Today we have a lecture scheduled along with a tour of a hydroelectric power plant along the Danube. Our lecture was presented by Professor Habersack from Vienna's University of Natural Resources. The professor works in the Institute of Water Management and Hydrology. He presented on the management of the Danube River. Because the river stretches through so much of Europe (on the order of 11 countries) and approximately 1100 meters in length, the European Union is considering legislation to regulate the river's treatment and use. Within the area surrounding Vienna, Professor Habersack focuses on the stretch of river east of Vienna. The primary problem that faces the people in this region is erosion of the river bed. There is currently an erosion rate varying between 2 and 3.5 cm per year. This is a delicate problem for the Viennese as the Danube is very closely tied to the livelihood of the city. Over the last 200 years, engineering projects have been conducted to ensure that the river is brought into check, and capable of being controlled. The design for the walls protecting the city is to protect against a 10,000 year flood level. Along with the walls protecting further erosion of the river banks, there are also the numerous bridges whose concrete piers must be considered. The increasing amount of river bed erosion will endanger both elements of city design. The primary response for the Vienna is to import sediment to deposit along the river bed.
However, there are a number of other factors that Vienna must consider. 60% of the country's electricity is derived from hydroelectric along the Danube. This creates another level of problems with numerous critical locations for inland transportation (defined as low water depth during low river flow times of the year), the river also runs through areas regulated as national parks with strict laws pertaining to sedimentation, high maintenance costs related to the sediment insertion on a yearly basis and the continued costs associated with flood management. Professor Habersack showed data detailing the level of river bed degradation over the last 50 years. During this time, the bed of the Danube has degraded slightly less than one meter.
Again, this creates the likelihood of undercutting the concrete piers of bridges and the walls protecting the banks of Vienna itself. However, the Austrians as a nation also want to make better use of the river for transport of goods. The ability to increase the traffic on the river by two completely loaded ships over the course of one year's time would replace 93 railcars and over 100 trucks per week in that same time. This would help alleviate strain on the rails and roads of Austria, with careful regulation helping to resolve two areas of civil engineering challenge facing the country.
Following the professor's lecture we met some of the students studying in the department and met them for lunch at a nearby café. After lunch, we were taken to the Freudenau hydroelectric power plant in Austria. It generates approximately 110 megawatts annually, through the use of six turbines. This amounts to roughly the amount used annually by the city of Vienna. Only one of the other eight Austrian hydroelectric power plants is smaller than this one though. We were able to see a fairly large portion of the plant itself, including two of the turbine rooms. Due to security, we of course were not permitted to view the turbines themselves. Due to the horizontal alignment of the turbine and blades, a system has been designed to allow the flow of the river to be manipulated along the 90 degrees separating the axis of the river.
Following the tour the entire group had dinner at Zwolf-Apostel-Kellar, a restaurant located near the state opera house in a former wine cellar. The name translates to The Twelve Apostles' Cellar. The salad and entrée were served family style with incredible portions before individual desserts were served. The salad was lettuce with corn, peppers, lentils, carrots, and cucumbers in a creamy dressing. The entrée was a variety of meats including chicken breast, schnitzel, sausages, and ham with fried potatoes and mushrooms. The dessert choices were an incredibly rich chocolate torte and apple strudel that had just enough spice with delicately flaky strudel.
