Ch. 8.3 Surface Water and Groundwater

Essential Question:

How Do People use Earth’s Resource?

What is a River System?

How do Ponds and Lakes From and Change?

How Does Water Moe Underground?

Surface Water and Groundwater

Pg. 270-279

Land, Air, and Water ResourcesMs. De Los Rios

7th Grade

Vocabulary1. Tributary-a stream or river that flows into a larger river.

2. Watershed-the land area that supplies water to a river system.

3. Reservoir-a lake that stores water for human use.

4. Eutrophication-the buildup over time of nutrients in freshwater lakes and ponds that leads to an increase in the growth of algae.

5. Permeable-characteristic of a material that contains connected air spaces, or pores, that water can seep through easily.

6. Impermeable-a characteristic of materials, such as clay and granite, through which water does NOT easily pass.

7. Unsaturated Zone- the layer of rocks and soil above the water table in which the pores contain air as well as water.

8. Saturated Zone- the area of permeable rock or soil in which the cracks and pores are totally filled with water.

9. Water Table- the top of the saturated zone, or depth to the groundwater under Earth’ surface.

10. Aquifer- an underground layer of rock or sediment that holds water.

11. Artesian well- a well in which water rises because of pressure within the aquifer

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What is a River System? Pg. 271

The streams and smaller rivers that feed into a main river are

tributaries.

Tributaries flow toward the main river because they are pulled by the force of gravity.

A river and all the streams and smaller rivers

that flow into it together make up a river system.

Fig. 1 Surface Water and Groundwater pg. 271

River SystemThe lower Suwannee River flows past Gainesville, Florida, and empties into

the Gulf of Mexico.

Circle a river system on the map

What is a River System? Pg. 272

The land area that supplies water to a river system is a

watershed, or drainage basin.

One watershed is separated from another by a ridge of land

called a divide. The streams on each side of a divide flow in

different directions.

Major Watersheds of the United States

The land area that supplies water to a river system is called a watershed.

•Draw the path that water would take from the Platte River’s source to the ocean.

•Which watersheds would the water pass through?

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Assess your Und.

Fig. 2 Surface Water and Groundwater pg. 272

How Do Ponds and Lakes Form and Change? Pg. 273

Ponds and lakes form when water collects in hollows and in low-lying areas of land.

Unlike rivers, ponds and lakes contain still or standing water.

Sunlight reaches to the bottom of all parts of a pond, but most lakes

have some bottom areas that are too deep for much sunlight to

reach them.

How Do Ponds and Lakes Form and Change? Pg. 273

Lakes can form when a river bends as it encounters obstacles.

A new channel forms that cuts off the bend.

The cut-off bend becomes an oxbow lake.

• Some lakes formed from depressions created by ice sheets that melted at the

end of the Ice Age. • Others were created by movements of

Earth’s crust that formed long deep rift valleys.

• Lakes can form when a volcano blocks a river and they can form in the empty

craters of volcanoes.

What are Ponds and Lakes?

1.Complete the Venn diagram to compare and contrast characteristics of lakes and ponds.

2.Based on your answers, write an operational definition for lake.________________________________________________________________________________________________________________________

Apply it!! Surface Water and Groundwater pg. 273

Lake Formation Pg. 274

In Florida, many lakes have formed in natural depressions called sinkholes. People can also create a lake by building a dam. A lake that stores water for human use is a reservoir.

If you watch a lake or pond over many years, you will see it change. In time, the lake may shrink and become shallower.

Natural processes and human activities can cause lakes to disappear.

Eutrophication. Pg. 275

What can cause lakes to disappear?

Natural processes and human activities

When lake organisms die, bacteria break down their bodies and

release nutrients into the water. Over time, nutrients can build up in

a lake in a process called

eutrophication. Algae use the plentiful nutrients

and grow into a thick layer that blocks sunlight form reaching

lake plants.

The lake plants die and the animals that eat them die as well.

Decaying material piles up and the lake becomes shallower and

eventually fills in.

Eutrophication Pg. 275

Human activities can cause eutrophication. Fertilizer in

runoff from farmlands contains nutrients that

increase eutrophication when the runoff enters pond and

lakes.

Eutrophication Write a caption for

each diagram to explain the changes that occur during eutrophication?

Assess your Und.

Fig. 4 Surface Water and Groundwater pg. 275

How Does Water Move Underwater? Pg. 276Underground water generally comes from

precipitation, which soaks into the ground.

Water underground trickles down between particles of soil and through cracks and spaces in layers of rock.

Because they have large and connected pores, materials such as sand and gravel allow water to pass through, or permeate and are called

permeable materials. Other materials, such as clay have few

or no pores or cracks or the pores are very small. These materials are less

permeable than sand. Granite is impermeable, meaning that water

cannot pass through easily.

Water Zones pg. 277

The top layers of rock and soil contain air as well as water and are called the unsaturated zone.

At some depth the water reaches the saturated zone, a level where the pores in the ground are saturated with water.

The top of the saturated zone is called the water table. The saturated zone reaches deep into the Earth even though the rock becomes less permeable the deeper you go.

Do the Math!

R. Pg 278/9

Springs and WellsSuppose you are a farmer looking for water sources.

Draw lines showing where you would drill a regular well and artisian well. Explain why you chose those locations.

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Assess your Understanding.

Fig. 6 Surface Water and Groundwater pg. 278