Distribution of Water permafrost and ground ice in these areas GY 102 Final Exam Review Topic 7 Water Settings of Earth s Water 1 Oceans 96 5 of near surface water 2 Glaciers 69 of freshwater water is also in 3 Groundwater 30 of freshwater 4 Rivers important for sources of water transportation 5 Lakes Fresh or salty but saline or brackish between fresh and saline in dry climates 6 Swamps and other wetlands water is on surface 7 Water in minerals may be large amount 8 Biological water water is also in permafrost 9 Atmosphere 0 001 of Earth s water in and ground ice in these areas atmosphere as clouds rain snow etc In ltration water seeps into group Ways Water Moves 1 Air currents 2 Condensation 3 Perception rain snow hail 4 5 Groundwater ows 6 Groundwater ows onto surface 7 Transpiration from plants 8 Most perception into ocean some evaporates on way down 9 Evaporations ocean lakes rivers When water evaporates it leaves the salt behind so the moisture in the atmosphere is fresh and rainfall is fresh Ocean currents also move water Water can move between the surface and groundwater in rivers and lakes and many other settings Hydrologic Cycle Model Circulation and transformation of water throughout the Earth s atmosphere hydrosphere cryosphere lithosphere and biosphere water vapor ice and energy owing continuously in an open plumbing system Composed of currents of water Surface Water Soil Water Balance Equation Sample Water Budget Phoenix AZ Dry warm climate Kingsport TN How does slope of the water table in uence groundwater ow Steeper slope faster ow Faster if water table is steep Slow if water table is gentle Flow in different directions along groundwater divide Types of Drought Meteorological Agricultural Hydrologic Socio economic Aquifers A rock unit that can store and transmit water to a well or spring in useful amounts porosity and permeability Uncon ned aquifer open to Earth s surface and to in ltration Con ned aquifer overlain by less parable materials Perched aquifer underlain by low permeability unit Artesian aquifer water rise some maybe to surface Artesian has no implication about water quality or taste some are salty water Porosity Amount of open pore space how much it can store Expressed as 10 30 high porosity Dependent on size shape orientation and degrees of compaction of mineral grains Permeability Measure of interconnectedness of pores how well it transmits Primary intragranular Secondary fracture systems solution networks Permeable allows passage of water Sand Sponge cake Impermeable obstructs water movement Clay Butter icing Effects of Over pumping Groundwater Before over pumping water table is fairly at and water ows to left past small well Larger well causes cone of depression in water table changing direction of ow A cone of depression forms because water cannot ow fast enough to replenish the amount of water that is withdrawn from the well In many cones the water table becomes steeper near the well because water is withdrawn too fast Water table drops aquifer compacts land subsides Earth ssures at edge of subsided area Along coast freshwater oats on saltwater so draws into saltwater Ways water can become contaminated 1 Mining and naturally mineralized rock 2 Land ll 3 Septic tank 4 Leaking tank in gas station 5 Truck fuel spill 6 Brought from outside area 7 Brought by river 8 Dry cleaner 9 Factory wells spills emissions 10 Households farms 11 Fuel storage tanks Ways groundwater contamination moves With groundwater down water table Cab be ltered if ows slowly such as through sands Not ltered if ows rapidly like in limestone caves Contamination largely moves with groundwater down the slope of the water table Can be naturally ltered out with enough time ows slowly and in contact with material like sand Not ltered if ows rapidly through a rock such as a limestone with open cavities Importance for considering the direction of groundwater ow when sighting the relative positions of a water well and contamination sources such as a septic tank In general put the well uphill of a septic tank but be aware of what is farther up the hill Ways to track and remediate groundwater contamination Spreads out due to diffusion and mixing forming contamination plume We can study by contouring water table and contamination Drill wells to intercept plume pump and treat water Contamination spreads out due to diffusion and mixing forming a contamination plume Contour water table and concentration of contaminant to track plume Drill wells to intercept plume pump out and treat water Dispose of contaminated water or treat it with activated charcoal or certain geologic material Topic 8 Fluvial System Drainage Basins Area drained by one stream boundary between basins is a drainage divide Streams and volume of ow Stream carries moving water through one or more channels Amount of water varies with time and is measured in volume per time discharge Plot of discharge versus time is a hydrography This hydrography shows discharge ow increasing during a ood then decreasing as ood ends Tributaries and Drainage Networks Smaller subsidiary channels are tributaries Tributaries spread out discharge over time Types of Drainage Patterns Dendritic Radial Structurally controlled Ways material is transported and deposited Fine particles can be carried in suspension oating in water Soluble ions are dissolved in and carried by moving water Sand grains can roll and bounce along saltation Cobbles and boulders mostly roll and slide during high ows Material moving on river bed is bed load Size of largest particles that can be moved competence Ways rivers vary over time Rivers vary in discharge during the year due to snowmelt wet dry seasons ect Vary in discharge such as peak ow during spring snowmelt or during a rainy season that begins in the middle of the summer Smaller uctuations record individual events like a storm or especially warm week that results in more snowmelt in the spring Rivers tend to be steep near their origin such as in hills and mountains less steep down stream Base Level The lowest level to which a river can erode base level Can be sea lake or closed basin High above base level much erosion Closer to base level less erosion Sea level is ultimate base level Landscape re ects decreasing gradients and how high it is above base level High above base level streams and rivers can have steeper gradients and erode sharply into terrain Closer to base level streams have lower gradient so less erosion