Pumping wells

Aquifer structure

The aquifer geology must have sufficient water-permeable materials, and a considerable amount of water can be produced from wells or springs.
Aquifers can be divided into free (or unconfined) aquifers and confined (or compressed) aquifers to distinguish whether there is a water surface and whether the total water head at the upper boundary of the aquifer is the same as the gravity head.
unconfined aquifer: There is a free water surface, and the total water head is at the same position as the water surface.
confined aquifer: There is no free water surface, and the pressure head at the upper boundary of the aquifer is greater than zero.
aquiclude: Compared with the aquifer, it is a very impermeable confined geological layer. The main soil components are usually clay and silt.
aquitard: Water permeability is worse than the aquifer, but better than the water blocking layer. It takes a very long time for water to pass through the impermeable aquifer, and the amount is very small. However, when the water head of the nearby aquifer drops, water is leaked to the aquifer. In this case Although the water supply rate is slow, but the area is large, so the amount is sometimes not negligible. .