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Using synoptic tracer surveys to assess runoff sources in an Andean headwater catchment in central Chile

Nauditt, A. and Soulsby, C. and Birkel, C. and Rusman, A. and Schüth, Christoph and Ribbe, L. and Alvares, P. and Kretschmer, N. (2017):
Using synoptic tracer surveys to assess runoff sources in an Andean headwater catchment in central Chile.
In: Environmental Monitoring and Assessment, p. 440, 189, (9), ISSN 15732959, DOI: 10.1007/s10661-017-6149-2, [Online-Edition: http://link.springer.com/10.1007/s10661-017-6149-2],
[Article]

Abstract

Headwater catchments in the Andes provide critical sources of water for downstream areas with large agricultural communities dependent upon irrigation. Data from such remote headwater catchments are sparse, and there is limited understanding of their hydrological function to guide sustainable water management. Here, we present the findings of repeat synoptic tracer surveys as rapid appraisal tools to understand dominant hydrological flow paths in the semi-arid Rio Grande basin, a 572-km(2) headwater tributary of the 11,696-km(2) Limar\' basin in central Chile. Stable isotopes in stream water show a typical altitudinal effect, with downstream enrichment in δ(2)H and δ(18)O ratios. Seasonal signals are displayed in the isotopic composition of the springtime melting season water line with a steeper gradient, whilst evaporative effects are represented by lower seasonal gradients for autumn and summer. Concentrations of solutes indexed by electrical conductivity indicate that there are limited contributions of deeper mineralised groundwater to streamflow and that weathering rates vary in the different sub-catchments. Although simplistic, the insights gained from the study could be used to inform the structure and parameterisation of rainfall runoff models to provide seasonal discharge predictions as an evidence base for decision making in local water management.

Item Type: Article
Erschienen: 2017
Creators: Nauditt, A. and Soulsby, C. and Birkel, C. and Rusman, A. and Schüth, Christoph and Ribbe, L. and Alvares, P. and Kretschmer, N.
Title: Using synoptic tracer surveys to assess runoff sources in an Andean headwater catchment in central Chile
Language: English
Abstract:

Headwater catchments in the Andes provide critical sources of water for downstream areas with large agricultural communities dependent upon irrigation. Data from such remote headwater catchments are sparse, and there is limited understanding of their hydrological function to guide sustainable water management. Here, we present the findings of repeat synoptic tracer surveys as rapid appraisal tools to understand dominant hydrological flow paths in the semi-arid Rio Grande basin, a 572-km(2) headwater tributary of the 11,696-km(2) Limar\' basin in central Chile. Stable isotopes in stream water show a typical altitudinal effect, with downstream enrichment in δ(2)H and δ(18)O ratios. Seasonal signals are displayed in the isotopic composition of the springtime melting season water line with a steeper gradient, whilst evaporative effects are represented by lower seasonal gradients for autumn and summer. Concentrations of solutes indexed by electrical conductivity indicate that there are limited contributions of deeper mineralised groundwater to streamflow and that weathering rates vary in the different sub-catchments. Although simplistic, the insights gained from the study could be used to inform the structure and parameterisation of rainfall runoff models to provide seasonal discharge predictions as an evidence base for decision making in local water management.

Journal or Publication Title: Environmental Monitoring and Assessment
Volume: 189
Number: 9
ISBN: 1066101761492
Uncontrolled Keywords: Andes,Mountainous runoff generation,Semi-arid central Chile,Stable isotopes,Steep elevation gradient,Tracers
Divisions: 11 Department of Materials and Earth Sciences > Earth Science
11 Department of Materials and Earth Sciences > Earth Science > Hydrogeology
11 Department of Materials and Earth Sciences
Date Deposited: 04 Apr 2018 12:24
DOI: 10.1007/s10661-017-6149-2
Official URL: http://link.springer.com/10.1007/s10661-017-6149-2
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