Statutory Assessment Instrument

Statutory Assessment Instrument

Flood risk

Flood defences to be assessed using new flood probability standards with effect from 1 January 2017

In the Netherlands, we have strict requirements for the strength of our primary flood defences. The Dutch Water Act sets out what needs to be done by the managers of those defences to determine whether the requirements are being met. The Ministry of Infrastructure and the Environment supplies the Statutory Assessment Instrument (WBI2017) for this purpose.

With effect from 1 January 2017, there will be new standards for flood defences in the Netherlands. The new standards are stated as flood probabilities and they guarantee a basic level of safety for everyone. There is additional protection in places where floods can result in large numbers of casualties or major economic damage.

The WBI fits in with the new standards. The instrument consists of a ministerial regulation and a number of documents stating how the assessment should be conducted. Things like software, schematisation manuals and technical reports are available for the implementation of the assessment.

Our role in the Instrument and the results

Deltares developed the technical elements and the software for the Instrument using new knowledge, insights from research and experience with the previous instrument.

The success of the instrument depends not only on its quality. The knowledge and experience of users, and existing data and information about the dike, are equally important. In order to acquire experience with the new instruments, dike managers and engineering firms practised with the technical elements and the software during a full-scale drill from September to late December 2016.

The combination of new knowledge, the tailoring in line with the new safety standards and the need for practical tools are what makes the Instrument such a challenge.
Goaitske de Vries
Deltares expert levees
I am sure that the Statutory Assessment Instrument wouldn't be there without Deltares. They have all the knowledge and that is where all the development took place.
Roald Lapperre
Director/Deputy Director-General of the Dutch Ministry of Infrastructure & the Environment

For this project Deltares has collaborated with the following partners:

  • Rijkswaterstaat

Want to know more about this project?

Goaitske de Vries
Expert levees