Water Availability and Quality in South Africa

KNOWLEDGE AREA:

 Environmental Studies

TOPIC 5:  Human Impact on the

Environment

Water Availability and Water

Quality



South Africa is  describe as a 

water scarce country

.



It is called a 

water scarce country 

because it 

receives

very little rainfall

.



The 

average rainfall received 

is 

450mm per year

.



This is 

very low

, it is 

about half the average rainfall 

of

other countries

.



Most of the country is 

arid and semi arid

.



The 

amount of rainfall received 

for the 

different parts

of the country

 is 

different

.



The 

west coast 

of the country is 

drier 

than the east

coast.



The 

dry conditions 

are also 

brought about 

by

evaporation and a warm climate

.



Water

 is a 

renewable resource

.



Despite this 

freshwater is not always available

.



There are 

4 major river systems  

in South Africa



These are…

1.

Limpopo

2.

Komati

3.

Maputu/Usuthu

4.

Orange River



These 

river systems are shared with

 the

neighboring countries

.

In South Africa water availability is influenced by the

following factors…

1.

Construction of dams

2.

Destruction of wetlands

3.

Increased temperatures

4.

Poor farming practices

5.

Droughts and floods

6.

Alien plants and the depletion of the water table

7.

Boreholes and their impact on aquifers

8.

Wastage

9.

Cost of water

We will now discuss these  factors.

1.

Construction of Dams

.

What is a dam?



A 

dam

 is a 

man made barrier 

that is 

built

across a

river 

.



Building of a dam 

leads to the 

formation

 of a 

lake

or reservoir

.



A dam has 

two functions

.



These are…

1.

To stock up water

2.

To control the flow of the river

The Main Purpose of a Dam

The main purposes of a dam are as follows…

a.

Supply of Water for Domestic and Industrial Use

.



During the 

rainy season water 

is 

collected

 and

stored

 in the 

dam

.



This ensures that 

water is available 

throughout the

year for both domestic 

and 

industrial use

.



This means that 

water

 is available 

all year round

even the 

dry season

.



During the 

dry season water 

may also be 

released

from the dam

.



This makes 

water available 

for the 

plants and animals

downstream

 that 

may not have water 

in the 

dry

season

.



This is also

useful

 for 

people living 

in 

informal

settlements

, because they are 

not

 supplied with

municipal water

.



They have 

access

 to 

water all year round

.

b.

Flood Control



Dams can be used to 

regulate the flow of water

.



During 

heavy rainfall

 the 

volume of water 

within

the 

river increases

.



The river can 

burst its banks

.



The 

areas along 

the 

river banks 

will become

flooded

.



This leads 

to great loss

 of 

both plant 

and 

animal

life

.



The dam can be 

used to store 

the 

water

 and

slow

 the 

release of water

.



The 

amount of  water  released 

can be

controlled

 through the  

sluice control

.



This 

prevents

 flooding downstream

.

c.

Generation of Hydro-Electricity



In this case 

water from a dam 

is used to

generate electric power

.



This type of power is called 

hydro-

electric power

.



From the diagram we

can see that the 

dam

must be higher

 than

the 

power station

.



Pipes

 carry the 

water

from

 the 

reservoir

 to

the 

power station

.



As the 

water falls 

it

turns

 the 

turbines 

in

the 

power station

.



In this way 

electricity

is generated

.

d.

Irrigation…



Is when 

dry land 

is

supplied

 with 

water

using 

pipes ditches

or streams

.



In 

dry areas

irrigation

 can be

used to supply

water 

to the 

plants

.

Cotton crop being irrigated 

using a system of canals



During the 

rainy season water 

is 

collected

 and

stored

 in the 

reservoirs or dams

.



During the 

dry season water 

can be 

distributed

over the land

 using a 

system of pipes or canals

.

Disadvantages of Constructing a Dam…

a.

Loss of Biodiversity



Construction 

of a 

dam leads 

to 

habitat

destruction

.



Habitats

 both 

upstream and downstream 

are

affected

.



Upstream

- here the 

water is collected

, this

results in 

flooding of the habitat

.  This in turn 

leads

to the 

drowning of many plant and animal species

.



