Measurement of saturated hydraulic conductivity with a sealed double ring infiltrometer at Page Ranch, Arizona

Abstract

A sealed double ring infiltrometer (SDRI) was used at Page Ranch, Arizona to measure saturated hydraulic conductivity (Ksat in a test clay pad, as well as to characterize preferential flow and transport mechanisms. Ksat varied from 3.5 x 10⁻⁹ to 2.2 x 10⁻¹⁰ cm/sec depending on treatment of matric potential at the wetting front. These in-situ Ksat values were about one order of magnitude less than the laboratory values that ranged from 10⁻⁷ to 10⁻⁹ cm/sec. Although the pad was not instrumented to detect a shallow wetting front, the dye front and water content data indicated that flow penetrated 4 to 6 cm by the end of the 75 day test. Tracer data suggested that bromide moved to 18 or 20 cm by diffusion and that the effective diffusion coefficient was 15 to 21 x 10⁻¹⁰ m²sec. Preferential flow, as judged by the uniformity of the dye front and bromide tracer movement, was insignificant.