IB ESS SL 4.2.8 Water Scarcity Mitigation Question Bank

Examples of strategies [2 max]:
i. reservoirs; dams; rainwater harvesting; water diversion projects; international sale of water resources; desalination; artificial glaciers; cloud seeding; water conservation/grey water reuse; restoration of wetlands; prevention of water pollution; pumping of aquifers;

Evaluation may include factors such as...
ii. impact of cost on economic sustainability of population;
iii. demand placed on human / physical resources;
iv. climate impact - carbon negative/neutral/positive;
v. impact on ecosystem resilience;
vi. impact on biodiversity;
vii. interference with natural cycles;
viii. limiting geographical/climatic factors;

The following examples of water management strategies and their evaluation show how credit can be given for any appropriate strategy.

Example 1: Rainwater harvesting;
Positive:
does not impact natural water cycle / replenishment rate / impossible to reduce natural income;
free natural capital;
useful for watering plants/irrigation / washing / fire protection / (thus) reduces consumption of groundwater/other freshwater resources;

Negative:
availability restricted temporally and spatially (unequal distribution of rain / unpredictable supply);
usually not safe for drinking;
can't satisfy needs of irrigation of commercial agriculture;

Example 2: Desalinization;
Positive:
sustainable if energy required produced by photovoltaic cells; sea water is more available than freshwater; provides accessible/safe drinking/irrigation water;
salt may be used for producing useful chemical products (sodium hydroxide, hydrochloric acid);
reduces pressure on freshwater reserves that need protection;
Negative:
requires huge amounts of energy / increase GCC if fossil fuel used; not available in landlocked countries;
building of facilities result in environmental damage/pollution; disposing of salt (brine) poses environmental hazards/pollutes ocean / salt is contaminated so can't be eaten;
high cost to build and operate that may be economically unsustainable;
Notes: Award [1 mark] for each appropriately identified strategy for improving access to freshwater up to [2 max].
Do not accept simplistic statements not clearly linked to sustainability, eg. cheap / efficient / doesn't need elaborate equipment/scientific expertise.
Accept statements such as "its cost is too great to be economically sustainable / its cost may divert economic resources away from habitat/species protection / resource requirement maybe unsustainable for LEDCs".
Award [5 max] if only positive OR only negative evaluation OR only one strategy evaluated.
Award [1 max] for each clear negative or positive evaluation of each factor.