Groundwater Groundwater Water beneath the Earths surface How

Groundwater

Groundwater Water beneath the Earth’s surface How does it get there? It seeps down through the soil and enters spaces called pores

Aquifer Body of rock or sediment which large amounts of water can flow and be stored Pores and fractures must be connected so that water can flow freely The attraction of water to soil holds water in the soil. Gravity pulls water down to the impermeable rock when the soil becomes saturated

Porosity What is it? Things that affect Porosity: Sorting: the amount of uniformity in the size of rock or sediment particles Particle packing: loosely or tightly packed Grain shape: irregular or rounded/square

Permeability What affects permeability? Connection of pores and cracks Size of the pores Sorting

Zones of an Aquifer Zone of Saturation: Lowest zone and is the layer of the aquifer in which the pores space is completely filled with water Water table Zone of Aeration: Uppermost: area where water forms film around the topsoil Middle: dry and contains air Bottom: capillary fringe: water is drawn up from zone of saturation

Movement of Groundwater Flows downward in response to gravity Rate depends on permeability and gravity Passes quickly through highly permeable rock Flows more quickly when there is more gravity exerted on the water such as a steep slope

Topography The depth of the water table depends on: Surface topography Permeability of the aquifer Rainfall Rate of water use The water table matches the contours of the surface

Conserving Groundwater has a long renewal time it takes a long time to replace water that has been removed. Since it takes so long to replace water, it is important to conserve the water available. Only use what you need Recycle water Cut down on pollution

Wells and Springs Wells and springs are two ways groundwater reaches the earth’s surface Well: a hole dug below the level of the water table Spring: the natural flow of groundwater to the Earth’s surface at a place where the surface dips below the water table Play Well

Radium Springs

Warm Springs

Warm Springs

Warm springs pool #2

Artesian Formations A sloping layer of permeable rock that is sandwiched between two layers of impermeable rock. Permeable rock is the aquifer Caprock is the top layer of impermeable rock Artesian wells flow freely without being pumped Artesian springs form when a crack forms in the caprock

Hot springs and Geysers Hot springs: Water that is heated to at least 37°C and rises to the surface before cooling. Hot rocks heated by magma heat the water Geysers: Hot springs that periodically erupt from surface pools or small vents Heat and pressure turn the water into steam which rapidly erupts Play how geysers work

Chemical Weathering by Groundwater Water accumulates dissolved minearls as it travels underground Hard water: high concentration of dissolved minerals Soft water: low concentration of dissolved minerals

Chemical Weathering by Groundwater Some effects of Chemical Weathering: Soap scum Caverns Stalactites Stalagmites Sinkholes Karst topography

Caves

Ruby falls

Stalagmites When drops of water fall on the cavern floor, calcite builds up to form an upward-pointing cone

Stalagmites

Stalacite When water containing dissolved calcite drips from the ceiling of a limestone cavern, some of the calcite is deposited on the ceiling As calcite builds up, it forms a suspended coneshaped deposit Often, a stalacite and a stalagmite will grow until they meet and form a calcite deposit called a column

Stalactites

Remember: Stalactites hold tight to the ceiling while stalagmites might reach the ceiling. How caves are formed

Sinkholes A circular depression that forms at the surface when rock dissolves, when sediment is removed, or when caves or mines collapse Most sinkholes form by dissolution, in which the limestone or other rock dissolves where weak areas in the rock, such as fractures, previously existed. The dissolved material is carried away from the surface and a small depression forms

Sinkholes

Sinkholes

Guatemala in April 2007 swallowed an entire factory

Caused by city’s drainage system Building was empty 20 meters across, 30 meters deep and nearly perfectly round

How Florida's sinkholes form Play

Texas

Sinkholes Natural Human impacted-result from: abandoned septic tanks, land-use practice and water pumping

Karst topography is a landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite. [1]

Animations Play