【6】Groundwater is nonrenewable

Groundwater is the portion of the Earth's water cycle that flows underground. Groundwater originates from precipitation that percolates into the ground. The ocean is the natural sink for groundwater flows.

Unlike surface water, groundwater does not recycle readily. Rates of groundwater turnover vary from days to years, and from centuries to millennia, depending on aquifer location, type, depth, properties, and connectivity. The average time for the renewal of groundwater is 1,400 years . Shorter renewal times tend to be associated with shallow groundwater, while longer renewal times are associated with deep groundwater. Significantly, renewal rates of deep groundwater are about 1/15 of those of shallow groundwater. To some extend, the groundwater is practically nonrenewable; once used, they are not likely to recharge any time soon.