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IB ESS SL4.1 Water systemsQuestion Bank

4.1 Water systems

Question 1

Question 1(b)

(a)

Label the diagram below to show water flows into and out of Lake Naivasha.

Diagram for water flows into and out of Lake Naivasha

Diagram for water flows into and out of Lake Naivasha

Lake Naivasha is in the tropical grassland biome and is the only freshwater lake in the Rift Valley in Kenya.
It is shallow, with average depth about 6 m; surface area varies from 102 km^2 to 150 km^2 due to irregular rainfall.
Water sources are the Malewa and Gilgil rivers, rain from storms over the nearby Aberdare range, and groundwater flow.
Water leaves by evaporation, transpiration from aquatic vegetation and underground flow.
The lake and shoreline provide habitats including papyrus swamps, freshwater lake/river habitats and Crescent Island; there are no native fish.

[ 2 ]

Question 1

Question 1(b)

Question 1(b)(i)

(a)
(i)

With reference to Figure 1 (c) and Figure 8, identify which of the three channels of the Danube River delta has been most extensively straightened by dredging and state why this has been done.

Figure 1(c): Map of the Danube River delta and Kiliya, Sulina and St George channels

Figure 1(c): Map of the Danube River delta and Kiliya, Sulina and St George channels

Figure 8: dredging is carried out so sediment carried by the river does not interfere with navigation.
Dredging involves scooping out sediment using heavy machinery and has also been used to straighten channels.

Figure 8(a): Bucket dredging

Figure 8(a): Bucket dredging

Figure 8(b): Grab dredging

Figure 8(b): Grab dredging

[ 2 ]

Question 1(c)

Question 1(c)(i)

(b)
(i)

With reference to Figure 7, calculate the percentage decrease in average sediment flow between 1971-1980 and 1981-1990.

YearsAverage sediment flow / tons yr^{-1}
1921-196067.5
1971-198041.3
1981-199029.2

Figure 7: Changes to sediment flow into the delta

[ 2 ]

Question 1(c)(ii)

(ii)

Suggest what effect this change in the sediment flow would have on the maintenance of the Danube River delta.

YearsAverage sediment flow / tons yr^{-1}
1921-196067.5
1971-198041.3
1981-199029.2

Figure 7: Changes to sediment flow into the delta

The Danube River delta is where the Danube flows into the Black Sea and includes UNESCO Biosphere Reserves and a World Natural Heritage site.
A delta is formed by continuous deposition of sediment carried by the river; sediment adds height and helps it extend into the sea.
The delta is a wetland ecosystem rich in plants, birds and fish, including over 1000 plant species, 300 bird species and endangered sturgeon.
Moldova takes nearly 20% of its water supply requirements from a branch of the Danube.

[ 2 ]

Question 1

Question 1(a)

Question 1(a)(i)

(a)
(i)

State the source of energy that drives the Earth's ocean currents.

[ 1 ]

Question 1

Question 1(b)

Question 1(b)(i)

(a)
(i)

From the information in the resource booklet and your own studies, identify two inputs and two outputs of water associated with Inle Lake by labelling the boxes in the diagram below.

Diagram for inputs and outputs of water associated with Inle Lake

Diagram for inputs and outputs of water associated with Inle Lake

Figure 3(a): Map of Inle Lake, Myanmar (Burma)

Figure 3(a): Map of Inle Lake, Myanmar (Burma)

Inle Lake facts: freshwater lake, second largest in Myanmar (Burma).
Surface area 116 km^2; average depth 2 m; maximum depth 3.7 m.
Monsoon rains raise lake surface by 1.5 m.
Many endemic species are found there; about 70 000 people live around and on the lake.

[ 2 ]

Question 1

[Maximum number: 2]
Figure 1(b): Map showing Swakop River in Namibia

Figure 1(b): Map showing Swakop River in Namibia

Figure 4(b): Camera trap data for high and low mesquite areas

Figure 4(b): Camera trap data for high and low mesquite areas

Figure 5(a): Uranium prices from 1980 to 2013

Figure 5(a): Uranium prices from 1980 to 2013

Question 1(b)

(a)

Identify three natural sources of water available in the Swakop area.

