Groundwater

Availability can also change through the year: a wet season may replenish stores, whereas a long dry season reduces river flows and groundwater recharge. The important comparison is between usable supply and demand in a particular place and period.

Groundwater is stored beneath the ground. An aquifer is a layer of permeable rock that holds groundwater and allows it to move through spaces or cracks. Groundwater can be reached using wells or boreholes, so access requires suitable equipment rather than simply being close to a surface water source.

Some people paid companies to drill wells to obtain groundwater. However, drawing more water from underground lowered groundwater levels. In affected areas, the ground settled, causing subsidence that damaged property.