Down stream 

– there is 

less water

.  Therefore

the 

river banks dry out

, resulting in the 

death of many

species

.  When the 

flood sluices are opened 

then

many of the 

remaining species drown

.

b.

People and their Livelihoods are Affected.



Many 

people depend 

on the 

river 

for their

livelihoods

.



Some 

people use 

the 

river

 for 

farming

, while other

people use the 

river for fishing

.



Damming

 of the 

river results 

in 

less 

water

downstream

.



When the 

flood gates 

are 

open

 the 

river banks 

and

sometimes the 

surrounding areas 

can 

flood

.



This result in a 

large number of people being

displaced

.



Therefore they 

lose their homes 

and 

source of

income

.

c.

The Natural Balance of the River is Upset…



When a dam is constructed across a river 

lose soil is

held back

.



This means that 

down stream 

the 

nature of the

river is changed

.



This 

affects all 

the 

plants and animals living

downstream

.



Once again when the 

flood gates 

are 

open

 the 

river

banks downstream

 are 

flooded

.



Plants die 

and 

animals

 are 

forced to leave the area

.



The 

river downstream 

can also 

become drier 

and this

can 

lead to soil erosion

.



Under 

normal conditions 

during the 

rainy season 

the

fertile soil 

is 

deposited

 on the 

river banks

.



The 

dams 

prevents

this from 

happening

.



Eventually the 

soil 

on the 

river banks downstream

becomes 

less fertile

.

A Dam

Irrigation

2.

Destruction of

Wetlands



A 

wetland

 is an

area

 where the

land 

is 

saturated

by 

water

.



This maybe 

surface

or ground water

.

Cape Lowland Freshwater 

Wetland

Characteristics of a

Wetland:

o

Waterlogged soil

o

High water table

o

Many aquatic

plants

o

Area is covered by

water for a greater

part of the year.

Greater St. Lucia Wetlands

Some examples of wetlands are…

o

Springs

o

Marches

o

Swamps

o

Floodplains

o

Pans

o

Estuaries

o

Riverbanks and

o

Wet grasslands

Some examples of wetlands

The Role of the Wetland in an Ecosystem…



They 

purify

 the 

water

 by 

acting as a filter 

for

pollutants

 found in the 

water

.  They are so

successful

 as 

purifiers

 that 

artificial wetlands 

are

being 

created

 to 

treat domestic and industrial

waste

.



They 

store

water

 and are therefore able to

supply water 

for 

domestic and livestock use

,

especially in times of 

drought

.



They 

control

 floods 

and in this way 

reduce soil

erosion

.



They ensure that the 

water table always has water

.



They are also a 

habitat

 for 

many plants and

animals

 that 

require

 an 

abundant water supply

.

Factors that lead to the destruction of the Wetlands…



Wetlands

 can be 

destroyed

 by 

draining the

water 

and then 

filling it with soil 

to 

create space 

for

housing or even agriculture

.

Other factors that lead to the destruction of

wetlands are…

o

Overgrazing which leads to soil erosion

o

Incorrect placement of dams

o

Urban development

o

Pollution

o

Mining



These 

factors lead 

to the 

changes in the flow 

of

water and the water quality

.



This eventually 

leads 

to the 

destruction

 of the

wetland

.

A wetland

3.

Increased Temperatures…



Global warming 

has 

lead

 to 

higher

average temperatures

.



These 

higher temperature 

have 

increased

 the

rate of evaporation 

from 

rivers, lakes , seas and

soil

.



Even 

transpiration

 has 

increased

.



Therefore 

water available

 for 

domestic,

industrial and agricultural use 

by 

humans

 has

been 

reduced

.

4.

Poor Farming Practices…

Poor farming practices include…

o

Inefficient irrigation



In many countries open 

ditch irrigation 

is used.



This 

water

 is 

easily evaporated 

because the 

ditches

are not covered

.



Water

 is also 

lost through 

the 

sides and bottoms 

of

the 

drains

 because these 

drains are not waterproof

.

This is called 

seepage

.



Irrigation 

of the rivers 

upstream reduces water

supply downstream

.



A 

more efficient type 

of 

irrigation

 is the 

drip

irrigation

.



In this method 

water is released 

in 

direct contact

with the 

crops either above or below ground

.



