Assessment method of multiple flood protection improvements in a water system governed by a storm surge barrier: The case of Ramspol Barrier

Abstract

Climate change is adding more and more pressure to the water systems. The area which is protected by the storm surge barrier of Ramspol have high probability of flooding for climate projections in 2050 and 2100.
Nowadays, the development of the technology is providing with numerous tools and analytical models for the engineers. However, in the early stages of assessment is important to have in hand a decision making method capable to fast and reliably highlight the most promising solutions.
In this thesis an assessment method of multiple flood protection improvements have been developed in order to highlight the most promising ones. The assessment method is based on three decision making parameters, the decrease of water level maximum, the cost and the ecological impact. To handle the first aspect, the wind set-up formula, a lake level formula, the normal flow depth formula and the probabilistic model Hydra-NL have been used for the water level calculations. The implementation cost has been calculated using rough dimensioning and characteristic unit values. To qualitatively assess the aspect of the ecological impact, the concept of the ecological sign has been developed. The qualified improvements can be then handled from a second detailed assessment. In this thesis the second assessment stage is only a recomendation and have not been applied.
The method which developed have been applied for the case of Ramspol Barrier. From the 20 designed improvements, 5 have been qualified as the most promising and those are the construction of a breakwater in IJssel Lake, the construction of an outflow channel at Ketelbrug, the sizing-up of Zwarte Lake, the raising of the height of the dikes and the construction of flood plains.