Context: Floods are a recurrent feature during the monsoons in Assam. Still, the Centre and state governments have not found ways to contain the toll taken by the raging waters.
Significance of floods in Kaziranga’s ecosystem

• The entire area of Kaziranga formed by alluvial deposits from the Brahmaputra and its tributaries — is centred on the river.
• There is a consensus that floods are necessary for Kaziranga by virtue of it being riverine ecosystem.
• The regenerative nature of floods helps replenish Kaziranga’s water bodies and maintain its landscape, a mix of wetlands, grasslands and semi-evergreen deciduous forests.
• The floodwaters also function as a breeding ground for fish.
• The same fish are carried away by the receding waters into the Brahmaputra — in a way, the park replenishes the river’s stock of fish too.
• The waters also help get rid of unwanted plants such as water hyacinth which collect in huge masses in the landscape.

Reasons of flood in Brahmaputra valley
Natural Reasons

• High sedimentation and changing course of river: River Brahmaputra is in its youth stage in valleys of Assam which leads to frequent changes in course causing flood as water swells up. Further, the river comes from a high slope (Tibet) to a flat plain in Assam, its velocity decreases suddenly and this results in the river unloading the sediment.
• Monsoonal rainfall: India receives ~80% of rainwater from monsoon and that too is erratic and uneven in nature. High concentrated rain in parts of north-east leads to heavy rainfall in short time causing flood.
• Topography of region: Guwahati’s topography — it’s shaped like a bowl — does make it susceptible to water logging which is exacerbated by flooding.

Anthropogenic reasons

• Unplanned expansion of the cities: Lack of scientific approach in planning has led to severe encroachments in the wetlands, low lying areas, hills and shrinkage of forest cover. This also contributes in higher sedimentation of the areas. The denuded hills and loss of wetlands lead to artificial floods.
• Lack of cooperation among basin states: The rainwater from Meghalaya and the surrounding hills often causes flash floods in Guwahati. However, recognition of the problem has not led to any meaningful conversation between the two states on flood control.
• Overreliance on embankments: The state has primarily relied on embankments to control floods since 1950’s. The pressure of the surging water and frequent changes in course of river takes a toll on these walls and they need constant reinforcement — by all accounts, that hasn’t happened in Assam.

Suggested solutions

• Preventing encroachment in green cover: State needs to bring in public domain the bye-laws associated with constructing building, implement the environment impact assessment in letter and spirit and mobilize people for participative approach in preventing loss of green cover.
• Refocusing on traditional methods: Traditional methods of water harvesting used by ethnic communities of northeast need to be practiced to prevent flooding with low-cost sustainable model.

Road Ahead

• “Integrated basin management” one that needs all the basin sharing (China, India, Bangladesh and Bhutan) countries to come to an understanding about taking measures in the catchment areas is the only long-term solution. For that, interstate relationships, political cooperation and the role of the government are important.

About Kaziranga National Park

• It is located in the State of Assam and is the single largest undisturbed and representative area in the Brahmaputra Valley floodplain.
• The park was declared as a National Park in 1974 and was also declared as a Tiger Reserve in 2006.
• In 1985, the park was designated as a World Heritage Site by UNESCO
• It is also recognized as an Important Bird Area by BirdLife International for the conservation of avifaunal species.
• It also houses the world’s largest population of Great One-horned Rhinoceros (IUCN Status- Vulnerable).

Additional Facts

• Kazi 106F: It is described as the country’s only Golden Tiger which resides in the Kaziranga National Park.It is also known as ‘Tabby tiger’ or ‘Strawberry tiger’.