There is 

less lost of water due 

to 

evaporation

.

o

Incorrect ploughing methods



If 

ploughing occurs up and down 

a 

hill 

then 

water

run-off leads to soil erosion

.



Therefore 

top soil is washed away 

and 

vegetative

cover is reduced

.



Lack of vegetation 

will lead to 

water flowing away

.



This 

reduces

 the 

water holding capacity 

of the

soil

.



Ploughing

 should 

occur along the contours 

of the

hill

.

o

Overgrazing



Overgrazing

 leads to 

parts of the soil 

being 

exposed

because the 

layer of vegetation 

is 

removed

.



The 

hooves 

of the 

grazing stock compact 

the 

soil

.



This means that their 

hooves break up the soil

particles 

into 

very tiny pieces

.



This 

soil

 is now 

easily eroded by wind or water

.



Therefore the 

top soil removed

.



The 

soil 

becomes 

degraded

.



Available water 

is 

not held 

by the 

soil

 therefore

the 

water holding capacity 

of the 

soil

 is 

reduced

.



These 

practices 

affects the 

availability of water

.

5.

Droughts and Floods…



Availability of water 

is 

affected

 by 

droughts and

floods

.



South Africa 

experiences 

periods of droughts

that 

alternates

 with 

periods of floods

.



It is thought that 

climate change 

would 

lead

 to

more frequent periods 

of

 droughts and floods

.



Climate change 

may 

lead

 to a 

much wetter

rainy season

 and a 

much drier dry seasons 

in

South Africa

.



This will lead to 

more droughts and floods

.



Flooding

 will 

result in increased soil erosion 

and

rich top soil 

will be 

washed away into 

the 

rivers

and dams

.



Flooding

 will 

reduce

 the 

soil’s ability 

to 

support

crops

.



The  

frequent droughts 

in the 

drier western parts

of the country 

will 

effect the fresh fruit industry

.

6.

Exotic Plantations and the Depletion of the

Water Table



Exotic plants 

are also know as 

alien plants

.



Alien plants 

are those 

plants

 that 

do not 

occur

naturally in an area

.



These 

alien plants 

have 

very long roots 

that can 

reach

the water table

.



Some

alien plants 

also 

require large amounts 

of

water

. Example the wattle.



These 

alien plants 

are 

grown

for shade 

or as

plantations 

for 

commercial purposes

.



In the 

short term 

it has a 

lot of economic value 

but



in the 

long term it absorbs large amounts 

of 

water

.



This 

water may be absorbed 

form the 

water

table

.



Therefore the 

amount of water available

 for

indigenous plants and animals 

is 

greatly reduced

.

Water Hyacinth

7.

Boreholes and their Effects on Aquifers



Before we discuss this we must first know…



A 

borehole

 is a

deep narrow hole

drilled

 in the 

ground

to 

access

underground water

.

A borehole



An 

aquifer 

is an

underground layer 

of

permeable rock 

that is

saturated with water

.



Groundwater

is 

formed

 when

surface water from

precipitation slowly

passes

 through the

upper layers 

of the

soil

.

Diagram showing Aquifer



Until 

it 

finally reaches 

the 

layer of permeable

rock

.



This 

continues until 

the 

soil and permeable rock

becomes 

saturated with water 

forming the

aquifer

.



Ground water 

is an 

important source 

of 

water

.



t is 

used

 for 

domestic and agricultural purposes

as well as for 

drinking water

.



A 

borehole 

is used to 

extract the ground water

.



The 

top layer 

of the 

saturated layer 

is called the

water table

.



The 

water

 from the 

aquifer reaches 

the 

surface

through 

springs or fountains

.



This occurs 

naturally

.



It can also 

naturally reach 

the 

surface

 by 

seeping

into 

rivers or lakes

.



This 

water

 is then 

naturally replenished

.



When 

a borehole is used to extract groundwater

, the

water is extracted faster 

than it can be 

replenished

.

This can lead to…

o

A 

lower

 water table is.

o

Aquifers

 can 

become depleted

.

o

The 

amount of water 

in 

rivers and lakes 

can be

reduced

.

o

The 

soil can collapse 

because of a 

loss of

underground support of the water

.

o

Salt water 

can 

seep 

into the 

ground water 

near the

coast 

and 

reduces

 the 

amount of available fresh

water

.

