Methoden zur Abschätzung der Verschmutzungsempfindlichkeit des Grundwassers

The increasing threat of groundwater contamination by pollutants has led to the development of methods to assess groundwater vulnerability on a regional scale. An assessment of groundwater vulnerability will also be required by the coming EU framework directive on water. The concept of groundwater vulnerability is discussed and available methods are presented. These include hydrogeological complex and setting methods, analogue relations and index methods, point rating and matrix systems, mathematical models and statistical approaches. The methods and their principal characteristics are explained and summarised with emphasis on their regional usability.     

Missstände bei der Vollziehung des Baurechts. Aktuelle Fälle aus der Volksanwaltschaft 2007

Aufgabe der Volksanwaltschaft ist es, auf Grund von Beschwerden oder von Amts wegen Missst?nde in der Verwaltung des Bundes und – auf der Grundlage landesverfassungsrechtlicher Erm?chtigungen (Bgld, Krnt, N?, O?, Sbg, Stmk, Wien) – der L?nder einschlie?lich des eigenen Wirkungsbereichs der Gemeinden zu prüfen. In diesem Zusammenhang hat die Volksanwaltschaft auch wichtige, praxisrelevante Rechtsfragen des Baurechts zu kl?ren. Die Ergebnisse sollen ein- bis zweimal pro Jahr bundesl?nderweise und in Leitsatzform dokumentiert werden.     

Anwendung des Neutralisationspotenzials bei der Bilanzierung von Säure-Base-Reaktionen im Umfeld des Braunkohlebergbaues

Acidic conditions of seepage and groundwater originating from open pit minings in Lusatia are described using the neutralization potential, which is based on the concept of acidity. Acid formation and buffer reactions can be reduced to three elemental reactions: oxidation of pyrit/reduction of sulfate, dissolution of carbonate and gypsum equilibrium. These reactions are combined in a genetic model in order to interpret the origin of mineral and acid contents of different groundwaters influenced by lignite mining. The statistical results of these calculations are summarised in order to calibrate parameters of a prognostic model. The method described here is used to prepare restoration measures.     

Missstände bei der Vollziehung des Baurechts. Aktuelle Fälle aus der Volksanwaltschaft 2008/1

Aufgabe der Volksanwaltschaft ist es, auf Grund von Beschwerden oder von Amts wegen Missst?nde in der Verwaltung des Bundes und – auf der Grundlage landesverfassungsrechtlicher Erm?chtigungen (Bgld, Krnt, N?, O?, Sbg, Stmk, Wien) – der L?nder einschlie?lich des eigenen Wirkungsbereichs der Gemeinden zu prüfen. In diesem Zusammenhang hat die Volksanwaltschaft auch wichtige, praxisrelevante Rechtsfragen des Baurechts zu kl?ren. Die Ergebnisse sollen ein- bis zweimal pro Jahr bundesl?nderweise und in Leitsatzform dokumentiert werden.     

Charakterisierung von Karstgrundwasserleitern durch Simulation der Aquifergenese und des Wärmetransports

This paper is intended to provide an overview of an integrated modelling approach which allows for long-term simulations of aquifer genesis and for short-term simulations of heat transfer in karst aquifers as well. This approach is based upon a conceptual model of karst systems incorporating their dualistic flow pattern, calcite dissolutions kinetics and heat transport processes. The modelling tool which has been developed proves to be a useful device for testing hypotheses on the structure of karst aquifers and for investigating typical scenarios of the development of carbonate aquifers. For this purpose, two examples referring to a dendritical conduit network which is coupled to a fissured system are discussed.     

Pumpspeicherbecken im Karstgrundwasserleiter des Weißen Jura der Schwäbischen Alb

Extensive geological and hydrogeological investigations have been undertaken for the planned pumped-storage hydroelectric power plant in “Blautal” (Swabian Alb, Germany) in order to characterise the Jurassic karst aquifer in which the lower reservoir will be constructed. The preferred option for the plant setup is to integrate the lower reservoir into the groundwater without sealing. Therefore, in order to reliably predict the impact of the pumped storage plant operations on the surrounding drinking water wells and groundwater dependent ecosystems, a comprehensive database has been developed to assess the hydraulic conditions of the karst aquifer. A large scale geological site investigation was carried out to characterise the rock mass and extensive hydraulic tests were performed in many boreholes. The results of the hydraulic characterisation were then implemented in a three dimensional flow model. In this paper, the first results of the geological and hydrogeological investigations are presented and discussed.     

