Chapter 13 How much water do we have? Only 30% of the earth is water and most of them are found in oceans and seas. 2.8% of the earth ’ s water is fresh water. 75% of the fresh water is stored as ice bergs and glaciers. 21.4% of the fresh water is groundwater. 3.6% of the fresh water is found in rivers and lakes = 0.1% of the earth ’ s total amount of water.
Climate changes The disturbance of the hydrologic cycle has led to an increase of prolonged droughts and famine all around the world. Ice are melting and the sea level has began to rise. Ice sheets melting
Deforestation Canopy of the forest and vegetation areas slows down the surface runoff of the rain. When trees are cut down, the water flows into the river quickly, increasing the amount of sediments flowing into the river, contaminating the clean water, decreasing water supply. Increase in pollution Farmers who farm near rivers use pesticides and chemicals to kill weeds and pests. Rain comes and wash them into the river, polluting the water. Water pollution
Poor farming practices Monoculture = one single crop planted over and over again It reduces soil fertility and hence causes soil leaching and severe soil erosion Farmers rearing excessive herds of cattle= overgrazing This occurs especially on marginal land that is exposed to severe soil erosion.Water ways are blocked due to sedimentary, causing flooding. Chemicals fertilisers pollute the water and decrease water supply.
Increase in Agriculture Activities As the world ’ s population increases, the demand of food increases and so do the demand of water needed to water the crops and other purposes. Industrial and commercial Industrial activities require a large amount of water and rapid industrial growth will need a lot of water. (e.g.9.5l of water is needed to refine 1l of gasoline.
Why water is a scarce resource 2.8% of the earth ’ s water is fresh water Climate changes Increase in the no. of prolonged droughts Uneven distribution of rainfall Places with low annual precipitation are likely to suffer from drought Deforestation With lesser trees canopy, the water flows into the river faster causing soil erosion Poor farming practices Monoculture Overgrazing Using chemical substance over cropping The rising demand for water Increase in population Increase in agriculture activities Increase in industrial and commercial activities
Chapter 14 - Response to the rising demands for water
The allocation of water might cause regional tensions and conflicts.
*E.g. If a country occupy the downstream water of a river and the water received is polluted, the country occupying the upstream would be blamed.
Such problems can be solved by international agreements . It helps to settle or prevent cross-border disputes over water resources.
*E.g. Great Lakes Basin spans eight states of USA and two provinces of Canada. Thus in 2004, they signed the Great Lakes Basin Sustainable Water Resources Agreements. Special attention was given to relate the amount of water withdrawn.
1. Turn water off when soaping during shower & washing hands
2. Take short shower instead of long bathe
Use a mug or cup to contain water when brushing teeth
Wash only at full load when using washing machine
Wash vegetables & fruits in a pan of water than under running tap
Water plants with water recycled from washing rice, vegetables &
Responses To Rising Demand For Water Increase price of water - Effective tool to control demand -Slow down demand of water Increasing water supply Water conservation - Educate public on how to conserve water Catchment Areas Technology International Agreements
Construction of dams
Constructing of reservoirs
E.g. Singapore 1/2 to 2/3 turn
Desalination : A process that removes salt from seawater Water Reclamation : A process that recycles used water - e.g. NEWater of Singapore -Helps to allocate shared water resources among countries -Established to protect, conserve & manage water source
“ The Four National Taps’’ Strategy Water Catchment -1/2 to 2/3 of Singapore as catchment areas by 2009 -Currently Singapore have 14 reservoirs with Marina Barrage as the 15 th Imported Water -Water agreements with Malaysia, supplying half of Singapore’s demand -Water carried by pipelines NEWater (Reclaimed Water) - Purification of treated used water to produce NEWater Desalinated Water -Meets 10% of our demand PUB - Mission: Ensure efficient, adequate & sustainable water supply -Manages water supply, water catchment & used water in an integrated way -Encourages all Singaporeans play a part to conserve water, keep water catchments & waterways clean, and build relationship with water so that we can enjoy our water resources
From this project, I learned that the time taken to revise my work and to study reduces and that if everybody works together to compile the notes, it is much faster and easier to understand the topic. It is not time consuming and the notes that everyone has compiled are very easy to understand and I can master the topics much more easily than before. I also learned that teamwork is very important and that studying in groups aren’t that bad. Next, from what I have learnt, I think that we should cherish what we have now and conserve what we can. For example, water. As a scarce resource, we should use it wisely and too, understand our water supply. -Suli
Reflections… With all the water shortages Singapore faced and solved, I truly learnt the importance of conserving water. Though there is no serious water shortage in the world currently, we should foresee the problem and solve it NOW and not let the problem develop. Although we have already found the solution of our shortage problem in Singapore, we should not be contented with the current situation and continue wasting water but to sought for more solutions to get ready for a yet-to-come crisis of water if there is one. Overall, the must important factor to supply more water is to RECYCLE, REUSE, REDUCE! It’s also a pleasant to work with such a wonderful group to complete this revision slides xD~~ -SzeHwee
Reflections… I feel that the rising demand of water is becoming a major problem that would threaten mankind in the future. A handful of rivers in the world are polluted due to the many centuries of usage. There are factors such as deforestation that in turn result in soil erosion and leaching too. If mankind continue to figure out ways to help lesson the demands; I feel that raising the cost is not a permanent solution. Without the water, even any amount of money could not buy it back. Ways such as stopping deforestation would certainly come in handy. It would be a better solution to prevent the problem from starting in the first place. -Gina
Overall, I’ve learnt about how Singapore derives its water sources from the 4 National taps, which are namely: Desalination, reclaimed water (NEWater), imported water though water agreements and water from Singapore’s Catchment areas. Although Singapore has 14 (going to 15 soon) reservoirs and has almost 2/3 of its land area as water catchment, we still have to rely on desalination and water reclamation, as well as imported water to augment our water supply and it is safer to have access to potable water through various alternatives should one of these means fail (eg. Water supply cut off from Malaysia due to hostile relations or drought due to change of climate).
The PUB has also come up with a comprehensive water conservation plan to urge consumers to use water efficiently. [eg: pricing water and educating the public to make efficient use of water.]