A borehole

8.

Wastage…



Wastage 

of 

water 

occurs in the 

domestic and

agricultural sectors

.



Wastage 

is also 

brought about by pollution

.

Lets look at each one…

Domestic…



In our households water may be wasted in the

following ways

…

o

Leaking pipes 

and 

dripping taps

.

o

Using 

washing machines 

and 

dishwaters

 when

they are 

not completely full

.

o

Filling

 the 

bath tub 

to the 

top

 or 

with more water

than is required

.

o

Brushing your teeth 

with the 

tap running

.

o

Watering the garden 

during the 

hottest part of

the day

, when 

maximum evaporation 

would

occur.

o

Washing your car 

with a 

hose instead of 

using a

bucket

.

Agriculture…



Here 

wastage occurs 

through 

poor irrigation methods

which we discussed earlier.

Pollution…



Pollution 

reduces 

the 

amount of available fresh

water

.

Some sources of water pollution are

…

o

Sewage

o

Industrial waste

o

Run-off water from farms

o

Detergents and cleaning agents

o

Radioactive wastes



South Africa

 is an 

extremely dry country 

with a

limited water resource

.



If we 

continue to waste water 

our 

country will

not be able to supply our water needs

.

The following steps can be taken to ensure that

water is not wasted…

o

Reduce pressure 

in the 

water pipes

, this would

reduce the chances of leaks developing in the

pipes

.

o

All 

household leaks must be fixed

.

o

The 

population must be educated 

on how to 

use

water wisely

.



These 

strategies

 were 

used

 by the 

Emfuleni

Municipality

 that 

experienced a large amount of

water wastage

.

9.

Cost



As 

South African 

we 

are extremely lucky

,

because our 

constitution states 

that 

everyone

has the right to safe, clean water

.



Therefore the 

first 6 kilo liters 

of 

water

 are

provided free

 to a 

family of 5 per month since

July 2006

.



This means that as 

consumers we only start

paying after the first 6 kilo liters

.



This ensured that 

more people 

had 

access to free

clean, safe water

.



Water quality 

refers to the 

physical,

chemical and biological characteristics 

of 

water

.



Water

 is 

used

 for 

domestic, industrial,

agricultural and mining purposes

.



Using the water 

in this way means that

substances become dissolved 

or 

suspended in it

.



The 

water becomes 

contaminated

and its

quality is affected

.

Lets look at the pollutants that are added to the

water for each of the above uses.

Domestic Pollutants…



Non-biodegradable Pollutants

o

Many 

detergents 

are biodegradable.  This means

that they are 

easily broken down 

by 

micro-

organisms

.

o

Phosphates

 are 

added to detergents 

and

shampoos

 to make 

rising easier

.

o

The 

phosphates end up in rivers, lakes and

streams 

etc.

o

This 

leads 

to an 

increase in the growth of algae

.



Pathogenic Bacteria in Sewage

…

o

Water contaminated 

with 

sewage 

has many

micro-organisms

 in it.

o

Even 

sewage water 

that has been 

treated

contains pathogenic micro-organisms

.

o

These 

pathogenic micro-organisms 

in the 

water

cause a 

number of water borne diseases 

such as

cholera, typhoid and dysentery

.

o

This can be 

avoided

 if the 

water is chlorinated

before being 

released

 into 

any body of water

.

Industrial Pollutants…



Some industrial pollutants are…

o

Heavy metals 

in 

industrial waste water 

example 

lead

and mercury

.

o

Paint, solvents glue 

and 

varnish

 that affect the

reproductive and respiratory systems

.  These

chemicals also affect 

short term memory 

and can

induce asthma and hearing loss

.

o

Oil and petrol spills 

from the 

shipping industry 

can

poison birds, clogs 

their 

wings preventing 

them from

flying

.  The oil also 

kills the phytoplankton

.

affecting all the other 

organisms in the food chain

since it is a 

source of food

.

o

Waste

 from the 

fertilizer industry causes an

increase in algal growth 

when it is released into

the water bodies.

o

Heat

 brings about 

thermal pollution

.

