The other 2.5% percent is fresh water found in lakes, rivers, streams, and glaciers, tapped in soil below the Earth’s surface and in the atmosphere.
Of that proportion of fresh water, 79% is ice, 20% groundwater & only 1% is surface water. Fresh water is a limitedresource.
What makes water so special? • Exists in three states of matter. • Dissolves almost anything b/c of its polarity
Why is water so special?? • Necessary for life..you are 70% water
GROUNDWATER • Groundwater is water stored beneath the Earth’s surface.
Water is pulled down by gravity underground where it contacts different layers of soil & rock.
Layers that water can pass through pores are called permeable. Layers with few pores are called impermeable.
Aquifer’s upper layer is called the zone of aeration. This layer has pores and water flows through.
The lower layer is called the zone of saturation and these spaces are saturated with water.
The water table depth is determined by the shape of the land and the amount of available water.
The water table will rise during times of heavy precipitation and will fall in times of drier weather.
The world’s largest known aquifer is the Ogallala aquifer, which resides below the Great Plains of the US.
This massive aquifer has supplied water to American farmers to grow the most abundant crop of grain in the world.
This water is monitored often because it provides us with much of our drinking water.
Just 1% of water is surface water found on the Earth’s surface. Sources of surface water are rain, melting snow, glaciers & ice caps.
Runoff is water that flows over land and has not been absorbed into the ground. Runoff can flow into streams, lakes or ponds.
River systems are a network of connected streams. These systems begin with a small stream flowing into a larger stream.
River systems flow into bigger areas called watersheds. A watershed includes all the land area that supplies water to a particular river system.
The interconnected nature of watersheds greatly influence how they are managed.
Where does all fresh water in PA eventually drain? CHESAPEAKE BAY
Five Major PA Watersheds • Great lakes Basin- only 1% lies in PA
Ohio River Basin- 2nd largest, provides drinking water for 13 million people
Susquehanna/Chesapeake Basin • largest watershed in PA covers 46% of the State
Potomac Basin • Delaware Basin- 3rd largest
Genese Basin • Smallest watershed in PA
Uses of Fresh Water • One third of the world’s people are affected by water shortages.
Many sources of surface water & groundwater are literallydrying up.
Globally, about 70% of our fresh water is used on agriculture. Industry accounts for approximately 22%.
Personal water usage is about 8%. These numbers can vary based on the country in which you live.
Lower income nations use more water for agriculture than high-income countries.
Agricultural Uses • Farmers & Ranchers must use water for their crops & livestock to provide food for you.
About 1500 liters (400 gallons) of water are needed to produce 1 kilogram (2.2 pounds) of wheat.
That’s more water than an average person drinks in one year! It takes 10 times that amount of water to produce 1 kilogram of grain-fed beef.
Industrial Uses • Almost all the items that you use are created through a process that needs water.
American factories use about 68 billion liters (18 billion gallons) of water to make & transport their products
Water is also used in the energy industry to generate electricity. Engineers use the water to cool down the machinery when it gets hot.
Water is also used to refine gasoline & oil. It takes between 1-2.5 gallons of water to refine a single gallon of gasoline.
Personal Uses • Each day the average person in the US drinks 2-5 liters of water.
We also use water for bathing, cooking, cleaning, doing laundry & flushing the toilet.
Water keeps our lawn looking nice & fills our swimming pools. Personal uses happening inside the home are called residential uses.