Following the proposal for the Delta Decision on Flood Risk Management in the Delta Programme 2015 and its embedding in the National Water Plan, another major step has been taken with the implementation of the new flood risk management policy. On 7 July, the House of Representatives adopted a bill to amend the Water Act. Delta Programme Commissioner Wim Kuijken is pleased with this new milestone.
Since 2010, the Delta Programme has worked on a proposal for new standards within a fundamentally different flood risk management policy. The new safety standards are founded on a risk-based approach. This means that in addition to the probability of a flood, the impact of a potential flood such as economic damage or fatalities is also taken into account when determining the normative height of flood defence systems. The new standard is expressed as a flood probability. As the impact may differ from one location to the next, standards have been set down for each individual dyke section.
The new standards are intended to ensure that every Dutch resident living behind a primary flood defence system will enjoy a minimum protection level of 10-5 per annum. This means that the individual risk of death as a result of flooding must not exceed 1 in 100,000 a year. A higher protection level is provided in areas prone to large groups of potential victims, major economic damage or serious damage due to failure of national vital and vulnerable infrastructure.
The development of the new standards is underpinned by an impressive study, conducted by a Dutch consortium comprising, inter alia, Deltares research institute, the Dutch Bureau for Economic Policy Analysis, HKV Consultants, Tilburg University, Delft University of Technology, and the Ministry of Infrastructure and the Environment. Within this study, a new calculation method has been developed that has been used to calculate the economically optimum flood protection level for the Netherlands. This has won the consortium a prestigious American award – the Franz Edelman Award – which was presented in 2013 during the Fourth National Delta Conference.