainage basin be divided into?

Answer 2

upper, middle and lower courses

Question 3

What is at the start and end of a drainage basin?

Answer 3

Start: Source
End: Mouth

Question 4

Definition of Drainage Basin

Answer 4

The area of land drained by a river.

Question 5

Definition of Watershed

Answer 5

The edge of highland surrounding a drainage basin. It marks the boundary between two drainage basins.

Question 6

Definition of Source (of a river)

Answer 6

The beginning or start of a river.

Question 7

Definition of River

Answer 7

Natural wide flows of freshwater across land that stores water temporarily before water flows into another water body.

Question 8

Definition of River Banks

Answer 8

Physical confines of a river.

Question 9

Definition of Confluence

Answer 9

The point at which two rivers or streams join.

Question 10

Definition of Tributary

Answer 10

A stream or smaller river which joins a larger stream or river.

Question 11

Definition of Distributary

Answer 11

Where rivers branch off to form smaller streams (somewhere at the mouth of the river).

Question 12

Definition of Mouth (of a river)

Answer 12

The point where the river comes to an end, usually when entering a sea.

Question 13

Definition of Ground Water

Answer 13

Groundwater is water that is stored in layers of soil and rocks following percolation of water, lying above an impermeable layer.

Question 14

Definition of Water Table

Answer 14

The top level of saturated ground in the soil - it rises and falls depending on the amount of rain.

Question 15

What is the Hydrological Cycle?

Answer 15

• The hydrological cycle is a sequence of processes that occur to ensure that water is naturally replenished on the Earth. This is a global circulation of water – a giant closed system. This means that there is a fixed amount of water in the system because water neither enter nor leaves the Earth and its atmosphere.

Question 16

What does the Hydrological Cycle consist of?

Answer 16

-	Inputs 
→ when water is added to a system
-	Transfers 
→ when water is moving within a system
-	Stores 
→ when water is stationary within a system
-	 Outputs 
→ when water leaves (exits) a system

Question 17

Inputs

Answer 17

→ when water is added to a system

Question 18

Transfers

Answer 18

→ when water is moving within a system

Question 19

Stores

Answer 19

→ when water is stationary within a system

Question 20

Outputs

Answer 20

→ when water leaves (exits) a system

Question 21

Precipitation

Answer 21

Input
- Any moisture that falls from the sky.
→ e.g. rain, snow

Question 22

Sun

Answer 22

Input

- Produces heat which makes water evaporate/condense.

Question 23

Infiltration

Answer 23

Transfer

- When water travels from the surface of the earth into the ground beneath.

Question 24

Surface run-off (overland flow)

Answer 24

Transfer

- When water travels across the surface of the earth.

Question 25

Channel Flow

Answer 25

Transfer

- Water that is travelling in rivers or streams.

Question 26

Through Fall

Answer 26

Transfer
- water that passes directly through a canopy or is initially intercepted by aboveground vegetative surfaces and subsequently drips from the canopy.

Question 27

Stem flow

Answer 27

Transfer
- When intercepted water drains from outlying leaves and branches and is channelled to the stems and trunks of vegetation.

Question 28

Leaf Drip

Answer 28

Transfer

- Intercepted water dripping off vegetation onto the ground.

Question 29

Percolation

Answer 29

Transfer

- When water travels deeper into the ground, from unsaturated ground into saturated ground.

Question 30

Groundwater flow

Answer 30

Transfer

• The movement of water through saturated ground, known as aquifer.
• Aquifer = rocks under surface that can hold moisture

Question 31

Through-flow

Answer 31

Transfer

- The lateral (horizontal) movement of water through unsaturated ground, close to the land surface.

Question 32

Interception

Answer 32

Stores
- When an object (building, tree) stops precipitation from reaching the ground beneath. (prevents water from falling directly on the ground).

Question 33

Vegetation Storage

Answer 33

Stores

- all moisture that is stored in vegetation.

