International Journal of Fisheries and Aquatic Studies
2020, Vol. 8, Issue 3, Part A
Climate change and anthropogenic impacts of the freshwater flow in the gorai river system of BangladeshAuthor(s):
Md. Shariful Islam, Md. Abdul Wahab, Muhammad Shahidul Haq, Shahroz Mahean Haque and Nafia Binte RyhanAbstract:
The Ganges River supplies fresh water to the South-West region of Bangladesh mainly through one of its distributaries—the Gorai River. The length of the river is 199 km and the area of the Gorai River catchment is 15,160 km². India commissioned a barrage on the Ganges River at Farakka in April 1975 to divert water and make the Bhagirathi-Hooghly River navigable. The Gorai used to discharge into the Bay of Bengal through the Mathumati and Baleswar Rivers. The Madhumati is connected to the Nabaganga at Bordia point. This is the drainage path of the Gorai water, which now reaches the Bay mainly via the Passur and Sibsa Rivers. The distribution of the Gorai River flow at Bordia between the Nabaganga and Madhumati Rivers and tidal conditions which influence the sediment concentration are not known. The objective of this study is to monitor the freshwater flow in the Gorai River System of Bangladesh. The study is carried out based on primary and secondary data sources. The variation of river flow within a natural range plays an important role in promoting the social-ecological sustainability of a river basin. In order to determine the extent of the natural range of variation, this study assesses hydrologic flow thresholds for the Lower Ganges River Basin. The flow threshold was calculated using twenty-two “Range of Variability (RVA)” parameters. The impact of Farakka Dam on the Lower Ganges River flow was calculated by comparing threshold parameters for the pre-Farakka period (from 1934 to 1974) and the post-Farakka period (1975–2013). The diversion has reduced the dry season discharge of the Ganges and Gorai rivers in Bangladesh. Statistical analyses indicate that the changes in the dry season discharge of these rivers are significant. The ecological consequences of such hydrologic alterations include the reduction of fish and agricultural diversity. Reduced discharge in the Gorai River has induced accelerated sedimentation and increased salinity in the southwest region of Bangladesh. The methodological approach presented in this study is applicable to other river basins.Pages: 37-43 | 460 Views 20 DownloadsDownload Full Article:
How to cite this article:
Md. Shariful Islam, Md. Abdul Wahab, Muhammad Shahidul Haq, Shahroz Mahean Haque, Nafia Binte Ryhan. Climate change and anthropogenic impacts of the freshwater flow in the gorai river system of Bangladesh. Int J Fish Aquat Stud 2020;8(3):37-43.