Back to Home Page
Back to Index

CONSERVATION CORNER
(For the week of July 14, 2008)
The Water Cycle
by James L. Cummins

Water covers three-fourths of the earth’s surface. There are many forms of water – ice, snow, rain, hail, dew, fog and steam. The majority of this life source is sea water. It is from our oceans that most of our precipitation comes, although cleaned of its salt and minerals. So, how does this happen? Water moves from land to clouds to land and back to the ocean in an on-going cycle. This cycle is known as the water cycle, or the hydrologic cycle. Let's take a closer look at it.

Every year about 95,000 cubic miles of water evaporates from the oceans and land. This water evaporates into the atmosphere, leaving impurities behind. This evaporated moisture moves across the earth in the form of water vapor. A small portion of this water vapor is visible to us as fog, mist or low-lying clouds. The water vapor then condenses, filling the clouds and then releasing back to the earth in one of the various forms of water depending on region, climate, season and topography.

When water falls to the ground, some of it soaks into the soil and the rest runs off. The water that is absorbed by the ground sustains plant and animal life in the soil. The rest finds its way into underground reservoirs where almost all of this water re-enters the water cycle, which then starts over.

Humans can do little to alter this cycle, however we can manage and conserve water as it becomes available. Water management begins with soil management. Because our water supply comes as precipitation falling on the land, the fate of its fallen form depends on the condition of the soil it reaches.

A rainstorm on bare soil loosens soil particles and causes runoff, carrying the particles away. This is known as soil erosion. This repeated action ruins land for many uses and is the source of sediment that fills streams, pollutes water and shortens the useful life of dams and reservoirs.

In areas where much of the land is paved or covered, runoff occurs up to ten times faster than on unpaved lands. The water that falls here rapidly flows down storm drains and sewer systems carrying debris and other pollutants to nearby streams.

A human needs only a little over a gallon of water a day in order to fill his or her basic needs. Currently, however, we use close to 1,600 gallons each day to supply our needs and comforts which include cooling purposes, lawn maintenance and beautification, recreational endeavors and industrial supply.

The demand for water continues to rise as population increases bringing demand for more water. This is precisely why quality management of precipitation is so vitally important.