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

Abstract

Karst water resources are estimated to provide drinking water to 10%-25% of the world's population (Ford & Williams, 2007; Stevanović, 2019). In some countries and regions, for example, Austria and Slovenia, karst water resources account for approximately half of the total water supply (Hartmann, Goldscheider, et al., 2014; Stevanović, 2019). Chemical weathering of carbonate rock results in a strong subsurface heterogeneity in karstic areas, which leads to groundwater recharge and storage behavior substantially different from the nonkarstic regions (Bakalowicz, 2005; Hartmann & Baker, 2017). Climate projections suggest strong changes of temperature and precipitation in almost all karstic regions in the world (Christensen et al., 2007). 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 (

Dissolving the mystery of subsurface controls on snowmelt–discharge dynamics in karst mountain watersheds using hydrologic timeseries

“…However, comparing flow metrics directly rather than runoff ratios assumes uniform recharge depths, which may be unreasonable in mountain watersheds spanning a large elevation range. Variations in Q N over the baseflow period may be attributed to piracy routes feeding water either into (elevated baseflow) or out of (reduced baseflow) each subcatchment (Hartmann et al, 2014; Liu et al, 2021) or to different conduits engaging at different times. Outlet‐normalized median baseflow magnitude can help highlight systems with basinwide gains or losses, but this response is also influenced by aquifer connectivity and storage (see below).…”

“…Assessing streamflow sensitivity to snowmelt variability via improved understanding of groundwater controls in these hydrologic systems is critical (Godsey et al, 2014;Liu et al, 2021;Tague & Grant, 2009).…”

“…Segura et al (2019) and Hellwig et al (2020) also reported short-term buffering of drought year summer baseflows in areas underlain by porous geology. Liu et al (2021) found that karst controls between 65% and 93% of the total streamflow sensitivity to precipitation across watersheds. However, the climate sensitivity of karst-influenced watersheds remains unclear due to the combined influence of overland flow, fast conduit flow and slower matrix-dominated flow pathways.…”

“…However, the climate sensitivity of karst‐influenced watersheds remains unclear due to the combined influence of overland flow, fast conduit flow and slower matrix‐dominated flow pathways. No framework has been widely adopted for characterizing these systems with respect to groundwater controls on streamflow, and recent work suggests varied sensitivity to interannual changes in snow accumulation and melt volumes (Hartmann et al, 2017; Liu et al, 2021). Understanding dominant flow pathways and sources in karst mountain watersheds is critical for predicting streamflow trends and assessing hydrologic vulnerability to climate change.…”

Unraveling the time-dependent relevance of input model uncertainties for a lumped hydrologic model of a pre-alpine karst system

“…In cases where snowmelt represents a controlling factor in the water balance of karst areas, Doummar et al (2018) showed that groundwater recharge estimations are most sensitive to temperature variations. That is mainly due to the importance temperature has for the timing of snow accumulation and melt and the resulting control on a spring's discharge behavior (Liu et al 2021).…”