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Building with Nature Guideline > BwN Approach > Steps and phases > Construction 

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Construction phase


In previous phases the problem definition, project scope, project strategy and design have been addressed. The construction phase elaborates and discusses the project execution approach. EDD can be used to optimise the work method and the selection of materials.


Important aspects to consider involve:

  • Optimisation of the work, selecting appropriate equipment and materials, timing of activities, etc.
  • Optimisation of the design taking a lifecycle perspective.
  • Application of adaptive construction methods to manage unpredicted direct (and if possible indirect) effects.
  • Involvement of stakeholders, information provision and receptiveness to suggestions.


Building with Nature approachTraditional approach
Eco-dynamic projects aim to jointly optimise the cost-effectiveness of a project, its embedding in the natural environment, the use of natural processes and the creation of new opportunities for nature. Careful selection of materials and optimisation of the layout can yield significant advantages. Involvement of stakeholders in this optimisation process may help to turn hesitation and opposition into enthusiasm and cooperation. Room for experimentation and adaptive project development and management are important elements.Traditionally projects are optimised in the construction phase by minimising construction time, costs and risks. Delivering the required functionality within these constraints is considered optimal. Aspects considered are reuse of materials that can reduce construction cost, cost-effective timing of construction activities, functional combinations with other projects, financial constructions, optimising of operation and maintenance with design aspects. There is a tendency to use proven technologies in order to reduce risks.



A variety of EDD optimisations is possible in the Construction Phase. What works best varies from site to site. Reducing construction costs can be favourable in one situation, whereas construction times may be critical in another. Careful timing of construction activities, considering aspects such as the breeding season, may reduce environmental impact. Also (minor) adaptations to the project design may enhance the potential for ecological development.


Examples where EDD has been applied in the construction phase are:

  • Ecological borrow areas: (for 2nd Port Extension of Rotterdam): adaptation of the work method resulted in a seabed landscape with enhanced (re)colonisation capabilities.
  • Hard Eco-constructions: application of specific near natural materials/variation of sorting and material choice led to increased habitat diversity. Smart re-use of old worn-out materials further enhances the ecological value of hard structures by providing a less smooth and more suitable substrate for flora and fauna.


It is important to realise that the people handling the construction phase are seldom the same as those that handled the previous phases. As a result, a lot of important knowledge acquired in these previous phases but required for the construction phase may be lost. This is especially the case between the design and the implementation phase of a project when the project team is often completely changed. Knowledge transfer from phase to phase is very important to obtain optimal results. This can be achieved by adequate documentation, but personal communication in a project setting works best. Even better is involvement of team members that were also active in previous phases.


This chapter provides guidance on eco-dynamic construction approaches. Where appropriate, we suggest useful methods and tools.

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Step 1) Understand the system

In the BWN approach a good understanding of the system in and with which the project is to be realised is paramount and a first step. It has already been an important activity in the Project Initiation and Planning and Design phases. In the construction phase other experts will look at the project from different angles with more emphasis on technical and commercial aspects and practical implementation. Also environmental issues remain important, in relation to license requirements as well as the environmental effects during execution.

BwN approachTraditional approach
In the BWN approach the design and the way in which it is realised are optimised with respect to all system aspects. Apart from keeping costs and environmental impacts within acceptable bounds, also ecological and economic benefits are important. Timing of the work in line with natural processes may be an issue, as well as adaptive management of risks and opportunities.The Scope of Work describes the building activities and the envisaged result. The focus is on a simple and cost effective project meeting environmental requirements. Understanding processes is limited to those relevant to the cost-effective execution of the work. Less attention is paid to processes relevant to Operation and Maintenance, because this is usually not part of the contract.

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Step 2) Identify realistic BwN alternatives

The previous phases have defined a design and scope for further optimisation (see Next phase from previous chapter). Modes of operations and innovations can be elaborated in this phase. In the previous phases, the EDD process has led to the identification and selection of a preferred alternative. Work in this phase will focus on optimising implementation. Yet, this may feedback on the design and forward on operation and management.

