Numerical simulation of potential cumulative infiltration in tropical soils with macropore

Abstract

A few experiments have been conducted to examine an artificial macropores and their size effects on water flow and solute transport [1-4]. Allaire-Leung, et al. [ I ] found that water percolation rate with open-open (0-0) macropore was two orders or magnitude higher than those with no macropore. Similarly, Zhou, et al, [2] found that the infiltration rate in the 0-0 macropore was 10-50 times greater than those with no macropore and the other macropore types in their treatment. Biopori has become recently popular approach in reducing surface runoff. However, the effect of its diameter and length on different soil types has not been numerically investigated. The water flow through a loamy soil (2mm sieved and 15% of initial water content) containing an artificial cylindrical macropore having 8 cm in diameter and 9 cm in length was observed through a soil column having 20 cm in diameter and 20 cm in height HYDRUS 2D/3D was employed to simulate the water now of the observed data. Water flow of the nine soil data sets of the previous study [5] were then simulated using the initial water content which is at h = -100 em H2o. Potential cumulative infiltration in soils were then determined based on the water flow without and with a macropore sizes of 10 cm in diameter and 100 cm in length. Soil texture was updated according to US Department of Agriculture (USDA) classification.