Agricultural Pollutants…



Pesticides and herbicides 

ends up in the 

rivers

and dams

.

o

They affect 

fat metabolism, nerve transmission,

resistance to infection

 and can 

cause breast

cancer

.



Many 

fertilizers contain nitrous oxide 

which is a

greenhouse gas 

and will lead to 

climate change

.

o

Fertilizer reaching the rivers 

can cause 

increase in

algal growth

.

Eutrophication and Algal Bloom…



Eutrophication

 occurs when there are

highly concentrated levels 

of 

nutrients

 such as

phosphates and nitrogen 

in the 

water 

that may

lead

 to the 

increased growth 

of 

organisms 

in the

water

.



This usually 

occurs

 when 

artificial fertilizer

, used

by farmers or from the fertilizer industry, is

washed off into rivers, streams and lakes

.



This 

increases the nutrient content of the water

.



Some of the 

nutrients

washed off 

into the 

rivers,

lakes or streams

 are

nitrogen and phosphorus

.



The 

high nutrient content

speeds up 

the 

growth of the

green matter 

in the 

water

especially algae

.



This is called 

algal

bloom

.



The 

algal growth 

is so 

rich

that it forms a 

carpet on the

river

.

Algal Bloom



The 

algae prevents light 

from 

entering the water

.



This means that the 

plants found within water

may not receive 

enough 

sunlight

 for

photosynthesis

.



Therefore the 

plants will die

, because they 

do not

have any food

.



The 

dead plants 

then 

attract bacteria 

to the 

river

.



The 

bacteria uses 

up 

large amounts of oxygen

.



Therefore the 

amount of oxygen available 

for

other organisms 

in the 

water decreases

.



This 

leads to the death 

of a 

large number 

of

organisms

.

Effect of Mining on the Quality of Water…



Water 

is used during the 

mining of metal ores and

coal

.



This 

water

 is usually 

returned to the environment

.



This water is 

hot and acidic

.



It has a 

temperature

 of about 

47˚C 

and a 

pH

 of about

3.6

.



This water is called 

acid mine water 

.



Acid mine water leads 

to 

thermal pollution 

because

of its 

high temperature

.



Acid mine water 

is formed when 

old or disused mines

are 

flooded

 with 

groundwater

.

Acid mine water is

formed in the

following way…

o

When 

coal or metal

ores are mined

, 

pyrite

is released

.

o

Pyrite 

is a 

common

mineral found

 in

sedimentary rock

.

o

It contains 

sulphur

.

o

When 

water flows

over the pyrite

 the

water reacts 

with

Pyrite

with the 

sulphur –bearing minerals

.

o

This 

chemical reaction turns 

the 

water

 into an

acid

.

o

This water is called 

acid mine drainage (AMD)

.

o

This 

acidic water 

may also 

contain toxic heavy

metals

.



Sometimes this 

water is drinking water

.



This 

water 

can cause 

serious health problems 

if

consumed 

by 

humans

.



The 

population size 

of the 

aquatic organisms

decrease 

when 

acid mine water 

is released into

rivers, lakes and streams

.



This happens because the 

heavy metal content 

of

the 

water increases

.



The 

pH 

of the 

water is also lowered

.



The 

high heavy metal content 

and the 

lower pH

can poison

 the 

organisms in the water

.



All other 

organisms

 in the 

food chain 

are

affected

.



Even 

humans are affected 

when they 

feed

 on the

fish

 for example.

Pyrite

Thermal Pollution…



Thermal pollution 

refers to an 

increase

in the temperature of the water in rivers, lakes,

streams and oceans

.



Thermal pollution 

usually 

occurs when water 

is

used

 as a 

coolant in industry

.



Therefore 

large amounts of hot water 

is 

released

into 

rivers, lakes, streams and oceans

.



This has the following effects on the water…

o

Some 

organisms benefit

.

o

However 

thermal pollution drives oxygen out 

of

the 

water in 2 ways

.

o

These are as follows…

•

Remember that 

hot water  drives the oxygen out

.

Therefore the 

water has less oxygen

, causing

many organisms to die due to a lack of oxygen

,

•

The 

temperature of the water increases 

and this

causes 

algal bloom

.  This 

uses up much oxygen

,

which in 

turn reduces the amount of water

available for organisms causing them to die

.

o

The 

high temperature increases the metabolic

rate of organisms

, therefore they would need

more food

.

