Brief on Old Brahmaputra: Go with Flow
Old Brahmaputra River is a distributary of the Brahmaputra (Jamuna) River though in past, it was the dominant flow path of the mighty Brahmaputra River. The Old Brahmaputra River is the lifeline of the Jamalpur-Mymensingh region of Bangladesh and serves various ecosystem services such as source of drinking and domestic water, irrigation, fisheries resources, navigation and so on. However, the upstream reach of Old Brahmaputra River is facing serious siltation of sediments in recent years and consequently, the river offtake cut-off from the parent river during dry season. Offtake management is a key issue in order to keep the river alive all year round; ensure dry season flow in other connected rivers with Old Brahmaputra (such as the Sitalakha, Jhinai, Bansi, Banar); and make the present dredging scheme in Old Brahmaputra by Bangladesh Inland Water Transport Authority (BIWTA) sustainable.
The objective of this project is to assess the morphological characteristics of the Old Brahmaputra offtake and to develop suitable off-take management options (structural and non-structural). Furthermore, innovative dredging options will be explored in the river reach to ensure dry season flow in Old Brahmaputra River and its distributaries along with other water usage/ecosystem services in the river are also studied. The flow ratio of Old Brahmaputra and Brahmaputra rivers has decreased significantly from 1960s but a slight increasing trend of the ratio is noticeable from 2009 to 2017. Historical satellite images of the offtake area suggest that some interventions are needed for stabilizing the offtake. In this context, the offtake management options are being simulated with mathematical models in order to find a sustainable option to stabilize the offtake and ensure dry season flow in the river for sustaining ecosystem services.