GEOL 1250 Lecture Notes - Lecture 20: Aquifer, Subsidence, Ore
28 May 2016
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Document Summary
Water saturated rock with a high porosity and permeability to allow water to be extracted. Sinking of the water table on either sides of the well. Can result in permanent lowering of the water table if extraction is more than the rate of refill. Sustained use of yield of an aquifer. Amount of water that can be withdrawn constantly and over a long period of time. If the rate of extraction exceeds the sustained yield. Spaces that give the rock permeability compact and can no longer be part of the aquifer. Sinking of ground when aquifer is depleted. Water mining is a particularly serious problem because water is fossil water acquired during the glacial age (they are in between impermeable layers and have a small refill zone. In coastal aquifers, freshwater floats on seawater. If too much water is pumped from the aquifer, seawater will invade it and destroy the source of fresh water.
