TIWAG Tiroler Wasserkraft AG

Innsbruck, Austria

TIWAG Tiroler Wasserkraft AG

Innsbruck, Austria
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Eberhardt E.,University of British Columbia | Perzlmaier S.,TIWAG Tiroler Wasserkraft AG
Engineering Geology | Year: 2010

This paper presents the geometry, kinematics and temporal deformation characteristics of a deep-seated rockslide system, the "Hochmais-Atemkopf", situated above the Gepatsch dam reservoir in Northern Tyrol, Austria. Results from surface and subsurface geological investigations and deformation monitoring indicate that the Hochmais-Atemkopf rockslide system involves several sliding masses, one on top of the other, characterized by different velocity characteristics with displacements being greater for the shallower slide bodies. During the initial impounding phases of the Gepatsch reservoir, uplift forces beneath the foot of the slope led to the activation of one of these shallower slide bodies, moving it more than 10 m downslope in 2 years. After continuous deceleration of the sliding mass, the deformation rates reduced to about 2 to 4 cm per year. These were found to show seasonal fluctuations that correlated with reservoir levels and drawdown conditions, with induced slope accelerations peaking when reservoir levels were at their lowest. This suggests, in part, a controlling mechanism based on seepage forces where reservoir drawdown drives the episodic rockslide deformation behaviour. Together, the data and analyses presented demonstrate the importance of integrating detailed geology and monitoring data to derive a basic understanding of the kinematics and controlling mechanisms of a deep-seated rockslide system in advance of undertaking comprehensive numerical modelling. © 2010 Elsevier B.V. All rights reserved.

Helfricht K.,Alpnter for Climate Change Adaptation | Helfricht K.,University of Innsbruck | Schober J.,TIWAG Tiroler Wasserkraft AG | Schneider K.,Alpnter for Climate Change Adaptation | And 3 more authors.
Journal of Glaciology | Year: 2014

Knowledge of the spatial snow distribution and its interannual persistence is of interest for a broad spectrum of issues in cryospheric sciences. In this study, snow depths derived from airborne laser scanning are analyzed for interannual persistence of the seasonal snow cover in a partly glacierized mountain area (∼36 km2). At the end of five accumulation periods, the snow-covered area varied by 16% of its temporal mean. Mean snow depth of the total area ranged by a factor of two (1.31-2.58 m), with a standard deviation of 0.42 m. Interannual correlation coefficients of snow depth distribution were in the range 0.68-0.84. Of the investigated area, 75% was found to be interannually persistent. The remaining area showed variable snow cover from year to year, caused by occasional avalanches and changes in surface topography as a result of glacier retreat. Snow cover underwent a change from a homogeneous distribution on the former glacier surface to a more heterogeneous snow cover in the recently deglaciated terrain. A geostatistical analysis shows interannual persistence in scaling behavior of snow depth in ice-free terrain with scale break distances at 20 m. Scale-invariant behavior of snow depth is indicated over > 100 m on smooth glacier surfaces.

Cammerer H.,University of Innsbruck | Thieken A.H.,University of Potsdam | Lammel J.,AlpS GmbH | Lammel J.,TIWAG Tiroler Wasserkraft AG
Natural Hazards and Earth System Sciences | Year: 2013

Flood loss modeling is an important component within flood risk assessments. Traditionally, stage-damage functions are used for the estimation of direct monetary damage to buildings. Although it is known that such functions are governed by large uncertainties, they are commonly applied - even in different geographical regions - without further validation, mainly due to the lack of real damage data. Until now, little research has been done to investigate the applicability and transferability of such damage models to other regions. In this study, the last severe flood event in the Austrian Lech Valley in 2005 was simulated to test the performance of various damage functions from different geographical regions in Central Europe for the residential sector. In addition to common stage-damage curves, new functions were derived from empirical flood loss data collected in the aftermath of recent flood events in neighboring Germany. Furthermore, a multi-parameter flood loss model for the residential sector was adapted to the study area and also evaluated with official damage data. The analysis reveals that flood loss functions derived from related and more similar regions perform considerably better than those from more heterogeneous data sets of different regions and flood events. While former loss functions estimate the observed damage well, the latter overestimate the reported loss clearly. To illustrate the effect of model choice on the resulting uncertainty of damage estimates, the current flood risk for residential areas was calculated. In the case of extreme events like the 300 yr flood, for example, the range of losses to residential buildings between the highest and the lowest estimates amounts to a factor of 18, in contrast to properly validated models with a factor of 2.3. Even if the risk analysis is only performed for residential areas, our results reveal evidently that a carefree model transfer in other geographical regions might be critical. Therefore, we conclude that loss models should at least be selected or derived from related regions with similar flood and building characteristics, as far as no model validation is possible. To further increase the general reliability of flood loss assessment in the future, more loss data and more comprehensive loss data for model development and validation are needed. © 2013 Author(s).

