Temporary Flood Barriers

In this report temporary flood barriers are investigated. Temporary flood barriers are barriers that are installed during a flood event and are removed after the flood event. With the increasing climate change effects, flood events are becoming more frequent. During floods, sandbags are often used as temporary flood barriers. Filling and placing sandbags is time-consuming and requires a lot of manpower. That is why in this report other forms of temporary flood barriers are investigated, namely the Mobile Dike, Boxwall and Geodesign Barrier. The research question that is answered in this report is:

How can video analysis be used as a new monitoring tool for the behaviour of temporary flood barriers?

This question is answered by investigating the failure mechanisms of the temporary flood barriers and by testing the temporary flood barriers on a test site in Roermond, The Netherlands. Five cameras were installed to observe the water levels. Furthermore, the water levels were measured by divers that measure the hydrostatic pressure, from which the water level can be derived. 

All the temporary flood barriers remained stable during the tests. This was not predicted in the failure mechanism calculations, which indicated that the Boxwall and the Geodesign Barrier were not stable when no water was present. In the calculations the wind force for the design of structures was used. During the tests there was a much smaller wind force, which explains why the flood barriers remained stable. 

The water level was detected in two ways: with cameras aimed at water level scales and with divers. Graphs were made of the water level plotted against the time. The graphs from the water level scale data resemble the graphs from the diver data, but the graphs from the diver data are much more precise.  

Video analysis can be effectively used as a new monitoring tool for the behaviour of temporary flood barriers. In this report is focused on water level monitoring, but for further research, video analysis can also be used to detect deformation, displacement or damage of the temporary flood barriers. Another possibility for further research is the use of video processing techniques in Python to improve the accuracy of the water level detection in the video analysis. Video analysis can also be used to detect the water level before the temporary flood barriers are installed. If the water level exceeds a certain value, a signal can be given indicating a flood and the need to install the temporary flood barriers.