A soil moisture monitoring network to characterize karstic recharge and evapotranspiration at five representative sites across the globe

Abstract

Abstract. Karst systems are characterized by a high subsurface heterogeneity, and their complex recharge processes are difficult to characterize. Experimental methods to study karst systems mostly focus on analysing the entire aquifer. Despite their important role in recharge processes, the soil and epikarst receive limited attention, and the few available studies were performed at sites of similar latitudes. In this paper, we describe a new monitoring network that allows for the improvement of the understanding of soil and epikarst processes by including different karst systems with different land-cover types in different climate regions. Here, we present preliminary data form the network and elaborate on their potential to answer research questions about the role of soil and epikarst on karstic water flow and storage. The network measures soil moisture at multiple points and depths to understand the partitioning of rainfall into infiltration, evapotranspiration, and groundwater recharge processes. We installed soil moisture probes at five different climate regions: Puerto Rico (tropical), Spain (Mediterranean), the United Kingdom (humid oceanic), Germany (humid mountainous), and Australia (dry semi-arid). At each of the five sites, we defined two 20 m×20 m plots with different land-use types (forest and grassland). At each plot, 15 soil moisture profiles were randomly selected and probes at different depths from the topsoil to the epikarst (in total over 400 soil moisture probes) were installed. Covering the spatio-temporal variability of flow processes through a large number of profiles, our monitoring network will allow researchers to develop a new conceptual understanding of evapotranspiration and groundwater recharge processes in karst regions across different climate regions and land-use types, and this will provide the base for quantitative assessment with physically based modelling approaches in the future.

Integrating field work and large-scale modeling to improve assessment of karst water resources

“…Most springs Fig. 4 Location of soil moisture monitoring plots and collected karst spring hydrographs (combined and adapted from Berthelin et al 2020a, b;Olarinoye et al 2020) over the karst regions of the world (Chen et al 2017;Goldscheider et al 2020). AU Australia, GB United Kingdom (UK), DE Germany, ES Spain, PR Puerto Rico located at higher elevations (<1,200 m, H1 and H2) have lower discharges.…”

“…Fig. 1 Distribution of soil-moisture probe profiles at one of the 20 m × 20 m plots (adapted fromBerthelin et al 2020a, b) …”

Development and Application of Cell-Phone-Based Internet of Things (IoT) Systems for Soil Moisture Monitoring

“…Researchers have used in-situ sensing sites or networks to measure, record, and transmit soil moisture data from many locations worldwide [1]. For example, traditional sensing technologies that measure soil moisture include the neutron probe [5], time-domain reflectometry (TDR) [6] [7], frequency-domain reflectometry (FDR) [8], capacitance [2] [9] [10], and heat dissipation [11]. However, researchers have used other emerging in-situ and proximal sensing techniques, such as cosmic-ray neutrons [1] [12], global positioning system (GPS)…”

Assessing Streamflow Sensitivity to Precipitation Variability in Karst‐Influenced Catchments With Unclosed Water Balances

“…Recent achievements in karst research include the creation of a karst spring discharge database to promote data availability for karstic regions (Olarinoye et al, 2020), relating soil moisture networks to karst groundwater storage and flow (Berthelin et al, 2020), using tracer experiments to detect fast and slow pathways and the connectivity of conduit systems (…”

“…Climate change will affect hydrological dynamics and water availability in karstic regions by an unknown extent. New approaches to understanding the impact of climate change on karstic regions are therefore of great importance.Recent achievements in karst research include the creation of a karst spring discharge database to promote data availability for karstic regions (Olarinoye et al, 2020), relating soil moisture networks to karst groundwater storage and flow (Berthelin et al, 2020), using tracer experiments to detect fast and slow pathways and the connectivity of conduit systems (…”