Question 34

Surface Storage

Answer 34

Stores
- Any water that is held on the surface of the earth
→ e.g. lake or pond.
→ Some surface stores like puddles may only be temporary.

Question 35

Soil-Moisture Storage

Answer 35

Stores

- Water that is stored below the surface in unsaturated ground.

Question 36

Groundwater Storage

Answer 36

Stores

- Water that is stored in saturated ground.

Question 37

Channel Storage

Answer 37

Stores
- the volume of water contained within the banks of a river will operate as a water store between its initial input and ultimate output.

Question 38

Saturated Ground

Answer 38

basically soil with moisture or water absorbed

Question 39

Unsaturated Ground

Answer 39

basically soil with no moisture or water absorbed

Question 40

Evaporation

Answer 40

Output

- Liquid water from surface stores and rivers turning into water vapour (gas).

Question 41

Transpiration

Answer 41

Output

- Liquid water evaporating from vegetation.

Question 42

What is Evaporation and Transpiration collectively known as?

Answer 42

Evapotranspiration

Question 43

River runoff/discharge

Answer 43

Output

- Eventually most rivers enter the sea and discharge the river’s flow into the sea.

Question 44

What are the products of the hydrological cycle?

Answer 44

Water vapour and water

Question 45

Does the atmosphere store water?

Answer 45

Yes

it is part of stores

Question 46

Condensation

Answer 46

Output

Water vapour condenses into water.

Question 47

Why does infiltration and percolation occur?

Answer 47

Percolation is the movement of water through the soil itself. As the water percolates into the deeper layers of the soil, it reaches ground water, which is water below the surface. The upper surface of this underground water is called the “water table”. Ground water can intersect with surface streams to appear at the surface as springs, and it flows generally downhill toward the ocean.
The nature of the surface influence the rate of infiltration, while the nature of the subsurface terrain affects the flow of groundwater.

Question 48

What is porosity?

Answer 48

• Porosity is a measure of the pore spaces between rock sediments and its ability to hold a fluid.

• Mathematically, it is the open space in a rock divided by the total rock volume (solid and space). The average soil has a porosity of about 50%, and the pores are filled with air or water depending on the moisture content.

Question 49

What is Permeability/ Pervious(ness)?

Answer 49

• Permeability (or pervious(ness)) is a measure of the ease of flow of fluids through a porous material.

• A rock may be extremely porous, but if the pores are not connected, it will have no permeability.
• Likewise, a pervious rock may have a few continuous cracks or joints which allow ease of fluid flow, but when porosity is calculated, the rock doesn’t seem very porous.

Question 50

ability of a rock to allow fluid to flow through an interconnected network of pores is called _____?

Answer 50

permeability

the ability of a rock to allow fluid to flow through an interconnected network of pores is called permeability.

Question 51

Are porosity and permeability related?

Answer 51

Yes

• Porosity and permeability are related properties of any rock or loose sediment. Both are related to the number, size and connections of openings in the rock. They affect the flow of water and control the distribution of groundwater. An underground layer of rock or sediment that serves as a storage reservoir for large volumes of groundwater is called an aquifer. Groundwater is an important source of freshwater.

Question 52

Does porosity and permeability affect the flow of water and control the distribution of groundwater?

Answer 52

Yes

• Porosity and permeability are related properties of any rock or loose sediment. Both are related to the number, size and connections of openings in the rock. They affect the flow of water and control the distribution of groundwater. An underground layer of rock or sediment that serves as a storage reservoir for large volumes of groundwater is called an aquifer. Groundwater is an important source of freshwater.

Question 53

Definition of Aquifer

Answer 53

• Aquifer = rocks under surface that can hold moisture

An underground layer of rock or sediment that serves as a storage reservoir for large volumes of groundwater is called an aquifer.

Question 54

Groundwater is an important source of freshwater. Is this true?

Answer 54

Yes

Question 55

Rank the 3 types of soil by its ability to handle water.

Sand, Clay, Loam

Answer 55

1. Sand
   - The water goes down the deepest vertically/ extensively
2. Loam
3. Clay