Statistical Study on Pre & Post Monsoon Variation of Groundwater Level in Theni District, Tamil Nadu -India

The water table is the level at which the groundwater pressure is equal to atmospheric pressure. It may be conveniently visualized as the ‘surface’ of the groundwater in given vicinity. It usually coincides approximately with the ‘phreatic surface’, but can be many feet above it. As water infiltrates through pore spaces in the soil, it fIrst passes through the zone of aeration, where the soil is unsaturated. At increasing depths water fIlls in more spaces, until the zone of saturation is reached. The ability of the aquifer to store groundwater is dependent on the primary and secondary porosity and permeability of the rock or soil. The form of a water table may change and vary due to seasonal changes, topography and structural geology. In some regions, winter precipitation is of ten higher than summer precipitation and so the groundwater storage is not fully recharged in summer.