Variability of transit time distributions with climate and topography: A modelling approach

Investigating young water fractions in a small Mediterranean mountain catchment: Both precipitation forcing and sampling frequency matter

“…Consistent with this behaviour, F yw was found in several studies to increase during wetter years (Bansah & Ali, 2019;Clow, Mast & Sickman, 2018;Remondi, Botter, Burlando & Fatichi, 2019;Wilusz, Harman & Ball, 2017;Zhang et al ., 2018) and in wetter catchments (von Freyberg et al , 2018;Remondi et al ., 2017). The importance of rainfall intensity dynamics on catchment MTT orF yw was also stressed by several authors (von Freyberg et al ., 2018;Soulsby, Piegat, Seibert &Tetzlaff, 2011, Remondi et al ., 2019Wilusz et al ., 2017). Furthermore, Stockinger et al ., (2019 showed that catchmentF yw was not only sensitive to (long-term) changes annual hydro-climatic variations, but also to (short-term) changes of the starting date of a sampling campaign.…”

Variability of Water Transit Time Distributions at the Strengbach Catchment (Vosges Mountains, France) Inferred Through Integrated Hydrological Modeling and Particle Tracking Algorithms

“…Up to now, studies about the temporal variability of TTDs and RTDs have mainly relied on concentration measurements of conservative geochemical or isotopic tracers [14], the underlying idea being to employ conceptual models or convolution kernels to determine the shape of the distributions that properly relate input and output geochemical signatures (e.g., [18,22,26]). Studies of distributions based on catchment flow and transport modeling are also available, but these have only received consideration as valuable alternatives to tracer-based studies [27][28][29][30][31][32][33][34]. The hydrological models used in these studies range from simply-conceived rainfall-runoff relationships (e.g., [30]) to more complex, fully distributed models (e.g., [31][32][33][34]).…”

“…Studies of distributions based on catchment flow and transport modeling are also available, but these have only received consideration as valuable alternatives to tracer-based studies [27][28][29][30][31][32][33][34]. The hydrological models used in these studies range from simply-conceived rainfall-runoff relationships (e.g., [30]) to more complex, fully distributed models (e.g., [31][32][33][34]). Transport processes are described using either conceptual approaches or explicit calculations such as the Eulerian resolution of an advection-dispersion equation or Lagrangian particle-tracking simulations.…”

“…Their application is more expensive in terms of computational costs, but they also render time-varying TTDs and RTDs in relation to the succession of physical processes and flow pathways that occur in the watershed. To date, few studies based on physically based distributed models have investigated the temporal variability of TTDs or RTDs on actual catchments using transient-flow conditions [31][32][33][34]. Most of the previous work on TTDs and RTDs based on catchment modeling have considered saturated-groundwater flow alone (e.g., [35]), and/or steady-state flow conditions.…”

Modeling Travel Time Distributions of Preferential Subsurface Runoff, Deep Percolation and Transpiration at A Montane Forest Hillslope Site

“…Fiori and Russo [34] evaluated the variability of soil hydraulic characteristics in a hillslope mantle to obtain the resulting travel time distribution. Using a fully distributed hydrological model coupled with a conservative tracer transport component, Remondi et al [35] highlighted a considerable variability of travel times in catchments with contrasting climates and the pronounced effect of catchment topography on the inferred travel time distributions. Ameli et al [36] used a physically based subsurface flow model coupled with a particle movement module to assess hillslope travel time distributions.…”