Adaptive Deltamanagement

The Delta Programme approach is based on adaptive delta management: we are looking far ahead, examining the issues we will face, and we are using these insights to timely take such measures as are appropriate and affordable at that time. We ensure that we can always respond flexibly to new opportunities and new insights: for example, by gradually giving the rivers more room, or by reinforcing the coast with sand replenishment to be adjusted as needed - more sand or less, or at a different location.

The Delta Programme has investigated what short-term and long-term solutions are needed to protect the Netherlands from flooding, to ensure an adequate supply of freshwater, to climate-proof our country, and to make it water-resilient. Finalising measures for the fifty to a hundred years ahead is difficult and in most cases not advisable. After all, solutions must be able to grow along with new insights and circumstances. On the other hand, we need to be prepared considering that it took several decades to complete the Delta Works. Moreover, we wish to ensure that it remains possible to implement the solutions by the time they are needed, at minimum cost. This involves taking the right steps at the right time: adaptive delta management.

Key elements in adaptive delta management

Key elements in adaptive delta management are:

  • linking short-term decisions to long-term issues in the fields of flood risk management and the freshwater supply;
  • ensuring the solutions are flexible;
  • having several strategies ready and being able to switch quickly if the situation changes (adaptation tracks);
  • linking flood risk management and freshwater supply investments to investments in, for example, spatial planning and nature, ensuring that redevelopments are water-resilient and climate-proof wherever possible.

Thus, we are making sure that sensible measures are taken now, while at the same time keeping sufficient options open in the future for the measures required then to protect the Netherlands from high water and to ensure a sufficient supply of freshwater.

Examples of the adaptive approach

An example is the approach to the replacement of hydraulic structures such as locks, sluices, weirs, and storm surge barriers. These structures are deteriorating, not just in terms of wear and tear but also from a technological perspective. Rijkswaterstaat has now made an estimate of which structures will have to be replaced and when for the coming fifty to one hundred years. By linking these replacements to developments in the Delta Programme we will avoid situations such as replacing an old sluice and then having to install a pump ten years later to cope with higher water.

Another example is the gradual and flexible expansion of the Climate-proof Water Supply in the central part of the Netherlands. Additional fresh water supplied from the River Lek and the Amsterdam-Rijn Canal is used to combat salinisation and drought. As the need to call on this water supply will increase in the future, the Delta Plan on Freshwater Supply sets out a gradual expansion of this Climate-proof Water Supply. The first step is an expansion from approx. 7m3 per second to approx. 15m3 per second via both Gouda (Waaijer sluice) and Bodegraven (Bodegraven sluice). This expansion is scheduled to be completed by 2021.

Monitoring, Analysing, Acting

Rather than waiting to be overtaken by new insights or developments, an adaptive approach entails continually being alert and taking cost-effective measures at the appropriate time. With the “Monitoring, Analysing, Acting” method, the Delta Programme maps out the progress made to date.

The Monitoring, Analysing, Acting method provides insight into four issues:

  • Are we still on schedule, is the implementation proceeding according to plan, and are we achieving the goals?
  • Are we still on track: do any new developments constitute reason to adjust choices made earlier?
  • Integrated approach: are we tackling the taskings in an integrated manner?
  • Participation: are government authorities, businesses, NGOs, and residents participating on a wide scale wherever necessary?

This method was adopted in 2017 and used in the purview of Delta Programme 2018. The Delta Programme regularly explores whether the course needs to be adjusted. To this end, the Signal Group was set up in 2017. The Signal Group is tasked with identifying and monitoring changing circumstances that could be relevant to the Delta Programme as a whole. The Signal Group is composed of experts from several authoritative institutes that are of relevance to the Delta Programme: the Royal Netherlands Meteorological Institute (KNMI), the Netherlands Environmental Assessment Agency (PBL), Deltares, Wageningen University & Research Centre (WUR), Rijkswaterstaat – Water, Traffic and Environment dept, and Statistics Netherlands (CBS). The Signal Group uses a method based on 8 indicators that generate timely and reliable information in order to adjust the Delta Programme strategies. The findings of the Signal Group and the impact, if any, of the signals identified on the Preferential Strategies, are presented in an annual report, communicated in the annual Delta Programme, and discussed with representatives of the Delta Programme regions and topics. A case in point involved the signal regarding a potential acceleration in sea level rise, which in 2019 prompted the Minister of Infrastructure and Water Management to initiate a multi-year Sea Level Rise Knowledge Programme. Over the next few years, this will generate more information on the probability and impact of an accelerated rise in sea level in terms of the Dutch delta, and on the options to sensibly anticipate such acceleration.

Six-year review

Once a year, the outcomes of the Monitoring, Analysing, Acting method are used to assess whether the implementation of the projects agreed upon is on schedule. The strategies can be adjusted annually. In addition, the Delta Decisions and Preferential Strategies are subjected to a systematic review every six years (see Delta Programme 2015). The six-year review is intended to carefully check whether developments necessitate adjustment of the Delta Decisions and Strategies, and, insofar as applicable, set down proposals for such adjustments. The first review will be conducted from mid-2018 until 2020; its results will be presented in Delta Programme 2021. The six-year review will lead to up-to-date Delta Decisions and Preferential Strategies: a new “photo” following a careful check and if need be, another adjustment in response to external and internal developments, incorporating the earlier adjustments (DP 2016 to DP 2020).