Karst springs, groundwater and surface runoff in the calcareous Alps: assessing quality and reliance of long-term water supply

Abstract The interdisciplinary geohydrological analysis of an area of 220 km 2 in the calcareous Alps of Lower Austria assesses the possibilities for long-term high-quality water supply from an Alpine shallow karst area. Geological and hydrogeological research quantifies dependencies of groundwater distribution and storage on rock types and on the fracturing of host rocks in an area which is typical of large Alpine regions. Estimated water budgets show a complex linkage and significant groundwater exchange between topographical catchment areas. Deep groundwater flow mostly follows tectonic fractures which became increasingly permeable by karstification. Fracture architecture and preferred groundwater pathways are analysed by structural geology techniques which support the delimitation of catchment areas and the linkage of groundwater sheds to infiltration areas. Geochemical, hydrochemical and pedological studies assess the sensitivity of groundwater chemistry to the input of polluted precipitation. Ion exchange during soil-water interaction leads to significant modification of the cation and anion ratios depending on soil type. The chemistry of soils and weathered zones strongly influences groundwater quality. The study shows the strength of interdisciplinary research including hydrogeology, hydrology, structural geology, pedology, geochemistry, soil and water chemistry, which provides integrated information on infiltration, groundwater pathways, quantified flow, groundwater discharge and pollution risks

Identifying the flow systems in a karstic-fissured-porous aquifer, the Schneealpe, Austria, by modelling of environmental 18O and 3H isotopes

The Schneealpe karst massif of Triassic limestones and dolomites with the altitude up to 1800 m a.s.l., situated 100 km SW of Vienna in Kalkalpen, is the main drinking water resource for the city. The catchment area of about 23 km2 is drained by two springs: the Wasseralmquelle (196 l/s) and the Siebenquellen (310 l/s). This karstic aquifer is approximated by two interconnected parallel flow systems of: (a) a fissured-porous aquifer, and (b) karstic channels. The fissured-porous aquifer is of a high storage capacity and contains mobile water in the fissures and stagnant water in the porous matrix. The water enters this system at the surface and flows through it to drainage channels, which are regarded as a separate flow system, finally drained by both springs. The channels are also connected with sinkholes, which introduce additional water directly from the surface. Measurements of 18O and tritium in precipitation and springs were modelled by a combined application of lumped-parameter models. Modelling yielded information on the mean values of the following hydraulic parameters: (1) The volume of water in the whole catchment area is 255×106 m3, of which about 1.8×106 m3 are in channels and 253×106 m3 in the fissured-porous aquifer. (2) The total volumetric flow rate is 506 l/s, of which 77 l/s comprises direct flow from sinkholes to springs and 429 l/s are contributed to fissured-porous aquifer. (3) As the volume of the massif is 16.6×109 m3, the total water saturated porosity (fissures and micropores of the matrix) is 1.5% and the channel porosity is about 0.01%

Isotopic composition of Danube water in the pre-delta section from the years 2009 - 2012

The isotopic composition of river water in the Danube Basin is mainly governed by the isotopic composition of precipitation in the catchment area, evaporation effects play only a minor role. Short-term and long-term isotope signals from precipitation are thus transmitted through the whole catchment. The isotopic composition of Danube water in the Delta region so provides an integrated isotope signal for climatic/hydrological conditions and changes in the whole catchment. The aim of this investigation was to establish a representative isotope monitoring near the Danube Delta. The results showed that the Danube River is regarding isotope content fully mixed at the bifurcation of the Danube Delta arms. Therefore routine sampling at only one location in the pre-delta region should be sufficient to obtain a representative isotope record for the whole Danube Basin. The δ 18 O time series from November 2009 to May 2012 (sampling twice a month) shows seasonal variations in the range of -9.8 ‰ ± 0.7 ‰ with a minimum in spring and a maximum in autumn. The tritium results exhibit the influence of short term contaminations due to human activities. The expected “environmental” tritium content of river water in Central Europe would be about 10 TU. During this investigation 3 H values up to 100 TU were observed in the pre-delta section. This indicates short terms releases of tritium from local sources such as nuclear power plants in the Danube river system

Radiocarbon Dating of delta-18O-delta-D Plots in Late Pleistocene Ice-Wedges of the Duvanny Yar (Lower Kolyma River, Northern Yakutia)

From the 17th International Radiocarbon Conference held in Jerusalem, Israel, June 18-23, 2000.The Duvanny Yar cross-section located in the Lower Kolyma River valley of Northern Yakutia (69 degrees N, 158 degrees E, height above the Kolyma River level 55 m), has been studied and dated in detail by radiocarbon. The sequence mainly consists of sandy loam sediments with large syngenetic ice wedges. Their width at the top is 1-3.5 m. Allochthonous organic material occurs in high content, concentrating as 0.5-0.7 m lenses. Shrub fragments, twigs, and mammoth bones are accumulated in peaty layers. Through interpolation based on a series of 14C dates, dating of the host sediments provides an approximate age for the ice wedges. The 14C dates of various types of organic material are sometimes very close, but not all in agreement. Therefore, the dates do not accurately show the age of the delta-18O and delta-D plots. A new approach is developed to a 14C dating strategy of syncryogenic sediments with high admixture of allochthonous organic material. The main purpose of this study is to consider detection of inversions or disturbances in the syngenetic permafrost sediment at the Duvanny Yar cross-section by 14C date series. Direct accelerator mass spectrometry (AMS) dating of the ice confirmed the relatively young age of ice wedges.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Temporal and spatial distribution of isotopes in river water in Central Europe: 50 years experience with the Austrian network of isotopes in rivers

<p>The Austrian network of isotopes in rivers comprises about 15 sampling locations and has been operated since 1976. The Danube isotope time series goes back to 1963. The isotopic composition of river water in Central Europe is mainly governed by the isotopic composition of precipitation in the catchment area; evaporation effects play only a minor role. Short-term and long-term isotope signals in precipitation are thus transmitted through the whole catchment. The influence of climatic changes has become observable in the long-term stable isotope time series of precipitation and surface waters. Environmental ³H values were around 8 TU in 2015, short-term ³H pulses up to about 80 TU in the rivers Danube and March were a consequence of releases from nuclear power plants. The complete isotope data series of this network will be included in the Global Network of Isotopes in Rivers database of the International Atomic Energy Agency (IAEA) in 2017. This article comprises a review of 50 years isotope monitoring on rivers and is also intended to provide base information on the (isotope-)hydrological conditions in Central Europe specifically for the end-users of these data, e.g. for modelling hydrological processes. Furthermore, this paper includes the 2006–2015 supplement adding to the Danube isotope set published earlier.</p

Isotope studies in large river basins: a new global research focus

Rivers are an important linkage in the global hydrological cycle, returning about 35%of continental precipitation to the oceans. Rivers are also the most important source of water for human use. Much of the world's population lives along large rivers, relying on them for trade, transportation, industry, agriculture, and domestic water supplies. The resulting pressure has led to the extreme regulation of some river systems, and often a degradation of water quantity and quality For sustainable management of water supply agriculture, flood-drought cycles, and ecosystem and human health, there is a basic need for improving the scientific understanding of water cycling processes in river basins, and the ability to detect and predict impacts of climate change and water resources development