Infrastructure adaption (Task 2.2)

The expected glacier retreat in the coming decades due to atmospheric warming will offer new perspectives for the construction of reservoirs and hydropower plants in the periglacial environment. However, the immediate proximity to the glacial environment will pose challenges in terms of construction, operation and maintenance, especially regarding future sediment input. This research project will focus on the reconstruction of past sediment yield and prediction future sediment yield and the propagation of these sediments in the reservoir.

Operating high-head hydroelectric power plants under alpine conditions may expose facility components to hydro abrasion due to mineral suspended sediments in the works water. Particularly, turbines can be affected by wear, leading to a considerable efficiency decline affiliated to power and financial losses. The project’s objective is to develop an enhanced guideline for the design of desanding facilities to improve the settling efficiency, putting an emphasis on the effects of various geometrical parameters as well as different headwork arrangements.

Large concrete Dams have to be monitored continuously, since the hazard that the failure of the structure would cause is large. Firstly, established procedures for dam behaviour analysis and models from literature considering the influence of temperature are studied and evaluated. Secondly, new approaches considering the temperature influence shall be developed and tested. The focus of the current research project is on statistical models predicting the crest displacement of concrete dams.

This project is supported by “The Ark: Promoting innovation in Valais”.

The objectives are the following:
The systematic study of different geometries of diaphragm’s orifice (throttle) in order to de-rive general design criteria.
Study the stability of all the system (high-head power plant) to complete the existing stability criteria like the Thoma (1910).
Study the behaviour of head losses at dia-phragm throttles in transient flows.
Facilitate the management of high-head power plant.

The main objective consists in the development of a catalog of diaphragm’s orifice. From this catalog, the shape of the diaphragm for a certain wished head loss can be derived in an efficient way. The first type of geometry tested is an asymmetric diaphragm such as the ASME standard.

PhD research funded by the Swiss National Science Foundation (SNF).

For this project, a physical model of a stepped spillway is used to investigate its performance by systematically varying all relevant parameters:
the approach flow Froude number Fo
the approach flow depth ho
the pseudo-bottom (chute) angle φ
the step height s
the deflector angle α
the deflector height

Restoration of natural conditions in riverine environments is one of the main objectives of the new water protection law approved in 2011 (Vision Gewässer 2100) by the Swiss Federal Confederation. In this framework, dammed rivers may benefit from sediment bypass tunnels (SBTs) construction. In fact, through sediment flushing during flood events they can re-establish sediment river continuum possibly modifying downstream river morphology. The main objective of this research is to analyze the dynamics of downstream morphology evolution and quantify ecological effects and possible consequences on flood protection.

The goal of this research project is to develop a dam break analysis tool. A user friendly, numerically accurate and robust, and cost and time saving application shall be implemented. This application aims at supporting the decision makers in their risk assessment. Embedded in QGIS and BASEMENT, both existing software packages, the main focus of the project is on the quantification of the numerous uncertainties in dam break modelling.

The objective of this project is the development of a methodology that is suitable for alpine catchments. The existing PMF models will be ameliorated by considering the meteorologic and hydrologic aspects. Spatial distribution of the extreme precipitations for a certain region and their representation by implementation of an SIG module will be established. The methodology for extreme flood computations has to be clear, precise and rigorous. The program Routing System will be modified and completed with the new features. User manuals will be elaborated and workshops will be organized.

The aim of this project is to develop a planning framework for project specific strategy (PFPSS) which incorporates adaptive operation, robust design and real option analysis into the design process for hydropower projects. With this project we make important steps towards a better understanding of the application of innovative design approaches for management of uncertainty in the hydropower sector.

Turbines of high- and medium-head hydropower plants (HPPs) operating at sediment-laden rivers are subject to wear (hydro-abrasive erosion), which may lead to high maintenance costs and production losses. Data on suspended sediment load, turbine wear and efficiency reduction, obtained from measurements since 2012 at a case study at HPP Fieschertal, Switzerland, are evaluated to contribute to improving the efficiency and cost effectiveness of such HPPs.

Increasing reservoir sedimentation result in a loss of global storage capacity and requires for sustainable sediment management at reservoirs. Sediment bypass tunnels divert inflowing sediment around the dam to the downstream river reach and thus prevent reservoir sedimentation and reestablish sediment continuity. However, most of the facilities suffer sever hydroabrasion. Therefore the relation between hydrological and sedimentological impact, lining properties and abrasion is investigated based on prototype experiments in several Swiss bypass tunnels.