Flood management is a crucial part of disaster prevention and mitigation, particularly in the context of changing climate scenarios and socioeconomic development. The National Disaster Management Authority (NDMA) is a critical agency tasked with handling these challenges. Understanding the implications of flood management and the role of the NDMA is vital in comprehending a recent study on residual flood damage.
Residual Flood Damage Under Intensive Adaptation
The recent study titled “Residual Flood Damage under Intensive Adaptation” discusses how the risk of river flooding is likely to increase due to climate change and socioeconomic development. The study attempts to estimate the global cost of implementing adaptive flood measures based on local economic scenarios and costs of adaptation measures.
The focus here is on estimating the cost of Residual Flood Damage (RFD), which refers to the increases in flood damage that are unavoidable even under an adaptation strategy grounded in feasible adaptation costs. Infrastructure measures employed to mitigate flood risks form a significant part of this adaptation strategy.
How Is RFD Calculated?
RFD is part of the total Expected Annual Damage (EAD), an average of flood damages calculated over numerous events. The calculation method involves subtracting past Expected Annual Damage (from 1970-2000) from future EAD estimates (projected over 1000 years).
Key Findings of the Study
A striking finding from the study is that Assam will require 943 years of flood protection measures to avoid a catastrophic situation like the current one if its pace of preparedness and climate adaptation does not increase.
Flood-prone states like Bihar, Uttar Pradesh, and Meghalaya, on the other hand, will need 966, 935 & 996 years respectively. Riverine floods in India, which are considered one of the major natural disasters, have emerged as significant contributors to the country’s economic losses.
Facts and Figures on Flood Damage
The total flood-related losses in India were estimated to be over Rs 37 lakh crores from 1953-2017, as per the Central Water Commission. The study estimates RFD in South Asia to be around USD 4 million and adaptive costs around USD 3 million.
RFD, as a percentage of the gross domestic product, remained high in eastern China, northern parts of India, and central regions of Africa. There is potential to reduce RFD with shorter construction periods or lower adaptation costs, implying an immediate need for appropriate adaptation actions, including enhanced financial support for high-risk regions.
Understanding Flooding and Its Impact
A flood is an overflow of water onto land that is normally dry and can occur due to heavy rains, ocean waves coming onshore, quick snow melts, or dam or levee breaches. Floods can result from a few inches of water or may cover a house to the rooftop. They can occur within minutes or over a long period and may last days, weeks, or longer.
Flash floods are particularly dangerous as they combine the destructive power of a flood with incredible speed. These occur when heavy rainfall exceeds the ability of the ground to absorb it, or when water fills normally dry creeks or streams.
National Measures for Disaster Risk Reduction
The NDMA, Sendai Framework for Disaster Risk Reduction, National Flood Commission, Disaster Management Act, 2005, and Flood Plain Zoning are part of the measures instituted for disaster risk reduction. These are fundamental in preparing for and mitigating the impact of floods.
Impact of La Nina and El Nino on Floods
La Nina and El Nino have varied effects on climate and consequently, flooding patterns. La Nina is characterized by usually cold ocean temperatures in the equatorial Indian Ocean, and El Nino by unusually warm ocean temperatures in the equatorial Pacific Ocean. The impact of these phenomena on the monsoon climate and flood patterns is a topic of keen interest and study.