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Avaliability of Water
Transcript of Avaliability of Water
Floating debris can build up and block the flow of water into the river
Long periods of time without precipitation
Store water ensuring supply in droughts
Weaken flood peaks
Recharge ground water
Availability of water
Construction of dams:
Dams are structures designed to stop or hinder the flow of water in a given body.
Exotic plantations and the depletion of the water table:
Approx. 80% (+- 1,5 million hectares) forests in SA = exotic plantations (pine and eucalyptus)
Water is a necessity for life on earth. Only 1% of the water on earth is suitable for usage.
Water consumption has increased dramatically over the past decade which has resulted in a rapid increase in water wastage.
Cost of water
Water demand has increased over the years due to urbanisation and industrialisation.
South Africa is forecast to have a water deficit of 1,7% by 2025.
Mpanda Nkua dam in Mozambique
The average rainfall for the country is 450 mm per year.
This is below the world average of 860 mm per year.
In global terms, South Africa is classified as "water short" and moving towards "water stressed".
Dams in South Africa
In a current survey the dams in South Africa are 99%-105% full.
These high statistics could be due to the fact that there has been a high percentage of precipitation in the past month
These statistics are good and means that our availability to water is also good.
It is important to bear in mind that the time to save water is when there is water to save
By building more dams we are trapping more water and therefore have more water to use
Building the Dam will stop the river flooding and destroying people's living areas
Once a dam is constructed, electricity, mainly hydroelectric, can be produced at a constant rate.
The lake's water can be used for irrigation purposes which can contribute to our farming
To be considered a wetland a piece of land must have:
• waterlogged soils
• water loving plants
• high water table
Destruction of wetlands:
Wetlands around South Africa
Poor farming practices:
Poor land management on farms has a major affect on water availability . Eroded soil flows into rivers which decreases the storage capacity of dams. If fertilizers are poorly added or pesticides are used, the run off will pollute the water and kill off aquatic life.
The largest part of South Africa with fresh water is agricultural land. 63% of that fresh water goes to irrigation and only 12% of that land is cultivable and only 3% is truly fertile. 1,5% of that land is actually under irrigation, showing how much water is clearly used and wasted.
Droughts and floods
Droughts and floods are the natural disasters that are known to kill the most people when they occur.
Borehole and the effects on Aquifers
Groundwater is particularly valuable when surface water (lakes, rivers) is inaccessible/scarce.
USA: groundwater supplies drinking water to:
half total population
nearly all rural population
50 billion GL daily= agricultural
Causes of droughts and floods
Lowering of water table:
Reduction of water in streams and lakes
Increased costs for user
Deterioration of water quality
There has been over 30 recorded floods in Ladysmith and all caused from the Klip River. Rubbish and litter were blocking the stormwater drains therefore the drains couldn't carry away the heavy rains.
Reduction of water in streams and lakes:
Water flowing in rivers and streams is mostly seepage of groundwater into the streambed.
"therefore" if the water table level drops, so will the level of water in lakes, rivers and streams that it supplies to.
When water is taken out of soil-
and drops Due to mostly human activities- removal of subsurface water.
Increased costs for user:
As water level drops- water must be lifted higher to reach wells.
If a pump is used to lift the water (instead of artesian wells) more energy is required to drive pump.
The drought in Namibia is said to be the worst drought they've experienced in 14 years. This drought is expected to affect the agricultural sector on an economic level but is expected to rise again in 2014 when rainfall is on the raise again. Droughts are one of the natural disasters that affects the economy the most.
Wetlands are important because they:
What are the consequences of destroying them?
Less pure water
Less reliable water supplies
Lower agricultural productivity
More endangered species
Why is Water Wastage such a big problem?
Deterioration of water quality:
Not all groundwater is fresh water.
Most very deep groundwater and water under oceans is saltwater.
Water Wastage Statistics in Households
Water wastage has increased by 127% since the 1950's
-95% of water entering households goes down the drain.
- 1 gallon = 3.78541
Global Water Wastage is increasing twice as fast as population growth. We are therefore not living sustainably and will lead to issues regarding water in the future.
Importance of Elasticity regarding Water Costs
Water is a necessity and therefore the demand for water should be inelastic across all income brackets. Inelastic means consumers are unresponsive to price changes.
Water Rates per Month
Example of consumption charges:
(1) 6,9040 kl free. (2) 5,1780 kl @ R7,60. (3) 10,9320 kl @ R11,61. (4) 16,9860kl @ R17,20.
Line Graph showing Water Tariff for 2013-2014
Lowering of the water table:
To pump groundwater, well needs to reach below water table.
If water table level drops - deepen well/new well/lower pump in order to reach it.
potentially dangerous to environment if water is drawn out faster than it is replenished.
Natural disasters that have a great affect on the economy
Natural disasters that kill the most people
Graph showing the extent of Wetland loss around South Africa
Diagram of an Aquifer
Graph showing the amount of freshwater vs. how much saltwater there is in groundwater
Diagram showing groundwater seepage into rivers
Image of a pump that withdraws water
Diagram showing the effects of land subsidence
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Water is a necessity and therefore demand should be inelastic across all income groups. This means that consumers are unresponsive to changes in price.
Sue Blaine, "Agriculture is putting SA in deep water" Business Day, May 1 1985. Web. 17 April 2013. http://www.bdlive.co.za/business/agriculture/2013/04/17/agriculture-is-putting-sa-in-deep-water
Prevention Web, disaster statistics. Web. http://www.preventionweb.net/english/countries/statistics/?cid=160
Via Afrika Georgrapy Grade 10 learners book. Book. Pages: 245,250, 251
a deep, tap- root system in moist areas
fibrous roots in dry areas.
Either way, eucalypts tap into a lot of groundwater, which leads to lower levels of water.
Koos Marais, "The Big Lie - Is There Place for Green Politics?" July 1990. Web. 16 June 2013. http://www.geasphere.co.za/southafrica.htm#TheBigLie
Forest Ecology and Mnagement, "Conversian of Atlantic forest into native and exotic tree plantations" 9 Aug 2006. Web. 10 May 2013. http://planet.botany.uwc.ac.za/NISL/Gwen's%20Files/GeoCourse/Blog/Articles/AtlanticForestZurita.pdf