Life at the borderline: Responses of Ganges river dolphins to dry‐season flow regulation of river and canal habitats by the Farakka barrage

Exploitable potential is an ultimate derivable of theoretical potential, technical potential and/or storage potential. A number of hurdles come across when a potential site has to be exploited, thus, all theoretically and/or technically available potential cannot actually be developed/ exploited. Nepal is not an exception in this respect. Exploitation of run-of-river schemes has much less hurdle in comparison with storage development. The storage development, particularly the larger scale development, has even international implications, because the benefits of such development spread far beyond the national boundary. In the Nepalese case the downstream country, particularly India, is reluctant to recognize the downstream flow regulation benefits arising from flood-control and dry season flow augmentation. As such the current focus of exploitation of Nepalese hydro-potential should be on run-of-river type development and smaller size storage developments which can easily be materialized without much hurdle, but in a coordinated and well scheduled manner in a way not to hamper the larger storage development at the opportune future dates.HYDRO Nepal JournalJournal of Water, Energy and EnvironmentIssue: 19Page:1-5

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Reviving the “Ganges Water Machine”: where and how much?

Hydrology and Earth System Sciences ◽

10.5194/hess-21-2545-2017 ◽

2017 ◽

Vol 21 (5) ◽

pp. 2545-2557 ◽

Cited By ~ 2

Author(s):

Lal Muthuwatta ◽

Upali A. Amarasinghe ◽

Aditya Sood ◽

Lagudu Surinaidu

Keyword(s):

Groundwater Recharge ◽

Water Availability ◽

Water Demand ◽

Assessment Tool ◽

Monsoon Season ◽

Dry Season ◽

Ganges River ◽

Water Shortages ◽

Basin Water ◽

The Ganges

Abstract. Runoff generated in the monsoon months in the upstream parts of the Ganges River basin (GRB) contributes substantially to downstream floods, while water shortages in the dry months affect agricultural production in the basin. This paper examines the potential for subsurface storage (SSS) in the Ganges basin to mitigate floods in the downstream areas and increase the availability of water during drier months. The Soil and Water Assessment Tool (SWAT) is used to estimate sub-basin water availability. The water availability estimated is then compared with the sub-basin-wise unmet water demand for agriculture. Hydrological analysis reveals that some of the unmet water demand in the sub-basin can be met provided it is possible to capture the runoff in sub-surface storage during the monsoon season (June to September). Some of the groundwater recharge is returned to the stream as baseflow and has the potential to increase dry season river flows. To examine the impacts of groundwater recharge on flood inundation and flows in the dry season (October to May), two groundwater recharge scenarios are tested in the Ramganga sub-basin. Increasing groundwater recharge by 35 and 65 % of the current level would increase the baseflow during the dry season by 1.46 billion m3 (34.5 % of the baseline) and 3.01 billion m3 (71.3 % of the baseline), respectively. Analysis of pumping scenarios indicates that 80 000 to 112 000 ha of additional wheat area can be irrigated in the Ramganga sub-basin by additional SSS without reducing the current baseflow volumes. Augmenting SSS reduces the peak flow and flood inundated areas in Ramganga (by up to 13.0 % for the 65 % scenario compared to the baseline), indicating the effectiveness of SSS in reducing areas inundated under floods in the sub-basin. However, this may not be sufficient to effectively control the flood in the downstream areas of the GRB, such as in the state of Bihar (prone to floods), which receives a total flow of 277 billion m3 from upstream sub-basins.

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Effect of Ganges River Morphological Dynamics and Farakka Barrage on Upward Migration and Catch of Indian Shad (Tenualosa Ilisha) in Bangladesh

Tyumen State University Herald Natural Resource Use and Ecology ◽

10.21684/2411-7927-2016-2-3-34-58 ◽

2016 ◽

Vol 2 (3) ◽

pp. 34-58

Author(s):

Hasan Faruque ◽

Dewan A. Ahsan ◽

Maminul H. Sarker ◽

Elena F. Gladun

Keyword(s):

Ganges River ◽

Upward Migration ◽

Farakka Barrage ◽

Tenualosa Ilisha

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Impact assessment of structural barriers and flow regulation on the Ganga River morphology and ecology

10.5194/egusphere-egu21-14018 ◽

2021 ◽

Author(s):

Gaurav Kailash Sonkar ◽

Kumar Gaurav

Keyword(s):

Ecological Impact ◽

River System ◽

Flow Regulation ◽

Ganga River ◽

Structural Barriers ◽

Lateral Connectivity ◽

Discharge Data ◽

Minimum Flow ◽

Farakka Barrage ◽

Dolphin Population

The Ganga-Brahmaputra river system in the Himalayan Foreland supports diverse aquatic fauna. Decades of flow regulation through dams and barrages have affected their habitat suitability. To evaluate the impacts of large barrages on the morphology and habitat ecology we studied two different reaches (middle and lower) of the Ganga River. These reaches are the habitat of the endangered Ganga River dolphin (Platanista gangetica). In a reach in the middle Ganga between Bijnor and Narora barrage, a reported rise in dolphin population has been documented. In contrast, near the Farakka barrage in the lower reach of the Ganga River, a significant decline in the dolphin population has been observed.We use Corona and time-series Landsat satellite images along with flow discharge data to assess the morphological and ecological impact of the barrages. In middle Ganga, the dolphin habitat is isolated between the Bijnor and Narora barrage where the minimum flow is available throughout the year for the dolphins to thrive. &#160;On the other hand, in the lower Ganga, contrasting impacts are observed in the proximity (upstream/downstream) of the Farakka barrage. In the downstream, reduction in water (by one-third in the pre-monsoon discharge) and sediment discharge has decoupled the channel belt to its floodplain resulting in a loss of lateral connectivity. The presence of minimum flow between the Bijnor and Narora barrage has aided the dolphin population rise while the loss of lateral connectivity and excess siltation at the Farakka barrage has made the river reach unsuitable for habitation. &#160;&#160;

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