Earth s Water. 97% Salt 3% Fresh

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1 Earth s Water 97% Salt 3% Fresh

2 Of the 3% Freshwater 77% is in icecaps and glaciers (frozen) 22% is under the surface (groundwater) 1% is other: lakes, streams, rivers, etc. Surface water Supports cities and populations with irrigation, drinking water, power, transportation, and food

3 Water that fills and moves through spaces in rock and sediment beneath Earth s surface is called groundwater Largest single source of freshwater available to us! Groundwater is stored underground in, aquifers similar to the way a sponge absorbs water

4 An aquifer fills with water from rain or melted snow that drains into the ground. wells drilled into aquifers provide water for drinking, agricultural and industrial uses These wells are drilled into the zone of saturation (area where all spaces are filled with ). water The top of the saturated zone is called the water table

5 Water tables generally follow the topography (slope) of the land. Water tables rise and fall depending on amount of precipitation, drought, human use, etc.

6 The ease with which water moves depends on porosity -how much space exists between rocks/sediment refers sorting to whether or not the rocks are the same size. Sorting influences the porosity.

7 The ease with which water moves depends on - permeability measure of rock/soils ability to transmit water For a rock to be permeable, the open spaces must be. connected gravel is permeable while granite is impermeable

8 The use of groundwater by, humans plants and animals, evaporation of water and natural movement of water drains aquifers. Precipitation and absorption replaces groundwater in aquifer by moving through the recharge zone. In many communities, groundwater is the only source of. freshwater Although groundwater is renewable it takes a long time to be replenished and we are using aquifers faster than they can be. recharged

9 Recharge of an aquifer is impacted by land use. Parking lots and roads decrease recharge while natural parks and wetlands increase recharge.

10 Land covered with freshwater at least part of the year is called a. wetland : Marshes plants that are non-wooded (cattails, reeds) : Swamps have wooded plants such as trees and shrubs Protected by federal and state law.

11 Purposes of Wetlands o Trap and filter sediments, nutrients, and pollutants o Reduce likelihood of floods o Buffer shorelines from erosion o Provide spawning grounds and habitat for plant and animal life (including threatened and endangered species) o Recreational areas

12 Rivers are created when precipitation exceeds evaporation. As excess water moves down slope as it runoff erodes rock and soil forming a valley with a permanent stream. River systems consist of one main stream and lots of connected streams / tributaries that flow into the main stream. Examples include the Nile, Amazon and Mississippi Rivers. Rivers change with age

13 Parts of a river include o -all Watershed of the land that drains into the same location/body of water (river, stream) o - Bed the area eroded by water oflood - Plain flat area that drains into river but will flood if the water level rises o - Bank the edges of the bed shoreline o - Load what the river carries in the water o, Dissolved bumping along bottom, suspended by the moving water

14 The imaginary line that separates two watersheds is called a. divide

15 The volume of water moved by a stream in a given time period is the stream s discharge othe faster a stream flows the higher the discharge and the greater the load a stream can carry. othe speed of a stream depends on gradient (change in elevation of a stream/ steepness of the stream s slope. River systems change continuously because of weathering and. erosion Streams eventually turn into rivers as erosion causes them to become, longer wider and deeper.

16 Weathering is the breakdown of rocks and sediment. There are 2 types of weathering -requires Chemical a chemical reaction Carbonation: water and carbon dioxide forms carbonic acid which breaks rocks apart Oxidation: reaction with oxygen (rust) Plant Acids : mainly from roots Acid Precipitation

17 : Mechanical breaking down rocks without chemical reactions Examples include Ice wedging: water expands as it freezes in cracks, making cracks bigger with each freeze/thaw cycle : Organic Plant roots growing into and spreading cracks, animals walking on, digging in or otherwise breaking up rocks : Abrasion Wind carried particles slamming into each other (think sand storm)

18 Weathering leads to, erosion which is the movement of weathered pieces of sediment. The rate of erosion depends on the composition of rock, the exposure (surface area), the climate (wet, warm climates erode fastest) and topography (slope of land) Erosion can be really fast (landslide) or really slow.

