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Chapter 11 The Flow of Fresh Water
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11-1 The Active River Water Cycle Erosion
The removal and transport of surface material Can occur from wind, rain, ice, and snow Cause of the Grand Canyon and MN’s lakes
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11-1 The Active River Water Cycle
The continuous movement of water from water sources Lakes/OceansAir LandInto Ground Lakes/Oceans Evaporation Occurs when liquid water from the Earth’s surface and from living organisms changes into water vapor Condensation Occurs when water vapor cools and changes into liquid water droplets that form clouds in the atmosphere Precipitation Rain, snow, sleet, or hail that falls from clouds onto the Earth’s surface
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11-1 The Active River Water Cycles Runoff Infiltration Percolation
Water that flows across land and collects in rivers, streams, and eventually the ocean Infiltration The movement of water into the ground due to the pull of gravity Percolation The downward movement of water through pores and other spaces in soil due to gravity
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11-1 The Active River
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11-1 The Active River River Systems Tributaries
Smaller streams or rivers that flow into larger ones Make up a network to drain and area of land
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11-1 The Active River River Systems Drainage Basins
The land drained by a river system Includes the main river and all tributaries U.S.’s main basin is the Mississippi Extends from the Rocky Mts. to Appalachian Mts.
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11-1 The Active River River Systems Divides Separates drainage basins
Usually an area of higher ground than the basin it separates
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11-1 The Active River Stream Erosion Channel
The path that a stream follows Start out small and steep Becomes wider and deeper the longer they go
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11-1 The Active River Stream Erosion Gradient
The measure of the change in elevation over a certain distance High gradient has more energy to erode rock and soil (Elevation)/(Distance)= Gradient
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11-1 The Active River If a river starts at an elevation of 4,900 meters and travels 450 km downstream to a lake that is at an elevation of 400 meters, what is the stream’s gradient? 4,900 m – 400 m = 4,500 m 4,500 m / 450km = 10 m/km
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11-1 The Active River Stream Erosion Discharge
Amount of water a stream or river carries in a given amount of time With an increase, the energy, speed, and load increases
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11-1 The Active River Stream Erosion Load
Materials carried in a stream’s water Affected by the stream’s speed Faster the speed the larger the load Bed Load Large materials like pebbles and boulders
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11-1 The Active River Stream Erosion Load Suspended Load
Small rocks and soil in suspension Causes river to look muddy Dissolved Load Materials dissolved in the water
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11-1 The Active River Stages of a River Youthful Rivers
Erodes its channel deeper rather than wider Water flows quickly Sides of channel are steep and straight Few tributaries
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11-1 The Active River Stages of a River Mature Rivers
Erodes its channel wider rather than deeper Gradient is not as steep as a youthful river Fewer falls and rapids Fed by many tributaries Has more discharge than a younger river
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11-1 The Active River Stages of a River Old Rivers Low gradient
Low erosive power Deposits sediments in its channel Has wide flood plains Has fewer tributaries than a mature river because tributaries have merged
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11-1 The Active River Stages of a River Rejuvenated Rivers
Occur where the land is raised by tectonic forces Steepens the gradient Terraces often form on both sides of the stream valley
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11-2 Stream and River Deposits
Deposition Process by which material is dropped or settles out of a solution Soils and rocks drop out of rivers and deposit in the river bed Will change the shape of the river
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11-2 Stream and River Deposits
Deposition in Water Alluvium Rock and soil deposited by streams Occurs at places where the speed of the current decreases Placer Deposit Where heavy minerals, like gold, are deposited
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11-2 Stream and River Deposits
Delta A fan shaped deposit at the end of a river Occurs where the river enters a large body of water
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11-2 Stream and River Deposits
Deposition on Land Alluvial Fan Occurs where alluvium meets a flat plain A fan shaped deposit that is on dry land Flood Plain The land that an over flowing river will cover Will leave a layer of alluvium Very fertile soils
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11-3 Water Underground Ground Water
Water located within the rocks below the Earth’s surface Zone of Aeration Usually filled with water only after a rain storm Zone of Saturation Where water accumulates in spaces between rock particles
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11-3 Water Underground Ground Water Water Table
Underground boundary where the two zones meet Rises during wet seasons Drops during dry seasons
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11-3 Water Underground Aquifers
A rock layer that stores and allows a flow of ground water Porosity The amount of open space between individual rock particles Aquifer must be porous Permeability Rock’s ability to let water pass through it
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11-3 Water Underground Aquifers
Best are formed of sandstone, limestone, or layers of sand and gravel Cover large underground areas Important source of water for cities and agriculture
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11-3 Water Underground Aquifers Recharge zones
Ground surface where water enters an aquifer Restricted to areas where the rock is permeable Depend of the water cycle to maintain a constant flow of water
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11-3 Water Underground Springs Where water will flow out of the ground
Important source of drinking water Artesian Spring Springs that form where cracks occur naturally in the cap rock Pressurized water in the aquifer flows through cracks to the surface
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11-3 Water Underground Wells
A human made hole that is deeper than the level of the water table Will dry up if… It is not below the top of the water table during the dry season If to much water is taken to fast
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11-3 Water Underground Underground Formations Cave formations
Formed by erosion and deposition Dripstone Water that drips from cracks in a cave’s ceiling Composed of limestone Stalactites Build from the ceiling down Stalagmites Build from the floor up
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11-3 Water Underground Underground Formations Sinkholes
When a cave collapses and the surface ground falls in Can form lakes or swamps
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11-4 Using Water Wisely Water Pollution Nonpoint Source Point Source
doesn’t come from one source street gutters, fertilizers, and eroded soils Point Source Comes from one particular source Sewer pipes or factory drains
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11-4 Using Water Wisely Cleaning Water Sewage treatment plants
Factories that clean the waste materials out of water Primary Treatment Solid objects are removed using screens Small particles sink to the bottom Secondary Treatment Water is mixed with oxygen and bacteria Chlorine is added to disinfect Water is released
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