Integrated time‐lapse geoelectrical imaging of wetland hydrological processes

Abstract

17Wetlands provide crucial habitats, are critical in the global carbon cycle, and act as key 18 biogeochemical and hydrological buffers. The effectiveness of these services is mainly controlled by 19 hydrological processes, which can be highly variable both spatially and temporally due to structural 20 complexity and seasonality. Spatial analysis of 2D geoelectrical monitoring data integrated into the 21 interpretation of conventional hydrological data has been implemented to provide a detailed 22 understanding of hydrological processes in a riparian wetland. This study shows that a combination 23 of processes can define the resistivity signature of the shallow subsurface, highlighting the 24 seasonality of these processes and its corresponding effect on the wetland hydrology. Groundwater 25 exchange between peat and the underlying river terrace deposits, spatially and temporally defined 26 by geoelectrical imaging and verified by point sensor data, highlighted the groundwater dependent 27 nature of the wetland. A 30 % increase in peat resistivity was shown to be caused by a nearly entire 28 exchange of the saturating groundwater. For the first time, we showed that automated 29 interpretation of geoelectrical data can be used to quantify shrink-swell of expandable soils, 30 affecting hydrological parameters, such as, porosity, water storage capacity, and permeability. This 31 study shows that an integrated interpretation of hydrological and geophysical data can significantly 32 improve the understanding of wetland hydrological processes. Potentially, this approach can provide 33 the basis for the evaluation of ecosystem services and may aid in the optimization of wetland 34 management strategies. 35

Current uses of ground penetrating radar in groundwater-dependent ecosystems research

“…In the absence of precipitation, many wetlands and seasonal-water ecosystems reveal their dependence on shallow groundwater for the sustenance of riparian flow, river base-flow, and adequate moisture levels in soil-root and unsaturated zones (Fan et al, 2013;Chambers et al, 2014;Uhlemann et al, 2016). Most of GDE are currently threatened by a combination of global climate forces that extend drought periods and local human-induced pressures such as land-use changes and pollution (Yuce, 2006;Ribeiro, 2009;Kløve et al, 2011;Silva et al, 2012).…”

Three‐Dimensional Time‐Lapse Geoelectrical Monitoring of Water Infiltration in an Experimental Mine Waste Rock Pile

“…Various applications of the ERT method have been presented over the past two decades for: hydrogeological studies (Clément et al, 2014; Hübner et al, 2017, 2015; Nimmer et al, 2008), agricultural applications (Cassiani et al, 2012; Michot et al, 2003; Uhlemann et al, 2016b), ground water resources (Binley et al, 2002; Kuras et al, 2009), tracer and contaminant plume monitoring (Audebert et al, 2016a, 2016b; Koestel et al, 2009, 2008; Kuras et al, 2016, 2014; Power et al, 2014; Rucker et al, 2011; Wilkinson et al, 2010), geotechnical applications (Chambers et al, 2014, 2015; Uhlemann et al, 2016a, 2017) and mining environmental issues (Anterrieu et al, 2010; Dimech, 2018; Dimech et al, 2018, 2017; Intissar, 2009; Power et al, 2018).…”

Continuous and event-based time series analysis of observed floodplain groundwater flow under contrasting land-use types

“…Many ecosystem services provided by floodplains are controlled by hydrological processes (Uhlemann et al, 2016); particularly, interactions between floodplain groundwater and surface water bodies (Krause et al, 2007), which in turn are functions of surface water-groundwater connectivity and pressure head gradients between the systems. In the current work, results suggest greater stream-aquifer exchange at the BHF than the Ag site, as evidenced by greater magnitude, longer duration, and more frequent negative flows at the BHF.…”