Moving water shapes land 5-2 Notes Moving water shapes land

Streams Shape Earth’s Surface What do you notice these three streams all have in common?

Streams Shape Earth’s Surface You probably noticed (among other things): The land is higher than the water The land is sloping down to the water The water is moving downhill

Streams Shape Earth’s Surface Running water is the major agent of erosion shaping the landscape of Earth.

Streams Shape Earth’s Surface Running water shapes landforms by moving sediment in the processes of erosion and deposition.

Streams Shape Earth’s Surface A stream is a body of water-large or small-that flows down a slope along a channel.

Drainage Basins and Divides Streams flow into one another to form complex systems. Small streams flow into larger ones.

Drainage Basins and Divides The area of land in which water drains into a stream system is called a drainage basin.

Drainage Basins and Divides Most drainage basins eventually drain into a lake or ocean. Example: the Mississippi River drainage basin empties into the Gulf of Mexico.

Drainage Basins and Divides Drainage basins can be a few kilometers wide or can take up a large portion of a continent.

Drainage Basins and Divides Drainage basins are separated by ridges called divides-a ridge from which water drains to one side or the other.

Valleys and Floodplains As streams flow and carry sediment, they form valleys.

Valleys and Floodplains In high mountains, streams often cut V- shaped valleys that are narrow and steep.

Valleys and Floodplains In lower areas, streams may form wide valleys that include floodplains-an area of land on either side of a stream that is underwater when the stream floods.

Valleys and Floodplains When a stream floods, it deposits the sediment it carries onto the floodplain. This makes floodplains very fertile-able to support a lot of plant growth.

Valleys and Floodplains The floodplains of the Mississippi river are some of the best places for growing crops in the U.S.

Stream Channels As a stream flows through a valley, its channel may run straight in some parts and curve in other parts.

Stream Channels Curves and bends that form a twisting, looping pattern are called meanders.

Stream Channels Over many years, meanders can change position and get cut off from the rest of the stream. A cut-off meander forms a crescent shaped lake called an oxbow lake.

Alluvial Fans and Deltas Alluvial fan- a fan- shaped deposit of sediment at the base of a mountain created by a stream.

Alluvial Fans and Deltas Alluvial fans are formed when a stream leaves a steep valley and enters a flatter plain.

Alluvial Fans and Deltas Delta- an area of land formed by the buildup of sediment at the end of a river. Over time, a delta builds up into a fan-shaped plain.

Alluvial Fans and Deltas Over a very long time, a river can build up a huge delta that reaches out to sea.

Water Moving Underground Forms Caverns Not all rainwater runs off the land and flows into streams. Some of it evaporates, some is absorbed by plants, and some soaks into the ground to become groundwater.

Water Moving Underground Forms Caverns At a certain depth below the surface, the spaces in soil and rock become completely filled with water. The top of this region is called the water table.

Water Moving Underground Forms Caverns Water below the water table is called groundwater.

Water Moving Underground Forms Caverns As groundwater flows through rock and soil, it causes erosion. Groundwater erosion causes certain rocks (like limestone) to dissolve.

Water Moving Underground Forms Caverns Over time, this process produces open spaces called caves. Very large caves are called caverns.

Kartchner Caverns, Arizona

Carlsbad Caverns, New Mexico

Onandaga Cave, Missouri

Waitomo Glowworm Cave, New Zealand

Cave of Crystals, Mexico

Water Moving Underground Forms Caverns Sinkhole- a basin formed when the roof of a cave suddenly falls in

Devil’s Toilet Bowl, Florida

Devil’s Sinkhole, Texas

Guatemala City Sinkhole, Guatemala

Heavenly Pit Sinkhole, China

Great Blue Hole, Belize

Review 1. A sinkhole is formed by the collapse of A. an alluvial fan B. a cavern C. a moraine D. a kettle lake

2. Rivers transport sediment to A. Drainage basins B. Oceans and lakes Review 2. Rivers transport sediment to A. Drainage basins B. Oceans and lakes C. The water table D. Moraines

Review 3. Drainage basins are separated by a A. moraine B. divide C. tributary D. barrier island

Review 4. In high mountains, a valley carved by a stream has the shape of a A. U B. Crescent C. Plate D. V

Review 5. An oxbow lake is formed by the cutting off of a A. meander B. drainage basin C. sinkhole D. glacier