Water scarcity

Water scarcity is a lack of drinkable water available in a given area. The lack of sufficient available water resources to meet the demands of water usage within a region. 

Water scarcity already affects every continent and around 2.8 billion people around the world at least one month out of every year. More than 1.2 billion people lack access to clean drinking water.

It mostly affects arid and deserted areas, and places where the water is too polluted to drink. It is a social, environmental and economic problem in many countries. 

Water scarcity can be the result of both human and natural causes. Changes in climate and weather patterns can cause the availability of water to drop. Common human causes include over-consumption, bad governance, pollution, and increases in the demand for water.

The states of water

Water is known to exist in three different states:

• solid, 
• liquid or 
• gas.

Clouds, snow, and rain are all made of up of some form of water. A cloud is comprised of tiny water droplets and/or ice crystals, a snowflake is an aggregate of many ice crystals, and rain is just liquid water.

Water existing as a gas is called water vapour. When referring to the amount of moisture in the air, we are actually referring to the amount of water vapour. If the air is described as "moist", that means the air contains large amounts of water vapour. 

VIDEO - The states of water

Erosion

Erosion is the process of natural forces moving rocks and soil. Rocks and soil can be referred to as earth materials.

The natural forces that make erosion happen are:

water	water	Happens when water moves the pieces of rock or soil downhill and carries small pieces of material with it.
	waves	Carry away small pieces of material. A wave can wash up onto the surface of rock or soil and then carry away pieces of material as it flows back into the ocean or lake.
Wind		Occurs when wind moves pieces of earth materials. Wind erosion is one of the weakest kinds of erosion. Small pieces of earth material can be rolled along the ground surface by wind. Very small pieces can be picked up and carried by the wind. Occasionally, wind can carry small pieces of earth materials over large distances.
Ice		Usually happens when a glacier moves downhill. As the ice of the glacier moves downhill, it pushes and pulls earth materials along with it. Ice erosion is one of the strongest kinds of erosion because glaciers can move very large rocks.
Gravity		Is the simplest kind of erosion. Gravity simply pulls loose earth materials downhill. Landslides are dramatic examples of gravity erosion).

Erosion is a geological process. Geology is the study of the structure of the earth and the processes that change the earth. Erosion occurs only at the earth's surface.

Most of the energy that makes erosion happen is provided by the sun. The sun's energy causes the movement of water and ice in the water cycle and the movement of air to create wind. If the sun did not provide energy for erosion, only gravity erosion would still occur.

Erosion can cause problems that affect humans. Erosion can also cause problems for humans by removing rocks or soil that support buildings.

Las Vegas and the desert water pipeline

The city of Las Vegas wants to pump up to 300 billion litres of water a year out of the Nevada desert and transport it 480 kilometres south to the thirsty city.

In Las Vegas, where the population had been doubling every ten years, planners had an idea. What if there were a way of pumping the water towards Las Vegas? 

Water was ever an issue in the American west. For 100 years, Nevada and other south-western states have shared the waters of the Colorado river (and Lake Mead). 

But Lake Mead begins to decline in the past decade as Las Vegas expands. 

The city, which for years has been drawing more water from its Lake Mead reservoir than has been flowing in, could be at serious risk of going dry in 20 years, said Pat Mulroy, the manager of the Southern Nevada Water Authority. 

The city needed a new plan. When you have got a community of 2 million people and it is 90% reliant on the Colorado river you have to have a contingency plan, she said. The Water Authority has spent 79 million dollars to buy up water rights and they wants to pump up to 300 billion litres of water a year. A study last summer warning the pipeline would lower water tables in some valleys by up to 60 metres over the coming decades. Smaller springs would dry up completely and the animals that depend on them would die off.

Water in the Netherlands

Section 16  - Water in the Netherlands

40% of the Netherlands is below sea level.

The struggle against the sea / water (the fight against).

New landscapes are created.

• terps = protection against the rising sea level.

• dikes = initially only used as protection, later more offensive, to reclaim land. For example salt meadows (= kwelders) outside the dikes were reclaimed.

Polders

Water level is regulated. 

Types of polders:

• - sea polders
• - peat polders
• - “droogmakerijen”

Problem = outside water can seep through the dikes into the polder.

More space for water

In the past = ‘watermanagement’ = to keep the land dry.

In the future = ‘watermanagement‘ = water will be retained, areas will be deliberately flooded.

Why ? Climate change – (1) summers drier, winters wetter. (2) sea level is rising.

Space for rivers

• to keep the land dry water was discharged by (1) digging ditches and canals or (2) strainghtening out streams (3) pumping stations.
• in the future water will even be retained, certain areas will be deliberately flooded.

A permanent coast

• dikes must be reinforced due to the rising sea level.
• sand replenishment = due to erosion.

Dehydration

• dehydration (verdroging) drop in the ground water level.
• extinction of certain vegetation = drought.
• water table has dropped by 30 cm. 

Why?

1. farming (water extraction for irrigation)
2. drinking water (water extraction)
3. industry (water extraction)
4. asphalting = less water can subside into the underground (deceased infiltration / seep through) 

Managing and Reducing Losses from Water

Water Treatment Process

Water in lakes and rivers often contains impurities. The water can also contain bacteria and other microbiological organisms that can cause sickness and disease. So water from most surface water must be cleaned before is can be consumed. That's the work of a wastewater treatment plant.

How does the dirty water you flush down a toilet get cleaned safely before it's released to the environment? How water is treated and delivered to your home as water that is safe to drink. Follow a drop of water from the source through the treatment process.

Different steps in the Water Treatment Process:

Coagulation 
Coagulation removes dirt and other particles suspended in water. Alum and other chemicals are added to water to form tiny sticky particles called "floc" which attract the dirt particles. The combined weight of the dirt and the alum (floc) become heavy enough to sink to the bottom during sedimentation.



Sedimentation
The heavy particles (floc) settle to the bottom and the clear water moves to filtration.

Filtration

The water passes through filters, some made of layers of sand, gravel, and charcoal that help remove even smaller particles.

Disinfection
A small amount of chlorine is added or some other disinfection method is used to kill any bacteria or microorganisims that may be in the water.



Storage
Water is placed in a closed tank or reservoir in order for disinfection to take place. The water then flows through pipes to homes and businesses in the community.

Access to water

Access to water: People with access to an improved water source (%)

Access to an improved water source refers to the percentage of the population with reasonable access to an adequate amount of water from an improved source, such as a household connection, public standpipe, borehole, protected well or spring, and rainwater collection. Unimproved sources include vendors, tanker trucks, and unprotected wells and springs. Reasonable access is defined as the availability of at least 20 liters a person a day from a source within one kilometer of the dwelling.

More than 2.6 billion people—over 40 per cent of the world’s population—do not have basic sanitation, and more than one billion people still use unsafe sources of drinking water.

Four out of every ten people in the world don’t have access even to a simple latrine.

Five million people , mostly children, die each year from water-borne diseases.

Erosion

The process known as weathering breaks up rocks so that they can be carried away by the process known as erosion. Water, wind, ice, and waves are the agents of erosion that wear away at the surface of the earth.


Erosion by water

VIDEO: Erosion by water

Pump Aid - How to insure long term sustainability

http://www.youtube.com/watch?v=AvHHzBxupy8

To break the cycle of poverty in Africa, access to clean water for drinking and water for irrigation must be improved. Pump Aid builds appropriate technology water pumps, called Elephant Pumps that can be maintained by poor rural communities without any outside assistance.

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