Mrinal Talukdar
For the rest of India, Assam and floods are often seen as synonymous, with many believing that floods are the state's biggest problem. In reality, this is not the case. While floodwaters cause damage, they recede quickly, allowing life to regenerate within weeks and for normalcy to return.
The true devastation occurs when an embankment gives way, leading to a catastrophic tragedy in its path.
However, beyond the immediate impact of floods, a more persistent and insidious problem plagues the region: erosion. Since 1950, Assam has lost approximately 7.4 per cent of its landmass, translating to about 8,000 square kilometers. This is equivalent to the size of a major district in the state.
While earthen embankments are commonly used to manage floods, their role in exacerbating or mitigating erosion is a subject of much debate. This article examines whether earthen embankments are necessary and analyzes their effectiveness and potential drawbacks in addressing Assam's erosion crisis.
The British rulers sought to discourage the demand for ‘bunds,’ but some years after independence, it became a popular method to get votes from Muslim-dominated constituencies of the old Goalpara district. By the 1970s, it had become a mainstay of Assam politics, providing both votes and money as a complete ecosystem was built around it.
The Assam Embankment and Drainage Act, 1953, repealed the Assam Embankment and Drainage Act, 1941. It provides for the construction, removal, and maintenance of embankments, as well as the drainage and improvement of land in Assam. The preamble of this Act emphasizes its role in ensuring the effective construction, maintenance, management, and removal of embankments to protect land and property from flood damage and waterlogging, ultimately enhancing agricultural productivity and safeguarding human settlements.
Under this act the first embankment in Assam was constructed on the Brahmaputra River at Palasbari, near Guwahati, in 1954. This initiative was part of the post-independence efforts to control floods and manage water resources in the region.
Assam has
Earthen embankments, or bunds, have been the go-to solution for flood control in Assam. These structures line riverbanks, aiming to prevent floodwaters from inundating nearby areas.
Benefits
Immediate flood relief: Embankments act as barriers, containing floodwaters within the river channel and protecting adjacent lands. This is crucial during the monsoon season when the Brahmaputra swells significantly.
Short-term erosion mitigation: By preventing floodwaters from reaching riverbanks directly, embankments can reduce erosion in the short term.
Drawbacks:
Altered sediment flow: Embankments disrupt the natural flow of sediment. By confining floodwaters, they cause sediment to accumulate within the river channel. This can lead to:
Increased flood levels due to a raised riverbed
More severe erosion when embankments fail
Downstream erosion: Embankments can worsen erosion downstream. Confined within a narrower channel, the water velocity increases, exerting greater erosive force downstream of embankments.
Structural weaknesses: Embankments are susceptible to breaching or overtopping during severe floods, leading to catastrophic failures and potentially even more destructive flooding.
Environmental impact: Embankments disrupt the natural floodplain ecosystem. Floodplains, which are periodically inundated, are vital for:
Groundwater recharge
Nutrient deposition
Biodiversity
Loss of fertile agricultural land
The massive erosion-induced displacement, the inhabitants of the chars have either relocated in search of land or become daily wage laborers, severing all ties with agricultural ownership.
When these dispossessed people travel to Upper Assam and North Bank (considered the stronghold of indigenous people) in search of work, they are often viewed as illegal Bangladeshi immigrants — an idea deeply ingrained in Assamese political discourse.
Mainstream Assamese nationalist organizations and media subject them to humiliation, treating them as if they have come to encroach on their land and the politics of hate started from that point.
A more comprehensive approach is needed to tackle Assam's erosion woes. Here are some promising alternatives and complementary measures:
Reforestation and vegetative barriers: Planting trees and restoring vegetation along riverbanks creates a natural barrier against erosion. Additionally, roots help bind the soil, reducing the impact of water currents.
Riverbank reinforcement: Using more durable materials like concrete or geotextiles can offer better protection against erosion. These materials are more resistant to water's erosive forces and can help stabilize the banks over the long term.
Floodplain management: Allowing rivers to follow their natural courses and floodplains to function naturally can help reduce the impact of floods and erosion. Techniques like floodplain zoning and creating floodwater retention areas can mitigate floods while preserving the natural ecosystem.
Community-based approaches: Involving local communities is crucial for sustainable solutions. Initiatives like constructing bamboo barriers and promoting sustainable land use practices empower residents to protect their land and livelihoods.
Integrated river basin management: A holistic approach to managing the entire Brahmaputra River basin is essential. This involves coordinating efforts across regions and sectors, considering the entire river system's dynamics. Integrated river basin management can help balance flood control, erosion prevention, and environmental conservation.
In conclusion the earthen embankments offer some temporary flood relief, but they are not a silver bullet for Assam's erosion crisis. A combination of engineering solutions, natural methods, and community engagement is needed to address this complex challenge. By adopting a multifaceted approach, Assam can work towards mitigating the impact of erosion, protecting its land and people, and ensuring a sustainable future.
