Syllabus:
GS3: Disaster and disaster management
Context:
Recently, researchers from IIT Delhi and IIT Gandhinagar have come up with a District Flood Severity Index (DFSI) accounting for the impact of the flooding events in all the districts of the country.
About District Flood Severity Index (DFSI)
- DFSI is a comprehensive index that ranks districts by flood severity, based on both flood magnitude and its impact on people.
- This index is jointly developed by researchers from IIT Delhi and IIT Gandhinagar.
- It is developed for measuring district level flood severity as districts are the basic units of administration, planning and disaster management.
- The index uses the annual data collected by the Indian Meteorological Department (IMD) since 1967 along with district population to get a first-cut measure of how severe a flood is in an area.
- It is India’s first significant attempt to chart a district-based, observation-driven measure of flood vulnerability and damage.
Parameters of the DFSI
- DFSI uses six factors divided into two categories.
- Flood Magnitude Factors: It includes the mean duration in days of all flooding events in a district, the percentage of the area that is historically flooded and population in the district.
- Impact of Flood Factors: The total number of deaths and number of people injured.
- This index in its current form does not account for the aerial extent of agricultural fields that have been flooded.
Key Findings
Top 5 Flood-Prone Districts by DFSI Score
- Patna (Bihar) – DFSI: 19.37
- Murshidabad (West Bengal) – DFSI: 19.01
- Thane (Maharashtra) – DFSI: 18.88
- North 24 Parganas (West Bengal) – DFSI: 18.86
- Guntur (Andhra Pradesh) – DFSI: 18.84
• Thiruvananthapuram district has faced over 231 flooding events, averaging more than four per year.
• Districts such as Lakhimpur, Dhemaji and Kamrup in Assam, and Gorakhpur and Ballia in Uttar Pradesh, also feature prominently, with some experiencing more than 200 flood events over five decades.
• Chamoli in Uttarakhand ranks in the top 30, highlighting the severe impact of rare but intense events like glacial lake outburst floods (GLOFs).
• The DFSI highlights the growing flood risks in urban centres such as Mumbai, Pune, and Nagpur, where rapid, unplanned development in low-lying zones has worsened the situation.
• Additionally, coastal regions in states like Tamil Nadu, Gujarat, Andhra Pradesh, and West Bengal are increasingly vulnerable to both cyclones and intense rainfall events.
Need for DFSI
- Flood Prone Country: India is among the most flood-prone countries, with around 1.13 lakh flood-related deaths between 1975 and 2015, averaging 2,765 annually. Its dependence on the southwest monsoon, which delivers 75% of rainfall in just four months, heightens flood risk.
- Districts are core units: Researchers emphasized the need for a district-level flood severity index since districts are the core units for administration and flood management in India.
- Reporting limitations: The study uses annual data from the IMD since 1967, mainly covering major riverine floods. Smaller floods or urban events may be missed due to reporting limitations.
- Lucania in existing flood indices: Existing flood indices mainly focus on flood magnitude or inundation, without capturing their actual impact on people.