Maintenance of the main water system

How much money is needed to maintain dams, dikes and storm surge barriers and how does the Minister of Infrastructure and the Environment (I&M) intend to finance the work? We have audited the maintenance of the main water system in the Netherlands. This system protects the country against flooding, regulates the volume of water and helps improve water quality. Rijkswaterstaat, an agency of the Ministry of I&M, is responsible for managing the main water system. The average budget to maintain the system until the end of 2020 is €160 million per annum.


Our analysis found that the Minister of I&M had underestimated the cost of maintaining the main water system in the years ahead. In 2011 she had concluded that a further €151 million would be needed until the end of 2020 but these additional budget funds have since proved inadequate. We have calculated that the additional funding will have to be raised by a further €132 million. These funds can be found largely from existing sources but there will still be a financing shortfall of €32 million.

Rijkswaterstaat has made improvements in its financial statements but they are still not fully up to date. A sum has been reserved on the balance sheet for management and maintenance work on the three infrastructure networks (highways, main waterways and main water system) but it is not known precisely how much of this balance sheet item is available for the main water system because Rijkswaterstaat does not break the item down into its component parts each year. It last did so at the end of 2014, when it concluded that €68 million was available for the main water system.


Parliament should have been provided with more information regarding the additional measures and funds necessary to maintain the main water system. More information should also have been provided on the funding available in the balance sheet item. Rijkswaterstaat is taking measures to improve its information management. In our opinion, these measures should also improve the provision of information to parliament.


The Minister of I&M wrote in her response to our audit that her budget was sufficient to respond to serious risks. She had also taken measures for the period to 2030, with some of the funding being provided through I&M’s draft budget for 2017. According to the Minister’s calculations, however, there would still be a shortfall of €18 million. She thought this was acceptable as it would act as an incentive for innovation and efficiency gains.