Exploring Earth’s Freshwater

Chapter 12

Section 12-1 Water on

Earth

Distribution of Earth’s Water• Earth is 70% Water!• 97 % of Earth’s Water is Salt Water.• Salt water is salty because it contains minerals and salts

from weathered rocks and from underwater volcanoes.• 2 % of the Freshwater is frozen as ice near the North and

South Poles• That only leaves about 1% of the planet’s water available

for consumption for all living creatures!

Section 12-2 Surface Water

•Rivers, lakes, streams, ponds, and wetlands are all examples of surface water.

Surface Water

Types of Wetlands

A wetland is a low-lying land area where the soil is saturated with moisture either permanently or seasonally.

1. Marshes-shallow water with tall grasses. Freshwater marshes form near ponds and lakes. Saltwater marshes are found on the edges of estuaries; places where a river flows into the ocean.

2. Swamps- low-lying areas which look like flooded forests. Located in warm, humid climates where trees grow quickly.

3. Bogs- Bogs begin as shallow ponds or lakes that slowly fill with leaves and plants. Bogs are often in northern regions and formed from old glacial lakes.

•Because water does not flow in and out of a bog easily, they often have low oxygen. As a result, dead plants at the bottom of a bog do not break down but turn into Peat –an organic material that forms when dead plants are compressed.

•This layer of peat can be up to forty feet deep! Peat makes the bog acidic. Under the right conditions, this peat can turn into coal. The surface of a bog is often covered by a thick layer of Sphagnum or “Peat Moss.”

•Bog plants are well adapted to the high acidity, low oxygen, low nutrient supplies found in bogs.

•Cranberry vines grow really well in bogs. To help harvest the cranberries, farmers flood the bog.

Fun Facts About Bogs

•Note: Carnivorous Plants still photosynthesize, but “eat” insects to obtain nitrogen, since it is low in bog soil.

Fun Facts About Bogs•Bogs have Carnivorous Plants!!!

The Everglades: A Wetland•Water is the key to the Everglades, a unique region with both marshes and swamps.•The Everglades is a shallow stream of water that moves slowly over the land from Lake Okeechobee south to Florida Bay.

Role of Wetlands1. Wetlands provide habitats for many living things.2. Wetlands act like kidneys, naturally filtering water which can then be used by communities.3. Wetlands help control floods by acting like sponges, absorbing extra runoff from heavy rains.

They store the water and slowly release it back into streams, lakes, and groundwater. 4. Wetlands provide water during a drought.

What is Significant About This Article?

Brian Handwerkfor National Geographic NewsFebruary 9, 2005

“Louisiana's wetlands are being destroyed—an area the size of a football field disappears every 38 minutes.”

"With the rapidly depleting wetlands, people that have lived in southern Louisiana can tell that, over the last 30 years, large storms now come in faster, and the water rises faster, which gives less time to respond and less time to evacuate," said Denise Reed, a professor of geology and geophysics at the University of New Orleans.

"In the next few years it's going to get worse."

http://www.cbsnews.com/video/watch/?id=6773554n&tag=mncol;lst;2

•Example: In the last 70 years, over 2,000 square miles of Louisiana wetlands have been destroyed. •Wetlands are often drained and filled in and used for agriculture or development. (In Louisiana an additional problem is the levee system designed to prevent flooding – it blocks nutrients and sediments from entering the wetlands so they eventually disintegrate)

Why Must We Preserve and Protect Wetlands?

Levees

•Wetlands act as buffers against hurricanes because they slow down the storm, lessening its impact. •Hurricane Katrina would have likely been much less devastating to New Orleans if the wetlands would not have been destroyed!

Why Must We Preserve and Protect Wetlands?

•Engineers and scientists are now trying to create artificial wetlands to replace ones that have been destroyed.

Why Must We Preserve and Protect Wetlands?

Section 12-3:Ground Water

How Water Moves Underground•Groundwater-Water that moves and fills spaces underground.•Water underground trickles down between particles of soil and through cracks and spaces in layers of rock. Rock with connected pore space is considered to be permeable rock. •Ex. Sandstone

•As water soaks down through permeable rock and soil, it eventually reaches impermeable layers of material that it cannot pass through, for example clay. •When the rock reaches this layer, it begins to fill up the rock spaces above it.

How Water Moves Underground

•The area of permeable rock that is totally filled with water is called the saturated zone. The top of the saturated zone is the water table.

How Water Moves Underground

•The layer of rocks and soil above the water table is called the unsaturated zone.•Any underground layer of rock that has water in it (including the saturated zone) is called an aquifer.

How Water Moves Underground

Groundwater

•Groundwater, like surface water, moves downhill toward rivers or the ocean.

Bringing Up Groundwater•People can obtain groundwater from an aquifer by drilling a well below the water table. •They may also obtain water through by digging an artesian well. When rock above an aquifer is punctured, the release of pressure causes the water to rise up on its own!!

“Fiji Water” is from an Artesian Well

Fiji’s bottling facility built right on top of the artesian well

Shaler Water…

•While most of the Pittsburgh area draws its drinking water from one of the three rivers, Shaler’s water is actually ground water that comes from 14 wells located along the banks of the Allegheny River. •This underground aquifer (45 feet beneath the surface) originates beneath the Great Lakes and travels to Western PA, beneath our rivers. Although not a real river, is often referred to as “Pittsburgh’s underground river”.•The fountain at Point State Park draws water from this aquifer too!

Springs and Geysers•Sometimes, ground water comes to the surface naturally.

•When the water table is at the earth’s surface, a spring forms.• Spring water passes through the pore spaces in rock and soil which naturally filter harmful substances out of the water.•Hot springs and geysers form when heated ground water comes to the surface.•What heats the groundwater?

MAGMA!•What is the difference between geysers and hot springs?•Geysers occur when pressure builds up as heated water rises. When pressure is released, they erupt!•Hot springs form when hot water easily makes its way to the earth’s surface.

Section 12-4 Using Freshwater Resources

Uses of Water

Agriculture.

Interpreting Data:

Which of the categories of water use shown in the graph represents the largest use of water in the United States?

Water Pollution – Point Source•A type of pollution that comes from a specific source is considered point source pollution.

•Ex. Factories like oil refineries or sewage treatment plants (combined sewer overflow!) are common sources point source pollution.

•Clean Water Act-must obtain a permit before dumping wastes or treat wastes prior to dumping into a body of water.

Review: What is runoff?• Water that does not soak into the ground

and runs along the earth’s surface.

Water Pollution – Non-Point Source

Water Pollution – Non-Point Source

•When the point of origin cannot be identified, it is considered Non-Point Source pollution.•Runoff absorbs what ever it comes into contact with as it moves- pollution from nearby construction, lawn chemicals, oil, grease, gasoline, salt residues from road de-icing, and especially animal waste (and fertilizer) from farms.

I Only Drain Rain!•Never pour pollutants like paint or motor oil down any kind of drain!

What Can You Do to Reduce Water Pollution?•Avoid using

pesticides and lawn fertilizers.•Instead of paving your driveway, use gravel.•Plant things! Trees, grass and other plants help absorb water and reduce runoff!

What Affects the Amount of Water Available for Use?

• Pollution• Overuse • Drought

Section 12-5 See 12-5 Review

and Reinforce Worksheet