The water you drank this morning might have been the same water that once rained down on a Tyrannosaurus, froze on a woolly mammoth, flowed down the Nile to bring new silt to an Egyptian farm – or filled the bathing pool of Julius Caesar. The water we use now is the same supply that has been on Earth for billions of years. Its quality is renewed again and again by the natural water (hydrologic) cycle.
In the water world, water is commonly measured in acre-feet. But what is an acre-foot? One acre-foot equals about 326,000 gallons, or enough water to cover an acre of land, about the size of a football field, one foot deep. An average California household uses between one-half and one acre-foot of water per year for indoor and outdoor use.
The nation’s surface-water resources—the water in the nation’s rivers, streams, creeks, lakes, and reservoirs—are vitally important to our everyday life. The main uses of surface water include drinking-water and other public uses, irrigation uses, and for use by the thermoelectric-power industry to cool electricity-generating equipment.
Your water footprint is the amount of water that you use in a day. Every person has a unique water footprint based on the ways water is used. One easy way to begin the process of calculating your water footprint is to look at your family’s water bill for a month. Divide the amount used by the number of days in the month and then divide again by the number of people in your family. You might be surprised at how much water you use in a day at home. The actual amount used per capita varies greatly from person to person, region to region and season to season.
People use water for direct and indirect purposes. Direct purposes include bathing, drinking and cooking. In most developed countries, urban water users are connected to water through their municipal water delivery system and their home plumbing system. People turn on the tap, water comes out and they use it. Indirect water (also called “virtual water”) use refers to the water used to produce the g
Earth has a finite amount of fresh, usable water. Fortunately, water is naturally recycled (collected, cleansed, and distributed) through the hydrologic cycle. Humans have developed the technology to speed this process. However, because of diverse factors (drought, flood, population growth, contamination, etc.) water supplies may not adequately meet a community’s needs. Conservation of water can ensure that supplies of fresh water will be available for everyone, today and tomorrow.
Clean fresh water is vital to our lives and many of the plants and animals we depend on. Most people think water pollution comes directly from a factory or other known source, a type of pollution known as “point source pollution.” Because of laws passed in the 1970s, most of those sources of pollution have cleaned up their act. Today, the biggest source of pollution is us – you and me. This type of pollution is known as “nonpoint source pollution” because it can’t be traced to one single source; we can’t tell how much pollution is coming from where.