Vergleichende Temperaturfahnenprognose anhand zweier industriell genutzter Grundwasserwärmepumpen: FEFLOW vs. ÖWAV-Modell

Um die Bewilligungsfähigkeit von Grundwasserwärmepumpen (GWP) zu beurteilen, müssen Prognosen über die resultierenden Temperaturfahnen erstellt werden. In Österreich wird ein analytisches Modell (Regelblatt 207-2 des ÖWAV) zur Berechnung von Temperaturfahnen kleiner GWP (< 10 l s1) herangezogen. Für das ÖWAV-Modell erfolgte bisher keine systematische Überprüfung der Prognosen. Diese Studie beschreibt die Anwendungen eines analytischen (ÖWAV) und eines numerischen (FEFLOW) Prognosemodells auf zwei industrielle Kühlanlagen, die ergiebige Porengrundwasserleiter erschließen. Der Vergleich der beiden Modelle zeigt, dass eine detaillierte Kenntnis der Eingangsparameter, wie der Grundwasser-Isohypsenplan, die Entnahme- und Rückgabetemperaturen und die Konsensmenge, maßgebend für eine realitätsnahe Auswirkungsprognose ist. Bei einer guten Datengrundlage und einfachen hydrogeologischen Verhältnissen werden mit beiden Modellen gute Ergebnisse erzielt, die Abweichung zum tatsächlichen Wert liegt bei < 1 K. Erweisen sich die hydrogeologischen Umstände komplexer, kann das ÖWAV-Modell mit einer durchschnittlichen Differenz von rund 1,3 K zur tatsächlichen Grundwassertemperatur nicht mehr empfohlen werden.The geometry of heat-plumes created by groundwater heat-pumps (GHPs) must be determined in advance to confirm if they are acceptable according to local guidelines. In Austria, an analytical model (ÖWAV Regulation 207-2) is widely-used for determining plume geometries of small GHP installations (< 10 l s1), however a systematic evaluation of the ÖWAV Model has been lacking. This study applies an analytical model (ÖWAV) and a numerical model (FEFLOW) to two large-scale industrial cooling-plants in Austria that exploit productive porous aquifers. The model comparison reveals that detailed knowledge of the input parameters, such as groundwater levels, as well as extraction and injection temperatures, is crucial for realistic heat-plume predictions. Both models provide good results for sufficiently complete data sets and simple hydrogeological settings, since the deviation of < 1 K is within acceptable limits. The ÖWAV model is not recommended for complex hydrogeological settings, due to an average deviation of 1.3 K from the measured groundwater temperature in this case

Hydrogeology Journal / 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

Extensive in-depth research is required for the implementation of natural tracer approaches to hydrogeological investigation to be feasible in mountainous regions. This review considers the application of hydrochemical and biotic parameters in mountain regions over the past few decades with particular reference to the Austrian Alps, as an example for alpine-type mountain belts. A brief introduction to Austrias hydrogeological arrangement is given to show the significance of fractured hard-rock aquifers for hydrogeological science as well as for water supply purposes. A literature search showed that research concerning fractured hard-rock aquifers in Austria is clearly underrepresented to date, especially when taking the abundance of this aquifer type and the significance of this topic into consideration. The application of abiotic natural tracers (hydrochemical and isotope parameters) is discussed generally and by means of examples from the Austrian Alps. The potential of biotic tracers (microbiota and meiofauna) is elucidated. It is shown that the meiofauna approach to investigating fractured aquifers has not yet been applied in the reviewed region, nor worldwide. Two examples of new approaches in mountainous fractured aquifers are introduced: (1) use of CO2 partial pressure and calcite saturation of spring water to reconstruct catchments and flow dynamics (abiotic approach), and, (2) consideration of hard-rock aquifers as habitats to reconstruct aquifer conditions (biotic approach)

