Green corridor Olbeschgraben Trier Gottfried Kühn Prize 2009

Circuit

A paved footpath and cycle path follows the course of the green corridor as an extension of the existing circular path around the Trimmelter Berg and the Olbeschgraben. From here, connecting paths lead into the construction area and downhill to the existing hiking and service roads. The course of the paths opens up constantly changing views and spatial impressions. This is additionally supported by the opening of view corridors alternating with spatial condensations in the form of groups of trees and groves of trees. At 3 prominent points, wall-supported terraces or viewing pulpits to the valley are created.
This path, which is intended for use for maintenance measures of the retention system, as it were, also defines the valley-side boundary of the seepage troughs. Guided on an embankment, its elevation is accordingly oriented to the elevation of the infiltration troughs. Only in the southwestern area is the path elevated over a long-shaped crest modeled from excess excavated material.
The connection points to the spur roads from the construction area are specially designed. They cross the infiltration troughs in the form of bridge footbridges. Below these footbridges, the rainwater is discharged from the collection pipes into the swales; at the same time, they form the overflow thresholds for overcoming necessary height gradients within the swale system. Individual benches at the edge of the path provide smaller resting areas.

Play area

At the south-western tip of the development area is an intensively designed area with play facilities. Shielded from the building areas by planting and a ground modeling that is up to 2.50 m higher than the building area, a meandering recessed play area is oriented towards the adjacent edge of the forest. Complemented by groups of trees and bushes, a stimulating playground topography is created with sunny and shaded areas, with vantage points and retreat possibilities. The play offer of natural play materials such as tree trunks and pebble boulders is supplemented with conventional play equipment such as a play net made of robust cordage, a climbing tower as a signal at the crossing point of the paths and a slide. A small plaza with seating completes the play area. The arrangement of the stool benches allows for communicative get-togethers and stays at differently sunlit spots. The adjacent flat meadow area to the east offers space for space-consuming movement games. However, the installation of permanently installed goals or nets for ball games is not planned here.

Square at the Freschfeld

The transition of the main development path over the beginning of the Freschfeldgraben, at the linking point of the green corridors of the adjacent building areas, is designed as an exposed square. Here 5 paths meet, the square is an orientation, turning and distribution point. Bordered on 3 sides by troughs, the area seems to float above the water like a raft. Furnishing elements such as concrete loungers and a special paving reinforce the character of the square in the manner of a sun deck, as a meeting point, a place for observation and relaxation. Large-format slabs in a linear structure support the spaciousness of the square in interaction with the surrounding green space.

Drainage facilities

The planning area is drained using a modified separation system. The surface water is largely retained at the point of origin and infiltrated as far as the local subsoil conditions allow. Required retention and infiltration troughs are thus an essential component of the green corridor and influence the design scope. As a ribbon-like structure, they follow the course of the height strata along the building areas at the edge of the plateau. The interplay of the surface structure with weather-related changes (waterlogging and runoff) is part of the design and creates additional incentives for experience.
The hollows are created by digging them into the terrain or by filling in an embankment on which the edge path, which is basically on the valley side, leads to the hollows. Part of the grassed swales drains towards the Olbeschgraben green corridor, during the development of which appropriate provisions have already been made to connect to the existing retention facilities there. The remaining part drains to the Freschfeldgraben. The connection possibilities for drainage of future building areas have already been taken into account.

Central square

Due to its central location, this square is of particular importance as a landmark and point of orientation in the new district. Accordingly, a design focus lies in its space-determining shaping and a memorable materiality.
A redoubt-like earth sculpture pushes itself wedge-shaped against the axis of the access road and divides the street corridor spatially effective and widely visible into the subsequent subordinate development areas. This effect is supported by a homogeneous planting with striking trees (Zerr oaks) as well as by the use of contrasting colours for the paving of embankments (dark slate) and walls (light concrete). On the remote south-west side, this earth wedge significantly shapes the calm character of the residential path there. On a raised platform on the north side is a small plaza area with a good view of what is happening on the traffic areas. Adjacent to the east is an exit point for public transport. The sloping lawns under the trees can be used to a limited extent (inclined plane), but no special play or equipment facilities are planned here.

Equipment, materials, planting

The materials correspond in their simplicity to the character of the overall facility. They are primarily selected according to use-specific requirements. Paths and squares are designed as paved areas (concrete block paving). Furnishings are provided in simple form and in the minimum necessary quantity. Separate lighting of the green corridor is not planned. Only in the area of the central public open space special lighting elements (strip lighting) are used.

The greening concept is based on space-creating tree plantings and extensive shrub plantings along the property boundaries. The selection of species is essentially based on woody species typical of the site and native to the area in their natural occurrence. Intensive planting areas are only planned in isolated cases, in small sizes and only in direct interaction with recreational areas. The grouped use of particularly distinctive tree and woody species (e.g. oaks, bird cherries, walnuts) will create characteristic subspaces and focal points. Extensive meadow areas will determine the overall picture. Only areas in the direct vicinity of the playground and square areas will be designed as hard-wearing lawns. In the edge areas of the infiltration troughs, flower-rich tall herbaceous plants are initiated by sowing. For additional tree plantings in the street area, deciduous trees appropriate to the location were used with special attention to the growth characteristics with regard to crown and root development. The planting is carried out in underfloor tree planting quarters or greened/gravelled tree discs, depending on the use and availability of space.

back to overview

1. Circuit
2. Play area
3. Square at the Freschfeld
4. Drainage facilities
5. Central square
6. Equipment, materials, planting