Characterization of Soil Hydraulic Properties in the Pavanje River Basin, Karnataka, India

Abstract

Knowledge of the soil hydraulic properties is very important to solve many soil and water management problems related to agriculture, ecology, and environmental issues. The primary objective of this study was to characterize soil hydraulic properties for the Pavanje river basin soils that lie in the coastal region of Karnataka, India. This research work was mainly focused to develop and validate point and parametric PTF models based on nonlinear regression technique using the different set of predictors such as particle size distribution, bulk density, porosity and organic matter content. Soil samples were collected and subjected to laboratory measurements to get the basic soil properties such as particle size distribution, bulk density, and organic matter content and hydraulic properties like soil water characteristics curve and saturated hydraulic conductivity. The point PTF models estimated retention points at -33, -100, -300, -500, -1000, and -1500 kPa matric potentials and parametric PTF models estimated van Genuchten and BrooksCorey water retention parameters. The present study also developed and validated pedotransfer functions for the estimation of saturated hydraulic conductivity. In addition to this, an empirical relationship has been derived to approximate the soil moisture retention curve from saturated hydraulic conductivity for the sampled soils. The uncertainty analysis was done for all the measured and estimated soil physical and hydraulic properties. Runoff was also predicted for the forested hillslope soils from Green and Ampt infiltration method using measured values of saturated hydraulic conductivity, residual water content, porosity and water content at field capacity values. Finally spatial variability of all physical properties and hydraulic properties were studied for both agricultural and forested hillslope soils. The study of hydraulic properties done in this work could be very helpful for any hydrological modeling for this particular area.