Maerten van Heemskerckstraat (Maerten van Heemskerck Street) is a long street on the border between the towns of Heemskerk and Beverwijk. The street, including its sewers, needed to be renewed. The aim was to green the street and allow rainwater runoff from the street and houses to infiltrate locally. An additional challenge was that the street had been earmarked to become part of a provincial long-distance bicycle path. The street was narrow, with little greenery. Along it were one- and two-storey homes (a combination of social housing and private homes) and a primary school. The infrastructural adjustments to the street took place by mutual agreement between the two municipalities.
In 2016 the municipality of Heemskerk took the initiative to renovate the street. Within this project, management and implementation lay with the municipality of Heemskerk. Staff from the relevant departments of the municipality of Beverwijk were also an integral part of the project team and participated in decisions. At the administrative level, both municipalities already had an active policy on climate adaptation.
For Heemskerk, replacing the pavement was the most urgent matter; in the Beverwijk section the sewers needed to be replaced. In addition, the province designated Maerten van Heemskerckstraat as part of a regional through-cycle route. Together, these three tasks formed the basis of the project.
The municipality of Heemskerk had a policy that in all renovation and new construction projects, rainwater should be locally retained and infiltrated, and the public space should be greened. Within the Maerten van Heemskerckstraat project, infiltration was relatively easy to realise because of the sandy subsoil. Resident participation was part of the project, something which was relatively new for both municipalities. To make this possible, additional funding was made available to engage external expertise in this area. Heemskerk had furthermore been experimenting for some time with different forms of infiltration to increase internal expertise. Separate funding was available for research in this area, which was able to be used within this project. For the realisation of the long-distance bicycle route, the province provided a subsidy.
Approach and preparation
Within the municipality of Heemskerk, projects had been approached integrally for more than 5 years already. From the initial stages of any project, the relevant departments of the municipality were involved so that coordination could take place at the front end.
Preparation of the Maerten van Heemskerckstraat project started in 2016. At the initiative of the project manager, resident participation was given a more prominent role than usual. This had not been part of the plan in the initial phase, but the project leader believed that it would boost support and commitment.
The project was structured as follows:
- Initiation phase
- Definition phase and archaeological investigation
- Design phase
- Realisation phase
Using the Factor C methodology, the relevant stakeholders were identified: utility companies for gas, electricity and telecom, school board, housing cooperative, residents and, of course, the departments of both municipalities for sewerage, traffic and green management.
An approach was developed by the project manager in cooperation with the project team to properly inform and involve residents and the school. The primary school only had on-street parking spaces for pick-ups and drop-offs by bike and car. This created a nuisance and required attention. Representatives of the school were involved in the participation process.
The realisation of the long-distance provincial cycle path placed demands on the design and implementation of the new street. The cycle path had to be 4.5m wide and made of asphalt. This was not feasible within the street’s narrow profile. Because of this, plus the desire for greening, it was decided to construct a ‘car as guest’ street with a 3.54m bike path and a 0.48m rumble strip on either side.
The project included budget for pavement replacement, sewerage pipe relocation and replacement, and decoupling rainwater runoff from the sewerage.
The street became part of a regional through-cycle route. An additional grant was available from the province for this component.
The costs for greening the street fell under the climate adaptation budget.
In the narrow street profile, many tasks came together: two-way traffic, the regional bicycle route, parking, space for pedestrians and the desire for greening. Decoupling of rainwater runoff and local infiltration were also issues. With these starting points, a draft design was made, and it was discussed with the residents. The entire project preparation and technical elaboration were done in-house, up to and including the tender. Supervision of the implementation was done by the in-house project planner. Within the project, materials such as old pavement tiles were reused as much as possible.
Municipal policy stipulates that throughout all of Heemskerk rainwater must be allowed to infiltrate locally into the subsoil. Successes from previous projects were taken on board, and points for improvement were implemented. Underground crates, infiltration pipes wrapped with geotextile and permeable paving had not been sufficiently successful in the past, so these options were not chosen.
