Why don people use subsoil water in drought period in Australia?
I presume you mean groundwater. It is a complicated issue. First of all, in dry areas the water table may be low and is sensitive to withdrawal because the amount of input is low (you can’t take much out without drying out the aquifer). it may be that the materials at depth where the water is found is not very permeable or porous, so wells cannot get much water from a given location anyway, which may be why surface sources are used as the primary water supply in the first place. During a drought, the groundwater recharge is severely reduced, so it is common for many wells already in existence to go dry as the water table falls. It takes time to set up groundwater sources for the purposes of human consumption. You do not just go out and drill a well today and get it attached to the water supply network a week later.
