4 Properties of Water Cohesive – sticks to itself Adhesive – sticks to other materialsHigh specific heat – takes lots of energy to increase/decrease temperature
5 Properties of Water Water is polar Polar likes polar Oil is not polar – oil does not mix
6 Properties of Water Density = 1 g/mL Mass/volume (room temp)Density is effected by temperature and salinityMost dense at 4⁰CLeast dense - solidOnly substance to EXPAND when solidWhy is this a good thing?
7 Properties of Water Density influences ocean currents Warm water flows from equator to polesCold water flows from poles to equator
12 Water Cycle Evaporates –moisture in atmosphere; forms clouds Rain to Run off – streams, rivers, lakes, oceans, etcRain to infiltration – absorbed by vegetation, fills gaps in earth, becomes ground water
13 Water cycle Which would allow water to flow through more easily? Notice the gaps!!!!EasiestMost Difficult2nd Easiest
14 Water Cycle Create mural of water cycle Include the following: Run off, precipitation, evaporation, infiltration, condensation, and transpirationDefine each term on the back of your muralCan be found on page in blue Earth Science Book
15 River BasinsAn entire geographical area drained by a river and its tributariesCharacterized by all runoff being taken to same outlet
16 WatershedsSmaller area of land that drains to a smaller stream, lake or wetlandMany smaller watersheds within a river basin.
17 Ground WaterGround Water: the water that lies beneath the ground surfacefilling cracks and pores in all types of rockSourcerain and snow that falls to the ground, some percolates down into the ground
18 Porosity and Permeability Porous: a rock that holds much waterPermeable: a rock that allows water to flow easily through itImpermeable: a rock that does not allow water to flow through it easily
19 The Water Tablewater table: the upper surface of the zone of saturation
20 AquifersAquifer: a body of saturated rock or sediment through which water can move easilysandstone, conglomerate, limestone,bodies of sand and gravel
21 Movement of Groundwater Percolates into ground (downward)May travel down slopeMoves easily through porous rock and not through compacted rock or rocks w/o pores
22 Ground Water and Flooding Ground becomes too saturated – leads to floodingsaturated zone: the subsurface zone in which all rock openings are filled with water
26 WellsWell: cylindrical hole dug to penetrate aquifer within saturated zoneRecharge: addition of new water to aquifer
27 Balancing Withdrawal and Recharge Not balancing can result in:a regional water table droppingthe ground surface settling because the water no longer supports the rock and sedimentSubsidence of the land surface caused by the extraction of groundwater, near Mendota, San Joaquin Valley, CA. Signs on thepole indicate the positions of the land surface in 1925, 1955, and1977. The land sank 30 feet in 52 years.
29 Balancing Withdrawal and Recharge Towns may use artificial recharge to increase rechargeWater is stored in infiltration ponds = increase the rate of water percolation into the ground
30 Groundwater Pollution chemicals used for agriculture can find their way into groundwaterrain can also leach pollutants from city dumps into ground-water supplies
31 Groundwater Pollution May affect water years from nowMay take a long time to reach water
32 Groundwater Pollution Saltwater IntrusionMovement of saline water into freshwater aquifersContamination of drinking waterSalt water is denser, as freshwater is leached, salt water can take its place
33 Surface water Pollution Non-point pollution – pollution from many sourcesSedimentation, stormwater runoff, etcNot easily tracedPoint-pollution – pollution from one sourceEasily traced and easily taken care of
34 Water TreatmentMost water that goes down drains in urbanized areas are treatedRemoval of sludge from waterVery toxic waste that we must dispose of
35 Water Treatment Drinking water from salt water Desalination – removal of salt from saltwaterTakes lots of energy
36 Conservation Measures 1972 – Clean Water Act “restore and maintain the chemical, physical, and biological integrity of the nation’s waters.”1972 – Marine Protection, Research, and Sanctuaries Act1975 – Safe Drinking Water Act (groundwater and surface water)1987 – Water Quality Act
37 Conservation Measures Need to protect water sources for our futureIncrease population = increase need for waterIncrease population = increase pollutionMust take care of our water for our survival!
38 Hydroelectric Dams Build barrier in valley to retain freshwater Water rises to the same level as top of barrierUses water flow to also generate clean electricity.
40 Hydroelectric Dams Positive effects Long term large body of freshwater resourcePrevents water from reaching ocean quicklyProvides large areas with freshwaterClean electricityRecreationControl water flow – less chance of flooding
41 Hydroelectric Dams Negative effects (down stream) Reduces water flow Less water for down stream individualsLess water for wild lifeLess nutrients carriedMigrating/reproducing organisms cannot pass damDam break = massive flooding
42 Hydroelectric Dams Negative effects (upstream) Displaces wildlife/destroys lower level environmentsFloods towns/homes below level of damStagnant water = decrease in water quality
43 Hydroelectric Dams Much debate over building new power dams Several dams being destroyed to allow natural flowEnergy/water crisisAre dams our answer??