Candidate – The Netherlands
Submission by: Nik Berkouwer, OKRA landschapsarchitecten
Project name: GROTESTRAAT NIJVERDAL, Climate-adaptive city centre
Short description
OKRA transformed the central area of the city of Nijverdal into an attractive and lively place that is friendly and welcoming, with plenty of space for cyclists and pedestrians. The redevelopment of the 800-metre-long Grotestraat is notable because of its green-blue structure with climate-adaptive wadis and water-bearing plant pockets around the trees. The revitalisation of the central area and dealing with climate change go hand in hand in this project. Sustainable technical solutions for water management, water collection and drainage make the area climate adaptive and resistant to recent climate developments with periods of extreme precipitation and periods of severe drought and heat in summer. Rainwater is stored under the pavement to provide the trees with sufficient water and to feed a water playground with fountains. For this design OKRA was awarded the Water Resilient Cities Award 2019 for ‘The best sustainable drainage system for rainwater in an urban environment’.
Social cohesion
A meaningful place is created by designing a clear identity in the public space, fitting in with thehistorical context of the site and its inhabitants. It is essential to make a space with which people canidentify. The success of this project is partly determined by the residents, users and visitors of Nijverdal. The basis for the success was laid in the preliminary design drawn up with entrepreneurs, owners, residents, visitors, external experts and administrators in three participatory meetings. These meetings were inspiring, active and informative; discussions took place in a workshop-like setting.
Biodiversity
The water system in de Grotestraat is attuned to the naturally present considerable relief of more than thirty metres between the Sallandse Heuvelrug and the Reggedal. On the high part of the street, the water is disconnected from the pavement at the growing places of the trees. This water is buffered in rainwater crates underneath the plants, where it eventually evaporates through the foliage of the trees. On the low part of the street is a twelve-meter-wide wadi (bioswale) designed with a length of 120 meters and a storage capacity of 750 m3. In extreme downpours, the wadi captures the run-off from the water. Rainwater from the mountain is slowed down and drained into the stream course of the river Regge. By linking attractive living space to the climate wadi, double use is created for both the water system and users of the public space.
Economic factors
The redevelopment of the Grotestraat has resulted in a friendly and hospitable city centre on the border of the Sallandse Heuvelrug and the Reggedal. Existing restaurants and cafes along the new wadi have been given space in addition to existing terraces directly adjacent to the wadi. Nijverdal is back on the map with its green oasis in the heart of the city centre. The recent measurements of visitors to Nijverdal in the high season show a sharp increase.
Climate
OKRA has won the Water Resilient Cities Award 2019 for ‘The best sustainable drainage system for rainwater in an urban environment’ for the redevelopment of the Grotestraat. The annual Water Resilient Cities (WRC) award recognises the best projects using Sustainable Drainage Systems (SuDS) in Belgium, France, the Netherlands and the United Kingdom. Sustainable technical solutions for water management, water collection and drainage make the city centre of Nijverdal area climateadaptive, thus resistant to recent climate developments with periods of extreme precipitation and periods of extreme drought and heat in summer.
Wellbeing of visitors/users
The landscape qualities of the area on the Sallandse Heuvelrug are visible and experienceable right to the core of Nijverdal, which contributes to an attractive, healthy and liveable city centre. The substantial decrease in motorised traffic has led to more space for pedestrians and cyclists and good facilities for bicycle parking. Existing cafes and restaurants along the climate wadi have been given space for terraces directly adjacent to the wadi. Between the trees, there is also room for public (free) seating and a groundwater controlled water playground has been created in the centre of the wadi. The wadi forms both a spatial centre of gravity and a relaxed and shady place to stay. During the summer period, the Grotestraat is closed to car traffic for a number of days to provide extra space for events and festivities.
Selection, origin and quality of the products and materials
Key points were the reuse of high-quality materials and smart design within the framework of the existing underground infrastructure. We did not work with concrete materials, but with natural stone, because it ages better and also because it fits better with the history of Nijverdal. A diverse assortment of plane trees, lime trees, fly pines and larches naturally represent species in the area: ornamental grasses, ferns, perennials and shrubs form the picture. Some ten existing plane trees have been replanted elsewhere in the city.
The overall design
The redevelopment of the 800-metre-long Grotestraat is distinctive because of its green-blue structure with a climate-adaptive wadi and water-bearing plant pockets around the trees. The revitalisation of the city centre and dealing with climate change go hand in hand in this project. The landscaping qualities of the surrounding area are now visible and experienceable right to the core of Nijverdal. The area covered by the project is 19,200 m2. The street is 800 meters long and 24 meters wide. The surface of the planting areas is 6.000 m2; the storage capacity is 600 m2. The surface of the climate wadi is 1500 m2. The wadi has a storage capacity of approx. 750 m3.
The impact on the environment
The redevelopment of the Grotestraat has resulted in a friendly and hospitable city centre. Most importantly, the asphalt has been removed from the street, and the area has been set up as a residential area. The substantial decrease in motorised traffic has led to more space for pedestrians and cyclists and excellent facilities for bicycle parking. By linking attractive living space to the climate wadi, double use is created for both the water system and users of the public space.
Innovative value off the project
Sustainable technical solutions for water management, water collection and drainage make the city centre of Nijverdal area climate-adaptive, thus resistant to recent climate developments with periods of extreme precipitation and periods of severe drought and heat in summer. No other place in the Netherlands takes extreme rainfall, drought and heat into account in this way. Nijverdal will soon be used as a textbook example when it comes to storing rainwater in the city.
