The Aquifer Characteristics of the Dolomite Formation a New Approach for Providing Drinking Water in the Northern Calcareous Alps Region in Germany and Austria

Abstract

In the Northern Calcareous Alps karst springs and wells in porous groundwater bodies are the common sources of drinking water. While karst springs deliver water with short residence times and extreme variabilities in discharge, porous groundwater bodies include high risks of pollution according to intensive agricultural and industrial activities in the catchment areas. As alternative in this densly populated region in Germany and Austria the widespread but rarely used dolomitic unit Hauptdolomit (HD) was investigated. The purpose was to find indications to identify springs and wells dominated by an HD-aquifer and to find significant differences in age distribution and flow rates between HD-aquifers and karstified groundwater bodies. The assumption was that springs in HD-aquifers do not deliver very young waters and so show significantly lower vulnerability to pollution and less variability in discharge because HD features the necessary retention capacity and very slow diffuse flow on micro fissure systems and also exhibits larger fractures for water sampling and conduit flow. The main results of the study were: (1) the structural setting on the surface is not significant for the internal hydro-geological properties, (2) the hydrochemical signature gives a good evidence to identify an HD-catchment area, (3) the hydrograph curves show significantly less variability which is the most important advantage over karst springs, (4) mean residence times of 2 years to two decades are conducted by an age distribution which ranges very young as well as more than

Review: Natural tracers in fractured hard-rock aquifers in the Austrian part of the Eastern Alps—previous approaches and future perspectives for hydrogeology in mountain regions

“…Late Permian evaporitic sediments (gypsum, anhydrite, halite), the so-called BHaselgebirge^, form the basis of the NCA nappe complex and are the source of the majority of highly mineralised springs along the northern range of the NCA. The overlying Lower to Middle Triassic units are dominated by dolomitic lithology, the so-called BHauptdolomitf acies, which is predominant along the northernmost part of the NCA and can be characterised as fractured-karstic-porous aquifers (Maloszewski et al 2002;Hilberg and Schneider 2011). Upper Triassic, Jurassic, and Cretaceous sediments are carbonate dominated and provide extensive karst aquifers.…”

“…A general classification based on the cations calcium, magnesium, sodium, and potassium, and the anions bicarbonate, sulfate and chloride, is given by Piper (1944) and Furtak and Langguth (1967). While bicarbonate is the dominant anion species in a carbonatic aquifer, dominance of sulfate or chloride indicates evaporitic influences (gypsum or halite) in the aquifer; particularly in carbonate aquifers such as the NCA in Austria, the Ca-Mg ratio of groundwater indicates calcite (Ca > Mg) or dolomite (Ca ≈ Mg) dominance (Hilberg and Schneider 2011).…”

Seasonal Variability of Discharge from Selected Springs in Central Europe

“…A large typological diversity of springs is reflected in variable types of outflow, even within the same hydrogeological unit. The springs of the Northern Calcareous Alps, supplied from fissured and karstified dolomites, have both outflows of high and stable discharge rates and variable and seasonal springs (Hilberg 2010). Automatization of discharge measurements and increasing their frequency (even on a basis of a few minutes) allows the identification of an increasing number of intermittent springs.…”

Complementary use of dating and hydrochemical tools to assess mixing processes involving centenarian groundwater in a geologically complex alpine karst aquifer

“…show how the features of the geological framework can condition flow dynamics and residence time. There is little evidence of centennial groundwater in this type of system, except for some karst springs in the Austrian Alps that drain deep reservoirs connected to major faults (Han et al, 2007;Hilberg & Schneider, 2011). The fact that the groundwater age in alpine karst can be this old has major implications for hydrogeological management, and regarding its intrinsic vulnerability to pollution.…”