Introduction
The Molenwater park is a climate-proof redesign of an existing park in the centre of Middelburg. Situated next to the old park was the local theatre and in the park there were some historical objects. After local protests against an earlier design involving a new theatre, the Middelburg city council decided to renovate the existing theatre and to preserve and improve the park instead. New additions to the park include a wadi system that buffers rainwater from the surrounding buildings and streets, and measures improving local biodiversity.
Description of the area, task, area characteristics, motive
The park and surrounding area are a unique place in the city centre that required care and attention in the design. The city centre has four main urban open spaces. These are the Market, Abbey Square, Dam Square and this park called the Molenwater. The Markt, Abdijplein and Damplein are urban centre squares with a stony character. The Molenwater is just next to the actual city centre and has traditionally had a much greener character. Originally, in the seventeenth and eighteenth centuries, it was an open space and tidal basin, utilized as a ship turning basin, with the character of an urban inland lake.
Starting points, opportunities and bottlenecks
The Molenwater Park was used in various ways in the past. For example, as military exercise grounds, as a horse market, and as a riding ring for the annual horse ring riding. The Miniature Walcheren, a scale model of the (former) island Middelburg is located on, was also located there. With this public use in mind, the intention in creating a new design was to create a place where everyone can feel at home, and urban ecology goes hand in hand with the park function.
Together with the working group, opportunities and concerns were identified:
- preserving and developing the existing ecology (natterjack toad, insects, etc.);
- creating an open zone on the west side of the park, thus connecting the park with the city;
- preserving the still present historical green structure around parts of the park;
- preserving the beautiful elements such as the bandstand. The existing bunkers can also be used in the new park design.
The old park was divided into three parts. The aim was to make it a whole, with clear entrances. However, 120 parking spaces for the theatre and 2000m3 of water retention also had to be realised. Rainwater from the adjacent streets and buildings had to be retained and infiltrated into the park. Additionally, the maintenance of the new park had to fit within the usual Middelburg municipality budgets.
Middelburg’s municipal policy is that all restructuring or new construction projects pay attention to the climate challenge and local biodiversity. In this project, this translates into the realisation of the wadis, the large green share, the preservation and addition of trees and the specific measures for biodiversity.
Process
The Municipality of Middelburg, BoschSlabbers and the Molenwater Park working group have collaborated intensively in realising the final design.
The plans for the new Molenwater Park were worked on together with a group of local residents and park users in a series of six working sessions. The sessions resulted in broad support for the design. The final design was finalised in May 2018.
The project was part of the European Water Resilient Cities project.
Design and design considerations
The plan extends from facade to facade and includes the square in front of the City Theatre. The park design is characterised by a contemporary landscape style. A network of sloping paths connects the park to the city and the urban network. Opening up the edges of the park also strengthens the relationship between the city and the park. Vehicle parking is concentrated in the fringe zone and on the square in front of the City Theatre. The space in front of the theatre was transformed into a new urban space with a great amount of trees and thereby serves as a link between the park and the old city bastions along the Noordvest behind the City Theater. The water retention is made visible through the centrally located mirror pond and a cascading system of wadis.
Spatial
The edges of the new park build on the historical existing green structure consisting of a double row of trees. This historical green structure is still largely present along Zuidsingel and the eastern part of Molenwater. Removing the plant cover made this characteristic tree structure more visible again.
The entrances are marked by reusing the former light masts of the Markt in Middelburg. These provide a diffuse light and are appropriate for the surroundings of a city park like this one.
The original longitudinal parking in the streets adjacent to the park has been replaced by perpendicular parking. Low hedges and a semi-paved surface contribute to an attractive incorporation into the park environment. This makes the parking a kind of transition zone between street and park.
The slope profile of the surrounding streets has been adjusted where possible to allow rainwater to drain into the park and the wadi system.
Water system, a cascade of wadis
A cascade of wadis has been developed within the park design. Lowered ground-level zones (wadis) in a more extensively managed world, provide space to temporarily store rainwater from the surrounding area during heavy showers. The water can then be slowed down, and infiltrate or evaporate. This buffer is intended for water from rainwater sewage disconnected streets and roofs of houses in the immediate vicinity of the park, making the surrounding system more climate-proof.
The starting point was that the original sewage system should be retained as much as possible and integrated with the new sewer design, which was not easy.
Underneath the wadis are infiltration sewers. This was necessary because the existing soil has poor permeability. At the transitions from one wadi to the other, grids have been installed to move the water from one higher wadi to the next lower wadi, and to serve as a siphon to prevent the water level in the wadis from becoming too high in case of very prolonged precipitation or very extreme rainfall. In the latter case, the excess rainwater will be drained via an existing rainwater sewer to the surface water of the Noordvest behind the theatre.
