Ch 16 Groundwater

Ground water: H2O beneath the Earth’s surface Aquifer: rock or sediment that stores ground water

Porosity: empty space in a rock Permeability: water passes through Sandstone -- highly permeable -- large grains Limestone -- low permeability---- pores are NOT connected

Clay -------impermeable.

Zones of Aquifers: A) Zone of Saturation: area in which pore space is completely filled with water B) Zone of Aeration: upper surface of ground water which has lots of pores for air and tiny animals

Water Table: upper boundary of the zone of saturation Illustrate on the board

Depth of the water table depends on: A) how much water humans use B) amount of rainfall C) permeability of aquifer D) surface topography Pollution has NO effect on the depth of table

Water table is high in heavy rainfall Water table is low in times of drought

Special features of ground water: A) artesian well: a sloping layer of permeable sandwiched between 2 layers of impermeable rock

B)Ordinary springs: occur when the ground surface drops below the water table C) Hot springs: hot groundwater of at least 37oC that rises to surface. As it cools, minerals are deposited along the edge

D) mudpots: hot water in a sticky muddy depression. (Yellowstone ) E) Geysers: hot springs that stay below ground and form steam. The hot water forms steam which produces enough pressure that it blows up

Chemical Weathering: cause for mineral build up in ground water Chemical Weathering: cause for mineral build up in ground water. This produces: Hard water: water with minerals Valley and Ridge has hard water from the Ca in limestone Hard water will damage pipes and appliances

Karst topography: area that chemical weathering has eat away large sections of bedrock. Valley and Ridge of Va Because all of the “holes” in rock, polluted groundwater can travel a long way from a pollution sight

Non-point pollution sight: fertilizer from a pasture or field runs into a stream after a heavy rain Point pollution sight: a factory dumps waste water into a river through a pipe

Features of Karst Topography: 1) Caves: A) stalagmites: build up at the bottom of a cave. They form as the water filled with carbonate from limestone makes a “Hill” B) stalactites: build from the top, as carbonate filled water drips from the ceiling of cave

2) sinkholes: circular depression under surface as rock dissolves 3) natural bridges: an uncollapsed rock between sinkholes 4) Caverns: deep underground holes

Soft water---low mineral content It will form suds easier and does less damage to household items

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