On the estimation of hydraulic conductivity of layered vadose zones with limited data availability

Abstract

Vadose zone acts as a controlling agent for recharge and transport of contaminants into aquifers. Hence, for modelling and quantifying flow and transport processes in subsurface environments, hydraulic conductivity (K) of the vadose zone plays an important role. However, given the heterogeneity and anisotropy of subsurface systems, the in-situ measurement of K is a daunting task at a larger scale. The present study was conceived to evaluate the efficacy of salient pedotransfer functions (PTFs) to indirectly estimate the saturated hydraulic conductivity (K s) of a lateritic vadose zone of eastern India. Also, in-situ hydraulic conductivity along with basic soil physical properties was determined in different vadose-zone layers at three locations (bare plot, cultivated field and orchard). Four PTFs [Campbell, Rawls-Brakensiek/Cronican-Gribb (R-B/C-G), and Models 2 and 3 of Rosetta] were selected to estimate K s and their performances were evaluated. Based on the statistical indicators, it is concluded that Model 3 of Rosetta is capable of predicting relatively close values of K s for the lateritic vadose zones to some extent. To generalise the findings of this study, it is recommended that such field-based studies should be carried out at a larger scale in lateritic terrains with varying land use/land cover.

Statistical evaluation of testing conditions on the saturated hydraulic conductivity of Brazilian lateritic soils using artificial intelligence approaches

“…In lateritic soils, k sat becomes particularly affected by the soil structure. Moreover, this soil, typical of tropical regions from Africa, South America, and Southeast Asia 10 , 11 , are commonly formed from the weathering of rocks subjected to the high temperatures and humid climates typical of these regions 10 , 12 , 13 , and are characterized by often having a high void ratio, high clay content, and significant presence of iron and aluminum oxides and hydroxides, resulting in the aggregation of these fine particles 10 , 14 . Particle aggregation form macro and micropores in the soil, resulting in a bimodal pore-size distribution.…”