Effect of Alien Plants on Water Quality



Alien species 

are also called 

exotic species

.



Alien or exotic species 

refers to 

species

 that 

do not

occur naturally in an area

.



This means that the 

species were introduced to the

area

.



Alien species

 usually do 

very well in the new area

.



They 

thrive and reproduce 

and 

spread very quickly

.



These plants have 

no predators or pathogens 

in the

area

, therefore 

they outcompete the indigenous

plants

.



These 

grow so quickly 

that

they 

completely take over

the new environment

.



They 

completely change

the habitat

 and affect the

functioning of the

ecosystem

.



On 

example

 of an alien

plant is the 

water hyacinth

.



These plants have 

thick

fleshy leaves

 and

distinctive lavender

flowers

.

Water hyacinth



It 

reproduces very quickly 

and forms a 

carpet

over the surface of the water

.



The water hyacinth affects the quality of water in

the following ways…

o

Forms a 

continuous carpet 

on the 

surface of the

water

.

o

This 

prevents light 

form 

entering the water

.

o

Therefore the 

plants that are found in the body 

of

the 

water will not be able to photosynthesize

.

o

Eventually these 

plants will die

.

o

This affects other organisms in 2 ways

•

Firstly these 

plants are producers 

and a 

source of

food for many organisms

, these organisms have

no food

.

•

When the 

plants die

, they 

attract bacteria 

which

decompose the dead plants

.

•

The 

bacteria use up the oxygen 

in the 

water

.

•

This leads to a 

shortage of oxygen in the water

,

which 

causes the death of more organisms

.

•

These 

alien plants 

also 

clog the water ways

.

•

Therefore 

boating, fishing and other water sports

are 

impossible

.

•

Furthermore 

large amounts of money 

must be

used to clean up these waterways

.



Water need to be 

purified and re-cycled 

because

of…

o

The 

uneven distribution of water

.

o

Water pollution.

o

The water may 

contain germs

.

o

During 

flood sewer pipes 

may become 

damaged

and this can lead to 

contamination of water by

human faeces

.



Now lets look at each of this factors.

a.

Uneven Distribution of Water



Some 

countries or areas 

have 

more water than

others

.



Therefore 

not all people have access to clean

natural water

.



Purifying and re-cycling water 

is 

necessary

 so that

all people can have access to clean water

.

b.

Water Pollution



Water pollution 

may occur as a 

result of domestic,

agricultural or industrial use

.



Therefore the 

amount of water used needs to be

reduced

.



The 

water must 

also be 

recycled and re-used

.

c.

Water may contain Germs or Impurities



Rain water 

that is 

stored in reservoir or dams

contains small particles of dust, sand particles and

animal remains and litter

.



Water

 has to be 

filtered to remove these

substances

.



Water is filtered 

by a process called 

filtration

.



Filtration 

is a 

physical process 

by which the

water and particle are separated 

and 

then

removed

.



The 

water now looks “clean”

.



But the 

water

 may 

contain many germs  or

pathogenic micro-organisms

.



Therefore the 

water needs to be purified

.



During this 

process water is boiled 

and then

treated

 with 

chemicals to get rid 

of the

pathogens

.



Once the 

water has been filtered 

and 

purified

they are safe for human use

.



Purified water 

is then 

carried by pipes 

to 

all the

areas were it can be used

.

d.

Water contaminated by Human Faeces



More frequent and serious floods 

are common

because of 

climate change

.



The 

flooding can damage sewer pipes

.



Causing the 

release of human feces into the water

.



This can lead to 

disease

.

e.

Uneven access to Purified Water.



Not everyone in South Africa has access to clean

water.



Clean water for human consumption is very

important because…

o

Contaminated water kills 

a large number of

people.

o

75% of all diseases 

in developing countries is

spread by contaminated water

.



Dam

:  is a man made barrier that is built across a

river.



Irrigation

:  is when dry land is supplied with water

using pipes ditches or streams.



Wetland

:  is an area where the land is saturated

by ground or surface water



Alien/exotic plants

:  are those plants that do not

occur naturally in an area.



Borehole

:  is a deep narrow hole drilled in the

ground to access underground water.



