Rosenåen River and Basin

A nature like basin for local rainwater management

Due to the construction of a new railway line, Banedanmark, the Danish Rail Development Authority, and Brøndby Municipality have worked closely together to implement anumber of rainwater management projects.

The basin along along the piped Rosenå plays a central role in the overall protection concept. Brøndby Municipality and HOFOR have registered frequent flooding of areas close to  and on Brøndbyvester Boulevard. In the course of Banedanmark’s railway project, some old, and insufficient, rainwater basins had to be decommissioned and new ones had to be built. The partners agreed to establish a new separated sewer system ( a system where rainwater and waste water are collected and discharged separately)  and an open , nature like basin for rainwater collection. The basin is located in “Den Grønne Kile – The Green Pathch”, a 700 by 700 meter wide green space framed by 4 highways, in the western suburbs of Greater Copenhagen.

The new basin transports, stores and infiltrates rainwater. During cloud burst, the water level in the basin can be increased temporarily. The excess water is later discharged into the sewer system.

Quick Facts

Address: Midlergårdsvej, 2605 Brøndbyvester 55 ° 38’08.7 “N, 12 ° 25’01.4” E
Elements: Pre-basin with sand trap/ main basin/ green recreational areas

Usable volume: 20,800 m3

Participants: HOFOR, Banedanmark, Brøndby Municipality.

Room for everyday rain and cloudbursts

The main  asin receives rainwater from an area within a radius of about 2 km and discharges water via a southern outlet into Maglebæk Lake in Brøndby Strand. The lenghty shaped basin has is 950m long, 6,25m wide and about 3,5 m deep. There is an emergency overflow structure into the local combined sewer system. The new railway line runs north of the basin. The smaller pre-basin (sand trap) is located just north of the railway line. A small ditch connects pre and main basin.

The basin forms the landscape

The idea to create recreational value in the course of this project was central to the planning process. The planning parties therefore agreed to prefere an open system, rather than a closed system with undergorund pipes and basins. Open solutions create the possibility to create attractive recreational landscapes around them. Along the main basin a small path that invites for walks along the basin was established. The direct environment of the basins was prepared to host wild diverse nature, which will slowly grow over the coming years. In addition, a bridge has been built over the basin in order to maintain accessibility to the area despite the newly established basin.


HOFOR – Greater Copenhagen Utility, Brøndby Municipality and Banedanmark have worked together in this project.


Project Location

Similar Locations

There are more projects, which were established in connection with the new Copenhagen-Ringsted rail line. Please find them below: