Warta Geologi, Vol. 47, No. 2, August 2021, pp. 113 - 121





Description

Warta Geologi, Vol. 47, No. 2, August 2021, pp. 113–121

Saturated hydraulic conductivity (Ks) of earth materials in a weathering profile over the Kuantan Basalt, Pahang, Malaysia

John Kuna Raj

No. 83, Jalan Burhanuddin Helmi 2,
Taman Tun Dr. Ismail, 60000 Kuala Lumpur, Malaysia
Email address: jkr.ttdi.tmc@gmail.com

Abstract: Three broad morphological zones can be differentiated at the weathering profile; the top, 3.80 m thick, pedological soil (zone I with sub-zones IA, IB and IC) comprising soft to stiff, brown clays and the bottom bedrock (zone III) being an outcrop of vesicular olivine basalt. The intermediate zone II (saprock) is 1.12 m thick and consists of brown, very stiff, sandy clayey silt with many lateritic concretions. Laboratory constant head permeability tests show the saturated hydraulic conductivity (Ks) to vary with depth; sub-zone IB having a conductivity of 0.007 cm/hr, and sub-zone IC (saprolite), and zone II (saprock), having conductivities of 0.147, and 0.447, cm/hr, respectively. The conductivity values show no correlation with physical properties of the earth materials, but increase with increasing sand, gravel, and silt, contents. The conductivity values also decrease with increasing clay and colloid contents. The low hydraulic conductivity of sub-zone IB will lead to surface runoff and ponding over natural ground surfaces during rainfall events, though over disturbed ground surfaces, infiltration is anticipated in view of exposed saprolite and saprock earth materials with relatively high conductivity.

Keywords: Weathering profile, Kuantan Basalt, saturated hydraulic conductivity

DOI : https://doi.org/10.7186/wg472202102