The end of lignite production in the Lusatian region will create the future Lusatian lake chain (catchment area approx. 200 km²) from the former open-cast mines north of Senftenberg. This is currently being filled in a controlled manner from the rising groundwater and the existing floodwaters.
Four of the emerging lakes (Großräschener See, Geierswalder See, Partwitzer See and Sedlitzer See) will be directly connected in the future, so that a management slam of 38.9 hm³ and a flood lamella of 9.3 hm³ will be created. In the future, the control of these four lakes as well as the entire lake chain will be carried out via the newly created drain system/deepening Rainitza by connecting to the Black Elster. The plant safety must be ensured directly for the four lakes as well as indirectly for the Lusatian Lake Chain and the management of the operating and flood lamella.
On behalf of the Lusatian and Central German Mining Management Company (LMBV), Tractebel Hydroprojekt has been planning the connection of the emerging lake chain from the future Sedlitzer See to the Schwarze Elster since 2014 and overseeing the construction. In addition to the newly produced sealed gutter (conductor approx. 0.9 km, Rainitza approx. 1.9 km) with 7.0 m sole width, the planning includes a 2-field defensive structure, a 2-field sieve structure, a trough structure, a wild bridge, the associated open spaces and approx. 5.8 km of economic paths (see also report no. 63). In order to ensure sustainable management, a defensive structure with parallel water quality measurement and a level system for determining the delivery quantities was built at the entrance of the discharge system.
The 2-field defensive structure (field width 5 m each) was equipped with double-lift shooters. Structural steel with passive corrosion protection was used for the folding unit as a support system. The adjustment movement is carried out by means of increasing spindles and electric drive, which are accessible from the service. In order to ensure winter operation, a sealing surface trace heating system and an air bubble system were implemented. With an automatic control, the upper water level in Lake Sedlitz is regulated. A new transformer station was built to supply the defence system. In the case of revision, aluminium dam beams are used, which can be set with the help of a pliers bar. Outside the revision times, storage takes place in the dam beam bearing, which is also newly built.
Matthias Höhne - Freiburg i. Br., Dr. Holger Haufe - Dresden