Hydrological storage and transmission characteristics of an alpine talus

Abstract

Abstract:Alpine watersheds are the source region of some of the largest rivers in North America and elsewhere. Understanding of hydrological processes in alpine watersheds is important for understanding the response of river basins to meteorological forcing. Talus units in alpine watersheds have been suggested in the literature as potential reservoirs of groundwater, but relatively little is known about hydrological processes in talus. To develop conceptual understanding of alpine talus and determine its storage capacity and hydraulic properties, we investigated a talus unit in the Lake O'Hara watershed in the Canadian Rockies using ground-penetrating radar, electrical resistivity tomography, measurements of talus discharge, tracer tests, and isotopic hydrograph separation. The study talus, consisting mainly of quartzite and carbonate rock fragments, had very high hydraulic conductivity (0Ð01-0Ð03 m s 1 ) and fast hydrograph recession (exponential decay coefficient of 1 d 1 ), suggesting that its storage capacity is limited to a time scale of less than a week. Groundwater flow through the talus occurs in a relatively thin (0Ð01-0Ð1 m) saturated zone at the base of the talus, which appears to have discrete flow paths rather than a single continuous sheet. A late-lying snowpack, located at the top of the talus and cliff ledges above, sustains baseflow discharging from the talus, which provides moisture to alpine meadows downstream. Although this study indicates limited storage capacity of talus, further research is required to examine the storage and transmission characteristics of talus consisting of different types of geological materials or formed in different environments.

Impact of relict rock glaciers on spring and stream flow of alpine watersheds: Examples of the Niedere Tauern Range, Eastern Alps (Austria)

“…However, the actual storage is represented by the thickness of the saturated layer (e.g. Muir et al, 2011). Winkler et al (2016b) suggested that the lowest 10 to 15 m are supposedly build up by finer grained sediments that act as the main aquifer.…”

Investigating groundwater flow components in an Alpine relict rock glacier (Austria) using a numerical model

“…Mountainous and, in particular, alpine groundwater is contributing significantly to the stream flow of rivers in valleys and consequently in the foreland (e.g., Campbell et al 1995;Clow et al 2003;Tague and Grant 2009;Muir et al 2011;Welch et al 2012). With increasing population and propagation of tourist industries and recreational activities in mountainous areas, knowledge of the hydraulic behavior and storage capacities of mountainous aquifers is getting more important for sustainable water resources management as well as for predicting natural hazards, as for example flash floods and debris flows (e.g.…”

“…While the hydrogeology of moraines, talus and hillslope aquifers has been the subject of intensive investigations (e.g., Clow et al 2003;Roy and Hayashi 2009;Muir et al 2011), knowledge about the hydraulic behavior and storage capacities of rock glaciers is sparse (Krainer and Mostler 2002;Krainer et al 2007;Millar et al 2013;Winkler et al 2016a). Nevertheless, rock glaciers are common landforms all around the globe in mountainous areas and at high latitudes-for instance, in the Austrian Alps, KellererPirklbauer et al (2012) and Krainer and Ribis (2012) have identified a total of 4,792 rock glaciers covering an area of about 286 km 2 .…”

Controls on Rockfall-Talus Process-Response Systems, Kananaskis, Canadian Rockies

“…(iii) Rockfall and talus are notable contributors to drainage basin development, with topographic form itself having notable effects on hydrological functioning, including storage and transmission of water (Muir et al, 2011). Talus deposits associated with rockfalls are frequent occurrences in Kananaskis and other parts of the Canadian Rockies.…”

“…(ii) rockfalls represent a significant natural hazard; (iii) rockfalls and their locations of deposition affect sediment connectivity between hillslopes and channel networks (Hoffmann et al, 2013); and (iv) rockfalls have distinct morphological and sedimentological properties that affect the development of weathered layers in the landscape; (v) talus affects mountain hydrology, in particular the storage and transmission of water (Muir et al, 2011). For these reasons, it is important to obtain a better understanding of rockfall-talus process-response systems.…”