Maximum Flood Discharge of Dams Designed are not able to cope up with the present Flood Discharge?

MAx flood discharge is based on past data at the time of design and therefore most of our dams and bridges may not be in tune with these types of flash floods occuring one off in a large duration.No design will take into consideration such freak data .they are ignored in stastistical analysis.

I feel the problem lies in how and where the dams are constructed.the problem lies with POLITICIANS alone.its not the designers or consultants.These Politicians use their influence to distort the reccomendations ,change the location,area, height of the dam ---All parameters are manipulated to suit their political interests and vote banks and protect thier land if it lies in that area aganist submerging in the reservoir,or getting the dam constructed in a way to provide thenselves with the irrigation water in their lands even IF IT IS AGANIST THE DOWNSTREAM design.These politicians dont look from the nations point of view,its self interest which is foremost.

So the result is there is a vast change which will have happened between the design and actual construction( something like slip between cup and the lip but deliberate here)

If we see the history of design of every damned dam in india you will here locals mentioning this manipulation .

This is why many of the canals and height of the dams go aganist nature and end result is disaster .SAtelite images can now provide immense data and help us understand the topography better and also make sure that in case of freak calamities like this how and where the excess discharge will take route . so when a dam is constructed these also should be taken into consideration and such routes should not be designed for habitation

Take the case of surat sometime back....to save the structure the water was opened INTO the CITY!!!!!!!!!

IS THAT A DESIGN? So to cope with all crisis we need good design and construction to original expert design with disaster management in place

Tha is true.MFD is calculated based on catchment area,drainage,and 100 yrs history of rain falls,contour of the area.The fall out of constructing the dam is  that water table starts increasing around the surrounding area.The catchment area is not able to absorb rain water and pressure increases on drainage area.In my opinion, catchment area should be marked properly and no colonisation or any sort of encroachment allowed.i would rather say santuary should be developed.These are the precautionary measures at the design stage.For the post design,rain prediction should be more acurate so that proper monitoring can be done through opening of gates and discharg diverted. The man back up,u have to pay the price for the develpment.

Keshav ji your concern can not be ruled out but this question is about the construction of dam.

Pragya ji, first this is about dams and not about bridges and secondly as Mr Basab Ghosh has rightly pointed out that the capacity calculation is not about old and new construction technology.

It is correct that the flood levels are decided based on past history. It is very-very difficult to estimate future freak floods. Theoretically speaking if we can predict the future demographic trend of the catchment area based upon the predicted economic growth of country and that area then we can predict the land use pattern of the catchment area and thus the discharge into the river leading to prediction of flood level at the dam.

But all this is very complicated and with no guarantee of correctness.

Small dams at frequent intervals have to be constructed rather than constructing huge dam with high storage capacities. The small dams will distribute water evenly and the problem of flooding can be avoided during heavy rains.

maximum flood discharge is a historical figure and history does changes infact the practical construction is limited cost set by the I&W department and the same is sometimes not representative of all the parameters at site it is just representative parameters while it performs well in ordinary circumtances but some times in extradinaty circumtances it fails and in any satanard of indian design fatigue is not accounted for.

Stop constructing Dams

Any thing that we try to overcome the nature will not get success. One will definetely have the side effects of it. Olden days there were no dams which stores water in heavy quantity.
We used to have local water bodies which will be filled whenever there is rain. Now a days all such small and middle size waterbodies near the villages are dried up because the natural water catchment is controlled at some major points by these heavy dams. Result of which smaller waterbodies are not getting filled and Ground water level in those areas are going down.
Whenever there is heavy rain we can observe in last 100years floods caused more damage than in the past after construction of such dams. It is only after construction of such dams ground water level is touching more than 300ft in many villages where as earlier it used to be around 15 to 20 ft.

Nature will look for its own way to maintain the balance in nature. as a result we can witness those floods. Rain occured only for twodays. but the destruction caused would be beared by us lifetime.

I agree with you. We are still sticking to the old style of bridge construction ignoring the new technologies. For example, the recent flood in Andhra pradesh and Karnataka, broke many bridges and dams majority of which were made with old pattern of construction technology.