A Cone of Depression Formation
The phenomenon of a cone of depression occurs when a depression forms in the water table in an area around a pumping hole. The water pressure around the well is usually decreased because the water is pumped out faster than it can replenish. A decrease in pressure can cause water levels to fall, resulting in a conical depression. These factors determine the size of the cone, including the quantity of water being pumped, permeability and water availability to recharge the system. Groundwater systems can be affected by a cone of depression. This is because water can flow from nearby areas into the depression. It can also cause a reduction in water supply to the area. If the depression cone is large enough, the water table and streams that run through it may be affected. The fact that water tables can change, makes it difficult to predict the size of a depression cone.