4.2 Access to Fresh Water

Understanding

- Access to an adequate supply of freshwater varies widely. - Climate change may disrupt rainfall patterns and furher affect this access. - As population, irrigation, and industrialization increase, the demand for fresh water increases. - Freshwater supplies may become limited through contamination and unsustainble abstraction.

Inequalities of access to safe water occur:

- Between urban and rural areas. People living in urban areas are more likely to be connected to piped water. Some rural areas are remote and can be difficult to access. In 2014, 82% of people without access to water lived in rural areas. - Between the rich and poor. Those with wealth are most likely to have a reliable water supply. The poor in urban areas may live in slums and shanty towns that often have poor water access. - Between social groups. Some groups within society may be marginalized e.g. based on ethnicity, language or religion.

issues

- Climate change disrupts rainfall patterns - Slow water movement near the mouth of rivers accelerate sediment deposits, increasing delta size. - Underground aquifers are being exhausted, even ground above exhausted aquifers are sinking. - Fertilizers and pesticides pollute streams and rivers

Issues causing water degradation and scarcity

- Pumping rates from the aquifers are too fast: causing exhaustion making well unusable - Industries release pollutants into surface water bodies. - Industries and electricity plants release warm water into the rivers. Warm water can hold less dissolved oxygen than cold water, so aquatic organismsthat thake their oxygen from the water are negatively affected. Warm water outflow from power stations changes the species composition in the water.

Significant Ideas

- The supplies of freshwater resources are inequitably available and unevenly distributed, which can lead to conflict and concerns over water security. - Fresh resources can be sustainbly mangaed using a variety of different approaches.

Understanding #2

- Water supplies can be enhanced through reservoirs, redistribution, desalination, artificial recharge of aquifers and rainwater harvesting. Water conservation (including grey-water (water used to wash vegetable) recycling) can help to reduce demand but often requires a change in attitude by the water consumers. - Scarcity of water resources can lead to conflict between human populations - particularly where sources are shared.

Humans use fresh water for..

- domestic purposes - water used at home - agriculture - irrigation, for animals to drink - industry - including manufacturing, mining - hydroelectric power generation - transportation (ships on lakes and rivers) - marking the boundaries between nation states (rivers and lakes)

Solutions

1. Increase fresh water supplies by - reservoirs - redistribution - desalination of sea water - harvesting rainwater - artificially recharging aquifers 2. Reduce domestic use by using water efficient appliances 3. Grey- water recycling 4. Irigation: Selecting drought resistant crops

Water demand is continuing to rise due to..

1. growth in population 2.. increase in standard of living resulting in higher water consumption for washing, cleaning, gardening. 3. change to more meat based diet 4. growth of industry 5. increase in urbanization

Water Crisis

40% of the world population live with "some level of water scarcity" One human needs 20L a day. (WHO) One human needs 40L a day. (Agenda 21) There could be enough water in some at-risk areas, but much of it is used for agricultural purposes (where usage rates are tens of times higher than for domestic use).

Distribution

Agriculture uses water for irrigation and to provide water for livestock- usage rates are tens of times higher than domestic use. As a population expands, we need water to grow more food but, it is not that there is not enough water, it is that the distribution is uneven.

What causes water scarcity

Because of the increased global quality of life, we have water scarcity problems, and water degradation

increasing water resources: Reservoir

Benefits: Flood control, used to capture floodwater and reduce risk of flooding in downstream. Impacts: Loss of fish and mammal routes for migrating, dam walls block the route for migration for fishes.

Contamination

Contamination of water with arsenic is a major problem is some countries. Arsenic occurs naturally in the Earth's crust and this leads to contamination of groundwater in some regions.Use of groundwater contaminated with arsenic can lead to long term exposure. Effects include changes to the pigmentation of the skin, development of skin lesions, cancers of the skin, bladder and lung.

Global freshwater consumption lead to what problems?

Global Freshwater consumption is increasing because human population is increasing because a quality of life is improving. This increased freshwater use leads to two types of problems - water degradation: water quality deteriorates, less suitable for use - water scarcity

Irrigation and salinization (factor causing water scarcity)

Irrigation often results in soil degradation, mostly in dry areas because much of the water used in irrigation evaporates before it is absorbed by the crops. Dissolved minerals remain in the top layer of the soil, making it too saline (salty) for further agriculture. This process is called salinization.

Water Conflicts

Israel is facing water shortages. China's Three Gorges dam

The geopolitics of Israel's water shortage

Israel is suffering its drought, have to stop pumping from one of its main water sources from the Sea of Galilee. Caused from popultaion growth and improvement in quality of life that breaings desire to water lawns and gardens. Despite the shortage, Israel wil not reduce the amount of water supplied to jordan udue to peace treaty and Jordan is worst condition than Israel.

Competition

Over abstraction can lead to depletion of water resources. With limited water supplies the risk of conflict over this resource increases. Disputes over ownership and water rights may occur: Between individuals or groups within a country. Between countries where river systems are shared. It is important to manage water supplies sustainably to ensure sufficient future supplies. Groundwater and lakes need time to replenish. We need to control demand through water conservation strategies and also increase supplies.

Who Owns water?

Some countries have more than enough, while others are incredibly deficient in water resources. Though there is enough water for the entire population of the planet, it is the uneven distribution that is the problem. ex. Canada has 20% of world's fresh water supply while India only has 10% when the population is 30 times larger.

Surface freshwater and aquifers

Sources of freshwater are surface freshwater (rivers, streams, reservoirs, and lakes) and underground aquifers. The water can be extracted directly from surface or via wells from aquifers.

Sustainable use of resources

Sustainable use of resources allows full natural replacement of the resources exploited and full recovery of the ecosystems affected by their extraction and use.

China's Three Gorges dam update

Three Gorges hydroelectric dam provide 9% of all china's output saving co2 emissions. However, cause environmental degradation and threatened wildlife species. - Siberian Crane is endangered and their winter habitat is the wetlands that the dam floods. Dolphin is extinct due to pollution and loss of water flow downstream. - Pollution by toxic waste and materials used in building the dam makes the waters unsuitable for drinking and increase algal blooms and eutrophication in the water.

Water supplies

We can remove the salt from water in desalination plants but the costs in terms of energy are large, and only possible in wealthy countries. A major issue with desalination is that salt is a by-product and is often returned to the ocean, increasing the density of the water which then sinks and damages ocean- bottom, ecosystems. Unless we can find technology to desalinate water cheaply.

increasing water resources: use of greywater

greywater is used water that is clean enough to be used again, reduces the amount of waste water produced.

Aquifer

layer of porous rock, which hold water that it sandwiched between two other layers of impermeable rock. --> not sustainable. Water flow is extremely slow.