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.
- 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.