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Long-term transient groundwater pressure and deep infiltration in Alpine mountain slopes (Poschiavo Valley, Switzerland)

  • Larissa de PalézieuxEmail author
  • Simon Loew
Paper
  • 28 Downloads

Abstract

Bedrock aquifers in alpine catchments are important regional sources of freshwater. Data regarding bedrock groundwater-recharge processes are scarce and governing dynamics are poorly understood. The main datasets used to constrain regional groundwater recharge and flow, so far, have been based on indirect methods (environmental isotopes, river discharge rates, tunnel inflows). Here, a unique dataset is presented of long-term pore-water-pressure measurements from five deep boreholes situated in the upper reaches of a mountain slope at 1,500–2,300 m above sea level. In addition to multilevel pore pressure records, a detailed analysis of the hydrogeological conditions in the Alpine catchment is provided, along with the results from investigations of groundwater recharge mechanisms in response to variations in climatic conditions and hydraulic rock-mass properties. The recorded pressure data show annual pressure variations with amplitudes of 5–45 m and responses within a few days to summer rainstorms in the available depth range of 45–277 m below ground surface. One-dimensional analytical pore-pressure diffusion models and numerical infiltration models were applied to investigate pore-pressure dynamics and water-table variations. The model results reproduced the following parameters for the uppermost 100-m-thick layer: the observed amplitudes, rates and delays of pressure increase with porosities of 0.05–0.1%, specific storage of 5E-5 to 5E-7 m-1, and hydraulic diffusivities of 1E-1 to 1E-3 m2/s. Boreholes located in high-diffusivity areas (strongly fractured bedrock below coarse slope debris) had the strongest pressure variations and were most sensitive to weather conditions.

Keywords

Alpine recharge Groundwater recharge/water budget Transient pore pressure measurements Numerical modeling Switzerland 

Pression d’eau souterraine transitoire à long terme et infiltration profonde dans les versants de montagne des alpes (Vallée de Poschiavo, Suisse)

Résumé

Les aquifères de socle des bassins versants alpins constituent des ressources régionales d’eau douce importantes. Les données concernant les processus de recharge des eaux souterraines du socle sont rares et les dynamiques à l’œuvre mal comprises. Les principaux jeux de données utilisés pour contraindre la recharge et l’écoulement des eaux souterraines à l’échelle régionale reposaient jusqu’à présent sur des méthodes indirectes (isotopes environnementaux, taux de décharge en rivière, débits des sorties en galerie). Ici, une base de données unique est présentée sur les variations de pressions interstitielles mesurées depuis 10 ans sur cinq forages profonds situés dans les parties supérieures d’un versant montagneux, à 1,500–2,300 m au-dessus du niveau de la mer. En plus des enregistrements des pressions interstitielles à plusieurs profondeurs, une analyse détaillée des conditions hydrogéologiques dans un bassin versant des Alpes est fournie parallèlement aux résultats des investigations sur les mécanismes de recharge des eaux souterraines en réponse aux variations des conditions climatiques et des propriétés hydrauliques du massif rocheux. Les données de pression enregistrées montrent des variations annuelles, avec des amplitudes de 5–45 m et des réponses en quelques jours aux pluies torrentielles d’été dans une gamme de profondeurs accessible de 45–277 m sous la surface du sol. Des modèles analytiques unidimensionnels de diffusion des pressions interstitielles et des modèles numériques d’infiltration ont été appliqués pour étudier la dynamique des pressions interstitielles et les variations de la nappe phréatique. Les résultats du modèle reproduisent les paramètres suivants pour la couche supérieure de 100 m d’épaisseur: les amplitudes observées, les taux et les retards de l’accroissement de la pression avec des porosités de 0.05-0.10%, des emmagasinements spécifiques de 5E-5 à 5E-7 m-1 et des diffusivités hydrauliques de 1E-1 à 1E-3 m2/s. Les forages localisés dans les zones de forte diffusivité (socle fortement fracturé sous des dépôts de pente grossiers) ont présenté les variations de pression les plus fortes et ont été les plus sensibles aux conditions météorologiques.

