Advancing frontiers of Lathi-Barmer fresh water mesozoic formations of Barmer district

Abstract

In the Mesozoic super group identified in the Barmer district (India), there are two characteristic groups of fresh water bearing formations: Lathi sandstone of Jurassic age and the Cretaceous Barmer sandstone. Recent studies by satellite imagery have defined better the extent of these formations. As a result of intensive work carried out in the period 1952-1964 and subsequently, the Lathi-Barmer formations have been recognized as the most dependable formations in the district. Groundwater occurs in them under perched, phreatic, and confined conditions, the last varying in depth, aggregate thickness, and coarseness of the formation. The phreatic surface ranges from 27 to 75 m below ground level, whereas the piezometric surface ranges from 32 to 92 m. The discharges obtained from boreholes tapping 18-40 m thickness of granular zones range from 6 to 20 L per sec for a drawdown range of 2-15 m. While the specific capacity ranges from 25 to 750 L/min/m of drawdown, the transmissivity ranges from 90 to 1170 sq m/day and hydraulic conductivity from 5 to 32 m/day. (See also W91-03311) (Rochester-PTT).