Page 71 - AJWEP-v22i2

Flood risk assessment of Barak river valley

India’s climate is characterized by highly unpredictable management strategies in Assam to mitigate the
monsoon rainfall. The country is home to numerous impact of such disasters in the future.
large and small rivers, and prolonged heavy downpours The present study focuses on the Barak River, which
often lead to widespread flooding. India is a global is highly flood-prone. Each year, during the monsoon
hotspot for flooding. According to the Central Water season, it inundates the downstream floodplains and
Commission’s 2010 data, roughly 40 million hectares causes damage in the Cachar, Karimganj, and Hailakandi
of Indian land are susceptible to inundation, making it districts of Assam. The study aims to develop Barak
the world’s second most flood-prone country. Annually, River flood hazard models and risk assessments for the
an average of 7.6 million hectares bears the brunt of flood-affected villages.
these floods. Between 1953 and 2009, these floods Modeling and mapping flood hazard zones are
inflicted a staggering economic toll of approximately essential to flood disaster management. Flood hazard
200 billion dollars in damages while tragically claiming modeling methods are classified into three categories:
the lives of nearly 92,000 people. Flood damage in empirical, physical, and physically-based models.
9
India varies across states. Bihar, West Bengal, Orissa, The different types of empirical models are statistical,
Assam, Andhra Pradesh, and Gujarat are highly affected multi-criteria decision-making (MCDM), and machine
by flooding. In 2018, Kerala faced severe floods, with learning/artificial intelligence. Among the different
extensive damage to property, infrastructure, and MCDM models, the analytic hierarchy process (AHP)
agriculture, costing approximately Rs. 3000 crores for is the most extensively applied and well-known for
rebuilding efforts. Maharashtra, particularly districts flood hazard mapping. Other notable models in this
10
such as Mumbai, Palghar, Thane, Raigad, Satara, field include the frequency ratio (FR), Shannon entropy,
Sangli, Pune, and Kolhapaur, experienced significant and weight of evidence. According to Mudashiru
flood events in 2019 due to extremely heavy rainfall, et al., the application of empirical models in flood
17
emphasizing the importance of mitigation and adaptation hazard mapping has increased by 35% from 2000 to
strategies. Among all the states in India, 10 states 2019. The shift from labor-intensive manual flood
11
17
account for 46% of the country’s floods, with Uttar risk assessment technologies to high-tech digital
Pradesh and Bihar constituting the highest proportion. methods has enhanced risk assessment accuracy. The
18
Notably, 55% of Bihar’s geographical area is affected advent of different modern software, like Geographic
by floods, followed by Assam (50%), Uttar Pradesh Information System (GIS), in the 21 century, has
st
(37%), and West Bengal (32%). Physiographically, increased the application of modeling approaches in
Assam is primarily divided into two main drainage flood research, drawing considerable attention from
systems: the Barak Valley and the Brahmaputra flood researchers. Remote sensing applications have
Valley. Both river valleys are highly prone to flooding, enhanced the resolution and utilization of models in
which is closely linked to the monsoon season. The flood risk assessment and susceptibility mapping. The
formation of the monsoonal trough in the hilly and integration of remote sensing data with GIS, combined
plateaus of Assam leads to huge downpours, resulting with various hydrologic and hydrodynamic models, has
in excess accumulation of monsoonal rainfall in the enabled flood hazard, risk, and vulnerability mapping. 19
rivers and subsequent flooding in plain areas. Major
flooding events in Assam have been a recurring and 2. Study area
devastating natural disaster, impacting both life
and property in the region. The Brahmaputra River, The Barak River basin of India is the focus of the present
along with extreme rainfall events in the Arunachal research (Figure 1). The Barak River, originating from
Himalaya, contributes significantly to floods in Manipur, flows through Assam and further downstream
Assam. 12,13 Dhemaji district and Majuli Island through Bangladesh, ultimately emptying into the Bay of
14
15
are particularly notable as the worst flood-affected Bengal. The river basin area spans several states in India,
areas in Assam, with a significant portion of land including Meghalaya, Nagaland, Tripura, Manipur,
being inundated during flood events. The southwest Mizoram, and Assam. After passing through the Cahar
monsoon of 2019 brought heavy rainfall, leading to district of Assam, the river enters Bangladesh, and in
severe flooding in Assam, affecting millions of people certain places, it demarcates the boundary between India
and causing substantial damage to life and property. and Bangladesh. Physiographically, the Barak River
16
These events underscore the urgent need for improved basin is surrounded by hilly terrains on three sides:
flood forecasting models and effective flood hazard (i) the northern side is bordered by the North Cachar

Volume 22 Issue 2 (2025) 65 doi: 10.36922/AJWEP025040019