Efficacy of sand columns to increase the sub-soil moisture content of clay

Abstract

Many countries all over the world were suffering from severe shortage of water and this shortage can be solved using varieties of practices. The research presents a novel technique to increase the subsurface moisture in clayey soil by increasing the infiltration rates through vertical sand columns. In this research, two sand columns with different diameters (diameter = 50 mm and 100 mm) were constructed in the centre of a clay placed in two identical cylindrical containers made of steel (diameter = 1000 mm; height = 700 mm). A water layer with height of 30 mm was added to the top of the soil and allowed to percolate. Water content was determined at different depths and radial distances from the sand column after complete infiltration of water. The results showed that water content in clay increases with depth and decreases with increase in the radial distance from the sand column. Larger diameter of sand column resulted in higher values of water content at the same depths and radial distances with remarkable increase from 9 (for 50-mm diameter) to 16% (100-mm diameter) noticed at 550-mm depth and 450-mm radial distance. The promising performance of sand column was further found to be improved in terms of increasing the moisture content of clay in the path of choice by creating an obstruction to the water flow in opposite direction. This increase in moisture content was particularly noteworthy at greater depth (450 mm) and radial distance (550 mm) with increase from 9 to 20% and 16 to 26%, respectively, for 50-mm diameter and 100-mm diameter sand columns. Thus, the proposed methodology was found to be useful to increase the rate of percolation in low permeable clays in areas of less rainfall.