19 When the speed of water decreases, the ability of a stream to carry its load decreases and part of it becomes deposited as sediment. Sediment can be deposited where the mouth of a stream enters a larger body of water in a triangle shape called a delta

20 When a stream descends down a steep slope and reaches a flat plain, its speed suddenly decreases causing it to deposit some of its load on land in a -shaped fan deposit called an alluvial fan

21 Flooding can occur when the amount of rainfall or snow melting in an area increases rapidly. Flooding can be dangerous, costly, and can cause loss of habitat for plants and animals (humans included). Natural Protection: 1. Natural Levees (deposition on river banks) 2. Wetland areas 3. Ground cover (planting trees, shrubs, grasses is an indirect method of flood control Man-made Protection (Direct): 1. Dams 2. Artificial levees 3. floodways

22 Remember, rivers change with. age Scientists determine the age of a river by measuring the amount of load carried, the velocity and discharge, and the shape of its bed. Youthful V New/ Rivers shaped bed erosion straight Lots of Fairly and fast moving narrow rocks Rapids and jagged

23 In comparison to young rivers. Mature Rivers U shaped bed less erosion, slower but not boring Curves developing Few rapids (if any), smooth river bed

24 In comparison to young and mature Old U shaped bed, starting to fill SLOW Little rivers erosion- may be moving slow enough to deposit some heavier load Meanders - huge sweeping curves Oxbow lakes: Cut off meanders that form U shaped lakes!

25 Globally, irrigation (artificial application of water to land) is the most common use of water but it depends on location. For example 80% of Asia s water use is irrigation for crops, only 38% in Europe Globally about 8% of water use is for drinking and washing

26 Other water uses include Residential Industrial Agricultural Lawns, pools, hygiene, etc, Cooling tanks, power, etc, Crop irrigation Livestock food production

27 Water Pollution Point-Source water pollution is discharged from a single source Leaking septic tank Unlined landfills Leaking storage tanks- chemicals, waste, gasoline, other fuels Abandoned and active mines Public and industrial waste water treatment plants

28 Non-Point Source pollution comes from many different sources, and cannot be tracked to specific a location Examples include Chemicals from road treatments City run-off from parking lots, roads, etc. Chemicals from homes, golf courses, or farms Feces from livestock Polluted precipitation Oil or gas from personal watercraft

29 Common Forms of Pollution 1. Wastewater: Much of the water used by homes, industries, etc must be treated before released back to the environment. Sometimes, however, this wastewater can be a source of nitrogen and phosphorus pollution. Excess N and P cause an overgrowth of plants that suffocate other life (eutrophication) Thermal changes temperature of water making species die out or invade 3. - Groundwater contamination of aquifer 4. Ocean

30 Water Quality refers to the condition of water for various purposes such as drinking, bathing, irrigation, supporting aquatic life, etc. Water can be hard or soft Hard water has lots of minerals dissolved Mostly magnesium,, calcium and iron Particles of Mg, Ca, and Fe are replaced by Sodium (Na) in a water softener Builds up deposits on pipes, surfaces, etc. Weathers the surface!

31 On the other hand, soft water contains few dissolved minerals Easier to lather soap (minerals can t attach to soap particles) Less damaging on pipes Can occur naturally or through a water softener system

32 Special Places with Water Hot Springs Due to geothermal heating Often very hard water- lots of dissolved minerals Stinky with sulfur in the mix Frequently thought to have healing powers

33 : Geysers Special Water Hot springs that build up pressure and release steam Some like clockwork (Old Faithful), some on irregular patterns 80% of world s geysers are in Yellowstone National Park WHY?

34 Special Water - Travertine deposits left behind as water cools and deposits minerals Famous in Yellowstone - Mudpots Hot springs with clay Clay looks like it is boiling. Stinky too

35 Special Water -(caves) Caverns are natural openings in rock. Most caves are created at or just below the water table when acidic groundwater moves through crevices in rock (limestone) and dissolves it away.

36 Special Water In addition to caves, sinkholes result when underlying rock dissolves naturally due to circulating. groundwater