Rock & Landforms I-5

Moving Water and Landscapes Water runs downhill –GRAVITY! Water runs downhill –GRAVITY!

Sheet flow or overland flow Initially, rain does not sink into the ground Initially, rain does not sink into the ground Rain runs off as broad sheets of water Rain runs off as broad sheets of water Water collects on down slope land surfaces forming narrower & deeper channels Water collects on down slope land surfaces forming narrower & deeper channels As water flows faster-erodes soil to form gullies, canyons & valleys As water flows faster-erodes soil to form gullies, canyons & valleys

Most canyons & valleys Have sloping sides Have sloping sides Gravity – pulls the rock & soil Gravity – pulls the rock & soil

Rivers and the Rock Cycle Review Review

Waves and Shorelines Beaches are masses of sand that are shaped by breaking waves Beaches are masses of sand that are shaped by breaking waves Often, sand travels great distances without getting anywhere! Often, sand travels great distances without getting anywhere! When waves approach the shore at an angle, the carry sand along the beach When waves approach the shore at an angle, the carry sand along the beach

Long-shore currents Currents flowing parallel to the beach Currents flowing parallel to the beach Carry sand, if strong enough Carry sand, if strong enough Volumes of sand can be moved along the beach Volumes of sand can be moved along the beach Engineers have devised ways to protect beaches & shorelines Engineers have devised ways to protect beaches & shorelines

Groins Long, wall-like structures along beaches Long, wall-like structures along beaches Act as barriers to long shore currents Act as barriers to long shore currents Controls or changes sand movement Controls or changes sand movement Causes the current to deposit sand on the up current side of the groin Causes the current to deposit sand on the up current side of the groin Builds up sand on the beach Builds up sand on the beach Beaches down-current lose sand Beaches down-current lose sand

Jetties Designed to keep sand from moving into a ship channel-making it too shallow for ship traffic Designed to keep sand from moving into a ship channel-making it too shallow for ship traffic Often built in pairs Often built in pairs

Breakwaters Barriers built offshore Barriers built offshore Prevents erosion, allowing the beach to grow Prevents erosion, allowing the beach to grow Beach behind the breakwater grows at the expense of the unprotected shoreline Beach behind the breakwater grows at the expense of the unprotected shoreline

Structures built to stop coastal erosion Work temporary Work temporary Often fail during large storms Often fail during large storms Often have to be rebuilt Often have to be rebuilt

As You Read Questions How are most landscapes formed? How are most landscapes formed? What types of landscapes are formed by moving water? What types of landscapes are formed by moving water? What are some structures that people have developed to prevent erosion along a shoreline? What are some structures that people have developed to prevent erosion along a shoreline?

Review and Reflect Questions What types of land material are most likely to erode quickly? What do you think erodes slowly? Why do you think this is so? What types of land material are most likely to erode quickly? What do you think erodes slowly? Why do you think this is so? How can human actions affect the natural process of erosion? How can human actions affect the natural process of erosion? Do you think humans should interfere with the natural process of erosion? Explain. Do you think humans should interfere with the natural process of erosion? Explain.

Review and Reflect Continued How is the atmosphere involved in the erosion process? How is the atmosphere involved in the erosion process? What connections can you make between erosion and the biosphere? What connections can you make between erosion and the biosphere? Why was modeling important tool in this investigation? Why was modeling important tool in this investigation? What was the independent variable in this investigation? What was the independent variable in this investigation? What was the dependant variable in this investigation? What was the dependant variable in this investigation?