Only 3 percent of the Earth’ s water is freshwater, and about two-thirds of this water is frozen in polar icecaps and glaciers. Most of the remaining freshwater is underground and only 0.3 percent is surface water.
Let’ s Examine The Water Cycle
Only 3 percent of the Earth’ s water is freshwater, and about two-thirds of this water is frozen in polar icecaps and glaciers. Most of the remaining freshwater is underground and only 0.3 percent is surface water.
We need the water cycle, but it’ s not what you might think.
There’ s pretty much the same amount of water in the world now as there was when the dinosaurs were running around doing their thing. It keeps getting recycled. Water doesn’ t get used up or destroyed, but it can get polluted.
The sun warms up the oceans, lakes and rivers, causing the water to evaporate. That evaporation condenses and makes clouds. Those clouds drop rain or snow on the earth. Some of that rain and melted snow soaks into the ground, but some runs off, making rivers, which eventually flow back into the sea. Even the water that soaks into the ground moves through the spaces in the sand, gravel and rocks.
How cool is that? The water went from liquid, to vapor( remember that evaporation part), to solid( ice and snow), and back to liquid with the power of the sun.
Something else interesting happened. When it evaporated, it left the salt and other stuff behind so those snowflakes and rain drops are pretty clean. Air pollution sometimes messes up a good thing, but that’ s another story.
Colorado plays a very important part in the water cycle.
In Colorado, most of the water we use comes to the state as snow in the mountains. In the spring, it melts and some is stored in lakes and reservoirs so that we can use it throughout the year.
Known as the“ headwaters state,” Colorado is the beginning of eight major rivers that flow to other states. In an average year, the outflow of the Colorado River alone is equal to the amount of the water used annually by more than 9 million households.
In other words, the snowballs you threw during the winter could melt and end up as drinking water in Los Angeles, California or El Paso, Texas.
Eighteen states and Mexico get water that starts its journey in Colorado. Virtually no water flows into Colorado.
That also means there are tens of millions of people downstream from us who are counting on us to help protect that water as it moves through our state— one more reason to be a Watershed Defender.
But what happens if it only snows half as much as usual? Or what happens if the reservoirs get polluted?
That’ s scary. Prolonged times of reduced rain and snow are called a drought. Reservoirs help us make it through dry times, but in a drought there isn’ t enough water to meet all the needs. Farmers are often the first to experience problems.
With less rain, farmers need to use more irrigation water from rivers to help plants grow. If there’ s not enough irrigation water, farmers are forced to plant fewer crops, plant less“ thirsty” crops or even skip planting altogether. Fewer crops mean less food.
Even when there’ s plenty of rain and snow, we have to be careful with our water. In Colorado, there is a demand for more water than there is supply. One reason is that population is growing. In 1850, Colorado was a frontier in the western expansion of the United States. The world population was 1.2 billion people. Fast forward to the year 2000 and Colorado had a population of 4.3 million people, while the world population had jumped to more than 6.1 billion people.
More people means a greater demand for food and water.
We’ ve been stuffing a bunch of big ideas and big numbers in our gear bag, but we need one more. The earth is a big place, and it’ s sometimes called the“ blue” planet. Why? The earth is mostly covered in water.
Here we go with the bad news again.
The oceans are salty, too salty for humans to drink and a big bunch of
6 Watershed Defenders produced by Colorado Foundation for Agriculture