The wadis will be designed in an ecological way, attracting dragonflies, butterflies and thus amphibians, among others. In addition, they form attractive play attractions for children.
Water system, the mirror pond
A mirror pond with a fountain has also been constructed. The mirror pond is also fed by precipitation from the paved surfaces adjacent to the park.
Water always has a great attraction for people. The mirror pond is therefore the park’s main attraction. It is filled year round, unlike the wadis which are usually dry. The mirror pond is designed to invite children to come play. A wide sitting edge surrounds the mirror pond. The zone between the edge of the pond and the seating edge can be flooded at the highest water levels, turning it into a (play) water square. The applied lines in the square – 1000m3, 1500m3, 2000m3 – make the storage function legible. The seating edge extends into a deck that seems to float just above the wadis.
Biodiversity, the natterjack toad
For years, Molenwater has been the habitat of the natterjack toad, a protected amphibian species that thrives in a pioneer environment. For their reproduction, they require small bodies of water that warm up quickly in early spring and then dry up again in summer. Furthermore, their habitat is in unshaded and low vegetated areas. They need hiding places in the form of relief.
The winter home of the natterjack toad in the Molenwater was known. This spot has been preserved and integrated into the park design. In addition, several so-called ‘toad bowls’ have been constructed to serve as breeding habitats. The toads are reflected in the design of the bowls (imprint in concrete). The bowls are also easy to keep clean.
Biodiversity, butterflies and dragonflies
The Molenwater Park has a spacious extensively managed zone around the wadis. This zone is filled with vegetation suitable for the damp environments of the wadis. This vegetation contains a varied range of nectar plants and thus forms a true nectar oasis for butterflies and dragonflies. Maintaining this vegetation requires specific mowing management (phased, especially in June/July). Examples of urban-nature butterflies that fit into the intended Molenwater Park biotope are: the little fox, the day peacock and the atalanta. Examples of dragonflies-city-nature butterflies suitable for the Molenwater Park are the blue glazier, the horse bee and the azure damselfly. Sites will be created within the wadis for the purpose of dragonfly reproduction.
Remediation
As is the case throughout the inner city of Middelburg, the Molenwater Park contains slightly contaminated soil. The situation at the site was mapped by means of soil analyses. Based on these results, a strategy was drawn up to process the soil to be excavated for the construction of the wadis and the mirror pond within the park. Some preconditions here are:
- the soil to be excavated was to be reused within the park
- this soil was covered with 30-50 cm of clean soil, creating an improved situation
- no excavation works were carried out within the crown projection of the trees to be preserved
- reallocation of soil took place outside the crown projections of the trees to be preserved
- construction of the wadis took place outside the crown projections of the trees to be preserved.
- the emerging soil was incorporated into the relief.
Planting, trees
Besides the fact that some trees had to be uprooted, an equal number of new trees were planted. With the choice of the species of trees, the goal was kept in mind to create a diverse stock. Furthermore, gestation trees were planted as much as possible. These provide food for bees and bumblebees and thus enrich the Molenwater Park’s nature. Some examples are: the honey tree, the red horse chestnut and the black walnut.
Planting, park lawn
The park lawn was partially enriched with herbaceous plants such as clover and daisy. This was concentrated in zones along the paths.
Furthermore, groups of blue irises were planted in the wet zones as an accent in a richly varied wadi flora.
Planting, shrubs
The shrub beds were replanted. In the edge zone, the shrub beds have a somewhat more natural character. These consist of ecologically interesting species such as dogwood, currant tree, wild privet, guelder rose, yew and lilac. The herb layer is sown with a forest mix. In other places near the entrances, the shrub beds are made up of lower ornamental shrubs such as hydrangea and butterfly bush. These are somewhat easier to manage and give an attractive look.
Result
The basic design is based on an attractive park for young and old with a multitude of play attractions such as stepping-stone courses through the wadis, the relief and path structure, the water square and the experience deck, and variety in atmospheric plant areas. Low small football goals were repositioned near the current football pitch.
Some play equipment was provided near the kiosk, near the entrance to the new theatre square. A long bench gives parents a view of the children playing.
Maintenance
Maintenance of the Molenwater Park fits into the regular management budget. The wadis are extensively mowed.
Lessons
Learning point in the project and also in other projects in the municipality of Middelburg is that natural wadis should be given time to function optimally. It appears that the infiltration capacity improves with the improvement of soil life through better rooting of the soil. It appears that improving the humus layer by adding composted green waste also improves the permeability of the clay layer. In Middelburg, they have been experimenting with the Bokashi system for soil improvement in recent years.
Source
Molenwaterpark, BoschSlabbers Landscape architects
Interview Bas Kole