Architect

Büro Stelzig landscape ecology and planning office, City of Soest.

Type of Area

Stream with artificial banks
Ornamental water feature or fountain

Land/water interaction

Promenade
Bridges
Riprap

Built Environment Types

Moderately built
Moderately green

Scale of Impact

Place
Block
District/Neighbourhood

Intervention Scale (Spatial)

Linear development – multiple interventions

Project Types

Urban waterfront development
Public space regeneration
Habitat creation/restoration

Urban/ Rural

Urban core

Visibility and Openness

Fully enclosed
Fully contained view

From a smelly stream to a city asset

The Soestbach renaturalisation project in Soest, Germany has rediscovered an urban stream by changing its formerly technical character into an accessible linear public space. It was planned, developed and built-in different stages from 1992 by Büro Stelzig landscape ecology and planning office, initiated by the City of Soest. Previously, the Soestbach was a rather malodorous stream with hostile conditions for the ecology and a high flow velocity. It was a completely technical space while remaining an almost invisible element in the cityscape until the creation of an overall concept to expose it. The construction phases revealed the water flow of the stream and its connected springs. The Soestbach enters the city as a stream meandering through a meadow, mainly fed by more than twenty freshwater and saltwater springs during its course through the centre of Soest. However, it was historically converted into a sewage canal until it was partly redesigned. In the last few decades though, questions of flood security gained more importance – flooding was always a problem for the city as the stream flows through the medieval town centre.

The Soestbach saw a major decline in typical floodplain flora and fauna of the key indigenous habitats and an increase in common and alien floristic and faunistic species. It also saw a loss of migratory fish and an impoverishment of the amphibious fauna. The main planning objective was to turn the Soestbach from a eutrophied gutter into an attractive city waterscape. The aim was to utilise all possible spaces for water expansion under the urban planning conditions and to intensify the ecological and morphological diversity within the limited profile of the city stream. The development goal also aimed to achieve a near-natural urban stream course using the role model of a gravelly lowland stream, although the actual design is a deviation from the official classification of natural rivers. A precondition for the project was to raise the stream bed by almost two metres to ensure a varied flow behaviour as found locally.

By also revealing the feeding streams, they would add to the core flow and different flow velocities to the main stream. These actions changed the stream’s behaviour and the flow of its groundwater.  It also reduced the bottom shear stresses and eliminated unpleasant smells. Furthermore, the palpable acoustic quality was enhanced by re-establishing the sound of splashing water through the addition of weirs and plant clusters placed to decrease the flow velocity. A combination of stone walls and metal railings forms the basic design material.

The quality of the meadow landscape was highlighted by re-establishing references to the local history of Soest, such as historical sculptures indicating flood heights and offering information about the stream landscape and its development. The planning focus was not directed towards aspects such as sports or events, because the visual and symbolic connection to this landscape is more important than direct access. The public space relationship was also improved through the redesign which not only made the water visible through balconies along the pedestrian routes and ramps or steps leading down to the stream; it furthermore introduced a new public space layer: a natural stream with artificial banks in the sense of a promenade passing through the city to be constantly experienced by its residents.