The modern concept of flood risk assessment and management combined with uncertainty analysis includes new ideas and approaches to hydraulic and hydrologic modelling, model calibration and validation, as well as measures for flood mitigation and cost-effectiveness of these measures. During the last decades, a lot of new and more or less different methods, concepts, initiatives, approaches, organisations, papers have appeared at national and international levels. It seems that these valuable initiatives did not achieve the necessary goals. Definite conclusion about most of new methods, concepts, approaches, initiatives and organisations dealing with flood attenuation and river restoration or revitalization is that their good intention did not considerably improve flood management. Their costs are very high and the success is questionable.
Agree with you. Flooding is a natural phenomenon which cannot be avoided by human activities. What we can do is reducing the vulnerability and the damages. We must study individual cases to find effective and affordable solutions. In some cases simple solutions like changing land use, resettlement of few families etc. work well. Modern flood protection works are mostly comprised of very expensive structures such as pumping stations with large capacities, flood walls along the rivers and warning systems with very sophisticated instruments which are funded by foreign agencies. The problems become worse when the countries fail to maintain them.
Dear Dr BONACCI
You are very right, but I think that there is a very reliable solution to protect against floods: it is the construction of dikes, dams and spillways. really these solutions are very expensive, but are very reliable. Even this solution has other advantage is the supply of the water table by precipitation water.
Best reagrds
I'm not totally sure I understand your question, so forgive me if my response misses the question. The problem we seem to face in the US is that we are tied in large part to the in/out, 100-year protection or nothing, paradigm of the NFIP. The other problem is that although the Corps is moving toward a risk based program, the decision makers are of an age where they don't understand it and are more comfortable with the old deterministic ways. I think the answer lies in a community exceedance probability curve. This could be used to both price a community based insurance policy and it could support a larger array of flood mitigation measures.
Construction of dykes is a straightforward solution. However, other than the cost, there are some problems associated with dykes. What will happen when the designed flood level (return period) is exceeded. We are maintaining a scheme with 10-yr protection and the dykes were over-topped several times. In each time, we had to cut open the dykes since evacuation (by pumping or gravity outlets) takes more time. Further, it is not suitable for tropical countries where the volume of water to be pumped is high and the cost is unbearable. There are many alternative methods for flood protection. Each method has its advantages and drawbacks. Selection of most appropriate method lies in the hands of experts. It is true that, there are occasions where 'nothing' is better than halfway solutions.
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