Riversare a lifeline of millions in every part of world wether it is India, Bangladesh or Netherland. The flood delivers rich and vital nutrients to the river valley between the foothills and plain areas. Almost every country had adopted River embankments as a flood management strategy. in India these embankments have afforded some form of flood protection to the rural and urban dwellers and villages have mushroomed around the embankments, such as this village school. But they are also susceptible to breaches. so the questions and concerns is: what impacts do embankments have on river dynamics? Do embankments reduce perceived flood risk?
Kundan,
I agree with Ilan but with a caveat. Civilization needs dikes and levees to reduce the occurrence of flooding but also we need to understand that understand that hazards that come with them. First of all we need to have a robust understanding of weather patterns, expected rainfall with the regions, the associated flood models and ultimately they need to be designed based upon an agreed upon return period.
In recent years, the Netherlands has approved a plan to mitigate the risk from the North Sea by designing for a 10,000 return period. This is a costly endeavor but in their eyes it is a viable financial commitment.
https://www.edf.org/blog/2015/08/19/what-we-can-learn-1000-years-dutch-flood-management
In the end the question is not whether embankments, dikes or levees are a false sense of security but rather what is the return period for the design event and to what standard are they built.
Please let me know if you have any questions.
Sincerely,
David Vaughn
Hi Kundan,
from a risk assessment perspective things are clear: building the dike (if done properly) can reduce the hazard, and if everything stays unchanged the risk will also be lower. Of course to people a dike can also be an invitation: yes, it makes areas near the river safer, but for a full understanding of the potential consequences a relatively deep understanding of the hazards processes as well as probabilities is required - a dike will likely withstand normal flood situations, thereby indeed providing a risk reduction. However, in extreme flood events that actually lead to dam/dyke failure the consequences will be extra severe. Also, areas protected by a dyke are often seen as safe, inviting more people to move there, hence the number of elements at risk (assets, people) increases. Because of that the overall risk can actually increase.
Best regards, Norman
This paper may give some other ideas to address these questions:Article Trust and its Effects on the Public's Perception of Flood Ri...
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