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Step 3) Evaluate and select alternatives


A Social Cost Benefit Analysis is the tool of choice in the planning and design phase, since it covers all the issues that are important to (political) decision making. Similar assessments are used to evaluate proposals, but can also be used to rank tender documents.

Normally contracting procedures involve award criteria, which should ideally meet the following conditions:

  • They correspond with the most important criteria in the decision framework used in the Planning and Design phase. The same main aspects should drive design and decision making in all project phases. Possibly, these criteria can be made more tailor-made and meaningful as the project progresses.
  • They cover all requirements set by authorities as well as legislation. It is important that licences and permits give room to optimisation and are not so stringent that they preclude better alternatives. As has been discussed in the Project Initiation and Planning and Design phases assumptions and prerequisites need to be tested to see whether they are indeed relevant and correct.
  • They work as environmental incentives, i.e. they are formulated in such a way that they stimulate optimisation on environmental aspects as well as on costs (see contracting aspects).

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Step 4) Elaborate selected alternatives

During the tendering or contracting period, the contractor and the client may agree upon the preferred final design and the way it will be implemented. 

In their further elaboration special attention should be paid to:

  • Detailing the work method and the project plan: clear definitions of intermediate construction stages, materials to be used and workflows. This involves a detailed timing of work in order to limit effects on habitats and protected species.
  • Project organisation and quality assurance program, at the contractor’s as well as the client’s side; a fixed and rigid structure will hamper flexible and open ways of working, based on adaptive monitoring, for instance. It should be possible to pro-actively implement interesting but unforeseen options, even if this would lead to amendments to the contract; the QA-program should secure the quality of such choices.
  • Environmental management & monitoring plan, including an inspection and test plan: it is essential to decide well before the start of the works which parameters are going to be monitored, how and for what purpose, and how the resulting data are going to be processed, presented, analysed and evaluated; moreover, one must identify adaptive or corrective measures that can be taken if necessary and agree on how and when they will be taken.
  • Environmental inspection and test plan: to be agreed with the client and the relevant stakeholders, for the sake of openness and clarity in the environmental management.
  • Adaptive management procedures. These procedures are closely linked to the monitoring plan. Adaptive measures can be taken during construction, or they can be part of the Operation&Maintenance Phase.
  • Stakeholder involvement: even during construction there are good reasons to involve stakeholders, for instance in design optimisation and work planning. Local residents, but also nature management organisations and municipalities will have valuable local knowledge.
  • Communication strategy: project execution requires timely information of the public; in BwN-type projects it is advisable to pay due attention to the natural processes, including the uncertainty they involve. Also, successes as well as unexpected developments should be communicated openly.


Next action will be that the project Organisation - Contractor and Project Owner jointly - assure that the works are executed as intended, as specified in above plans. Adherence to these principles requires close management monitoring, and adoption or adjustment of plans and procedures when required.


Next phases 

After finalisation of contractual and organisational matters, the execution of the work can start. This also means that the next phase, operation and maintenance, comes within sight.

Apart from the usual workflow management, important points of attention are:

  • Monitoring environmental effects: more than in mono-functional projects, BwN-type projects require monitoring of the environmental effects - positive or negative - during execution. In order to enable an adequate response, it is important to process the data right after acquisition and translate them into usable management information.
  • Keeping stakeholders and the public informed of the progress during execution. It is important not to stop informing the public at the end of the Planning and Design phase, even if it is no longer legally required. The use of modern communication media is recommendable.
  • Preparing for O&M procedures. A BwN-type project does not end at handover of the completed works, since the response of the natural system will take much longer to develop. This response will have to be monitored, and, depending on the situation, management and maintenance may be necessary. As nature is largely unpredictable, this management will always be adaptive. If the system is actively operated, like in the case of economic activities, this may interfere with the natural system. Monitoring is needed to assess whether this remains within acceptable bounds. Ideally O&M procedures and agreements are established prior to project execution, but this should not exclude revision and optimisation on the go.


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