A STUDY ON PERMEABILITY OF GRAVEL LAYER IN IMMEDIATE VICINITY OF THE RIVER AND CHARACTERISTICS OF UNDERFLOW WATER

Abstract

The permeability of gravel layer in immediate vicinity of the river calculated by various methods was examined. Field permeability test, calculation by Hazen and Creager equation, calculation from result of direct observation of underflow velocity in bore hole and calculation from dropped water level in bore hole as response to pumping well were examined to determine the permeability of gravel layer. There was difference of four to five orders of magnitude in comparison with permeability calculated by various method. Observation result of velocity of underflow water in bore hole showed 1.E+00 cm/s order which is very high velocity as velocity of underflow water.