Steffen Flath
Welcome Address
Ladies and gentlemen
There are 176 dams, water reservoirs and retention basins in Saxony. These are defined by the Saxony Water Act as having a height of more than 5 metres or a capacity of over 100,000m3. The capacity of these 176 reservoirs is approximately 630 million m3. In comparison to large reservoirs, this capacity may be small, but the functions of these dams in flood control, flow regulation and fresh water supply for drinking water are that they are of national significance. These structures are also often harnessed for electricity production, albeit on a small scale, and non-drinking water reservoirs are also used for recreation and tourism. The Saxony Water Act provides for management by the State Authority for Dams of all planning, building, operational and maintenance activities related to the most important dams, reservoirs and retention basins, i.e. those nationally important installations for flood control, drinking water supply and flow regulation. The State Authority for Dams is a state-owned concern under the control of the Free State of Saxony. It is also responsible for maintaining and developing approximately 3,000 km bodies of water of primary importance and the associated flood control mechanisms and another 118 km body of water. In our opinion, this type of organisation combines expertise and authority with the minimum of staffing. Saxony is particularly notable for the reservoirs at former brown coal open pit mines. These reservoirs are formed by flooding disused open pit mines. They have a storage basin for flood control, raising low water levels and for raw water. There are six of these reservoirs in existence and another five are currently being flooded.
A wide variety of technical solutions has been used, particularly in the construction of the dams themselves.
Our oldest structures had their origins in the 1500s and are closely associated with mining in the area. A system of reservoirs, man-made trenches and tunnels provided the Freiberg mines with the service water required for ore preparation and a power source to pump out the mines. These middle-aged structures are proof that even at this time the dams were very important for economy in Saxony. This water system, called by the old miner's name "Revierwasseranlaufanstalt Freiberg" (Freiberg water course system), is still used in the supply of drinking and raw water today. The structures damming these reservoirs are usually earth embankments with a loam seal. Many of these structures are of historic and cultural importance.
The 19th century saw the opening of a new chapter in the history of dam building in Saxony. The concentration of populations led to new demands on the drinking water supply. The Einsiedel drinking water dam at Chemnitz was constructed as a result of the lack of underground water sources. The Einsiedel is Saxony's oldest gravity dam having celebrated its 100th birthday in 1994. It was the first in a series of eleven masonry dams built up to 1952, the last being the Sosa in the Ore Mountains (Erzgebierge). The Kriebstein dam began the era of concrete dam construction in the twenties. Concrete dam construction flourished in the period after 1945 with the building of the Pirk dam and then the Pöhl, Rauschenbach, Dröda and Gottleuba dams. Saxony's newest and, at the same time, highest concrete dam is the Eibenstock commissioned in 1984.
Many types of structure have been used in dam construction. Homogenous dams, zoned dams, earth embankments with loam core, clay concrete and concrete, earth embankments with loam aprons as well as earth and rock fill embankments sealed with bitumen concrete.
The 20th century was characterised by its many new dam projects. The task for the 21st century is reconstructing and strengthening the dams we already have to ensure their continued operation and structural safety. The Werda, Neunzehnhain II and Carlsfeld dams have recently undergone complete reconstruction. Full reconstruction of the Bautzen dam is underway and work should to all intents and purposes be complete by the end of the year. Reconstruction of the Muldenberg dam has begun and preparations are in hand for the Klingenberg dam.
This year sees the start of construction work on a "green" flood retention basin in the Müglitz valley in Lauenstein/East Ore Mountains (Osterzgebirge). There are no plans for new dam building in Saxony in the immediate future. Nevertheless, the State Development Plan does include provisional locations for dams.
The recent experience of extended periods of dry weather has demonstrated that, in spite of falling demand for fresh water for industry, agriculture and drinking water, the capacities available in the Saxony dams can be drawn on when required. There has been an increase in demand as the result of the reconstruction of the water management regimes of the brown coal regions for the supply of flood water for the open pit mines and for raising low water levels brought about by mining. The long-term climate changes forecast for Saxony with the anticipated effects on the water management regime – a general decrease in total yearly precipitation, generally lower rainfall in spring and summer and an increase in extreme local weather conditions – present an opportunity to consider the long-term role our dams and reservoirs have to play in facing the challenges of the future.
Ladies and gentlemen,
As one of the German federal states with the greatest number of dams, the Free State of Saxony is honoured by the decision of ICOLD to hold the first Annual Meeting in Germany in the year 2001 in Dresden, the state capital of Saxony. At the same time, I believe that the choice of Dresden is also a recognition of the achievements of the dam and hydraulics engineers in the new federal states and of the new Dresden University of Technology, which has the first hydraulics laboratory in Europe, the Hubert Engels laboratory.
To open the symposium on "Benefits and concerns about dams" I would like to welcome you personally and on behalf of Prime Minister of the Free State of Saxony, Professor Dr. Biedenkopf.
May I take this opportunity to wish the symposium and the workshop tomorrow every success and to express my hope that all participants will find it a valuable opportunity to learn and exchange new ideas.
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