The Phoenix Lake in Dortmund is an outstanding example of structural change in the city and the Ruhr area. An artificial lake measuring around 24 hectares was created on the site of the former Phoenix-Ost steelworks and opened to the public in spring 2011. With its 24 hectares of water surface, the lake even exceeds that of the Alster in Hamburg. Excavation work for the lake began in September 2006, with around 2.5 million cubic metres of soil being moved. Flooding of the lake began on October 1, 2010 and reached the first target level about a year later.
The lake, which is 1.2 km long and 320 metres wide, serves not only as a local recreation area, but also as a rainwater retention basin to protect the residential and commercial buildings downstream on the banks of the Emscher from flooding. The maximum depth of the lake is around 4.6 meters with a capacity of around 600,000 m³ of water. To maintain the water quality, a phosphate elimination plant was built north of the lake, which can filter up to 90 m³ of lake water per hour to remove phosphates and thus maintain the water quality.
The promenade at Phoenix Lake and the surrounding areas offer a variety of leisure opportunities. In addition to the opportunities for walking, jogging, cycling or skating, there are also offers for water sports enthusiasts, although swimming, surfing, diving and fishing are not permitted in the lake. High-quality residential areas, commercial units, restaurants and a marina have been built around the lake, making the lake an attractive place for residents and visitors. The first catering establishment on the lake was the "Fénix" restaurant in the southern harbor district, which offers an outdoor terrace along the promenade.
The Phoenix Lake is therefore not only a testament to the successful structural change from an industrial past to a modern residential and leisure area, but also an important element in the concept of urban development and flood protection. It plays a central role in the renaturation of the Emscher and, through its diverse uses and the surrounding commercial and catering options, contributes to improving the quality of life in the region.