Where On Earth Is the Water?

Ocean-water dependent species and ecosystems have two luxuries that freshwater-dependent species and ecosystems lack:
- Ocean-water exists in one BIG connected mass distributed all over the world. Freshwater exists in multiple locations all over the world
- Ocean-water exists mostly in just one form: as a liquid; Freshwater, however, exists in vapor (e.g. as a gas), liquid and solid (e.g. as ice) form

Global Distribution of Water
Water covers much of the Earth's surface:
- Ocean-water is the predominant (97.5% of the total) variety.
- Just 2.5% of the total water on Earth is freshwater. 
Freshwater Locations
Ignoring movement of freshwater between various deposits of freshwater on Earth, Freshwater exists in 8 locations:
- In glaciers as ice and in liquid form
- As groundwater in underground aquifers
- In Freshwater lakes
- In wetlands
- Dissolved in soil
- Suspended in the atmosphere
- In flowing rivers, and
- In plants and animals
Historical Sources of Freshwater
There are two types of sources that humankind has tapped for its freshwater needs:
A. Freshwater Bodies
Freshwater lakes, wetlands and rivers were humankind's earliest sources of water. These sources are still major sources of freshwater because they are continuously replenished. We may choose to extract freshwater at rates greater than the replenishment rate, but that is another subject.
Plants were probably a major source of freshwater for humanity, because all food contains freshwater. With the harnessing of agriculture (about 10,000 years ago) and the resulting improvement in diet, humans get a lot of their required freshwater from the food they eat and digest.
B. Water moving between bodies of freshwater
While all water is always in continuous motion, Evaporation and condensation are the primary ways freshwater moves between different freshwater bodies. 
Tapping New Sources of Freshwater
Of the 8 freshwater bodies, the single ocean-water body and the ways water moves between these bodies, there are only 6 possible new sources of freshwater:
1. The freshwater in the atmosphere is nearly 5 times MORE than the freshwater in all the rivers on Earth.
2. The freshwater in soil is nearly 6.6 times MORE than the freshwater in all the rivers
3. The freshwater in plants and animals
4. Artificially converting seawater into freshwater i.e. desalination.
5. Making freshwater from scratch - our bodies make between 300 and 400 ml of freshwater per day through the biological process of metabolism - hence our name for this water is "metabolic water"
6. Catching freshwater as it moves from one source to another - Rainfall is the predominant such source.
Increasing Freshwater Supplies
In addition to the above 6 choices, there exists, of course, the option to use less water by recycling used water, increasing water use efficiency and reducing the amount of water that is wasted.
The Task Before Us
Which of the above 6 "new sources" of freshwater and using less water should we focus on and why?

Water Defines Climate Everwhere

Water in the troposphere, the atmosphere closest to the surface, conditions the Earth. In some locations water runs the local heating system while, at the same time, it acts as the cooling system in other locations. Water has an inordinately strong effect on climate. 


What is climate?

Climate Map
Source - blueplanetbiomes.org

Climate is weather averaged over a long period of time, usually, 30 years.
In this averaging, weather is defined by many variables. The predominant variables are temperature, precipitation and wind movement.


Temperature

Air Temperature Variations
Source - griffin.uga.edu

Temperature is a measure of the 'heat' in any location.
This 'heat' is the sum of the amount of energy deposited on a place by sunlight and the amount of energy existing on Earth at that place.
Water in the atmosphere and in surface bodies acts as the controller of heat distribution around the planet.
Water in the wind moves heat from one location to another.
Ice sheets and clouds cool the Earth's surface by reflecting the heat energy back into space.
Ocean and river currents transport heat to locations far and near.


Precipitation

Source - valdosta.edu

Precipitation IS water - in every form that water exists!









Water's Venetian Blind effect

Source - b4i.ie

Water in the air (with other greenhouse gasses like carbon dioxide) acts in much the same way as slats in a Venetian blind. 
The angle of each slat influences how much of the suns' heat and light enters a room. We can move the slats to form a 'closed' surface to, in effect, stop most light and heat from entering a room. We can fully 'open' the blinds to allow entry of the most amount of light and heat into a room.
In a similar way, nature manipulates the water content of air at individual locations (in conjunction with other parameters) to influence (raise and lower) in a very large way the temperature at a particular location.

Gravity: Nature's Tool for Moving Water Over Long Distances

Water flows naturally over long distances if a single condition exists: The elevation at the beginning location is higher than the elevation at the ending location. The force of Gravity naturally moves water from higher to lower elevations.


Human Settlements Around Nature's Rivers

The River Nile
Source - abbaymedia.com

Running downhill, rivers deliver water to communities all along its length. 
The longest river, The Nile, is over 6,600 km long 
Traversing this distance, the Nile sustains communities of life in ten countries, namely, Ethiopia, Eritrea, Sudan, Uganda, Tanzania, Kenya, Rwanda, Burundi, Egypt, Democratic Republic of Congo and South Sudan.
The Nile originates at an elevation of 2,700 m (above sea level) and ends in the Mediterranean sea after its 6,600 Km journey.
The Nile and the other rivers contain an estimated 0.006% of all the freshwater on Earth. These 509 cubic miles of freshwater are regularly replenished by the hydrological cycle.


Human Settlements Away From Rivers and Lakes
Gravity is the first natural force that humanity learned to harness to bring water from a river or a lake to a human settlement.
Surface Structures
The first known successes by humanity to use gravity for irrigation were in four regions of the world: In Egypt around the Nile river, in Mesopotamia around the Tigris and Euphrates rivers, in India around the Indus and Ganges Rivers and in China around the Huang He (Yellow) river.
The larger channels feed water into the smaller and smaller channels using the force of gravity. The channel beds have to be sloped correctly for gravity-fed water to move from channel to channel. 
This method of irrigation, known as furrowed irrigation, is still widely used in the world. It originated as early as 5000 BC.
Underground Piping

Source - en.wikipedia.org

The puquios in Peru, use gravity to channel surface water into pipes dug out under ground by humans, that end at a settlement. Peru and the many other human communities in the Andes Mountains, used this method extensively to channel water into pipes.
Arranging a number of puquios to feed into a single pipe is said to have provided enough freshwater for a community of over a hundred people.