(6.3.2) Are water resources being managed sustainably?

Why might a region’s water supply need to be managed?

countries with low precipitation

need to conserve, manage and redirect water

to ensure the needs of the country are met

What is irrigation?

a process by which plants are artificially watered

What is a resovoir?

man made lakes

dead branches of lakes that only have water during the rainy season

How do reservoirs enable irrigation?

water is stored during the rainy season

and released during the dry season

What are aquifers?

layers of porous rock that store huge quantities of groundwater underneath them

What is abstraction?

the process of groundwater extraction:

drilling through the rock (forming a bore)

pumping out the water

What is over-abstraction?

When more water is abstracted than can be replenished through recharge

What is a water transfer scheme?

a way to move water from an area with surplus to an area with a deficit

reservoirs collect water, pipes/canals transport it

Why is rainfall in South Africa uneven?

rainfall is seasonal + most falls on east coast

therefore, inland areas get less water

What is the Lesotho Water Project?

Lesotho is:

• landlocked

• mountainous

• has a low population

• receives 1000mm of rain a year

Therefore, water is transferred from Lesotho’s Katse Dam to the Guateng region of South Africa via pipes.

What are the social impacts of the Lesotho water project?

Lesotho

• highlanders have better access to education, healthcare

• steadily growing middle class

• project seen as a sellout

• 30000 displaced people to build reservoir- backlash

• access to family is difficult

• villagers are scared of the dam

South Africa

• more available water

• drought mitigation

• wealth inequality

What are the economic impacts of the Lesotho water project?

Lesotho

• earned $44 million/year

• electrically self-sufficient

• infrastructure put into place

• created 16,000 jobs

• loss of farming land

South Africa

• since the government had to borrow money for the scheme,

  people have to pay for the water- too expensive for some

• supports economic activity

What are the environmental impacts of the Lesotho water project?

Lesotho

• Hydroelectric power supply

• destruction of unique wetland

South Africa

• influx of freshwater is restoring the ecosystem

  • reduces acidity of Vaal River Reservoir

What alternative method is Limpopo in South Africa using to harvest water? How does it work?

Harvesting water from fog:

• hang mesh-nylon nets on poles

• fog condenses and pools to gutter below

• water passes through sand and flows to where it is needed

What are the benefits of rainwater harvesting?

• simple

• sustainable

• relatively cheap

• no electricity needed

• repairs are easy

What are the limitations to rainwater harvesting?

• it is not foggy everyday

• foggy areas are far from rural communities

• many rural communities do not have a piped supply from reservoir

• repairs are essential

What are the physical reasons that so much water is abstracted in India?

• seasonal rainfall- dry seasons

• surface stores are often polluted by human waste

• monsoon season means aquifers aren’t fully recharged in seasons with lower rainfall

What are the economic reasons that so much water is abstracted in India?

• drilling a well is cheaper in the long term than paying expensive water vendor

• Gov sparked a green revolution and crops use more water than traditional crops do

• cheap electricity → drill deeper → dries out as neighbours do the same

What can over-abstraction do to the water table?

the groundwater level can drop lower

What are the social impacts of over-abstraction in India?

• food insecurity as water level doesn’t support crops

• poverty

• climate-driven migration increases

What are the economic impacts of over-abstraction in India?

• loss of agricultural productivity

  • water depletion

  • crop failure

• loss of industrial productivity

• cost of water increased

• pumping from greater depths costs more electricity

• disproportionate impact on poorer parts of society

What are the environmental impacts of over-abstraction in India?

• groundwater depletion

• salination

  • can lead to seawater intrusion in coastal areas

• desertification

• loss of wetlands

• habitat loss, reduced biodiversity, disrupted food chains

  • as groundwater fed ecosystems collapse

What possible routes could India take?

Top-down:

• hard management

• dams

  • unpopular due to inadequate compensation

Bottom-up:

• grassroots self help schemes

• creating small stone and earth dams

  • small pools of water

  • soak in slowly

  • natural recharge of aquifers