Presentation on theme: "Water lot of water? What physical and human factors affect water supply? Is supply and demand balanced in different parts of the world?"— Presentation transcript:
Water lot of water? What physical and human factors affect water supply? Is supply and demand balanced in different parts of the world?
Human influences on water supply and demand Humans affect the hydrological cycle at many points of flows and storage: Disruption of water cycle Land use changes affect interception + infiltration + surface storage; Eg urbanisation, deforestatio n Water abstraction affects ground water storage, and can create salinisation and salt water incursion Flood management + dam construction affect channel flow + storage By Quantity ( adding to or abstracting) or Quality(pollution )
Graphs p 34 and 35 Pearson How is water used on a worldwide scale? How is water used in the UK?
Blue water flow is the visible part of the hydrological system: surface flows and then recharging aquifers Green water flow is water intercepted, stored in soil and released by vegetation by evaporation and transpiration Grey water is polluted water Supply can be from: Surface sources groundwater sources In the UK 2/3 of supply is from surface and 1/3 from groundwater, with regional variations. Freshwater is effectively a finite resource since only about 1% of freshwater is easily available for human use. The water footprint indicates how much is required by consumers- and in an increasingly globalised world, the footprint of someone in a country like the UK will not be just local as so many products using water will have been produced elsewhere!
The cost of everyday items ….in litres of water. One sheet of A4… One slice of bread… One apple.. One cup of coffee.. One pint of beer.. One pair of leather shoes.. One packet of mixed salad One bag of crisps.. One litre of milk.. One cotton tee-shirt.. One pair of jeans.. One 100g bar of chocolate.. One glass of wine..
The cost of everyday items ….in litres of water. One sheet of A4…10 One slice of bread…40 One apple..70 One cup of coffee..140 One pint of beer..75 One pair of leather shoes..16,600 One packet of mixed salad..50 One bag of crisps..185 One litre of milk One cotton tee-shirt One pair of jeans..10,850 One 100g bar of chocolate One glass of wine..120
Some key definitions p 61 Oxford and p 37 Pearson Domestic Water shortage low level of water supply relative to basic needs. measured by annual renewable flows (in cubic metres) per head of population, or the number of people dependent on each unit of water Water stress often taken as less than 1700m3 per person per year growing conflict between users and competition for water declining standards of reliability and service harvest failures and food insecurity. Water scarcity supply of water per person falls below 1000m3/year an imbalance of supply and demand a high rate of use compared to available supply, especially if the remaining supply is difficult or costly to tap. Physical water scarcity reached when 60% of river flows are diverted for agricultural, industrial & municipal purposes; globally over 75% is now used Physical water scarcity is shown by: Severe environmental degradation Declining groundwater and water allocation which favours some groups over others. Arid and semi-arid areas are most at risk Economic water scarcity when less than 25% of rivers are used, and there is abundant supply potential: water does not reach the poorest people This is often due to political reasons and conflict: easiest to solve by low technology solutions: small dams, water harvesting from roof tops etc. It is targeted by NGOs like Water Aid
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Water Supply In India 1.Monsoon Climate Due to the movement of the ITCZ Little supply Dec – May Monsoon June - Oct Low Pressure due to the position of the ITCZ High pressure due to descending air 2. Changing Discharge in the Ganges, Indus and Brahmaputra. This varies seasonally due to the Monsoon and snow melting in the Himalayas Ganges Brahmaputra Indus 3. Geology Aquifers in the North = good water supply
Cherrapunjis (in India)missing water? LO: Why cant we have water everywhere? Why? Water scarcity isnt just the fault of people
Thinking /guwahati/ _1_drinking- water-water-resources-wettest-desert /guwahati/ _1_drinking- water-water-resources-wettest-desert What are the physical and human reasons that water is an issue in Cherrapunji, India?
Watch the clip and read the article…in pairs Complete a table of the physical reasons and human human reasons why water supply in Cherrapunji has changed Highlight where there are potential overlaps between the two columns. Decide which of the reasons is the strongest by scoring them in order (1 for most important, X for least important. The strongest reason gets the lowest score)
Factors affecting Cherrapunji Physical geography – Monsoon climate – variability – Saturation of ground – impervious – Climate change? Human Geography – Lack of dams – cant harness variable supply – Aquaculture, NOT agriculture – Overpopultion
Yemen Sanaa, capital of Yemen, has no renewable water. At 2,300m above the sea, the city cannot use desalinated water and the only solution could be to move the capital. Read p 38 Pearson
UK water supply Lets examine the reasons for the variation in water demand and supply in the UK.
Estimated changes in demand for water Work out the estimated changes in different regions of the UK Show this on the map after discussing with your partner What are the advantages / disadvantages of the methods used?
Areas of water surplus /water deficit Using a range of Atlas maps and information, annotate the outline map of the UK to help identify the reasons why there is a water surplus /deficit in the areas identified. Add as much detail as you can around your map.
Water resources and climate change? P 38 Pearson
The key players who affect the supply and demand for water?
Water companies Governments – national and state/local authority UN, WTO and TNCS Agriculture Industry/business Recreation/tourism Domestic users Charities Nature conservation
California p Oxford Why are we doing this case study? California p Oxford With reference to differing examples, explain how differing stakeholders views could lead to water conflict (15) Referring to examples, assess the potential for water conflict in areas where demand exceeds supply (15)
1.Explain the physical controls on the supply of fresh water in California (think about the climate, river systems and aquifers etc ) 2.How is human activity affecting the water availability in California? 3.What are different key players likely views on the water issues in California? 4.What are the environmental implications of supplying water to California? 5.What are the economic implications of supplying water to California? IN DETAIL
Why will conflict arise here ? Hoover Dam Phoenix – 1.5 million residents 7 states covered : Wyoming / Colorado New Mexico / Arizona California / Nevada Utah Las Vegas 1.8 million Mojave Desert Salt water : Pacific Ocean and gulf of California Colorado 1 of the bread basket states Glen Canyon Dam
History of the Colorado Basin Colorado Compact 1922, allocated the water rights between the different states 1920s law of the River divided the river into the Upper basin states, who had responsibility to supply the lower states Over time new treaties have been signed and Mexico has also been involved Now there is a giant plumbing system, with more than 10 major dams to give water to over 30 million people Lots of the treaties were established in the 1920s, since then population, industry and climate here have all changed
Stakeholder and what they think including specific detail Farmers City dwellers Environme ntalists Indigenous groups Mexican People US federal Gov Farmers City Dwellers Environmentalist and recreationists Indigenous Groups Mexican People US federal Government Complete the Conflict matrix, but also put in their opinions in detail in the first column