4.2 Water Access, Use and Security

Water security is

having access to sufficient amounts of safe, drinking water to meet needs of people and ecosystems

Key components of water security

• sufficient supply

• safe drinking water

• sustainable management

2 types of water scarcity

• physical

• economic (water shortages, transport, lack of infrastructure

Factors influencing water security

1. Climate - temp, precipitation and evaporation rates

2. infrastructure - moving and treating water

3. politics - shared resources, transboundary conflicts

4. poverty - main cause, millions of ppl around the world don’t have access to clean water

How does poverty in africa influence water security

• 420 million lack basic water

• 780 million lack sanitation services

What is hydropolitics

• Politics surrounding availability of water resources

• can be an issue when river moves through multiple countries (eg: Nyle 11 countries)

Global inequality of water security

• 2 billion people lack safe drinking water

• uneven distribution

What is the result of increased usage of freshwater

water scarcity and water degradation

What is water degradation

water quality deteriorates - less suitable for use

Why the availability of drinking water decreases?

• Climate change - disrupts rainfall patterns, less and uneven

• low water levels in rivers - eg: Colorado River

• Underground aquifers exhausted due to agriculture

• extraction from aquifers is too fast

• contamination of freshwater

• eutrophication

• sewage release from industry

• warm water

Why is warm water release from power plants a problem?

carries less oxygen

Why is pollution important when considering water availability

• Polluted water reduces water quality, meaning the water is less useful, so the availability also reduces

What is an aquifer

Layer of porous rock between two layers of impermeable rocks

Why may aquifer take a long time to refill and replenish

• Water is filled by infiltration

• but there is a very small area for the water to infiltrate and water flows very slowly

How can we increase freshwater supplies in some areas?

• Build more reservoirs

• redistribution

• desalination

• rainwater harvesting system

Benefits of building dams and reservoirs

• Allows to regulate water supply

• flood control

• irrigation during drought - increases crop production

• Hydroelectric power - no CO2

• recreation

Drawbacks of dams and reservoirs

• water weight can stress the Earth’s surface - dam collapse

• costly and time consuming

• displacing locals in flood zone

• disrupts local ecosystems

Two types of rainwater harvesting systems

Aquifer recharge - water is stored itnto wells and used to artificially recharge aquifers

water tank storage - water collected from guttering and stored for later use

Benefits of harvesting rainwater

• supplies relatively clean water and reduces demand

• reduces need for import

• can create wetlands

• less runoff

• can be retrofitted

drawbacks of harvesting

• unpredictable rainfall

• many don’t have access/skills to install equipment

• systems need maintenance

• poor installation can lead to disease

How can we reduce domestic use?

• more efficient devices

• water metering

• grey water recycling

How can we reduce agricultural use of water?

• Irrigation reduction (drought resistant crops, closed pipes, trickle system over spraying)

• pesticides reduction

• use of organic fertiliser to slowly release nutrients

• Vertical farming - allows to control the environment, no soils, no weeds, 85% less water

What is desalination

• removal of salt from seawater

• Distillation or reverse osmosis

Desalination pros

• provides accessible water source for the areas with no other water supply

• reduces pressure on freshwater supplies

Desalination cons

• high energy use - high cost

• brine discharge - less O2 in the water

Why did water become a big issue in Israel

• population growth

• improved quality of life

• less rainfall due to climate change

• irrigation

• conflict