Action frameworks for land subsidence

Published: 14 December 2015

More and more administrators realise that subsidence in the Netherlands is increasingly affecting the quality of life in urban and rural areas. The damage caused by subsidence is increasing every year: flood damage, damage to railways and roads, dikes, pipelines and buildings. Something has to change. That is clear. But how should we go about it? The workshop ‘How to tackle land subsidence' during the Knowledge Tasting organised by Deltares, STOWA and the Dutch Association of Regional Water Authorities gave people a taster of the possible approaches.

What measures are feasible and who can I work with?

Water scientists, administrators and civil servants working for municipal and provincial authorities discussed the question ‘what measures are you considering as an organisation?’ These measures were shared and placed in an action framework. The action framework made it clear whether measures were pro-active (i.e. tackled the cause) or reactive (i.e. addressed the impact of subsidence) and whether responsibility resides with public or private bodies. This resulted in a list of measures that fit in different action frameworks. In this way, it was soon found that it is a good thing to start conversations with stakeholders by pointing out that things will change because current practice is no longer adequate. The next step is to think about what action is needed.

action frameworks for land subsidence explained during workshop

Chris Seijger explains how frameworks can make the discussion concrete and help government authorities to change their approaches to subsidence

The participants then selected two measures and assessed them on the basis of criteria including: administrative support, technical and financial feasibility, how adaptive the measures are and when they can be implemented (2016-2050). A clear picture of how measures match up to these criteria helps to determine the chances of success. One of the measures discussed was the phasing out of areas where levels are kept high to prevent damage to foundations, and the possible approaches. During the session, it emerged that one water authority was intending to phase out this approach, while another was actually working on introducing it. The participants proposed ideas such as phasing out the approach over a period of thirty years so that home-owners are not suddenly faced with a problem, and subsidies for new foundations in areas with soft soils.

Method provides a concrete picture of ‘who will do what, and when’

‘This action framework method for subsidence based on governance is new,’ explains Chris Seijger, a researcher at Deltares specialising in governance and spatial development. ‘We go beyond an exploration of the technical measures and make governance concrete by discussing various options with stakeholders: who will do what, and when. The method helps governments to explore measures and action styles for land subsidence. At present, what you often see in practice is that nobody feels responsible for land subsidence and that people pass the buck. Even though we are all affected by the nuisance and the costs. The frameworks can make the discussion concrete and help government authorities to change their approaches to subsidence. In this way, promising measures are identified.’

The method has already been used in the municipalities of Gouda and Almere and at the Zuiderzeeland water authority.