Md Al- Fahad

The Old Brahmaputra River, once a lifeline for millions, has now deteriorated significantly due to siltation, habitat degradation, and excessive water extraction. Its revival is crucial not only for biodiversity but also for sustaining the livelihoods that depend on inland fisheries and agriculture.

Scientific studies have documented the rapid sedimentation and reduction in water flow in the Old Brahmaputra. Research by Islam et al. (2010) indicates that excessive sediment deposition has led to significant morphological changes, diverting much of the water towards the Jamuna River. This has resulted in the formation of shoals, loss of aquatic habitats, and declining fish stocks.

Hydrological data from the Bangladesh Water Development Board (BWDB) show a significant drop in the river's discharge over the past decades. The average dry season flow has declined from approximately 3,000 cubic meters per second (cms) in the 1960s to less than 500 cms in recent years (BWDB, 2022). This decline has severely impacted aquatic biodiversity and reduced water availability for irrigation, threatening food security in the region.

Inland fisheries, once thriving in the Old Brahmaputra, have suffered greatly. According to the Department of Fisheries (DOF, 2023), fish catches from the river have declined by nearly 60% over the last three decades due to habitat destruction, pollution, and overfishing. Indigenous fish species such as Tengra (Mystus spp.), Pabda (Ompok spp.), and Rita (Rita rita) have seen drastic population reductions.

A socio-economic survey by Haque et al. (2021) revealed that 70% of fishing-dependent households in the region have shifted to alternative livelihoods due to declining fish stocks. This transition has exacerbated poverty and food insecurity in fishing communities.

To restore the river, targeted dredging can help regain its depth and flow capacity. Rahman et al. (2018) suggest that sustainable dredging, combined with riverbank stabilization, can improve the Old Brahmaputra’s navigability and ecological health. Implementing community-led conservation programs, establishing fish sanctuaries, and enforcing seasonal fishing bans can aid in restoring fish populations. Studies on successful models in other Bangladeshi rivers, such as the Halda, show that such initiatives can boost fish stocks (Kabir et al., 2020).

Ensuring equitable and sustainable water distribution between upstream and downstream regions is crucial. The government must engage stakeholders, including India, to negotiate sustainable transboundary water-sharing agreements. Additionally, riparian vegetation plays a critical role in preventing erosion and maintaining water quality. Restoration efforts should focus on reforestation along riverbanks and protecting adjacent wetlands to improve water retention and reduce siltation.

Reviving the Old Brahmaputra requires multi-stakeholder engagement. Government agencies, researchers, local communities, and international bodies must collaborate to implement sustainable river management practices. Investment in long-term river restoration projects, backed by scientific research and traditional knowledge, is essential to ensuring a resilient ecosystem and sustainable livelihoods.

The revival of the Old Brahmaputra is not just an environmental necessity but a socio-economic imperative. If timely actions are not taken, the river’s decline will continue to impact biodiversity, fisheries, and agriculture, worsening the struggles of millions who rely on it. A science-based, community-driven approach is the only way forward.

The writer is ex-President, River Defenders Club (BRF-RDC), Postgraduate Student, Bangladesh Agricultural University (BAU), Mymensingh-2202