Lágymányos Bay is an artificial bay built for river management and flood prevention purposes in the second half of the 19th century by constructing Kopaszi Dam. Despite the name the bay belongs to Nádorkert area. It preserves both historical and environmental values as well as Kopaszi Dam is one of the most popular recreational spots in the city.

Kopaszi levee Kopaszi levee has grown beyond its original river management function and has become a recreational center with various facilities for sports, dining and relaxation.

The bay covers an area of around 11 hectares.

Lower parts of Pest, Buda and Óbuda had suffered a lot throughout history from floods of the Danube. Levees on the Pest side constructed after the ice jam flood of 1775 were insufficient to prevent the unprecedented devastation of the spring flood of 1838. The extraordinarily cold and snowy winter as well as ice jams along the unregulated river foreshadowed the disaster at the beginning of winter. Ice at the tip of Csepel Island completely blocked the river causing flood to peak 1.5 meters higher than in 1775.

River regulation and flood prevention was inevitable to protect the dynamically developing Pest, Buda and Óbuda. Devastation had brought river regulation into sharp focus and plans were made to reduce exposure to ice jam floods over the next years.

First, the river arm at Lágymányos was closed in 1872 and soon an inlet lock and the levee were constructed. The rise in water level required the elevation of the quay by 2 meters. By the end of 1875 the levee was completed full length and then the troublesome Kopaszi reef was dredged.

The flood of 1875 required additional developments and the riverbed was further narrowed as well as the Soroksár arm of the Danube was closed. These constructions resulted in the current state of the Danube in the Budapest area.

There have been several concepts to leverage the levee and the bay since then. Right after works had been completed the idea of a winter cargo port with railway access was raised. In the early 20th century Nádorkert area experienced rapid development. 7 hectares of the northern bay area was filled up to build Budapesti University of Technology and Economics. In 1930 filling up the southern part of the bay started. Earth was taken from dredging the port area, which resulted in additional construction site and a usable port at the same time. By 1937 three more bridges were completed.

The bay also played an important role providing sports and recreational facilities, e.g. for fishing, rowing and swimming. It continued after WW2 as well but the condition of catering and sports facilities started to degrade following constructions in the area in the 1950s. In 2003 a company was founded to develop the bay area. Later on a yacht port, a canoe&kayak club and dragon boat club were established. A running track and small football field were also built for non-water sports fans. Following these developments and the revitalization of the green areas have made Kopaszi levee a popular recreational area by today. Fresh water supply is granted from the open end of the bay, which is especially clean since a waste water facility was launched in Csepel. The bay is surrounded by monuments such as the Roller Mill of Buda and the transformer house of Kelenföld Power Plant. The outer side of the levee gained a protected status in 1993 to maintain the rich fauna and flora.