29 research outputs found
Analysing flood history and simulating the nature of future floods using Gumbel method and Log-Pearson Type III: the case of the Mayurakshi River Basin, India
No full textFloods of the Mayurakshi River Basin (MRB) have been historically documented since 1860. The high magnitude, low-frequency flood events have drastically changed to low magnitude, high-frequency flood events in the post-dam period, especially after the 1950s, when the major civil structure (Massanjore dam, Tilpara barrage, Brahmani barrage, Deucha barrage, and Bakreshwar dam) were constructed in the MRB. The present study intends to find out the nature flood frequency using the extreme value method of Gumbel and Log-Person type III (LP-III). The results show that the highest flood magnitude (11,327 m3 s˗1) was observed during 1957–2009 for the Tilpara barrage with a return probability of 1.85% and the lowest (708 m3 s˗1) recorded by the Bakreshwar weir during 1956–77 with a return probability of 4.55%. In the present endeavour, we have computed the predicted discharge for the different return periods like 2, 5, 10, 25, 50,100, and 200 years. The quantile-quantile plot shows that the expected discharge calculated using LP-III is more normally distributed than that of Gumbel. Moreover, Kolmogorov–Smirnov (KS) test, Anderson–Darling (AD), x2 distribution show that LP-III distribution is more normally distributed than the Gumbel at 0.01 significance level, implying its greater reliability and acceptance in the flood simulation of the MRB
Quaternary Alluvial Stratigraphy and Palaeoclimatic Reconstruction in the Damodar River Basin of West Bengal
No full textAnalysing the influence of Farakka Barrage Project on channel dynamics and meander geometry of Bhagirathi river of West Bengal, India
No full textAssessing the Groundwater Potentiality of the Gumani River Basin, India, using Geoinformatics and Analytical Hierarchy Process
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An Enquiry into Fitting Natural Channel Shape to Geometric Shape: A Study on River Jalangi, India
No full textAnalysis of Social and Psychological Terrain of Bank Erosion Victims: A Study Along the Bhagirathi River, West Bengal, India
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Assessing environmental awareness activism to river decay and recurring pollution using parallel multiple mediator model
No full textThe decay of rivers coupled with its escalated pollution is a concern worldwide. The present study intends to assess the agony of the riverine people due to the contamination of the Churni River and the transformation of their grievance into environmental activism at individual and community levels for rejuvenating the river and for a secured livelihood. The study observed an enriched concentration of biological oxygen demand, nitrate, and phosphate and a reduced concentration of dissolved oxygen during 2011–2020 due to the release of untreated industrial wastewater, sewage from urban areas, and agricultural runoff into the river. A systematic investigation reveals pollution-induced socio-psychological trauma and community awareness leading to the active involvement of the people in the environmental awareness movement, which was mediated by self-efficacy, self-responsibility, self-identity, and community value. A parallel multiple mediator model was employed, which included 29 parameters for exploring the key-mediated factors for the environmental movement. The model-based results identified that self-responsibility and community-value for upper stretch villages and self-efficacy and community-value for the lower stretch villages are significant mediators of environmental activism. A canonical component analysis predicted socio-demographic factors (e.g. age, dependency ratio female-male ratio, etc.) as intrinsically linked to environmental activism. This study is significant because it reveals how pollution and river degradation affect riverine people. It also clarifies how local grievances turned into environmental activism as a result of the documented socio-psychological trauma and growing community awareness. This study would thus play a pivotal role in understanding the human-nature complex to better planning and river restoration.</p
Measures of river channel efficiency through cross-sectional form
No full text The efficiency of an open river channel refers to how effectively the channel conveys water with minimal energy loss due to friction with the perimeter. Cross-sectional form, roughness characteristics and slope play pivotal roles in governing a channel’s efficiency. Previous studies commonly used hydraulic radius (Rh) and width/depth ratio (ζ=w/d̄) to assess channel efficiency. Rh lacks a dimensionless representation for comparing rivers of different sizes, while the ζ value has no specific scale (e.g., 0 to 1) to fix a channel's efficiency level. This research specifically investigates the influence of channel cross-sectional form on efficiency, assuming a given slope and roughness, and presents novel tools for measuring channel efficiency based solely on cross-sectional form. It is widely acknowledged that a semi-circular cross-section represents the most efficient channel form due to its minimal wetted perimeter. However, little attention has been given to comparing an open channel with an ideal semi-circular form and establishing a fixed efficiency parameter. Hence, three handy tools are proposed to measure the efficiency of open-channel cross-sectional forms. The first tool (E1) compares the cross-sectional area of the observed channel with the area of a semicircle having an equivalent perimeter; we define channel efficiency, E1, as the “ratio of the cross sectional area (A) of the channel, to the area of a theoretical semicircle (Ac) having the same wetted perimeter P”. The second tool (E2) compares the wetted perimeter of the channel with the perimeter of a semicircle of the same area as the observed cross-section. Finally, the third tool (E3) assesses the width/depth ratio of the observed channel by comparing it to the width/depth ratio of a semicircle of the same area. The effectiveness of these tools was validated using a computed dataset of size 1080 and a field-based dataset comprising 45 cross-sections obtained from the Jalangi River in India. The major highlights of the methods are as follows. • Three new indices of channel efficiency are proposed using the cross-sectional form. • The proposed methods are unit-free, with known scale limits for comparison.• The proposed indices are validated using field data from a tropical river