Presión transitoria a largo plazo de las aguas subterráneas e infiltración profunda en las laderas de las montañas alpinas (Valle de Poschiavo, Suiza)

Resumen

Los acuíferos del basamento en las cuencas alpinas son importantes fuentes regionales de agua dulce. Los datos relativos a los procesos de recarga de aguas subterráneas son escasos y la dinámica que los gobiernan no se conocen bien. Los principales conjuntos de datos utilizados para identificar la recarga y el flujo regional de las aguas subterráneas, hasta ahora, se han basado en métodos indirectos (isótopos ambientales, tasas de descarga de los ríos, ingresos en túneles). Aquí se presenta un conjunto de datos únicos de mediciones de presión de poros a largo plazo de cinco pozos profundos situados en los tramos superiores de una ladera de montaña a 1,500–2,300 m sobre el nivel del mar. Además de los registros de presión de poros en varios niveles, se proporciona un análisis detallado de las condiciones hidrogeológicas en la cuenca alpina, junto con los resultados de las investigaciones de los mecanismos de recarga de las aguas subterráneas en respuesta a las variaciones de las condiciones climáticas y las propiedades hidráulicas de la masa rocosa. Los datos de presión registrados muestran variaciones anuales con amplitudes de 5-45 m y respuestas en pocos días a tormentas de verano en el rango de profundidad disponible de 45-277 m bajo la superficie del suelo. Se aplicaron modelos analíticos unidimensionales de difusión de presión de poros y modelos numéricos de infiltración para investigar la dinámica de la presión de poros y las variaciones de la capa freática. Los resultados del modelo reprodujeron los siguientes parámetros para la capa superior de 100 m de espesor: las amplitudes, tasas y retardos observados de aumento de presión con porosidades de 0.05-0.1%, almacenamiento específico de 5E-5 a 5E-7 m-1, y difusividades hidráulicas de 1E-1 a 1E-3 3 m2/s. Los pozos de sondeo ubicados en áreas de alta difusividad (basamento fuertemente fracturado debajo de pendientes de escombros gruesos) tuvieron las variaciones de presión más fuertes y fueron los más sensibles a las condiciones climáticas.

阿尔卑斯山坡(瑞士Poschiavo峡谷)长期非稳定地下水压力和深部入渗

摘要

高山流域基岩含水层是重要的区域淡水水源。关于基岩地下水补给过程的数据很少,而且对其动态变化的控制机理了解很少。到目前为止,用于约束区域地下水补给和流动的主要数据是基于间接方法(环境同位素,河流流量,隧道渗入等的量测)。本文提供了一个独特的数据集,包括位于海拔1,500–2,300米的山坡上游的五个深井内的孔隙水压力的长期监测数据。除了不同海拔位置的孔隙压力记录,本文还提供了阿尔卑斯流域水文地质条件的详细分析,并对气候变化和岩体水力特性变化影响下的地下水补给机制进行了调查分析。记录的压力数据显示年际压力变化幅度为5到45米,并记录了由于夏季暴雨引起持续几天的压力变化(监测深度范围为地表以下45-277米)。应用一维分析孔隙 - 压力扩散模型和入渗数值模型研究了孔隙压力动态演变和水位变化。模型结果重现了地表下100米范围内的特征:所观测到的水压力变化幅值、水压力增加的速率和延迟效应等随孔隙率(0.05–0.1%)、单位储水系数(5E-5至5E-7 m-1)以及压力扩散系数(1E-1至1E-3 m2/s)等的变化。位于高扩散系数区域(在斜坡粗碎片下方的强烈破碎基岩区域)的钻孔显示出最强的压力变化,并且对天气条件最敏感。

Pressão transitória a longo prazo das águas subterrâneas e infiltração profunda nas encostas das montanhas alpinas (Vale de Poschiavo, Suíça)

