Water source dynamics of high Arctic river basins

Abstract

Arctic river basins are amongst the most vulnerable to climate change. However, there is currently limited knowledge of the hydrological processes that govern flow dynamics in Arctic river basins. We address this research gap using natural hydrochemical and isotopic tracers to identify water sources that contributed to runoff in river basins spanning a gradient of glacierization (0–61%) in Svalbard during summer 2010 and 2011. Spatially distinct hydrological processes operating over diurnal, weekly and seasonal timescales were characterized by river hydrochemistry and isotopic composition. Two conceptual water sources (‘meltwater’ and ‘groundwater’) were identified and used as a basis for end‐member mixing analyses to assess seasonal and year‐to‐year variability in water source dynamics. In glacier‐fed rivers, meltwater dominated flows at all sites (typically >80%) with the highest contributions observed at the beginning of each study period in early July when snow cover was most extensive. Rivers in non‐glacierized basins were sourced initially from snowmelt but became increasingly dependent on groundwater inputs (up to 100% of total flow volume) by late summer. These hydrological changes were attributed to the depletion of snowpacks and enhanced soil water storage capacity as the active layer expanded throughout each melt season. These findings provide insight into the processes that underpin water source dynamics in Arctic river systems and potential future changes in Arctic hydrology that might be expected under a changing climate. Copyright © 2013 John Wiley & Sons, Ltd.

Impact of Changing Hydrology on Nutrient Uptake in High Arctic Rivers

“…River discharge ranged from 5 to 240 L s −1 (Table ) and was representative of the small rivers found in this area of Svalbard during summer (Blaen et al ., ). There was no evidence of substantial hillslope groundwater inflow throughout the study reaches.…”

Environmental drivers of macroinvertebrate communities in high Arctic rivers (Svalbard)

“…Pfankuch index decreased with reduced meltwater contribution and SSC was negligible in non‐glacier‐fed rivers, suggesting that rivers sourced largely from ground water create less‐disturbed habitat conditions than rivers dominated by meltwater (Milner et al ., ; Parker & Huryn, ). Increases in EC and decreases in pH associated with reduced meltwater contributions support this hypothesis because ionic enrichment most likely reflects solute acquisition from active layer soils during subsurface flow (Cooper et al ., ; Hodson et al ., ; Blaen et al ., ), while declines in pH are associated with soil development in proglacial areas (Anderson et al ., ).…”

Using stable isotopes to estimate travel times in a data‐sparse Arctic catchment: Challenges and possible solutions

“…This makes environmental tracers, particularly stable isotopes, potentially useful tools for hydrological monitoring. Tracers provide integrated insight into the hydrological functioning of catchments and have been used previously to assess water sources and flow paths in Arctic and permafrost settings (Ala‐aho, Soulsby, et al, ; Blaen, Hannah, Brown, & Milner, ; Lamhonwah, Lafrenière, Lamoureux, & Wolfe, ; Obradovic & Sklash, ; Song et al, ; Yi et al, ). In addition to their capacity to quantify water provenance, flow paths, and transit times, tracer studies provide insights for calibration and testing more detailed conceptual and numerical models at different spatial scales (Ala‐aho, Tetzlaff, McNamara, Laudon, & Soulsby, ; Birkel, Soulsby, & Tetzlaff, ; Soulsby et al, ; Stadnyk, Delavau, Kouwen, & Edwards, ; van Huijgevoort, Tetzlaff, Sutanudjaja, & Soulsby, ).…”