Our Society needs a better understanding of how we get clean water for all human needs It isn’t the pollution that’s harming the environment. It’s the impurities in our air and water that are doing it. Dan Quayle

How Do We Use Earth’s Oceans? Seafood Minerals Fossil Fuels Fresh Water

Thirsty? How 'bout a cool, refreshing cup of seawater? No, don't take me literally! Humans cannot drink saline water. But, saline water can be made into freshwater, which everyone needs everyday. The process is called desalination, and it is being used more and more around the world to provide people with needed freshwater. Most of the United States has, or can gain access to, ample supplies of fresh water for drinking purposes. But, fresh water can be in short supply in some parts of the country (and world). And, as the population continues to grow, shortages of fresh water will occur more often, if only in certain locations. In some areas, salt water (from the ocean, for instance) is being turned into freshwater for drinking.

Desalination Plants

How Much is There? Approximately three-fourths of the earth is water.

What kinds are there? 97% of the water is salt water, and is found in the oceans of the world. 3% of the water is fresh water on which we depend.

Where is it found? Water comes from several places. Oceans Lakes Ponds Rivers

Where is Fresh Water From? Water Cycle Groundwater Water Table Aquifer Spring Wells Reservoirs

Water Cycle Fresh water does not run out because it is constantly being renewed through the water cycle. The water cycle, also known as the hydrologic cycle or H2O cycle, describes the continuous movement of water on, above and below the surface of the Earth. Water can change states among liquid, vapor, and ice at various places in the water cycle

Groundwater Groundwater comes from rain, snow, sleet, and hail that soaks into the ground. The water moves down into the ground because of gravity, passing between particles of soil, sand, gravel, or rock until it reaches a depth where the ground is filled, or saturated, with water. Groundwater makes up about 1% of the water on Earth (most water is in oceans). Groundwater makes up about 35 times the amount of water in lakes and streams. Groundwater occurs everywhere beneath the Earth's surface, but is usually restricted to depths less that about 750 meters. The volume of groundwater is a equivalent to a 55 meter thick layer spread out over the entire surface of the Earth. The surface below which all rocks are saturated with groundwater is the water table.

Water Table The water table occurs everywhere beneath the Earth's surface. In desert regions it is always present, but rarely comes to the surface. The water table is the underground depth at when the ground is totally saturated with water. Much of the Earth's potable water is actually locked up underground, and while it may not be as physically obvious as big lakes and rivers, it is critically important. When underground water deposits are large enough to be considered sustainable for use, they are known as aquifers. The water table could also be thought of as the top of the aquifer.

Aquifer Aquifers are underground reservoirs. The water that reaches these chambers is usually much cleaner than the water of reservoirs at the earth's surface. Almost no bacteria live in aquifers. Many pollutants are filtered out as the water passes through the soil on its way to the aquifer.

Springs Springs are areas in the Earth's surface where groundwater comes to the surface naturally. This can occur if the aquifer is on a slope and gravity pushes the water out through a crack, or if pressure in an aquifer pushes the water up. In any case, the water from a spring is usually accessible and relatively clean. Springs rely on aquifers to supply them with water.

Wells Water percolates into a drilled or dug hole when the zone of saturation is penetrated • pumping can create a cone of depression • lowering of the water table is a major problem in some areas

Reservoirs A reservoir is an artificial lake used to store water. Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such a brickwork or cast concrete.

Water Pollution

Water Pollution Humans depend on very small reservoirs of water for all our needs. These reservoirs cycle/ turnover very quickly As they cycle they can either collect pollution from other sources Precipitation, Runoff water, Groundwater, Industry, and Household waste be cleaned by passing through functioning ecosystems

Precipitation-Acid Rain Reactions to convert to acid take place in ~2 days - travel 1000 miles Down wind - Acid rain Dry Dep. vs Wet Dep. Dry Deposition 50 % of total Can react with plants - strip nutrients Tree dieback

Acid Rain and Trees

Forests affected by Acid Rain Northeast US Canada Northern Europe Asia

Acid Rain and Buildings Many buildings are made of concrete and or stone These compounds act as bases and react with acid The building technically “weathers” very fast, or Non technically “crumbles”

Europe The US Capitol

Industry Examples of Smog

How can fresh water be polluted?

How do we Purify Water?