Figure 3(c): Fact file on the Swakop water resources

Figure 3(c): Fact file on the Swakop water resources

[ 2 ]

Question 1

Question 1(b)

Question 1(b)(ii)

(a)
(i)

Identify three ways in which the exploitation of tar (oil) sands may lead to impacts on freshwater resources.

Tar sands are deposits of heavy crude oil in bitumen/tar, sand, clay and water. They are too thick to flow unless heated. Extraction becomes financially worthwhile as oil prices increase and can improve energy security for Canada and the USA. Water is pumped from local rivers, made into steam at 305°C and pumped into the tar sands so the oil can be brought to the surface. The mixture must be refined, and deposits may be mined by strip-mining or deep pit mines.

About 80% of global tar sands deposits are in Alberta, Canada, mostly in the Athabasca field. There may be 1350 billion barrels of oil, with about 10% extractable. Extraction is described as the largest capital project on Earth. The Keystone XL pipeline would carry crude oil south to US refineries and an extension may cross the Ogallala Aquifer, a major freshwater reserve providing drinking water to 2 million people.

Figure 4(c): Mining of tar (oil) sands

Figure 4(c): Mining of tar (oil) sands

Opponents say tar sands produce three times more greenhouse gas emissions than conventional fossil fuels; fossil fuels are burned to heat extraction water; underground carbon stores become available; oil produced is burned; boreal forest is cut down; wildlife is displaced or dies; only 10% of water taken from the Athabasca River is returned; toxic waste ponds may leak into river and groundwater; indigenous people may be displaced and face health impacts. Supporters say tar sands improve energy security for Canada and the USA; Canada supplied much crude oil to the USA; Keystone XL may create jobs; companies reinvest in carbon capture and storage; 7.5 million trees have been replanted.

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Question 2

[Maximum number: 2]
Figure 2(a): Water transfers and transformations after rainfall in forest and urban environments

Figure 2(a): Water transfers and transformations after rainfall in forest and urban environments

Figure 2(b): Global water demand by sector for 2014, and projected for 2025 and 2040

Figure 2(b): Global water demand by sector for 2014, and projected for 2025 and 2040

Question 2(b)

(a)

Calculate the difference in water infiltration between the forest and urban environments.

[ 1 ]

Question 2(c)

(b)

Outline how one storage in the hydrological cycle decreases with urbanization.

[ 1 ]

Question 11

[Maximum number: 4]

Figure 7: Threats to biodiversity and ecosystems within the Coral Triangle
Coral reefs and mangroves in the Coral Triangle have declined by over 40% since the 1970s; over 85% of coral reefs are threatened by population growth and human activity.
Threats include removal of mangroves, unsustainable/destructive fishing, demand for turtle products and shark fins, land-based pollution, tourism impacts and climate change.
Tourism threats include sewage, plastic waste, coral trampling, boat-anchor damage, stress to wildlife and collection of wildlife souvenirs.

MangroveSeagrassCoral reef
Nursery/habitat for fish and shellfishNursery/habitat for many speciesNursery/habitat supporting high biodiversity
Traps sediments and absorbs nutrientsTraps sediments and absorbs nutrientsFilters particulates, increasing water clarity
Absorbs CO2 and emits oxygenAbsorbs CO2 and emits oxygenProvides fish and shellfish
Reduces coastal erosion/storm impactsStabilizes sedimentSupports tourism/fisheries

Figure 5: Ecosystem goods and services in coastal marine habitats

Explain how the following land-based activities could have a damaging effect on marine ecosystems within the Coral Triangle:

Question 11(a)

(a)

deforestation

[ 2 ]

Question 11(b)

(b)

agricultural activity.

[ 2 ]

Question 3

[Maximum number: 2]
Figure 3: Impact of deforestation on the water cycle

Figure 3: Impact of deforestation on the water cycle

Question 3(a)

(a)

State one storage of fresh water not shown in Figure 3.

[ 1 ]

Question 3(b)

(b)

State one input of water into the atmosphere not shown in Figure 3.

[ 1 ]

Question 6

Question 6(a)

(a)

Explain how the production of cash crops (such as pineapples) may have an environmental impact on:

[ 1 ]

Question 6(a)(ii)

(i)

lakes or rivers.

[ 1 ]
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