Hydrogeologie im Tauernfenster Fallbeispiel Rauristal, Salzburg

Die Fallstudie in einem kleinräumigen Einzugsgebiet im Salzburger Rauristal diente dazu, die Hydrogeologie einiger für das Tauernfenster typischer Lithologien und Strukturen beispielhaft zu beleuchten. Das Untersuchungsgebiet ist geprägt von metamorphen geklüfteten Gesteinen des Penninikums und Subpenninikums (Schiefer und Gneise) und quartären Ablagerungen, wobei hier vor allem ein großer Bergsturz als prägendes Element zu nennen ist. Es wurde eine geologisch-hydrogeologische Kartierung des knapp 10km2 großen Gebietes auf Seehöhen zwischen 1500 und 2500m durchgeführt. Im Fokus der Geländearbeiten standen dabei hydrogeologische Aspekte wie Quellen, Vernässungen, Versickerungen oder Oberflächengewässer. Ergänzend wurden an drei Terminen Abflussmessungen am Hauptgerinne und drei seichte Bohrungen in einer Bergsturzmasse durchgeführt, um deren hydraulische Eigenschaften zu erkunden. Es wurden fünf Fließsysteme identifiziert: (1) Schichtquellen sind an den Übergang zwischen Zentralgneis und Schieferhülle gebunden. (2) Stauquellen treten in Verbindung mit Grundmoränen auf. (3) Quellhorizonte innerhalb der Schiefer und Gneise verlaufen entlang regionaler Kluftrichtungen. (4) Diffuse Quellaustritte sind auf oberflächennahe Zirkulationssysteme zurückzuführen. (5) Der Bergsturzkörper stellt einen sehr gut durchlässigen Aquifer dar. Eine Verwitterungsschwarte bildet eine oberflächliche Abdichtung, verbunden mit der Ausbildung zahlreicher kleiner stehender Gewässer.The aim of this case study in a small-scale catchment at altitudes between 1500 and 2500m asl in the Rauristal region in Salzburg was to investigate the hydrogeological character of some typical lithologies and structures along the northern margin of the Tauern Window. The study area is composed of metamorphic schist and gneiss of Penninic and Subpenninic nappes and various Quaternary deposits. Approximately 10km2 were mapped with regard to geology and hydrogeological aspects such as springs, surface runoff, and sinkholes. Discharge measurements were taken at three dates and three boreholes were drilled to investigate the hydrogeological context of a large landslide deposit. Five different flow systems were identified: (1) Layer-based springs at the boundary between gneiss and schist result from different hydraulic conductivities. While gneiss is a comparably highly permeable fractured aquifer, schists act as aquitards in this setting. (2) Barrier springs are related to moraine deposits. (3) Spring lines within schists follow the main regional fracture direction. (4) Numerous small springs are linked to near surface flow systems within debris layers. (5) The large landslide deposit represents an aquifer with good hydraulic conductivity. Due to weathering layers, this unit is locally impermeable for infiltration which leads to numerous small ponds in the upper part of the landslide deposit.(VLID)471852

Sand und Wasser: Analogieexperimente zur Geologie im Schulunterricht. GW-Unterricht|GW-Unterricht 142/143|

Die Vermittlung von Geologie ist eine große Herausforderung weil geologische Prozesse oft tief in der Erde oder nur sehr langsam ablaufen. Geologie ist zwar von großer gesellschaftlicher Bedeutung, spielt aber im Schulunterricht kaum eine Rolle. Modelle können Lernenden helfen, durch die direkte Beobachtung einige grundlegende geologische Prozesse zu erfassen. Grundwasser wird durch Modelle für die hydraulische Durchlässigkeit in porösen Medien thematisiert. Der Beitrag gibt eine detaillierte Beschreibung der Experimente und Lernziele

Hydrogeology Journal / Interaction of various flow systems in small alpine catchments : conceptual model of the upper Gurk Valley aquifer, Carinthia, Austria

