Towards a tracer-based conceptualization of meltwater dynamics and streamflow response in a glacierized catchment
Multiple water sources and the physiographic heterogeneity of glacierized catchments hamper a complete conceptualization of runoff response to meltwater dynamics. In this study, we used environmental tracers (stable isotopes of water and electrical conductivity) to obtain new insight into the hydrol...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-01-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/21/23/2017/hess-21-23-2017.pdf |
| Summary: | Multiple water sources and the physiographic heterogeneity of glacierized
catchments hamper a complete conceptualization of runoff response to
meltwater dynamics. In this study, we used environmental tracers (stable
isotopes of water and electrical conductivity) to obtain new insight into the
hydrology of glacierized catchments, using the Saldur River catchment,
Italian Alps, as a pilot site. We analysed the controls on the spatial and
temporal patterns of the tracer signature in the main stream, its selected
tributaries, shallow groundwater, snowmelt and glacier melt over a 3-year
period. We found that stream water electrical conductivity and isotopic
composition showed consistent patterns in snowmelt-dominated periods, whereas
the streamflow contribution of glacier melt altered the correlations between
the two tracers. By applying two- and three-component mixing models, we
quantified the seasonally variable proportion of groundwater, snowmelt and
glacier melt at different locations along the stream. We provided four model
scenarios based on different tracer signatures of the end-members; the
highest contributions of snowmelt to streamflow occurred in late spring–early summer and ranged between 70 and 79 %, according to different
scenarios, whereas the largest inputs by glacier melt were observed in
mid-summer, and ranged between 57 and 69 %. In addition to the
identification of the main sources of uncertainty, we demonstrated how a
careful sampling design is critical in order to avoid underestimation of the
meltwater component in streamflow. The results of this study supported the
development of a conceptual model of streamflow response to meltwater
dynamics in the Saldur catchment, which is likely valid for other glacierized catchments worldwide. |
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| ISSN: | 1027-5606 1607-7938 |