The
Biggetal dam is one of the largest
dams in Germany and the second largest in
North Rhine-Westphalia in terms of reservoir volume (see
list of dams in Germany). It is located in the center of the
EbbegebirgeNature Park between the towns of
Attendorn in the north and
Olpe in the south. Since 1965, it has been damming the left tributary of the
Lenne to the
Biggesee with a
rockfill dam in order to control the water flow in the Lenne and Ruhr and increase
flood protection.The
operator and
owner of the dam, also known as
Biggen for short, is the
Ruhrverband, based in
Essen, which operates a total of seven other dams in the
Sauerland region. As a special feature, the formerly independent
Listertalsperre was integrated as a forebay during construction.