Earth Science, 10e Edward J. Tarbuck & Frederick K. Lutgens Groundwater Chapter 3 (page 94) Earth Science, 6e Stan Hatfield and Ken Pinzke Southwestern Illinois College Sources of Earth’s water Distribution of fresh water in the hydrosphere Water, a renewable resource Illustrates the circulation of Earth's water supply Processes involved in the cycle • • • • • Precipitation Evaporation Infiltration Runoff Transpiration The hydrologic cycle Groundwater… Is the largest freshwater reservoir for humans. (90% of our water usage) Plays important geological roles • As an erosional agent, dissolving by groundwater produces • Sinkholes • Caverns • An equalizer of stream flow Features associated with subsurface water Groundwater characteristics Aquifer (closed/open aquifer) Aquitard or aquiclude Zone of saturation Zone of aeration Zone of recharge/Zone of discharge Water table Water beneath the surface (groundwater) Porosity Percentage of pore spaces Determines how much groundwater can be stored Permeability Ability to transmit water through connected pore spaces Springs Are where ground surface and water table meet: • Springs • Hot springs • Water is 6-9ºC warmer than the mean air temperature of the locality • Heated by cooling of igneous rock • Geysers • Intermittent hot springs • Water turns to steam and erupts Hot Springs Old Faithful geyser in Yellowstone National Park Geysers formation Water beneath the surface (groundwater) Features associated with groundwater • Wells • Pumping can cause a drawdown (lowering) of the water table • Pumping can form a cone of depression in the water table • Artesian wells • Water in the well rises higher than the initial groundwater level Formation of a cone of depression in the water table Artesian Well Pressure Surface An artesian well resulting from an inclined aquifer Treat groundwater as a nonrenewable resource Environmental problems associated with groundwater: • Pollution (Farming, industrial, etc…) • Land subsidence caused by its withdrawal • Salt water contamination Salt water contamination Water beneath the surface (groundwater) Geologic work of groundwater • Groundwater is often mildly acidic • Contains weak carbonic acid • Dissolves calcite in limestone • Caverns • Formed by dissolving rock beneath Earth's surface • Formed in the zone of saturation Water beneath the surface (groundwater) Geologic work of groundwater • Caverns • Features found within caverns • Form in the zone of aeration • Composed of dripstone • Calcite deposited as dripping water evaporates • Common features include stalactites (hanging from the ceiling) and stalagmites (growing upward from the floor) Dripstone formations in Carlsbad Caverns National Park Water beneath the surface (groundwater) Geologic work of groundwater • Karst topography • Formed by dissolving rock at, or near, Earth's surface • Common features • Sinkholes – surface depressions • Sinkholes form by dissolving bedrock and cavern collapse • Caves and caverns • Area lacks good surface drainage Development of karst topography Infrared image of karst topography in central Florida End of Chapter 3 GROUNDWATER No Talking Please 1 - PERMEABILITY IS: a) ABILITY TO STORE GROUNDWATER b) ABILITY TO STOP GROUNDWATER c) ABILITY TO TRANSMIT GROUNDWATER d) NONE OF THE ABOVE 2 - WHICH ONE OF THESE IS A MAJOR POLLUTANT IN OUR NORTH FLORIDA GROUNDWATER? a) b) c) d) PHOSPHATES SULFATES NITRATES CARBONATES 3 - WHICH FORCE PUSHES THE GROUNDWATER THROUGH THE ROCK? a) b) c) d) THE PRESSURE SURFACE THE DARCY COEFFICIENT THE HYDRAULIC GRADIENT THE SURFACE TENSION 4 - WHICH ONE (S) OF THESE IS (ARE) PART OF KARST TOPOGRAPHY? a) b) c) d) SINKHOLES CAVES AND CAVERNS SINKING CREEKS ALL OF THESE 5 - AN AQUIFER IS a) IMPERMEABLE ROCK ABOVE THE GROUNDWATER b) POROUS AND PERMEABLE ROCK THAT CONTAINS THE GROUNDWATER c) SAME AS AQUITARD d) NONE OF THESE 6 - THE WATER TABLE IS: a) TOP OF THE AQUIFER b) TOP OF THE ZONE OF SATURATION c) TOP OF THE ZONE OF AERATION d) NONE OF THE ABOVE 7 - WHICH ZONE CONTAINS THE GROUNDWATER? a) b) c) d) THE ZONE OF AERATION THE CONE OF DEPRESSION THE PRESSURE SURFACE THE ZONE OF SATURATION 8 - THE LOWERING OF THE WATER TABLE DUE TO HEAVY PUMPING IS: a) b) c) d) ZONE OF DEPRESSION ZONE OF SATURATION CONE OF DEPRESSION CONE OF SATURATION 9 - WHICH ROCK IS AN AQUITARD? a) b) c) d) SANDSTONE LIMESTONE CLAY NONE OF THESE 10 - THE FLORIDIAN AQUIFER IS MADE OF WHAT ROCK? a) b) c) d) CLAYSTONE SANDSTONE LIMESTONE MILESTONE 11 - AN ARTESIAN WELL EXISTS WHEN: a) IT LIES ABOVE THE PRESSURE SURFACE b) IT LIES BELOW THE PRESSURE SURFACE c) THE PRESSURE SURFACE IS ABSENT d) NONE OF THESE 12 - HOW MUCH OF THE OCEAN WATERS ARE IN THE HYDROSPHERE? a) b) c) d) 87% 70% 90% 97% 13 - HOW MUCH GROUNDWATER DO WE USE IN FLORIDA? a) b) c) d) 80% 70% 90% 97% 14 - A ROCK ABILITY TO STORE WATER IS: a) b) c) d) PERMEABILITY SATURATION POROSITY AERATION 15 – Which one of these is not source of nitrates pollution in FL? a. b. c. d. Farming Animal waste Septic Tank Fossil fuel burning 16 - WHAT MAKES WATER FLOW? a. b. c. d. 1. DISCHARGE 2. RECHARGE HYDRAULIC GRADIENT DARCY’S FORCE 17 – In Florida sinkholes are pathways to the groundwater a. True b. False 18 – Fine particles that float on a stream surface are called a. Bed load b. Suspended load c. Floating load 19 – Between stalagmites and stalagtites which ones hang from the ceiling? a. Stalagtites b. Stalagmites 20 - It is possible to check areas prone to sinkhole from satellite imaging using a. b. c. d. Laser beam Infrasound Ultrasound Infrared 21. Area where most of the runoff infiltrates the ground is called a. b. c. d. Zone of saturation Zone of discharge Zone of recharge Cone of depression 22. Every time we develop a new area we are doing what? a. Increase the demand for water resources b. Reduce the amount of water getting into the ground c. Reduce the recharge zone d. Increase the risk for water pollution e. All of the above 26. Well water or city water, they all are originating from the same aquifer a. True b. False c. Who cares! 23. How much groundwater is there in the hydrosphere? a. b. c. d. 97% 3% < 1% None of these 24. There are drugs in the groundwater you are drinking a. True b. False c. Great! d. Who cares! 25. What is safe to drink? a. b. c. d. City water Well water Bottled water None is safe, they all may contain pollutants e. Who care!