Year Review 2021

Making raised sandy soil areas climate-robust: the work goes on

Lumbricus closing symposium underlines need to continue knowledge programme

Over the last four years the Lumbricus programme has involved the conduct of practice-oriented research, but also the testing of measures to enhance the climate-robustness of raised sandy soil areas. On 3 March, the programme was concluded with a governance closing symposium. Senior researcher Klaasjan Raat on Lumbricus: ‘If you want to implement structural changes in water management, you first need to understand which measures are effective and what further impact they have elsewhere in the system.’

In December 2016, the Ministry of Infrastructure and the Environment and a consortium of Water Authorities, knowledge institutions and businesses formally agreed to collaborate in the Lumbricus knowledge programme. Lumbricus dovetails well with the Water in the Circular Economy (WiCE) programme of the drinking water utilities. The importance of Lumbricus became abundantly clear on the occasion of the programme’s closing symposium this week.

Dry years

KWR researcher Klaasjan Raat: ‘Even before Lumbricus got under way, we were discussing the need for a knowledge programme on the climate-robust configuration of the raised sandy soil areas. There was a realisation at knowledge institutions and Water Authorities that a changing climate would have an impact on water availability and that we needed to prepare ourselves for it. We couldn’t have anticipated that, during the course of the programme, we would be confronted with three dry years in a row: 2018, 2019 and 2020. But this only emphasised the need for preparation.’

Three themes

The programme has produced a great deal of knowledge, insights, instruments and working methods for the climate-robust configuration and management of river basin areas in raised sandy soils. This was done on the basis of three themes:

  1. Configuring and managing: Which measures can you take?
  2. Scaling-up and combining: What is the impact?
  3. Implementing and deploying: How do we manage it?


The conclusion of Lumbricus does not of course mean the end of collaborative work and learning. This will go on, among others, under the KLIMAP programme, in which the Lumbricus field trials will be continued and be replicated in a further five Water Authorities. ‘This is precisely the moment when knowledge development is important,’ says Raat. ‘The Netherlands is facing big water management and water supply challenges. A lot needs to and will happen in the water transition. Naturally, there are no-regret measures that you have to take on an ad hoc basis in drought years, like the temporary closure of culverts in the smallest waterways as a means of retaining more water. But if you want to implement real structural changes in water management, you first need to understand which measures – technical, policy, financial – are effective and which are not, and what further impact they have elsewhere in the system.’

Subirrigation and weir pilots

You therefore need not only to show that something works, but also understand why. Raat explains that important advances were made in Lumbricus. ‘Thanks, for example, to properly dimensioned and conceived pilots, such as with subirrigation and smart weirs in Stegeren. And with the development of tools like WaterVision Agriculture and WaterVision Nature, with which to calculate the impact of measures. This work goes on, with one of the key steps being the evaluation of measures at the level of an entire river basin.’

True collaboration

Numerous partners have collaborated in Lumbricus on climate-robust water management. What has this effort produced? ‘In the Netherlands we talk a lot about collaboration,’ says Raat. ‘But true collaboration only arises if you also literally work together. In projects, in the field, in the analysis, in the organisation of workshops, and in programme direction – in the doing. That’s how you learn the other’s language, how you really come to see the issues from different points of view – of the water manager, farmer, scientist, decision-maker – and how you can take steps together. This worked very well in Lumbricus, with a practically implementable and evidence-based reference work as an end product.’