Characterizing Groundwater Flow Dynamics and Storage Capacity in an Active Rock Glacier

verfasst von: Simon Seelig

Verlag: Springer Fachmedien Wiesbaden

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Über dieses Buch

Alpine aquifers play a critical role in the hydrology of mountainous areas by sustaining base flow in downstream rivers during dry periods and retarding flood propagation after heavy precipitation events. Progressing climate change alters climatic and meteorological boundary conditions as well as the hydraulic response of alpine catchments by ablating glaciers and thawing permafrost. Rock glaciers exert a controlling influence on the catchment response due to their prominent groundwater storage and complex drainage characteristics. This thesis investigates the hydrogeology and internal structure of the active rock glacier Innere Ölgrube (Ötztal Alps), which governs catchment runoff and is affected by permafrost degradation. A 3D geometrical model of its internal structure is obtained by combining geophysical data and permafrost creep modelling. Available data and new results are integrated into a conceptual hydrogeological model providing a sound basis for the implementation of a prospective numerical groundwater flow model. Hydraulic properties of the hydrostratigraphic units constituting the rock glacier are estimated and groundwater recharge fluxes quantified. Fundamental properties of the heterogeneous groundwater flow system within the rock glacier are discussed and compared to existing rock glacier studies.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Introduction

Abstract

Alpine catchment characterization is the key to evaluating the hydrological response of headwater catchments and predicting the hydraulic regime of downstream rivers and aquifers. The Alpine climate has been subject to significant changes during the last decades and is expected to be affected by the global climate response to increasing greenhouse gas concentrations during the 21^st century (Gobiet et al., 2014). River peak runoff is predicted to shift to winter and early spring, since less precipitation will fall as snow and the snow cover will start to melt earlier (Barnett et al., 2005).

Simon Seelig

Chapter 2. Study Site

Abstract

The active rock glacier Innere Ölgrube (OEG) is located in a small west facing side valley in the upper Kaunertal (Ötztal Alps, Austria). Its alpine 1.83 km² catchment constitutes a headwater tributary to the Fagge River. It is characterized by rugged topography largely surrounded by steep cliffs except to the West, where the hanging valley abruptly declines to the Kaunertal.

Simon Seelig

Chapter 3. Methods

Abstract

In order to achieve a comprehensive conceptual model of the OEG, the existing information is summarized and complemented by an evaluation of available data using a multi-disciplinary approach. Evaluation of surface displacement rates within the framework of a simple creep model yields a first approximation of the permafrost thickness distribution in those parts of the rock glacier that are not covered by geophysical measurements. A 3D geometrical model of the internal structure is obtained for the complete rock glacier by combining this approximation with the structures identified by the geophysical survey.

Simon Seelig

Chapter 4. Results and Interpretation

Abstract

The geometrical model is based on a high-resolution (1 x 1 m) digital elevation model of the rock glacier surface, interpolation involving 113 control points derived from the geophysical profiles, and 5510 surface displacement vectors distributed across the rock glacier surface. Long-term creep rates are calculated using n = 3, A = 2.4·10⁻²⁴ Pa⁻³ s⁻¹, ρ_AL = 1604 kg m⁻³, and ρ_PF = 1826.67 kg m⁻³. The obtained model consists of a set of four continuous surfaces which are spatially constrained by the rock glacier boundaries outlined by Wagner et al. (2019a) (fig. 2.3b).

Simon Seelig

Chapter 5. Discussion

Abstract

The ultimate goal in alpine catchment characterization is to predict hydrological responses at the watershed scale. First-order controls on the hydrological behavior of the Innere Ölgrube are identified by Wagner et al. (in prep.). The integration of a distributed parameter model focusing on dominant processes at the rock glacier scale into this generic framework requires a coordinated evaluation of models characterizing different scales (Grayson and Blöschl, 2000; Sivapalan et al., 2003).

Simon Seelig

Chapter 6. Conclusion

Abstract

This thesis integrates available data and new results into a consistent hydrogeological conceptual model of the rock glacier Innere Ölgrube. The model reflects site specific characteristics of the rock glacier and its catchment derived from a multi-disciplinary approach, provides a comprehensive basis for a prospective distributed parameter model at the rock glacier scale, and is constrained by a lumped parameter rainfall runoff model characterizing the catchment scale. It complies with the downward approach to hydrological prediction by attempting to explore the dominant processes identified to control the catchment response by Wagner et al.

Simon Seelig

Chapter 7. Outlook

Abstract

The results presented in this thesis represent an intermediate step in the quantitative characterization of the Innere Ölgrube catchment and provide a basis for a prospective distributed parameter model complementing the lumped-parameter rainfall-runoff model provided by Wagner et al. (in prep.). The specified aquifer geometry and boundary conditions can be easily integrated into a numerical groundwater flow model. The estimated hydraulic properties provide prior information and initial estimates for a corresponding parameter estimation routine and uncertainty analysis.

Simon Seelig

8. Correction to: Characterizing Groundwater Flow Dynamics and Storage Capacity in an Active Rock Glacier

Simon Seelig

Backmatter

Titel: Characterizing Groundwater Flow Dynamics and Storage Capacity in an Active Rock Glacier
verfasst von: Simon Seelig
Verlag: Springer Fachmedien Wiesbaden
Electronic ISBN: 978-3-658-37073-2
Print ISBN: 978-3-658-37072-5
DOI: https://doi.org/10.1007/978-3-658-37073-2