Answer:
Water found deep down the ground in sands and rocks is called groundwater. Overdraft of groundwater occurs when there is a reduction in the level of the groundwater due to depletion (or over use). In other words, when the use of groundwater exceeds its refill or recharge into its source (aquifers), an overdraft is said to have occurred. This will;
i. cause a reduction in water bodies such as rivers and lakes.
ii. result into a high cost of pumping.