Achleitner S.,University of Innsbruck | Schober J.,Alpnter for Climate Change Adaptation Technologies | Schober J.,University of Innsbruck | Rinderer M.,University of Zürich | And 4 more authors.
Journal of Hydrology | Year: 2012

During recent years a hybrid model has been set up for the operational forecasting of flood discharges in the 6750km 2 Tyrolean part of the River Inn catchment in Austria. The catchment can be characterized as a typical alpine area with large variations in altitude. The paper is focused on the error analysis of discharge forecasts of four main tributary catchments simulated with hydrological water balance models. The selected catchments cover an area of 2230km 2, where the non-glaciated and glaciated parts are modeled using the semi-distributed HQsim and the distributed model SES, respectively.The forecast errors are evaluated as a function of forecast lead time and forecasted discharge magnitude using 14 events from 2007 to 2010. The observed and forecasted precipitation inputs were obtained under operational conditions. The mean relative bias of the forecasted discharges revealed to be constant with regard to the forecast lead time, varying between 0.2 and 0.25 for the different catchments. The errors as a function of the forecasted discharge magnitude showed large errors at lower values of the forecast hydrographs, where errors decreased significantly at larger discharges being relevant in flood forecasting. © 2011 Elsevier B.V.

Among other major projects for the use of domestic hydropower, Tiwag (Tiroler Wasserkraft AG/Tyrol Water Power plc) is planning the expansion of the Kaunertal power station. Important components of the project are a new lower stage power station (Prutz 2), a new diversion tunnel to the Gepatsch reservoir with water catchments in the upper Ötztal valley and a new upper stage with a new reservoir at Platzertal. The choice of a location for the new reservoir was preceded by intensive scrutiny and evaluation of several alternatives. As well as non-technical aspects, this involved above all the consideration of aspects relating to hydraulic engineering, dam construction and engineering geology, with some of these areas being subjected to intensive investigations. Such aspects included the topographic suitability of the sites with reference to the size of the direct reservoir catchment area and the dam and reservoir cubage, ease of infrastructure development in the construction phase and ease of access in the operating phase, the altitude and length of the diversion tunnel for the collection works and the headrace tunnel, the impermeability of the reservoir basin, aspects relating to the foundations of the dam, the possibility of obtaining fill material for the dam, considerations relating to the sealing element and zoning of the dam, the vulnerability of the reservoir to gravitational processes and last but not least, the stability of the reservoir slopes taking into account the future effects of the retained water. As part of the development of the project, the aspects referred to above were investigated and explored for several reservoir site options. It can be demonstrated that the Platzertal upper stage solution represents the best choice, viewed both from the technical angle and in other respects. © 2012 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

The Kaunertal power station has been in operation since 1965. During one of the regular inspections of the facility, it was noticed that the entire pressure shaft and surge tank must be completely renewed due to the long years of wear and tear. The renewal is necessary as a result of the heavy hydraulic loading from power station peak operation and due to the fact that parts of the pressure shaft were constructed in a then unknown landslip and have since been subjected to additional loading from creep movement of the rock mass. The route of the new pressure shaft will run below the identified landslip with a sufficient safety factor, further south than the existing pressure shaft. The implementation of the project with its heart, the steel lined pressure shaft approx. 1,430 m long with a diameter of 4.3 m, to be constructed inside a PC segmental lining installed with the progress of the doubleshield TBM, will take place in 2012 to 2015. © 2012 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Bonapace P.,Tiwag Tiroler Wasserkraft AG | Hofer B.,Tiwag Tiroler Wasserkraft AG
Geomechanik und Tunnelbau | Year: 2015