Resumo

Os aquíferos de embasamento cristalino em bacias alpinas são importantes fontes regionais de água doce. Os dados referentes aos processos de recarga das águas subterrâneas são raros e as dinâmicas de controle são pouco compreendidas. Os principais conjuntos de dados usados para restringir a recarga e fluxo regional das águas subterrâneas, até agora, têm sido baseados em métodos indiretos (isótopos ambientais, taxas de descarga de rios, entradas de túneis). Aqui, é apresentado um conjunto de dados único de medições a longo prazo da pressão dos poros de cinco furos profundos situados nos limites superiores de uma encosta de montanha entre 1,500 e 2,300 m acima do nível do mar. Além dos registros multiníveis de pressão de poros, é fornecida uma análise detalhada das condições hidrogeológicas na bacia dos Alpes, juntamente com os resultados das investigações dos mecanismos de recarga das águas subterrâneas em resposta a variações nas condições climáticas e nas propriedades hidráulicas da massa rochosa. Os dados de pressão registrados mostram variações de pressão anuais com amplitudes de 5–45 m e respostas dentro de alguns dias para tempestades de verão na faixa de profundidade disponível de 45–277 m abaixo da superfície. Modelos analíticos unidimensionais de difusão de poro-pressão e modelos de infiltração numérica foram aplicados para investigar a dinâmica da pressão dos poros e as variações do lençol freático. Os resultados do modelo reproduziram os seguintes parâmetros para a camada mais alta de 100 m de espessura: as amplitudes, taxas e atrasos de pressão observados aumentam com porosidades de 0.05 a 0.1%, armazenamento específico de 5E-5 a 5E-7 m-1 e difusividades hidráulicas de 1E-1 a 1E-3 m2/s. Os furos localizados em áreas de elevada difusividade (fragmentos rochosos fortemente fraturados abaixo dos resíduos de declive grosseiro) apresentavam as variações de pressão mais fortes e eram mais sensíveis às condições meteorológicas.

Notes

Acknowledgements

The authors thank the Lagobianco SA and, in particular, Luciano Lardi, Roberto Ferrari, and Corrado Pelazzi, for providing the pore water pressure and hydraulic test data and assistance throughout the entire project; Peter Zwahlen for sharing his geological expertise and data interpretation of the study area; and Clément Roques for his valuable inputs.

Funding information

Financial support was provided by ETH Zurich and the Lagobianco SA.

Supplementary material

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ESM 1 (PDF 6212 kb)
10040_2019_2025_MOESM2_ESM.pdf (4.7 mb)
ESM 2 (PDF 4831 kb)