Water quality

:  refers to the physical, chemical

and biological characteristics of water.



Biodegradable

:  refers to substances that can be

broken down naturally by micro-organisms.



Sewage

:  refers to the urine, faeces and other

household waste that is mixed with the water.



Pathogen

:  these are organisms that cause

diseases.



Eutrophication

:  occurs when there are highly

concentrated levels of nutrients in the water that

may lead to the increased growth of organisms in

the water.



Algal bloom

:  refers to increase of algal growth as

a result of eutrophication.



Filtration

:  

is a physical process by which the

water and particle are separated and then

removed.



Thermal Pollution

:  r

efers to an increase in the

temperature of the water in rivers, lakes, streams

and oceans.



Acid mine drainage

:  

refers to the outflow of

acidic water from metal mines or coal mines.



Pyrite

:  

common mineral found in sedimentary

rock.



Acid mine water

:  

refers to the outflow of acidic

water from metal mines or coal mines

1.

A permeable underground water-bearing layer

of rock that stores or transfers ground water.

A.  Borehole

B.  Aquifer

C.  Pyrite

D.  None of the above

2.

A barrier built across a river in order to block

and control the flow of water…

A.  Dam

B.  Bridge

C.  Borehole

D.  Aquifer

3.

When water is run via pipes and canals to supply

water to crops

A.  Watering

B.  Spraying

C.  Filtering

D.  Irrigation

4.

Land that is saturated with water…

A.  Desert

B.  Wetland

C.  Aquifer

D.  Both B and C

5.

The water hyacinth is an example of a/an…

A.  Indigenous plant

B.  Alien plant

C.  Endemic plant

D.  Xerophyte

6.

Plants that are accidentally or intentionally brought

into an area…

A.  Indigenous plant

B.  Alien plant

C.  Endemic plant

D.  Xerophyte

7.

Level below the ground that is saturated with

water…

A.  Pyrite

B.  Sedimentary rock

C.  Aquifer

D.  Water table

8.

Mechanical method of extracting groundwater…

A.  Borehole

B.  Irrigation

C.  Aquifer

D.  Both A and C

9.

The physical, chemical and biological

characteristics of water…

A.  Water quality

B.  Water table

C.  Sewage

D.  None of the above

10.

When substances are broken down naturally by

micro-organisms is known as…

A.  Biodegradable

B.  Decomposition

C.  Non-biodegradable

D.  Both A and B

11.

Urine, faeces and other household waste that is

mixed with water is called…

A.  Wastes

B.  Pollution

C.  Sewage

D.  AMD

12.

Type of pollution where hot water is released

into rivers, lakes etc…

A.  Thermal pollution

B.  Eutrophication

C.  Global water

D.  Climate change

13.

Increase in the growth of algae because of

increased nutrients in the water…

A.  Eutrophication

B.  AMD

C.  Algal bloom

D.  Both A and C

14.

The liquid that is formed when old or disused

mines are flooded with groundwater is…

A.  AMD

B.  Acid mine water

C.  Eutrophication

D.  All of the above

15.

Toxic substance that maybe found in water that

may induce asthma and hearing loss

A.  Heavy metals

B.  Oil spills

C.  Paints and solvents

D.  Fertilizer

16.

When ploughing on a hill, ploughing should be

done…

A.  Downhill

B.  Across the contours

C.  Alternate downhill with across the contours

D.  Makes no difference

17.

Process by which a body of water becomes

saturated with nutrients is known as…

A.  AMD

B.  Seepage

C.  Eutrophication

D.  All of the above

18.

Alien plants are able to out compete indigenous

plants because…

A.  They have no pathogens

B.  They have no predators

C.  They have very long root systems

D.  All of the above

19.

Plants that form a continuous carpet on the river

and prevents light to pass through is…

A.  Algae

B.  Water hyacinth

C.  Both A and B

D.  None of the above

20.

Plants that clog up the water ways are called

the…

A.  Algae

B.  Water hyacinth

C.  Both A and B

D.  None of the above

1.

B

2.

A

3.

D

4.

B

5.

B

6.

B

7.

D

8.

A

9.

A

10.

D

11.

C

12.

A

13.

C

14.

A

15.

C

16.

B

17.

C

18.

D

19.

C

20.

B