The recent Kerala floods would indeed be studied in detail as to how, why and safety measures for future events
A. Among the many reasons, the important are
1.The rains are around 30% more than what the state should have received. This year, Kerala received 2086mm of rain. In 1924, Kerala has 3368 mm of rain and had similar floods with loss of life and property.Around 6 distrcits recieved 20-59% higher rains.
2.The heavy rains meant early raising water levels in the dams. Instead of the gradual build up to peak levels by septemeber-october, this year, the dams were full by July-August itself. Of the 59 dams, above 50 od them had reached peak levels. The gates of about 35 dams had to be opened for safety reasons. Idduki dam (highest arch dam in Asia),Mullaperiyar dam had to open its gates which brought all the water to the catchment areas of the Iddukki dam, that was already in danger zone.On August 10, all the five shuuters of the Idukki dam had to be opened and the waters flooded the downstream areas.
3.The human factor: the greed of few of us had led to the suffering for most of us in this situation. Rampant deforestation,stone quarrying, sand mining, brazen construction on the river banks and river beds.
4. The consequences of an ill-planned dam or hydroelectric project from the ecological point of view. The classic example is the push for the Atthirappilly hydro-electric project that has been said to have major ecological damage as per the Enviornmental assessement reports (page 85 of this pdf http://www.moef.nic.in/downloads/public-information/wg-23052012.pdf).
5.Ignoring the critical reports like the Gadgill report/Westerb Ghats ecology expert panel of 2011 about the importance of demarcating and preserving Ecological sensitive zones.
1.Malabar Migration: The huge movement of people over few decades upto 1970s-1980s added pressure on the pristine land (huge tracts of land converted for inhabitation and agriculture).
2. Ill-timing of opening of the dam gates: In the aftermath of the floods, few experts have questioned the delay in waiting for the dam levels to become critical and then opening the gates, it could have be done earlier in a controlled manner (https://www.dailyo.in/variety/kerala-floods-idamalayar-dam-idukki-dam-pinarayi-vijayan/story/1/26125.html).
3. Lack of Early warning and relocation of people at risk: was it at all possible to anticipate and do this, easier said than done.
4. Sub-optimal Disaster preparedness at the grassroot level: If we look at Japan and its earthqaukes, people are trained, have drills and kits in anticaption, perhaps such prepardness at the local village/taluk level is needed to mitigate the damage.