Development of the ‘Heiligkreuz’ area in Mainz

The city of Mainz is developing a modern residential and commercial area on a (in recent times) partly abandoned industrial site. The design of the urban structures was determined through a competitive process. The area is characterised by limited availability of space combined with a high population density. To optimise the technical development, igr undertook a surface water management study. The goal was to manage accumulating water on site, and to relieve pressure on the municipal waste water network. Due to the unfavourable underground conditions, infiltration was only possible to a limited extent.

The design intends that rainwater will be directed into the road structures and green spaces near the surface. The material make-up of the various development areas was taken into account in this regard, and was examined in a variety of options. In addition, infiltration ditches and sewers for retention and drainage will be used. Through a sensitive handling of street levels, drainage pathways will be created, which ensure that during heavy rain events (urban flash floods) floods produce the smallest possible amount of damage.

Services provided by igr

• Rainwater management study of public and private areas
• Preliminary planning of traffic facilities (internal development and traffic intersections with the surrounding road system)
• Landscape management planning report

Key figures

• ca. 33 ha planning area