Flood Hazard Zonation Atlas for Odisha

Mains Paper 3 : Disaster Management |

From UPSC perspective, the following things are important :

Prelims level : Not Much

Mains level : Flood control and management

Odisha has come out with a unique flood hazard atlas on the basis of historic flood inundation captured through satellite imagery over the period from 2001 to 2018.
It is expected to help the State manage floods more efficiently.

Flood Hazard Zonation Atlas

The National Remote Sensing Centre (NRSC) of the ISRO had taken the study on flood hazard Zonation for Odisha.
A large number of satellite images acquired over 18 years (2001-2018) were used. All satellite data sets were analysed and flood layers were extracted.
All the flood layers corresponding to a year are combined as one inundation layer, so that this layer represents the maximum flooded area in one year.
The NRSC analysis says about 8.96% (13.96 lakh hectares) of land in Odisha was affected by floods during 2001-2018. Out of total flood-affected area (13.96 lakh hectares), about 2.81 lakh hectares of land falls under high (inundated seven-nine times) to very high (inundated 10-14 times) flood hazard categories.
Eight out of 30 districts such as Bhadrak, Kendrapara, Jagatsinghapur, Balasore, Puri, Jajpur, Khordha and Cuttack districts are more flood-affected districts.
As high as 77% of Bhadrak and 70% of the Kendrapara district have been categorised as flood hazard.

Why Odisha?

Vast areas of the State are inundated when there is flooding every year in major rivers, namely, the Mahanadi, Brahmani, Baitarani, Subarnarekha and Rushikulya.
Some of the rivers like, the Vamsadhara and Budhabalanga, also cause flash floods due to instant run-off from their hilly catchments.
Damages due to floods are caused mainly by the Mahanadi, the Brahmani and the Baitarani, which have a common delta where floodwaters intermingle, and, when in spate simultaneously, wreak considerable havoc.
The entire coastal belt is prone to storm surges, which is usually accompanied by heavy rainfall, thus making the estuary region vulnerable to both storm surges and river flooding.

A useful resource

All such combined flood layers for 18 years were integrated into flood hazard layer representing the observed flood-inundated areas with different frequencies.
This layer was integrated with the digital database layers of Odisha.
The atlas would serve as a useful resource of information for policy makers, planners and civil society groups.

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