An earlier project with a crushed bluestone water-storing road foundation had proven successful. This principle was therefore taken as the starting point for this project and further developed based on previous experience. After determining the K-value – a measure of soil permeability – a choice was made regarding the type of water-storing road foundation to be used and its various components. Together with Wavin, an infiltration pipe with a larger cross-section than normal (125 mm) was developed.
This slotted pipe made of recycled plastic was applied without protective fabric (geotextile) and was laid in the bluestone foundation layer. The grain size of the bluestone is such that the foundation layer contains 40% hollow space. The pipe was laid between drainage gullies that have extra-large sand traps. The gullies were designed to flush the pipes through: water is injected into the gully on one side and extracted from the gully on the other side.
After the bluestone was laid, a month was waited for it to set before the asphalt was laid directly on it. The rainwater runoff from the houses was disconnected and carried to the bluestone road foundation by means of an infiltration pipe so that the remainder can infiltrate there.
The fact that the same person with a technical background was always involved in the technical elaboration, supervising the tendering process up to and including completion, meant that lessons could be learned from each project and that a lot of knowledge was built up in the municipality.
Maerten van Heemskerckstraat had very little vegetation. Only on the Beverwijk side there were small (woodland) gardens with a few trees and shrubs on some side streets.
For the new situation, a more colourful and biodiverse streetscape with as much greenery as possible was chosen together with the residents. Due to the narrow road profile and high parking pressure, there was not much room for large green spaces. As an alternative, as many narrow green spaces as possible were created for perennials, along with a number of tree patches with undergrowth between parking spaces. In front of the school, a number of large, raised planted containers with wide edges for seating were created. Residents could indicate a colour preference for groups of plants in the green spaces in their part of the street. Some residents planted façade gardens in collaboration with the municipality. Choosing a variety of flowering plants enhances biodiversity; this is also Heemskerk’s municipal policy. Reducing heat stress by planting trees that provide sufficient shade was only possible to a very limited extent within the limited public space. At strategic spots, trees were planted, surrounded by undergrowth, to create small cool spots.
Attention was paid to giving residents the opportunity to participate in the project. Walk-in evenings were held to inform residents about the project and climate adaptation. During these evening sessions, the plans were presented and people could contribute ideas about the (green) layout of the street. There was a lot of discussion about greenery versus parking spaces. Throughout the project, the municipality provided regular feedback on the progress and layout of the street.
The final choice of plants took place in autumn 2020 in cooperation with the residents. Because of Covid, physical meetings were no longer possible, so another way of communicating with the residents was sought. Maptionnaire, an e-tool for living environment participation, was used.
Initially, some residents had some resistance to planting trees in the street, but when the final greenery plan was presented, people decided they liked it so much that they wanted additional trees in the street after all.
Implementation started in mid-2020 and took place in four phases to minimise inconvenience to residents. The project was completed in the spring of 2021.
Normally in Heemskerk, the vegetation is managed by the municipality itself. This posed an interesting contrast within the project. In Heemskerk, there had not yet been any good experiences with managing perennials in green spaces, but in Beverwijk there had been. An expert third party was found for the maintenance of the green strips with the perennials. This party took care of the planting and maintenance for the first year. After this first year, the responsibility for maintenance was taken over by the municipality of Heemskerk.
Conclusion and recommendations regarding resident participation
- Good and communication and continuity in communication are important, both with regard to internal communication between disciplines and with external parties, such as residents and utilities.
- Be sure that the latest and complete versions of the design are communicated to all parties, as well as all changes (e.g. street lights that are wrong on drawings can lead to comments from residents).
- Include extra time and money in the planning and budget for surprises (e.g. it is not always clear where underground cables and pipes are located; this can lead to implementation delays).
- Create sufficient budget for resident participation; this costs extra time and therefore money.
- Be sure that discussion and planning of the (additional) costs for management of the extra vegetation happen with and by the management department.
- Ensure that the utility companies are involved from the start, so that plans are well coordinated.