References

  1. Achtziger-Zupančič P, Loew S, Mariéthoz G (2017) A new global database to improve predictions of permeability distribution in crystalline rocks at site scale. J Geophys Res Solid Earth 122(5):3513–3539.  https://doi.org/10.1002/2017JB014106 CrossRefGoogle Scholar
  2. BAFU (2006) Hinweiskarte der potenziellen Permafrostverbreitung [Indicating the potential permafrost spread]. Abteilung Gefahrenprävention, Bundesamt für Umwelt, Bern, SwitzerlandGoogle Scholar
  3. BAFU (2009) Ergebnisse der Grundwasserbeobachtung Schweiz (NAQUA): Zustand und Entwicklung 2004–2006 [Results of groundwater observation Switzerland (NAQUA): state and development 2004–2006]. Environmental status no. 0903, Bundesamt für Umwelt, Bern, Switzerland, 144 ppGoogle Scholar
  4. Beniston M (2012) Impacts of climatic change on water and associated economic activities in the Swiss Alps. J Hydrol 412:291–296CrossRefGoogle Scholar
  5. Benning LG, Sidler DM (1992) Petrographie der Margna- und Sella-Decke und des Malenco-Serpentinites zwischen Pass d’Ur und Pizzo Scalino (Val Malenco, Provinz Sondrio, Italien) [Petrography of the Margna and Sella Nappe and the Malenco-Serpentinite between the Ur Pass and Mount Scalino (Val Malenco, Sondrio Province, Italy)]. Swiss Bull Mineral Petrogr 72:213–224Google Scholar
  6. CH2014 – Impacts (2014) Toward quantitative scenarios of climate change Impacts in Switzerland, published by OCCR, FOEN, MeteoSwiss, C2SM, Agroscope, and ProClim, Bern, Switzerland, 136 ppGoogle Scholar
  7. De Marsily G (1986) Quantitative hydrogeology. Academic, San DiegoGoogle Scholar
  8. Deere DU (1963) Technical description of rock cores for engineering purposes. In: Felsmechanik und InQenieurgeologie [Rock mechanics and engineering geology]. Springer, Vienna, pp 16-22Google Scholar
  9. Figi D, Brunold F, Zwahlen DP (2014) Kennwertebericht: Felskennwerte [Report of rock mass parameters]. Büro für Technische Geologie, Sargans, SwitzerlandGoogle Scholar
  10. Finger D, Heinrich G, Gobiet A, Bauder A (2012) Projections of future water resources and their uncertainty in a glacierized catchment in the Swiss Alps and the subsequent effects on hydropower production during the 21st century. Water Resour Res 48:W02521Google Scholar
  11. Forster C, Smith L (1988) Groundwater flow systems in mountainous terrain: 2. controlling factors. Water Resour Res 24(7):1011–1023CrossRefGoogle Scholar
  12. Geokon (2009) Model 4500 series vibrating wire piezometers: instruction manual. Geokon, Lebanon, NHGoogle Scholar
  13. GEO-SLOPE Int. Ltd. (2015) Seepage modeling with SEEP/W: an engineering methodology. GEO-SLOPE, Calgary, ABGoogle Scholar
  14. Gleeson T, Manning AH (2008) Regional groundwater flow in mountainous terrain: three-dimensional simulations of topographic and hydrogeologic controls. Water Resour Res 44:W10403CrossRefGoogle Scholar
  15. Gleeson T, Novakowski K, Kurt Kyser T (2009) Extremely rapid and localized recharge to a fractured rock aquifer. J Hydrol 376(3–4):496–509.  https://doi.org/10.1016/j.jhydrol.2009.07.056 CrossRefGoogle Scholar
  16. Guyonnet D, Lavanchy JM (1992) Analysis of single- and crosshole tests at the BK-Site, Grimsel Test Site. Nagra technical report 91-09, Nagra, Wettingen, Switzerland, pp 31–71Google Scholar
  17. Kobel and Partner (2011) Projekt Lago Bianco - Konzessionsgesuch - Druckstollen, Wasserschloss, Druckschacht - Geologisch-geotechnischer Bericht [Project Lago Bianco - Concession request - pressure tunnel, surge shaft, pressure shaft - Geological-geotechnical report]. Kobel, Weinfelden, SwitzerlandGoogle Scholar
  18. Kölla E, Zuidema P (1993) Abflussprozesse während Starkniederschlägen im Modell, in Feldversuchen und in einem Hochwasserschätzverfahren: ein Rückblick auf vor 10 Jahren gemachte Erfahrungen [Model, field experiments, and estimation procedures for floods of discharge processes during heavy preciptiation: a review of experiences made 10 years ago]. In: Grebner, D (ed) Aktuelle Aspekte in der Hydrologie: Festschrift zum 60. Geburtstag von Herbert Lang [Current issues in hydrology: commemorative work on the occasion of the 60th birthday of Herbert Lang- Züricher Geographische Schriften 53 Broschiert. Zürcher Geographische Schriften, Heft 53, 1993, Geographisches Institut ETH Zürich, pp 200–207Google Scholar
