Erosion and sediment transport in the Ganges river basin (India)

Abbas, Nazar; Subramanian, V.

doi:10.1016/0022-1694(84)90162-8

Cited by 126 publications

(51 citation statements)

References 10 publications

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“…Both TDS and TDB seem to be affected by the possible threshold of erodibility reached at the cyanobacterial crust under the extreme runoff conditions (the largest rainfall together with the longest plots). This is consistent with our results with Eros and OM and with studies on chemical erosion in arid basins, where solute mobilisation is reported to be controlled in the first instance by the runoff, except for carbonates when their abundance is limited (Abbas & Subramanian 1984;France-Lanord et al 2003).…”

Section: Solutes In Runoffsupporting

confidence: 93%

Sediment content and chemical properties of water runoff on biocrusts in drylands

Lázaro

Mora

2014

Biologia

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In drylands, water erosion can be a process with important economic and ecological implications, and is very dependent on the soil surface cover. There is broad agreement that biocrusts protect the soil from erosion in a wide range of circumstances. However, there is little information available on the effect of rain and biocrust types on this protective capacity and there is particularly very little knowledge on the erosive effects of runoff on biocrusts, which are expected to be larger in larger drainage areas, on the resistance of biocrusts to the combined effect of raindrops plus runoff flow and on the solute mobilisation by runoff in biocrusts. To answer these questions, we performed 96 rainfall-simulationin situ factorial experiments, including two biocrust types (cyanobacteria and lichens), three rain types (42, 63 and 77 mm h −1 , always 20 min rain), four plot lengths (1, 2, 3 and 4 m long) and four replicates. In each experiment, runoff volume was measured and a runoff sample was taken to determine (i) the amount of dry matter in runoff, (ii) the amount of organic matter among the dry matter, (iii) the electrical conductivity, pH and alkalinity in runoff water. The main findings were: biocrusts strongly protected soil against water erosion, even under the most erosive conditions, and the protection increased with the successional development. Biocrusts were very resistant to the impact of raindrops and also to runoff flow, although an emergent hypothesis arose: under the most erosive conditions, a threshold of erodibility could be reached at the cyanobacterial biocrust. The lichen crust also protected the soil against the removal of soil soluble substances. The development of a biocrust could change the chemical composition of the solutes in runoff.

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Section: Solutes In Runoffsupporting

confidence: 93%

Sediment content and chemical properties of water runoff on biocrusts in drylands

Lázaro

Mora

2014

Biologia

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“…The sediment load reported by Goswami (1985) was derived for the period 1955±1979 (disregarding the gap in the data from 1961±1965 and in 1970). The sediment load of the Ganges (Table I) obtained from this work is in close agreement with the values reported by the Netherlands Engineering Consultants Ltd. (NEDECO, 1967in Khalil et al, 1995, Singh (1988) and Abbas and Subramanian (1984). The suspended sediment load for the Brahmaputra (Table II) estimated in this study conforms closely to the values reported by NEDECO (1967) and Subramanian (1987) and is also close to the estimates provided by Hossain (1992), Coleman (1969) and Holeman (1968).…”

Section: The Suspended Sediment Loads Of the Ganges And Brahmaputra Rsupporting

confidence: 91%

“…It should also be noted that, besides the Ganges±Brahmaputra River in Bangladesh, a signi®cant portion of the suspended load of the Ganges River is transported to the coastal sea through the Hoogly distributary. Abbas and Subramanian (1984) estimated that the suspended load of this distributary at Calcutta in India (Figure 1), was 328 million tonnes yr À1 . Taking into account the sediment load discharged through the Hoogly distributary (Figure 1), the mean annual suspended sediment load transported to the coastal sea by the Ganges and Brahmaputra rivers can be estimated to be about 850 million tonnes.…”

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confidence: 99%

The Ganges and Brahmaputra rivers in Bangladesh: basin denudation and sedimentation

et al. 1999

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Abstract:Every year the Ganges and Brahmaputra rivers in Bangladesh transport 316 and 721 million tonnes of sediment, respectively. These high loads of suspended sediment re¯ect the very high rate of denudation in their drainage basins. The average mechanical denudation rate for the Ganges and Brahmaputra basins together is 365 mm 10 3 yr À1 . However, the rate is higher in the Brahmaputra Basin than that in the Ganges Basin. Several factors, including mean trunk channel gradient, relief ratio, runo, basin lithology and recurring earthquakes are responsible for these high denudation rates. Of the total suspended sediment load (i.e. 1037 million tonnes) transported by these rivers, only 525 million tonnes (c. 51% of the total load) are delivered to the coastal area of Bangladesh and the remaining 512 million tonnes are deposited within the lower basin, osetting the subsidence. Of the deposited load, about 289 million tonnes (about 28% of the total load) are deposited on thē oodplains of these rivers. The remaining 223 million tonnes (about 21% of the total load) are deposited within the river channels, resulting in aggradation of the channel bed at an average rate of about 3 . 9 cm yr À1 . Although the Brahmaputra transports a higher sediment load than the Ganges, the channel bed aggradation rate is much higher for the Ganges. This study also documents a wide range of interannual, seasonal and daily variation in suspended sediment transport and water discharge. Interannual variation in sediment deposition within the basin is also suggested.

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“…The average annual rainfall varies from 760 mm at the western end of the basin to more than 2290 mm at the eastern end. The sediment load of the Ganges at Farraka Dam is 1235 t·km −2 ·y −1 [45]. The vast sediment deposition makes the soil alluvium cover more than 52% of the basin.…”

Section: The Ganges Basinmentioning

confidence: 99%

“…The Ganges-Kobadak (GK) Irrigation Project, the largest surface water irrigation project in the country, was conceived of in 1954 to improve the quality of life and economic solvency of the people living in southwest region by achieving self-sufficiency in food through increasing agricultural productivity. After the Farakka Barrage went into operation, the drastic fall in the available surface and ground water for farming led to a steady decline of rice production in the southwest region of Bangladesh [45]. As a consequence, the Ganges-Kobadak Irrigation Project came to a halt in 1994, which adversely affected 350,000 acres of agricultural lands [66].…”

Section: Impact Of Hydrologic Alterationmentioning

confidence: 99%

Impact of the Farakka Dam on Thresholds of the Hydrologic Flow Regime in the Lower Ganges River Basin (Bangladesh)

Gain

Giupponi

2014

Water

102

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Abstract: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 . The results demonstrate that due to water diversion by the Farakka Dam, various threshold parameters, including the monthly mean of the dry season (December-May) and yearly minimum flows, have been altered significantly. The ecological consequences of such hydrologic alterations include the destruction of the breeding and raising grounds for a number of Gangetic species, the increase of salinity in the southwest coastal region of Bangladesh and a reduction of fish and agricultural diversity. The major findings in this paper have a number of policy-level implications to aid water sharing mechanisms and agreements between the government of Bangladesh and India. The methodological approach presented in this study is applicable to other river basins.

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Erosion and sediment transport in the Ganges river basin (India)

Cited by 126 publications

References 10 publications

Sediment content and chemical properties of water runoff on biocrusts in drylands

Sediment content and chemical properties of water runoff on biocrusts in drylands

The Ganges and Brahmaputra rivers in Bangladesh: basin denudation and sedimentation

Impact of the Farakka Dam on Thresholds of the Hydrologic Flow Regime in the Lower Ganges River Basin (Bangladesh)

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