Simulation of Soil Water Content in Clayey Soils Where Dissolution and Precipitation of Pedogenic Carbonates Impact the Accuracy of Sensors Measuring Soil Water Content

Abstract

[EN]Soils are an important storage of water and an efficient filter that enables a certain percentage of precipitation to reach groundwater, contributing to hydrological resources. In this paper, soil water content (SWC) was monitored during 2 years to characterize the hydrological dynamics and quantify water resources. The studied soil is developed over a carbonate bedrock in the Mediterranean region of Croatia. The site has a classical red Mediterranean soil with high clay content and pedogenic carbonates. The hydrological monitoring along the soil profile was conducted using sensors based on frequency domain reflectometry (FDR) technology. However, soil characteristics resulted in factors other than SWC affecting the recorded signal. The measured SWC signals record short-term variability in response to precipitation events, although their absolute values and their long-term variability are unreliable. To better understand local hydrological dynamics, a 1D hydrological model was implemented. Basic corrections were applied to raw SWC signals to use measured data to calibrate the model. In average, the simulation explains 72% of the corrected SWC variability and properly reproduces the short-term variability measured by sensors, improving the original and corrected SWC signals. This research shows that even if FDR sensors provide unreliable data in problematic soils, the measured signals can still be used to calibrate hydrological models and to produce realistic simulated data. The methodology followed in this research can inspire similar observation-simulation studies and be used as a guide to improve the understanding of hydrological dynamics in any type of soil with technical difficulties to acquire quality observational SWC data.