  19. Loew S, Strauhal T (2014) Pore pressure transients in brittle translational rockslides. In: Sassa K, Canuti P, Yin Y (eds) Landslide science for a safer geoenvironment. Springer, Cham, Switzerland, pp 115–122CrossRefGoogle Scholar
  20. Manning AH, Solomon DK (2005) An integrated environmental tracer approach to characterizing groundwater circulation in a mountain block. Water Resour Res 41(12):1–18.  https://doi.org/10.1029/2005WR004178 CrossRefGoogle Scholar
  21. Masset O, Loew S (2010) Hydraulic conductivity distribution in crystalline rocks, derived from inflows to tunnels and galleries in the Central Alps, Switzerland. Hydrogeol J 18(4):863–891.  https://doi.org/10.1007/s10040-009-0569-1 CrossRefGoogle Scholar
  22. Ofterdinger US, Balderer W, Loew S, Renard P (2004) Environmental isotopes as indicators for ground water recharge to fractured granite. Ground Water 42(6–7):868–879.  https://doi.org/10.1111/j.1745-6584.2004.t01-5-.x Google Scholar
  23. Ofterdinger US, Renard P, Loew S (2014) Hydraulic subsurface measurements and hydrodynamic modelling as indicators for groundwater flow systems in the Rotondo granite, Central Alps (Switzerland). Hydrol Process 28(2):255–278.  https://doi.org/10.1002/hyp.9568 CrossRefGoogle Scholar
  24. Rango A, Martinec J (1995) Revisiting the degree-day method for snowmelt computations. J Am Water Res Assoc 31(4):657–669.  https://doi.org/10.1111/j.1752-1688.1995.tb03392.x CrossRefGoogle Scholar
  25. Rohrer MB, Braun LN, Lang H (1994) Long-term records of snow cover water equivalent in the Swiss Alps. Hydrol Res 25(1–2):53–64CrossRefGoogle Scholar
  26. Salzmann N, MacHguth H, Linsbauer A (2012) The Swiss alpine glaciers’ response to the global “2 C air temperature target”. Environ Res Lett 7(4).  https://doi.org/10.1088/1748-9326/7/4/044001
  27. Schmucki E, Marty C, Fierz C, Lehning M (2015) Simulations of 21st century snow response to climate change in Switzerland from a set of RCMs. Int J Climatol 35(11):3262–3273.  https://doi.org/10.1002/joc.4205 CrossRefGoogle Scholar
  28. Serquet G, Marty C, Dulex J-P, Rebetez M (2011) Seasonal trends and temperature dependence of the snowfall/precipitation-day ratio in Switzerland. Geophys Res Lett 38(7).  https://doi.org/10.1029/2011GL046976
  29. Sieber Cassina and Handke (2014) Beilage 3 zum Hauptbericht UVB 2. Stufe: FACHGUTACHTEN QUELLEN [Appendix 3 of the environmental impact report level 2: expert opinion springs]. Sieber Cassina and Handke, Chur, SwitzerlandGoogle Scholar
  30. Staub R (1946) Geologische Karte der Bernina-Gruppe und ihrer Umgebung im Oberengadin, Bergell, Val Malenco, Puschlav und Livigno [Geological Map of the Bernina Group and its surroundings in the Upper Engadin, Bregaglia Valley, Malenco Valley, Poschiavo, and Livigno]. Swiss Geological Commission, Swiss Academy of Sciences, Zürich, SwitzerlandGoogle Scholar
  31. Strauhal T, Loew S, Holzmann M, Zangerl C (2016) Detailed hydrogeological analysis of a deep-seated rockslide at the Gepatsch reservoir (Klasgarten, Austria). Hydrogeol J 24(2):349–371.  https://doi.org/10.1007/s10040-015-1341-3 CrossRefGoogle Scholar
  32. van Genuchten MT (1980) A closed-form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci Soc Am J 44(5):892.  https://doi.org/10.2136/sssaj1980.03615995004400050002x CrossRefGoogle Scholar
  33. Welch LA, Allen DM (2012) Consistency of groundwater flow patterns in mountainous topography: implications for valley bottom water replenishment and for defining groundwater flow boundaries. Water Resour Res 48(5):1–17.  https://doi.org/10.1029/2011WR010901 CrossRefGoogle Scholar
  34. Welch LA, Allen DM (2014) Hydraulic conductivity characteristics in mountains and implications for conceptualizing bedrock groundwater flow. Hydrogeol J 22(5):1003–1026.  https://doi.org/10.1007/s10040-014-1121-5 CrossRefGoogle Scholar
  35. Zangerl C, Eberhardt E, Evans KF, Loew S (2008) Consolidation settlements above deep tunnels in fractured crystalline rock: part 1—investigations above the Gotthard Highway Tunnel. Int J Rock Mech Min Sci 45(8):1195–1210.  https://doi.org/10.1016/j.ijrmms.2008.02.005 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Department of Earth SciencesETH ZurichZurichSwitzerland

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