Determining a composite value for the saturated hydraulic conductivity in a recharge area of the Guarani Aquifer System, using pedotransfer functions

Determinação de um valor composto para a condutividade hidráulica saturada em uma área de recarga do Sistema Aquífero Guarani, utilizando funções pedotransfer

ABSTRACT

The saturated hydraulic conductivity (K_s) is an essential property for modeling water and contaminants movement into aquifers. However, K_s is extremely variable, even when considering nearby locations, which poses a challenge for modeling at catchment scales. Field measurements of K_s are most of the time expensive, time-consuming and labor-intensive. This study aimed to obtain, for modeling purposes, and using pedotransfer functions (PTFs), a composite value of K_s at a catchment scale, in a recharge area of the Guarani Aquifer System. Soil samples were taken across the study area, and the K_s for each sampling point were determined by several PTF methods. At the same locations, K_s field measurements were taken using a Guelph permeameter. Average values of K_s for all the sampling points calculated by PTFs were similar to the average value obtained by field measurements. The use of PTFs proved to be a faster and simpler method to efficiently determine the K_s value for the watershed and to capture the stochastic variation in terms of soil pore combination at the watershed scale.

Keywords:
Guarani Aquifer System; Hydraulic conductivity; Pedotransfer function; Recharge area