Effect of pH on Saturated Hydraulic Conductivity of Lake Kojima Sediment

Abstract

As lake sediments are one of the cause of eutrophication, their effective use has been considered. When they are used as soil in a land, proper permeability is required. However, soil permeability has not completely been understood due to diversity of clays and organic compounds. We clarified permeability characteristics of Lake Kojima sediment, non-swelling clayey soil, by measuring saturated hydraulic conductivity (K). Decrease in K with percolation of dilute electrolyte solution was small when Ca was adsorbed by the soil. Particularly, decrease in K at pH11 was the smallest, because soil structure became stable with chemical reaction between soil particles and Ca. On the other hand, when Na was adsorbed, decrease in K was the smallest at pH5, and it became larger as soil pH increased. The obtained results could be explained qualitatively by the diffuse double layer theory.