Gefährdung des Grundwassers durch Freisetzung organischer Schadstoffe: Methoden zur Berechnung der in-situ-Schadstoffkonzentrationen

The release of pollutants from contamined soils can be due to desorption and dissolution from residual phase blobs or pools. Volatile compounds can diffuse from contaminated soil air into the groundwater. This paper discusses the basic release processes and presents methods for the calculation of the rates of desorption, dissolution and diffusion. These rates are a prerequisite for the determination of the in-situ contaminant concentration in groundwater. The necessary parameters can be estimated from empirical correlations or may be measured directly in laboratory experiments. Column experiments, e. g., yield maximum release rates in the case of slow diffusion limited desorption whereas dissolution of contaminants from blobs of residual phase results in maximum concentration (solubility) in the column effluent.     

Messung der Infiltrationsgeschwindigkeit von Oberflächenwasser mit Hilfe des natürlichen Isotops Radon-222

Owing to its different concentrations in groundwater and river water, the naturally occuring isotope radon-222 can be used as a natural tacer to determine the residence time of freshly infiltrated water and the infiltration velocity. In the study area, predominant correlation was found between the radon activity concentration of groundwater and the lithologic structure of the aquifer. Misinterpretation of low radon activity concentration measured near surface waters due to geological inhomogeneities can result in false assumptions about groundwater flow paths. The infiltration of river water into the adjacent aquifer during a flood wave was also ascertained by measuring radon activity concentration. Further the residence time of infiltrated water was determined at a sampling point installed beneath the river Elbe and infiltration velocity was calculated.     

Isotopenverhältnisse der Schwefel- und Kohlenstoffspezies aus Sedimenten und tiefen Grundwässern der Niederrheinischen Bucht

Combined hydrochemical, geochemical and isotopic investigations of solid and dissolved sulphur- and carbon-species from different aquifer levels allow to distinguish two geochemical cycles: The first one is represented by the sedimentary pyrites which have been formed during the Tertiary by bacterial sulplate reduction. These pyrites are characterized by strongly depleted δ ¹⁴ S-signatures. In accordance with a recent origin, the groundwater composition reflects the current sulphur- and carbon-cycling representing the second one. The activity of sulphate reducing bacterian can be deduced from a decrease of the sulphate concentration with depth and a simultaneous increase in δ ¹⁴ S- and δ ¹⁸ O-values as well as increasing hydrogen sulphide concentrations. Dissolved organic carbon, the substrate and electron-donor for the bacterial sulphate reduction, appears to be the limiting factor as its average concentration reaches only 1.6 mg/l. The concentration of dissolved inorganic carbon is slightly higher in the deeper groundwater levels. Due to its clearly negative carbon-isotope signature it can be identified as a product of biogenic oxidation of organic material.     

Bauplatz; rechtlich gesicherte Verbindung mit einer öffentlichen Verkehrsfläche; Erfordernis der Zustimmung des Landes

Eine Zustimmung des Landes zur Zu- und Abfahrt von einer Landesstra?e zum Baugrundstück ist nur für Bereiche "au?erhalb des Baulandes" erforderlich. Der Begriff "Bauland" ist ein raumordnungsrechtlicher Begriff, der im tir StG mangels erkennbarer anderer Anordnung oder klarer Intention des Landesgesetzgebers ebenfalls im raumordnungsrechtlichen Sinn zu verstehen ist.     

Heterogenität der Bodeneigenschaften und der Schadstoffbelastung eines ehemaligen Gaswerkstandortes

Risk assessment studies for PAH-mobility at contaminated sites need to take into account the spatial variability of PAH sources and siks as they control the release and redistribution of PAH. This study focuses on the delineation of characteristic soil profiles and their expanse at a former manufactured gas production site (Testfeld Süd) based on a screening of solid phase PAH-concentrations and soil physical and chemical properties. The contamination of the unsaturated zone is governed by medium molecular weight PAH. This strongly contrasts the findings for the aquifer and soils under sealed surfaces. For the unsaturated zone, PAH-patterns are constant, regardless of vertical position or solid phase concentration. However, total PAH-concentrations and soil properties vary over a wide range. This was successfully modelled by stochastic simulations on the basis of Markov Chain theory. For each individual soil profile the corresponding probabilities are given. Thereby, the contribution of PAH released from individual soil profiles to the overall output may be estimated by the use of one-dimensional physically-based transport models.     

