MR MUNZHELELE L
WATER RESOURCES
Water resource: are natural
resources of water that are
potentially useful for
humans, for example as a
source of drinking water
supply or irrigation water
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concepts
• Desalinisation: The removal of salts from ocean water
to make it more usable
• Grey water: Used water that can still be used for other
purposes
• Overfishing: Catching more fish than they reproduce
therefore reducing their population
• Inter-basin transfer: Linked pipes transferring water
from a high rainfall area to a dry area
• Salinity: The amount of salt in the ocean
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concepts
• Sustainability: Using resources carefully to ensure their
future availability
• Marine pollution: Dumping of waste products in oceans
• Fish quotas: The control in the numbers of fish which
fishermen may catch
• Ecosystem: The community where living and non-living
things exist together
• Ocean currents: Large-scale movements of water from
one part of an ocean to another
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concepts
• Mariculture: The farming of fish or other marine life for
food in the sea
• Hydrological (water) cycle: The natural cycling of
water between the oceans, the atmosphere and the
land
MR MUNZHELELE L
WATER IN THE WORLD
MR MUNZHELELE L
DIFFERENT FORMS OF WATER
SOLID LIQUID GAS
• Snow • Rivers • water vapour
• Ice • Lakes • steam,
• frost. • rain • clouds / mist
MR
MR MUNZHELELE L
MUNZHELELE L
WATER CYCLE (HYDROLOGICAL CYCLE) MR MUNZHELELE L
infiltration Water cycle: It involves
the continuous
movement of water
between the ground
(surface) and the
atmosphere.
MR MUNZHELELE L
WATER CYCLE (HYDROLOGICAL CYCLE)
1. Evaporation: loss of water from water bodies on the ground
(dams, lakes, rivers, the sea) - change in state from liquid to
gas (water vapour) through heating (radiation).
2. Transpiration: when plants lose excess water through their
leaf-structure. This contributes to the amount of water
vapour in the atmosphere
3. Condensation: upon reaching dew point temperature water
vapour condenses (changes back into water droplets), and
joins to form bigger drops and then falls to the ground as
precipitation (rain, snow, hall)
MR MUNZHELELE L
WATER CYCLE (HYDROLOGICAL CYCLE)
4. Dew point temperature: is the temperature point at which
the air can hold no more water (water vapor)
5. Surface Run-off: much of the rainwater runs off into stream
channels to reach the sea where the process of evaporation
occurs.
6. Infiltration: (soaking into the soil structure) of rainwater also
occurs and this forms the ground water reserves. Farmers
drill boreholes to extract this water when needed. Excess
groundwater also flows along a gradient to reach rivers and
the sea.
MR MUNZHELELE L
WATER CYCLE (HYDROLOGICAL CYCLE)
7. Water table: is the upper limit of groundwater reserves.
8. Precipitation: is any liquid or frozen water that forms in the
atmosphere and falls back to the earth
9. Groundwater: is water that exists underground in saturated
zones beneath the land surface.
10.Throughflow: The movement of water horizontally beneath
the land surface, usually when the soil is completely
saturated.
11.Water transfer: is moving water from one area to another
MR MUNZHELELE L
SIGNIFICANCE OF THE HYDROLOGICAL
CYCLE
• Replenishes water supply for the earth - fills up dams,
rivers, lakes and underground reservoirs.
• Responsible for climatic process - like rainfall.
• Continuous cycle - sustains the planet.
• Cools the earth through rainfall.
• Cleanses the atmosphere - rain bringing atmospheric
impurities back to surface.
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OCCURRENCE OF SALT AND FRESH WATER
SOURCES
• The largest salt water body on the planet is the sea.
• When rivers erode the landmass, they transport salt
from the land to the sea.
• Some smaller bodies of salt lakes also occur, like the
Dead Sea in Eastern Europe.
• Salt content in the lake is so high that plant life and
aquatic life is largely absent in the Dead Sea (hence its
name.
MR MUNZHELELE L
OCCURRENCE OF SALT AND FRESH WATER
SOURCES
• Fresh water masses occur as:
✓ Lakes,
✓ Dams,
✓ Rivers,
✓ Ice masses (glaciers),
✓ Underground rivers,
✓ Ponds,
✓ Oases
✓ Swamps.
✓ The atmosphere is also a source of fresh water.
MR MUNZHELELE L
human and physical factors influencing
the Unavailability of water in South Africa.
Human factors
• The population is increasing
• Commercial farmers are using more water for
irrigation
• Urbanisation
• Untreated waste water
• Mines and factories use a lot of water
• Pollution of water sources
MR MUNZHELELE L
human and physical factors influencing
the Unavailability of water in South Africa.
Physical factors
• Rainfall is not evenly distributed in South Africa
• Alien vegetation consumes more water
• Climate change
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THE WORLD'S OCEANS
MR MUNZHELELE L
THE WORLD'S OCEANS
• The largest ocean in the world is the Pacific Ocean.
