One of the most comprehensive and significant conservation projects in the biosphere reserve was concluded in 2000: the restoration of Kühnauer Lake. This largest backwater in the reserve was dredged and a causeway dividing the lake was removed.
Backwaters are a very characteristic element of floodplains, and many species depend on them for survival. Before people intervened in the Elbe with levees and bank reinforcements, the river often shifted its bed during flooding events. Sometimes a channel would be cut off from the main flow of the river, creating a backwater. The nturient content of this backwater increases steadily. This so-called eutrophication was articifically enhanced in Kühnauer Lake through fertilizer run-off and the division of the lake by the causeway. The lake grew shallower, and some areas began to convert to dry land. If interventionary measures had not taken place, the lake would have disappeared completely.
Many threatened and endangered plant and animal species live in and around this lake. Due to the rapid eutrophication, some species had disappeared by the 1980\s. The water chestnut is one example. A rare species in Europe in general, it had disappeared from Kühnauer Lake in the 1960?s. With help from the Allianz Fund for the Environment (Allianz Umweltstiftung), the water chestnut was reintroduced after the retsoration was complete. Other plants, formerly thought gone, have begun to return. The population of of rare fishes are also increasing.
The recreational value of the area has also increased. One example is the improved water quality at the local beach. Second, an educational trail leads visitors to interesting sites around the lake.
The project cost approximately 11 million DM. Involved in the project were the Allianz Umweltstiftung, EU, the German Federal Government, the German state of Saxony-Anhalt, and the city of Dessau.