Use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (Wetterstein Mountains, Germany)

Lauber, Ute; Goldscheider, Nico

Use of artificial and natural tracers to assess groundwater transit-time distribution and flow systems in a high-alpine karst system (Wetterstein Mountains, Germany) | Utilisation des traceurs naturels et artificiels pour estimer la distribution des temps de transit et les systèmes d’écoulement dans un système karstique alpin d’altitude (Montagnes Wetterstein, Allemagne) Verwendung künstlicher und natürlicher Tracer zur Erkundung der Verweilzeiten und Entwässerungsstrukturen in einem hochalpinen Karstsystem (Wettersteingebirge, Deutschland) Uso de trazadores naturales y artificiales para evaluar la distribución del tiempo de tránsito de Agua subterránea y los sistemas de flujo en un sistema kárstico alto alpino (Montañas Wetterstein, Alemania) 利用人工及天然示踪剂评价 (德国韦特施泰因山脉) 阿尔卑斯山岩溶系统中的地下水渡越时间分布和水流系统 Uso de traçadores artificiais e naturais para avaliação da distribuição do tempo de trânsito da água subterrânea e dos sistemas de fluxo num sistema cársico alpino de grande altitude (Montanhas Wetterstein, Alemanha)

2014

Lauber, Ute | Goldscheider, Nico

Groundwater in mountainous karst regions is vital for regional water budgets and freshwater supply. Owing to increasing water demand and climate change, detailed knowledge of the highly heterogeneous alpine aquifer systems is required. Multi-tracer analyses have been conducted in the steep karstic Wetterstein Mountains, which includes Germany’s highest summit, Zugspitze (2,962 m asl). Results of artificial tracer tests demonstrate well-developed flow paths through the unsaturated zone (up to 1,000 m thickness). Flow paths cross topographic divides and contribute to deep drainage systems underneath alpine valleys. Cross-formational flow has been identified. Quantitative analysis of tailing-dominated breakthrough curves and stable isotopes (¹⁸O) has enabled determination of the mean transit-time distribution. A fast-flow component with transit times between 3 and 13 days was found in karst conduits and open fissures, dependent on flow conditions. An intermediate-flow component, showing mean transit times of about 2.9–4.9 months, was found in well-drained fissures and fractures. A slow-flow component with mean transit times greater than 1 year is attributable to slow flow and low storage in the poorly drained fissures and rock matrix. The conceptual model enables a better understanding of drainage, water resources and vulnerability of the high-alpine karst system.

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