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Aquifer. An underground body of water held by rock (enough water to be usable). Water Table. The level of the water below the ground. Examples of Aquifers. Gravel, sand and deposits Fractured (broken up) Limestone. Solid rock, Granite Rocks with poor permeability
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Aquifer An underground body of water held by rock (enough water to be usable)
Water Table • The level of the water below the ground
Gravel, sand and deposits Fractured (broken up) Limestone Solid rock, Granite Rocks with poor permeability (water cannot pass though them easily) Good Aquifer/Poor Aquifer
Different Rock types 1. Granite 2. Gravel 3. Limestone
Porosity and Permeability • Porosity- the percent of the rock that is made up of spaces (air holes) • Permeability-how well connected the holes in the rock are, and how well water can travel through it.
Limestone and Karst Aquifers • Limestone dissolves because rain water is slightly acidic. Cracks and faults form in the limestone, and they can grow to be big caves over time. (see flyer passed around)
Recharge (Inputs) • Water entering the aquifer • Comes from precipitation that percolates through the ground • River water can also percolate through the ground to recharge the aquifer • Ground water recharge is reduced when ground surfaces are paved or compacted. (Impermeable)
Discharge • Ground water leaves the aquifer through springs and seeps, rivers, lakes and wells • Ground water mining is when water is pumped out faster than it recharges
Threats to groundwater quality • Faulty or too many septic tanks • Agriculture: Too much nutrients like fertilizers or animal waste. • Agriculture: Chemical pesticides • Gas Stations: Leaks in underground fuel tanks • Dry Cleaners: Spills and leaks of Chemical solvents • Other Chemical Leaks or spills.