The Tiroler Wasserkraft AG (Tiwag) currently operates eleven large hydropower stations (> 8 MW) and more than 30 smaller plants (< 5 MW) generating electricity for commercial consumption. Most of the larger stations are storage schemes in the high mountains, intended to be able to balance the opposing seasonal supply and demand situation in the Alps and current fluctuations in the network. The headrace tunnels and penstocks of the high-pressure power stations of Tiwag are some of the most highly loaded of their type in the world. Great emphasis is placed on sustainable use and low maintenance costs, starting with the construction. Some stations have already been in operation for more than 60 years. This article describes the experience with the headrace tunnels of some of the larger hydropower stations. © 2015 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

Egger A.,TIWAG Tiroler Wasserkraft AG
WasserWirtschaft | Year: 2011

The power plant Bruckhäusl replaces the approx. 100 year-old power stations Einöden and Söll/Leukental at the entrance to the Brixental in Tyrol. The design flow was raised to 12 from 5 m 3/s. Through the 2.2 km long penstock the water reaches to the Kaplan-S-turbine and is returned via a generously dimensioned underwater reservoir to the river. The residual water is delivered by a speed-regulated turbine at the weir.

Leblhuber P.,Tiwag Tiroler Wasserkraft AG | Bonapace P.,Tiwag Tiroler Wasserkraft AG
Geomechanik und Tunnelbau | Year: 2013

The penstock and the surge tank are being renewed at the two existing hydropower stations of Tiwag (Tiroler Wasserkraft AG) in the Kaunertal valley. The core of the works is the bored pressure shaft about 1,430 m long with an excavation diameter of 5.54 m and armourings of 4.3 m diameter, which is being installed inside a segment lining. When a tunnel is continuously bored by a shield TBM, the system restricts the scope for reaction to changes in rock mass behaviour. Special measures outside normal operation are expensive and time-consuming. In geomechanically difficult sections of the tunnel, the situation has to be assessed continuously to establish whether the expected ground conditions could significantly disrupt the tunnelling system. For this purpose, hammer drilling was undertaken systematically during the advance and seismic investigations were carried out, as well as core drilling. In order to achieve a secure mechanical connection between the steel lining or the concrete lining and the surrounding rock mass and activate the load-bearing capacity of the rock mass, grouting of the rock mass as well as contact and gap grouting are performed for the steel-lined sections and the concrete-lined surge tank riser shaft. The grouting of the rock mass immediately after the completion of the shaft drive is carried out according to the GIN method with a defined hole pattern and based on extensive tests. The results are systematically evaluated by the start of the contact and gap grouting after the installation of the steel lining. © 2013 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin.

In the Lower Inn Valley of the Tyrol, Autria, the existing railway line has been upgraded. In the course of these works a two-track tunnel with an excavated diameter of 13.03 m was built in the track section H3-4 Münster/Wiesing. The tunnel was excavated with a slurry TBM. Demanding geotechnical conditions on this difficult contract necessitated changes to the overall concept. After tendering and the award of contract, the client and the contractor started the construction phase with different expectations. We report on the strongly differing experiences of the parties during the construction of the works. At the end, we draw conclusions for both parties from the experience gained during the successful completion of the project. Im Tiroler Unterinntal wurde im Zuge des Ausbaus der bestehenden Bahntrasse im Streckenabschnitt H3-4 Münster/Wiesing ein zweigleisiger Tunnel mit einem Ausbruchsdurchmesser von 13,03 m ausgeführt. Zum Einsatz kam hierbei eine Schildmaschine mit flüssigkeitsgestützter Ortsbrust. Die besonderen Anforderungen im geotechnisch anspruchsvollen Baulos haben bereits in der Phase der Projektierung eine Reihe von Anpassungen des Gesamtkonzepts erforderlich gemacht. Nach Ausschreibung und Vergabe sind Auftraggeber (AG) und Auftragnehmer (AN) mit bestimmten tlw. nicht deckungsgleichen Erwartungshaltungen in die Bauausführung gestartet. Über dies und die tlw. davon stark abweichenden Erfahrungen, die während der Ausführung gemacht wurden, wird berichtet. Zudem werden die für beide Vertragspartner wesentlichen Schlussfolgerungen aus dem technisch und vertraglich erfolgreich abgewickelten Bauvorhaben zusammengefasst. © 2016 Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG, Berlin

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