Small alpine valleys usually show a heterogeneous hydraulic situation. Recurring landslides create temporal barriers for the surface runoff. As a result of these postglacial processes, temporal lakes form, and thus lacustrine fine-grained sedimentation intercalates with alluvial coarse-grained layers. A sequence of alluvial sediments (confined and thus well protected aquifers) and lacustrine sediments (aquitards) is characteristic for such an environment. The hydrogeological situation of fractured hard-rock aquifers in the framing mountain ranges is characterized by superficially high hydraulic conductivities as the result of tectonic processes, deglaciation and postglacial weathering. Fracture permeability and high hydraulic gradients in small-scaled alpine catchments result in the interaction of various flow systems in various kinds of aquifers. Spatial restrictions and conflicts between the current land use and the requirements of drinking-water protection represent a special challenge for water resource management in usually densely populated small alpine valleys. The presented case study describes hydrogeological investigations within the small alpine valley of the upper Gurktal (Upper Carinthia, Austria) and the adjacent Höllenberg Massif (1,772 m above sea level). Hydrogeological mapping, drilling, and hydrochemical and stable isotope analyses of springs and groundwater were conducted to identify a sustainable drinking-water supply for approximately 1,500 inhabitants. The results contribute to a conceptual hydrogeological model with three interacting flow systems. The local and the intermediate flow systems are assigned to the catchment of the Höllenberg Massif, whereas the regional flow system refers to the bordering Gurktal Alps to the north and provides an appropriate drinking water reservoir

Hydrology and Earth System Sciences / Understanding groundwater : students' pre-conceptions and conceptual change by means of a theory-guided multimedia learning program

Education on the subject of groundwater is crucial for sustainability. Nevertheless, international studies with students across different age groups have shown that the basic hydrogeological concept of groundwater defined as water within porous and permeable rocks is not an established everyday notion. Drawing from international research, a multimedia learning program Zwischen Regenwolke und Wasserhahn (between the rain cloud and the tap) was developed, which incorporates specific insights from the fields of conceptual change research, multimedia research, and the model of educational reconstruction. The effectiveness of the learning program was ascertained by means of two studies with Austrian seventh grade pupils as well as teacher-training students from the fields of biology and geography in order to ascertain the effectiveness of the learning program. Using a quasi-experimental research design, the participants' conceptions and knowledge of groundwater were determined in a pre- and post-test. The pupils and students greatly benefitted from working through the learning software independently. Their knowledge of groundwater increased significantly compared to the control group and there was a highly significant increase in the number of scientifically correct notions of groundwater. The acceptance of the program was also generally very high. The results indicate that theory-guided multimedia learning programs can play an important role in the transfer of research results to classroom settings, especially in science education.Ulrike Unterbruner, Sylke Hilberg, and Iris Schiff

A Petrographic Investigation of the Carboniferous Sequence from the Ibbenbüren Mine: Tracing the Origin of the Coal Mine Drainage

The mine drainage of the Ibbenbüren anthracite coal mine is characterized by exceptionally high concentrations of dissolved iron and sulfate. The elevated position of the coal field with respect to the surrounding area makes the neighboring sediments an unlikely source of these elements. Accordingly, it has been hypothesized that interaction between infiltrating rainwater and the fractured overburden is a key process governing the mine drainage chemistry. To test this hypothesis, two full-diameter core samples drilled above the discharging adit of the coal mine were investigated. The methodology combined several analytical techniques to identify and characterize traces of water–rock interaction related to both diagenesis and relatively recent weathering processes along open fractures. The coupled appearance of kaolinite-dickite-illite minerals in weathered and unweathered rock sections was clearly connected to the burial history of the Carboniferous sequence. In contrast, the formation of iron (oxide-) hydroxides together with the presence of oxidized pyrite in weathering profiles along both sides of the fractures was positively related to the geochemical footprint of the coal mine drainage. Thus, open fractures, possibly originated from mining activities, may play a significant role in the drainage chemistry, especially considering the rather poor hydraulic conditions of the overburden