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Fresh Water

Fresh Water. Rivers. What Is Erosion? Erosion is the process by which soil and sediment are transported from one location to another. Water and Erosion Water is a major agent of erosion. Rivers often carry eroded materials long distances. Water Cycle. Water Cycle.

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Fresh Water

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  1. Fresh Water

  2. Rivers • What Is Erosion? Erosion is the process by which soil and sediment are transported from one location to another. • Water and Erosion Water is a major agent of erosion. Rivers often carry eroded materials long distances.

  3. Water Cycle

  4. Water Cycle • What powers the water cycle? • What is different about the water cycle in rural and urban areas? • Don’t forget sublimation, transpiration, and deposition!

  5. River Systems • Tributaries A stream that flows into a lake or into a larger stream is called a tributary. • Watersheds A watershed, or drainage basin, is the area of land that is drained by a water system

  6. Water Sheds • What water shed do you live in? • What water shed do I live in? • Are there other water sheds in N.C.?

  7. World Water Sheds

  8. Erosion • GradientGradient is the measure of the change in elevation over a certain distance. • Discharge The amount of water that a stream or river carries in a given amount of time is called discharge. • Load The materials carried by a stream are called the stream’s load.

  9. River Stages • Youthful Rivers A youthful river erodes its channel deeper rather than wider. • Mature Rivers A mature river erodes its channel wider rather than deeper.

  10. River Stages • Old Rivers An old river has a low gradient and little erosive energy. • Rejuvenated Rivers Rejuvenated rivers are found where the land is raised by tectonic activity.

  11. Rivers and Farms • Even though flooding along rivers is potentially harmful, many farms are located near rivers. Why do people build farms along rivers?

  12. Deposits • Placer Deposits Heavy minerals are sometimes deposited at places in a river where the current slows down. This kind of sediment is called a placer deposit. • Delta As its current slows, a river often deposits its load in a fan-shaped pattern called a delta.

  13. Deposits • Floodplains The area along a river that forms from sediment deposited when a river overflows its banks is called a floodplain. • Flooding Dangers Floods can damage property and cause a loss of lives. Dams and levees are often used to prevent flooding.

  14. Water • A family lives 50 km from the nearest stream or lake and gets water from a well. Where does the water in the well come from?

  15. Water Table • The Water Table The zone of aeration and the zone of saturation meet at a boundary known as the water table.

  16. Aquifer • Porosity The percentage of open space between individual rocks is called porosity. • Permeability A rock’s ability to let water pass through is called permeability.

  17. Spring vs. Well • Artesian Springs An artesian spring is a spring whose water flows from a crack in the cap rock of an aquifer. • Wells A human-made hole that is deeper than the level of the water table is called a well.

  18. Geysers

  19. Underground Erosion/Deposition • Cave Formations Although caves are formed by erosion, they also so signs of deposition, such as stalagmites. • Sinkholes The roof of a cave can collapse, which leaves a circular depression called a sinkhole.

  20. Water Beneath the Surface Caverns  Characteristics of features found within caverns • Formed in the zone of aeration • Composed of dripstone • Formed from calcite deposited as dripping water evaporates • Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor).

  21. Water Beneath the Surface Karst Topography  Formed by dissolving rock at, or near, Earth's surface  Common features • Sinkholes—surface depressions - Sinkholes form when bedrock dissolves and caverns collapse. • Caves and caverns  Area lacks good surface drainage.

  22. While hiking, you realize your canteen is almost empty. Why should you not fill the canteen with water from a nearby stream?

  23. Pollution • Point-Source and Nonpoint-Source PollutionPollution that comes from one specific site is called point-source pollution. Nonpoint-source pollution is pollution that comes from many sources.

  24. Water Beneath the Surface Environmental Problems Associated with Groundwater  Overuse and contamination threatens groundwater supplies in some areas. • Treating it as a nonrenewable resource • Land subsidence caused by its withdrawal • Contamination

  25. Contaminated Ground Water • What are some problems associated with contaminated ground water? • Why is ground water so hard to clean once it is contaminated?

  26. What are some examples of point- source pollution? • What are some examples of nonpoint-source pollution? • Which one is easier to do something about? • Which one causes more problems?

  27. What is in the water? • Dissolved Oxygen Fish and other organisms that live in water need dissolved oxygen in the water to live. • Nitrates Elevated nitrate levels in water can be harmful to organisms because they lower the amount of dissolved oxygen in the water. • AlkalinityAlkalinity refers to water’s ability to neutralize acid. Acid rain can lower water’s alkalinity.

  28. How to clean water. • Primary Treatment In primary treatment, dirty water is passed through a large screen to catch solid objects. • Secondary Treatment In secondary treatment, the water is sent to an aeration tank, where it is mixed with oxygen and bacteria. • Another Way to Clean Wastewater A septic tank is a large underground tank that cleans wastewater from a household.

  29. Water • Water in Industry About 19% of water used in the world is used for industrial purposes. • Water in Agriculture Water must be used in agriculture to facilitate plant growth. • Conserving Water at Home Many people save water by installing low-flow shower heads and low-flush toilets.

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