Sustainability concept

Grasbrook is being developed on a site that has been optimized for port operations over the past few decades. To achieve this, bodies of water were filled in to create large and almost entirely impervious logistics areas, which were bounded by quay walls and rock fill. However, as port operations gradually declined, nature was able to reclaim parts of the area. Along disused freight tracks and silted-up areas in the “ Moldauhafen ” and “ Saalehafen ”—with their freshwater mudflats—riparian zones with various forms of spontaneous vegetation have developed.

The new Grasbrook builds on what already exists, reopens large areas to nature, and creates new parks and green spaces. It leaves the bodies of water intact and, by partially removing the quay walls, creates new connections to the water. Existing habitats are to be preserved and enhanced. The goal is to support the diversity of plant and animal species in the neighborhood. The green-lined streets and buildings with their green roofs and vegetated facades also contribute to this.

The impacts of climate change—such as extreme weather and heavy rainfall events, heat stress, and drinking water shortages—also play a role in the planning of Grasbrook. Decentralized and nature-based stormwater management is intended to contribute to the vegetation’s water supply in the long term. The goal is to retain and store stormwater and use it for irrigation.

Thanks to its dual waterfront location along the Elbe and the adjacent harbor basins Moldauhafen and Saalehafen , Grasbrook is well-positioned to handle heavy rainfall events. Nevertheless, for the street trees as well as the parks and green spaces, the plan is to keep stormwater within the neighborhood’s water cycle as much as possible rather than discharging it directly into the Elbe.

In addition to the green roofs and façades of the buildings, decentralized stormwater management also includes the green residential courtyards, in which rainwater is retained and stored above the mound level and used for irrigation on the construction sites. The drainage of the public street areas, especially on Grasbrook Boulevard, is carried out without traditional stormwater pipes. The rainwater is directed into the green strips planted with trees, seeps away and remains available in the existing soil layers to water the trees.

The concept of urban stormwater management thus follows the principles of Sponge City: rainwater is gathered, stored and released again as required. This makes it possible to dispense with sieve systems with pipes, shafts and discharge structures. In addition, the aim is to use graywater to save drinking water in building services.