• The other two oceans are the Atlantic and the Indian.
• The oceans consist of almost 71% of the planet's area
and are therefore able to supply much of our needs.
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IMPORTANCE OF OCEANS:
MR MUNZHELELE L
IMPORTANCE OF OCEANS:
Oxygen Food Energy Impact on Sports and
climate recreation
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IMPORTANCE OF OCEANS:
1. Oxygen
• Phytoplankton (microscopic organisms that live in
watery environments) in the ocean absorbs Carbon
Dioxide and releases Oxygen - through the process
of marine photosynthesis.
• Phytoplankton produces as much Oxygen as all the
trees in the world, and they remove 3 billion tons
of Carbon Dioxide every year.
MR MUNZHELELE L
IMPORTANCE OF OCEANS:
2. Food
• The oceans represent a source of protein supply (protein
must be consumed daily for human health). Fish, seaweed,
crustaceans, rock lobsters, and the larger mammals like
dolphins, whales and sharks are 'hunted' daily, using the
most innovative techniques in order to satisfy our need for
protein.
MR MUNZHELELE L
IMPORTANCE OF OCEANS:
3. Energy
• We use oceans for our energy supplies as fossil fuels are
becoming exhausted
• Coal, natural gas and crude oil are expected to run out in the
foreseeable future (coal in as little as in the next fifty years).
• Aside from tapping the underground reserves for these fossil
fuels in the sea itself, there are huge strides being made in
harnessing the power of the sea in other areas to generate
electricity.
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IMPORTANCE OF OCEANS:
• Turbines are placed in strategic positions where strong
wave action can be converted into hydro-electricity. There
are plans to place giant windmills in the paths of strong
tidal and ocean currents to again drive turbines to
manufacture hydro-electricity.
• Tides and ocean currents are also being used to reduce
seafaring costs. Observation of tides and ocean currents
help in sea transport.
MR MUNZHELELE L
IMPORTANCE OF OCEANS:
4. Impact on climate
• Cold currents flow equator wards and warm currents flow pole-wards in both
hemispheres. As a result of this oceans play an important role in circulating
energy (temperature in the world.
• If this was prevented from happening for whatever reason, the equator would
be much hotter and the poles much colder than at present.
• The ocean currents also play a significant role in regulating the climate of the
world. Keeping the sea temperatures warm in some places, like in the Gulf of
Mexico (by the warm Gulf Stream), its flow northwards towards Europe allows
this part of the world to be much warmer than other areas at the same
latitude.
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IMPORTANCE OF OCEANS:
• Another current playing a role in weather and climate is the cold Humboldt
Current off the coast of Chile and Peru (South America - west coast). This results
in the coastal parts being cool and relatively dry (arid. Changes to this current by
some abnormal warming or cooling results in the climatic phenomenon referred
to as El Nino and La Nina, which has a direct effect on human activities in these
regions.
• Around the South African east coast, the warm Agulhas and Mozambique currents
ensures moderate temperatures year-round and a summer rainfall pattern. Along
the west coast of South Africa flows the Cold Benguela Current which originates
in the Antarctic regions. Thawing icebergs release millions of tons of
phytoplankton into the cold waters and they are carried northwards by the
Benguela Current, resulting in our west coast being very rich in fish resources.
MR MUNZHELELE L
IMPORTANCE/ BENEFITS OF
OCEANS:
• It can be used to generate electricity
• Oil and gas can be derived from the ocean
• It serves as a source of oxygen
• For scientific research
• For trade
• For tourism
• Sports and recreation
• It serves as source of food
• It serves as the habitation for aquatic creatures.
MR MUNZHELELE L
IMPACT OF HUMANS ON OCEANS
MR MUNZHELELE L
IMPACT OF HUMANS ON OCEANS
1. Pollution
MR MUNZHELELE L
IMPACT OF HUMANS ON OCEANS
How to Reduce ocean pollution.
• Reduce/ban the use of plastics
• Promote recycling
• Participate in ocean/beach clean-up
• Educate beachgoers, hotels and ship owners to avoid
pollution
• Fine/punish those who pollute the ocean
• Reduce carbon footprint
MR MUNZHELELE L
IMPACT OF HUMANS ON OCEANS
2. Overfishing
• One billion people rely on fish as a key source of their daily protein.
• We live in a world that wants more and more seafood, making
overfishing and the associated environmental impact one of the
most important environmental challenges we face.
• Overexploitation is by far the main threat to the survival of several
important commercial fish populations and the lead cause in the
extinction of marine fish species.
