Water, Water Everywhere

"Water, water everywhere but nary a drop to drink." This plea of the Ancient Mariner calls to mind the rarity of pure drinking water in the vastness of the open ocean.

published before 1923
and public domain in the US

Saltwater oceans cover 71% of the Earth's surface and hold 97% of the planet's water. Glaciers and polar ice caps contain 2.4%, and all other land surface water such as rivers, lakes and ponds contain just 0.6%. The Antarctic ice cap contains 90% of all fresh water on Earth. Even though the amount of fresh water is only 0.6% of all available free water on the planet, it is enough to support our population of over 6 billion people. The collective mass of water found on, under, and over the surface of the Earth is called the hydrosphere. Earth's approximate water volume (the total supply of water in the world) is 1,360,000,000 km³ (326,000,000 mi³). This is enough water to fill half a million Olympic Size swimming pools for every man, woman and child on Earth.

A number of blogs ago (was it the July 4th Weekend?) I wrote about how my family was caught in a sudden hailstorm in Sequoia National Forest. This caught us by surprise but was part of the routine motion of water through our environment in the Water Cycle. This perpetual rotation of evaporation, precipitation and runoff moves water from the oceans to the dry land and back again, replenishing the fresh water supplies. Wind carries water vapor from over the ocean to land in a delicate balancing act as runoff flows back into the sea. Evaporation and transpiration from the land add to the ocean's water vapor falling as rain or snow. Condensed water in the air sometimes refracts the sunlight to produce rainbows at the edge of a storm front, reminding us of God's promise after the Flood (Genesis 9:15). Some water is trapped on land as snow or in lakes and rivers and provides reservoirs of fresh water for plants and animals living on the watershed. The movement of water through the Water Cycle constantly refreshes and replenishes this most precious resource.

We hear a lot about carbon dioxide and Global Warming but water is the ultimate global warming molecule. It has a high heat capacity and helps to regulate the temperature on the Earth's surface. Cloud cover regulates the environment as well, holding in the heat reflected from the surface or blocking the heat from the sun. Water has a significantly greater impact on temperatures than all of the carbon dioxide man has produced in his short tenure on this planet.

The movements of water alters the shape of our world hour by hour and day by day. Through erosion, runoff creates river valleys that provide rich soil and level ground for cities and towns to prosper. Some of this runoff can be diverted for agricultural irrigation. In my home State much of it travels through the California Aqueduct, a man-made ribbon of "milk and honey" (Leviticus 20:24), bringing Northern California water to the desert of Southern California, helping to keep LA green. Tides and waves continually change the shape and depth of marine water bodies and shorelines.
Water also infiltrates the ground and goes into underground storage areas called aquifers. This groundwater later flows back to the surface in springs, or more spectacularly, as hot springs and geysers like "Old Faithful" in Yellowstone National Park. Groundwater and fresh water are useful to humans as water resources, supplying wells and man-made reservoirs.

Fresh water runoff is often used for power generation. This hydroelectric power comes when water diverted from a river or lake drives a turbine generator. Many times a man-made lake formed behind a concrete and steel dam will supply the water to create the power. This form of electricity is a low-cost, non-polluting, renewable energy source. Pressurized water is used in water blasting and precision water jet cutters. Water is also used as a coolant in numerous applications from automotive engines to nuclear power plants.

Water is a remarkable resource, shaping our planet physically with its power, modulating our thermostat with its protective covering, creating energy with its motion, and providing refreshment to a thirsty World.

"He led you through the vast and dreadful desert, that thirsty and waterless land, with its venomous snakes and scorpions. He brought you water out of hard rock. (Deuteronomy 8:15 NIV)"