Einflüsse des geochemischen Milieus und der Eintragsform auf die Verteilung der anorganischen Redoxspezies des Arsens im Grundwasser

This study was initiated in order to investigate relationships between the arsenic species distribution, the geochemical conditions and the input source of As in groundwater. Water samples characterized in the study originated from four locations representing five different input sources. The redox conditions varied vrom oxid to sulfidic. Measurements indicate – as expected – that the As(III)/As(V)-species distribution is closely related to the redox environment. Nevertheless it cannot be predicted using the redox potenzial and the Nernst equation. Results clearly reveal a dependence of the species distribution on the As input species. Related to the redox conditions, an oxidation path of As(III) can be distinguished from a reductuion path of As(V). The kinetics of the redox reactions depend on the availability of reaction partners.     

Kfz-Pflichtstellplätze außerhalb des Bauplatzes

Kfz-Stellpl?tze in einer Entfernung von 940 m liegen nicht mehr im "Umkreis von zirka 500 m". Auf Besonderheiten eines Bezirkes oder Bezirksteiles (hier: der Wiener Innenstadt) kann in diesem Zusammenhang nicht Bedacht genommen werden.     

Zum Begriff des "oberirdischen Baukörpers" bei der Berechnung der überbauten Grundfläche gem § 32 Abs 2 sbg ROG 1998

Im Anwendungsbereich des sbg ROG 1998 muss die für die Berechnung der Grundfl?chenzahl (§ 32 Abs 2 sbg ROG) ma?gebliche "überbaute Grundfl?che" durch lotrechte Projektion des "oberirdischen Bauk?rpers" auf die Waagrechte ermittelt werden. In der Vollziehungspraxis bestehen – insbesondere im Zusammenhang mit Bauführungen in Hanglagen – verschiedene Rechtsauffassungen darüber, ob ein nicht mehr als 1 m über das angrenzende natürliche Gel?nde hinausragendes Gescho? (iSd § 32 Abs 5 sbg ROG 1998) einen berechnungsrelevanten Teil des oberirdischen Bauk?rpers bildet oder nicht.     

Neue Messe Mailand – Verglasung der Freiformfläche

The New Fair of Milan – glass on free-form surfaces. The glazing of free-form surfaces often has to fulfil many expectations – highly stressed, light-weight and economic. The construction must ensure post-breakage safety but still appear filigran and transparent. The glazing of the free-form surfaces of Milan's New Fair is described with special attention to structural analysis, details and typical problems resulting from the free-form geometry.     

Abschätzung der Subsidenz im Einflussbereich Geothermischer Anlagen

The estimate of possibly occurring subsidence within the vicinity of geothermal heating plants is indispensable for the judgement of their operational safety and environmental impact. In this study exploitation of a sandstone aquifer using a production and re-injection well was examined with the groundwater simulation program MODFLOW ( Harbaugh &; McDonald 1996) and the accompanying Interbed-Storage-Package ( Leake &; Prudic 1991). Parameter studies of a typical northern German geothermal aquifer showed that the hydraulic characteristics of the clay stone layer, which is sensitive to subsidence, have little influence on the absolute values of the subsidence. In contrast thereto, the hydraulic characteristics of the geothermally used sandstone layer have great impact on the subsidence. Subsidence will be on no account within the magnitude of meters, but most likely in the range of centimeters (2–3 cm), for both the production and the re-injection well. The results are in agreement with field observations.     

In-situ-Ermittlung der Tragfähigkeit von Brücken

Determination of the carrying-capacity of bridges “in situ”. At the University of the German Armed Forces Munich a project is currently under development, which deals with the quick estimation of the load-bearing capacity of bridges. For the reconnaissance and classification of a bridge, a maximum time of up to three days is allowed. It has to be considered, that no building documents of the bridge to classify are available. Therefore, the concept of the system bases on three columns: bridge reconnaissance, calculation of the carrying capacity and measurement of the bridge behaviour. During the phase of reconnaissance all relevant information about the bridge has to be gathered, especially geometrical and material parameters. An expert system is helping the team. The determination of the load-bearing capacity is also performed with the help of a software program. The correctness of the input data and the calculation model can be validated with the help of measuring and comparing the bridge behaviour. The system presented in this paper is open for any extensions. Classifying damaged bridges is subject of current develop-ment.