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negative results from overfishing
• It reduces fish resources
• Some fish species become extinct
• Overfishing affects other marine life that depends on fish for survival
(Imbalance of marine ecosystem)
• Fishermen will starve in the future as fish populations drop
• Overfishing reduces the amount of available food for people to eat
• Fishermen lose income
• Source of food is depleted
• The country loses on revenue
• A decline in fish stocks leads to job losses and hardship
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Benefits of fishing
• It provides employment opportunities for people who
engage in aquaculture
• Source of protein and nutrients
• Serves as a source of income
• It provides food to reduce hunger and poverty
• Improves food security
• Promotes economic growth
MR MUNZHELELE L
How to sustain fishing industry?
• Implement fishing quotas
• Have closed seasons for fishing
• Buy fish that is in season to give the fish time to
replenish their numbers
• Only allow fishing nets with larger holes for fishing
• Only people with permits must be allowed to fish
• Heavy fines for non-compliance
MR MUNZHELELE L
What is the challenge with regards to
water supply in South Africa?
• More than 65% of the country is arid to semi-arid - i.e. rainfall
is between 250 mm 400 mm per annum. Most of the rainfall
occurs in the eastern parts which - home to almost 75% of the
population.
• Agriculture uses about 70 % of our fresh water reserves,
mainly through the wasteful sprinkler and flood irrigation
methods. Very few farmers (less than ten percent) have
installed micro-jet and drip irrigation equipment on their
farms owing to the cost factor.
MR MUNZHELELE L
What is the challenge with regards to
water supply in South Africa?
• Water loss in urban areas accounts for almost 50 % of purified
water literally going 'down the drain'. Leaking pipes,
unmetered households, communal supply systems with taps
continuously running, theft, apathy and a lack of awareness
by members of the public make matters worse for water
conservation and supply.
• Changing climate affects the distribution of our rainfall. Too
much of rain falls in areas where there is little need for it.
Our dams are also built in areas where the change in climate
fails to fill them.
MR MUNZHELELE L
What is the challenge with regards to
water supply in South Africa?
• Urban development designs remove water from surfaces quickly and
efficiently in cities. This rainwater is lost as it channels its way to the
ocean. The rapidly growing urban population (urbanization) also
creates demands on our water supply.
• Pollution and abuse of our rivers, dams, groundwater reserves and
lakes is also an important factor to consider in South Africa. Poor
agricultural methods like the use of inorganic non-biodegradable)
insecticides and fertilizers finally end up in rivers where they
negatively affect aquatic ecosystems, thereby affecting their potential
to store water. regions.
MR MUNZHELELE L
What is the challenge with regards to
water supply in South Africa?
• Soil erosion is another actor that decreases the water-storing capacity
of our rivers and dams. Increasing the height of dam walls is costly and
dredging of dams to deepen them risky.
• Deforestation reduces infiltration and build-up of groundwater
reserves. Borehole vields have dropped significantly in S and this
affects irrigation during the dry seasons.
• Wetland (swamps) destruction - wetlands serve as a natural storage
facility. However, a need for land by a growing population, directly
affects them and the wildlife and cultivation they support.
MR MUNZHELELE L
What is the challenge with regards to
water supply in South Africa?
• Much of SA is rural and found in some of the most remote parts of the
country. Servicing these areas is a logistical nightmare in terms of
providing a network of piping and water services to these areas. In
addition, it is difficult to monitor and control the provision of water in
areas away from the urban regions.
MR MUNZHELELE L
Water management in South Africa
MR MUNZHELELE L
Water management in South Africa
Strategies by people (HOME)
• Do not leave taps running
• Close taps when not using water
• Fix dripping taps and leaks
• Use little water for each task
• Use water saving showerheads
• Use short showers instead of daily baths
• Run the tap slowly when rinsing any material
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Water management in South Africa
• Reduce flushing water by putting plastic bottle in a
cistern
• Reuse dirty water for cleaning
• Use grey water to flush toilets
• Switch the water off while shaving or brushing your teeth
• Collect plastic, glasses and metal for recycling, this will
reduce the amount of waste water.
• Limit population growth by taking birth control measures
MR MUNZHELELE L
Water management in South Africa
Strategies In the garden
Strategies In the community
• Use a watering can instead of
• Report leaking pipes to
a hose pipe
the municipality
• Collect rainwater from the
• Remove invasive alien
roof
plants
• Use bath water to water
• Educate others about
vegetables
using water sustainably
• Water plants in the evening
• Dam construction
• Avoid plants which use lot of
• Water transfer schemes
water.
MR MUNZHELELE L
Water management in South Africa
Strategies by the Municipality
• Increasing tariffs will make residents use less water
• Mend leaking tapes
• Desalinisation in coastal areas
• Construct more dams and reservoirs
• Offer training to consumers on water usage
• Hire skilled operators in water plants
• Recycle water
• Building dams to store water
MR MUNZHELELE L
Water management in South Africa
• Cloud seeding to artificially increase rainfall
• Crop rotation to protect soil to store water
• Redirecting water to provide for irrigation in areas prone to
drought
• Harvesting rain water from rooftops
• Development of sustainable agricultural practices
• Water-restrictions
