Section 1 the Hydrological (Water) Cycle

Hydrosphere Revision Booklet

Section 1 – The Hydrological (Water) Cycle

You need to be able to break this down into stores and transfers, all of which interlink to form the cycle. On your diagram highlight stores in one colour, transfers in another. The transfers are the processes.

The hydrological cycle is regulated by the biosphere and the lithosphere.

Regulated by / Explanation / Development
Lithosphere – rock type / Some rocks are porous, this means they can store water, (an aquifer). For example, chalk. / This is important because people can abstract water from the rock to use. For example, the chalk aquifers in SE England.
Some rocks are impermeable, this means they don’t let water in. / This means that water cannot be stored and therefore might increase the amount of surface run off and therefore the risk of flooding.
Biosphere / Trees intercept precipitation and absorb water. / This increases the amount of water in the vegetation store and decreases run off to the river, reducing the risk of flooding.
Tree roots can increase the amount of infiltration, increasing the amount of water in the soil store. / Also reduces risk of flooding.
Evapo-transpiration from vegetation returns water to the atmosphere store. / This is especially important in the Tambopata area of the Peruvian Amazon, where evapo-transpiration continues the water cycle and increases the amount of rainfall.

Exam Question

Explain how water is transferred from the land to the atmosphere and the lithosphere. (6 marks)

Firstly, ......

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Secondly, ……………………………………………………………………………………………………………

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………......

Thirdly, ………………………………………………………………………………………………………………

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Exam Question

Explain why the hydrological cycle is regarded as a system of stores and transfers. (6 marks)

Firstly, ......

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

Section 2 – The impact of unreliable and/ or insufficient water supply.

The best way to answer a question here is using the Sahel region (the southern fringe of the Sahara Desert). Water stress takes where demand for water by people exceeds supply. In Niger, one of the Sahel countries, population has grown by about 3% each year in an area that naturally has great variability in rainfall with frequent droughts.

As with any impacts questions use SEE structure Social Economic and Environmental.

Impact / Explanation / Development
Social / Extended drought (lack of rainfall) can cause crops to die and decrease yield causing people to suffer malnutrition and possibly famine. / This occurred in Niger between 2010 and 2012, with many people dying or becoming ill.
Social / People, especially women and children, are forced to walk many kilometres to find water. / This means children cannot go to school, reducing literacy rates.
Economic / Farmers lose money as their crops fail and animals die. / This can affect the nomadic cattle and goat herders in Niger.
Economic / The price of food can increase due to shortages. / This results in the poorest people, often in rural areas, being unable to buy food.
Environmental / Soil becomes very dry in an extended drought and can blow away, this is called desertification. / Important because it reduces soil fertility in the long term.
Environmental / Water holes dry up. / Wildlife lose their water supply impacting on habitats.

Exam Question

For an area you have studied, examine the impacts of an unreliable water supply. (6 marks).

Firstly, ......

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, most important impactis ......

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Section 3 Threats to maintaining a healthy water cycle

Questions here will either ask about water quality or water supply.

Water Quality refers to the cleanliness of the water of the water available to people and ecosystems.

Water Supply refers to the total amount of water available.

Water quality can be thought of as the percentage of the population who cannot access safe drinking water. Generally thought of as at least 20 litres of drinking water being available within 2km. Water quality does not necessarily link to low precipitation, more usually to poverty. That said, water quality is poorest in areas with unreliable rainfall – specifically the Sahel and East Africa (Ethiopia and Somalia).

The best example to use if asked about human activities that impact on water quality is the Citoram River in Indonesia.

Activity / Explanation / Development
Industry / Clothing factories along the river release dyes into the river as industrial waste. / This is important because the dyes contain arsenic and poison the water, impacting on the health of local people who drink the water.
Sewage / Poor sanitation systems mean sewage from houses goes directly into the river. / This means the water contains harmful bacteria leading to children becoming ill.
Agriculture / Excess nitrate fertiliser used on paddy fields in the rice farms is washed into the river. / This causes eutrophication – algal bloom, with bacteria that removes oxygen from the water. This kills the natural ecosystem, especially fish.
Agriculture / Slurry from local pig farms is washed into the river. / Also causes eutrophication.
Domestic Waste / Household rubbish, for example plastic, is thrown into the river. / This pollutes the river and destroys the habitat.

Examine how human activities can affect water quality. (6 marks).

Firstly, ......

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, most important impact is ......

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Human activity on water supply is best thought of as over-abstraction from stores, usually rivers or ground water stores. If too much water is removed then river discharge decreases and the water table (height of water in the ground in the ground) lowers.

Activity / Explanation / Development
Agriculture / Farmers abstract large volumes of water from rivers and aquifers to irrigate (water) crops. / In Uzbekistan this has led to the Aral Sea shrinking in size as the rivers feeding the sea have almost dried up. The crop being watered here is cotton.
Domestic use / Large volumes of water have been abstracted from aquifers for use by households in rapidly growing cities. / In Beijing in northern China, the water table is now much lower due to over-abstraction. This has led to wells drying up and villages in the nearby mountains being abandoned due to lack of water.
Deforestation / Cutting down of trees has decreased infiltration and increased run off. / This has led to an increase in flooding.
Reservoir and Dams / Reservoirs are used to store water. / This reduces the flow downstream, for example, downstream of the Hoover Dam on the Colorado has resulted in the river no longer reaching the sea.

Exam Question

Explain how human activities can affect water supply. (6 marks).

Firstly, ......

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, most important activityis ......

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Section 4 – Water Management

Here you need your three key case studies, they are on the case study sheets attached.

Large scale water management in a developed country – Hoover Dam / Lake Mead on the Colorado (USA).

Large scale water management in a developing country – Three Gorges Dam on the Yangtze River in China.

Small scale water management as an example of sustainable water management.

Remember that this links to the top down and bottom up development case studies in the human geography paper. You can use the same studies.

Describe the costs and benefits of a large scale water management project in a developing country. (6 marks).

Example used here is ……………………………………………………………………………………………………………………………………………

Firstly the main benefit is ...... ………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………..

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, ......

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Exam Question

Using examples explain why small scale solutions to managing water supplies are often sustainable. (6 marks).

Firstly, ......

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, most important aspect of sustainability is ...... ………………………………………………………………………………………………………………………..

Describe the costs and benefits of a large scale water management project in a developed country. (6 marks).

Example used here is ……………………………………………………………………………………………………………………………………………

Secondly, ……………………………………………………………………………………………………………

Thirdly, ………………………………………………………………………………………………………………

To conclude, ......

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