In 2024, Decisio evaluated the High Water Protection Programme (HWBP) subsidy scheme, in collaboration with organisational consultancy TwynstraGudde and architecture and engineering firm Sweco. Decisio examined more than 260 subsidies across 125 projects. By combining insights from data analysis with in‑depth discussions about specific water authority projects, we gained a clear understanding of how the scheme functions. The evaluation shows that, while the subsidy scheme contributes to efficiency, it also has several negative side effects.
HWBP subsidy scheme supports efficiency but has limitations
The HWBP subsidy scheme promotes efficiency and helps control the design of measures, project approaches, and the subsidy allocation process. At the same time, there is insufficient control over costs and risk provisions. This is evident from the fact that investment costs per kilometre and financial risk reserves in many projects exceed the ranges set out in the HWBP Project Approach Reference Framework and are considered desirable.
Higher cost estimates and risk reserves
Water authorities bear the implementation risk, which leads to conservative estimates and high reserves. This reduces the likelihood of budget overruns but increases overall costs. The effect is particularly strong in complex projects. The scheme provides insufficient guidance to limit this risk‑minimisation behaviour.
Adjustments to the scheme needed for future‑proof flood protection
In recent years, the implementing body of the subsidy scheme has introduced various guidelines to address undesirable effects of the scheme. One example is the reference framework, which includes rules on the costs and cost distribution of reinforcement projects. An important recommendation is to formally embed such guidelines, including the reference framework, in the revised subsidy scheme. This would ensure that the chosen solutions are legally secured.
More information
For more information, please contact Gerwin van der Meulen (g.vandermeulen@decisio.nl) or Guus Kersten (g.kersten@decisio.nl). You can also reach us by phone at +31 (0)20 670 05 62.
