A horizontal layer of sand of 6.2 m thickness is overlain by a layer of clay...

 

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A horizontal layer of sand of 6.2 m thickness is overlain by a layer of clay with a horizontal surface of thickness 5.8 m. An impermeable layer underlies the sand. In order to carry out a pumping test a well was sunk to the bottom of the sand and two observation wells sunk through clay just into the sand at distances of 14 m and 52 m from the pumping well. At a steady-state pumping rate of 650 litres/min., the water levels in the observation wells were reduced by 2.31 m and 1.82 m respectively. Calculate the coefficient of permeability of the sand if the initial piezometric surface level lies 1.0 m below the ground surface. A horizontal layer of sand of 6.2 m thickness is overlain by a layer of clay with a horizontal surface of thickness 5.8 m. An impermeable layer underlies the sand. In order to carry out a pumping test a well was sunk to the bottom of the sand and two observation wells sunk through clay just into the sand at distances of 14 m and 52 m from the pumping well. At a steady-state pumping rate of 650 litres/min., the water levels in the observation wells were reduced by 2.31 m and 1.82 m respectively. Calculate the coefficient of permeability of the sand if the initial piezometric surface level lies 1.0 m below the ground surface.

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Initial height of piezometric surface H 58 62 1 11 m Height of piezometric surface at ... View the full answer