Monitoring dual-season hydrological dynamics of seasonally flooded wetlands in the lower reach of Mayurakshi River,Eastern India

The seasonally flooded wetlands are often neglected due to their ephemeral and erratic appearance and small size, however, their hydro-ecological importance, socio-economic values are equivalent to the permanent wetlands. Using dual-season Landsat multi-spectral imagery, this study highlights a comprehensive monitoring of the hydrological dynamics of wetlands in the lower reach of the Mayurakshi River at a 14-year temporal resolution with the seasonal mode of 1987–2014 time frames. Our results demonstrate the seasonal and periodic hydrological variability of water presence frequency (WPF) in six wetland complexes defined for this study. The Hijal, Ghambira and Maldah wetland complexes are highly affected by the change of WPF, while Dwarka complex is relatively stable. The assessment of WPF change analysis showed that the method is proficient in identifying stable and physically vulnerable wetland patches and absolute loss of wetland inundation frequency resulting from various anthropogenic causes like regulation of river, dry farming practices and other integrated developmental works. The outcome of our study provides a robust basis for the fundamental hydrological and ecological studies and helpful for the conservation and management of seasonally flooded wetland resources in the tropical monsoon climate.     

Assessment and monitoring of urbanisation on Himalayan lacustrine environment-a case study in Mirik municipality area

The Mirik lake is a well-known tourist destination in the Darjeeling Himalayan region of West Bengal. In the last few decades, the lake area experienced a surge in demand for the hospitality industry with the consequences of unrestricted municipal town growth. On this perspective, this research work addresses the contemporary problems of the Mirk municipality area involving the lake system using technologies of remote sensing and GIS. In accordance with the primary objective, the detailed land use/land cover change analysis of the past twenty years shows a significant escalating trend in built-up area as it has increased from 149.85 ha in 2000 to 178.25 ha in 2020, where the lake expresses a steady reduction of its perennial part. The gradual shrinkage in the lake area may become of grave concern and therefore, this particular work tries to examine the water quality parameters of Mirik lake. Analyses have shown that the lake shrinkage may be attributed to waste disposal, landfill pollution etc., substantially contributed to the raised level of suspended sediment concentration (3724.26 mg/lit in 2020) near the boundaries. Moreover, the outcome of the developed water pollution model identifies that the western and south-western parts of the lake are the most polluted regions and confirms numerous inlets of the western side push up the level of phosphorus, nitrogen and biological oxygen demand in lake water. Such lake degradation is a real threat to the mountainous lacustrine environment, and it requires comprehensive plans for better management practices at some regular interregnum.

     

Role of panchayat (Local self-government) in managing disaster in terms of reconstruction,crop protection,livestock management and health and sanitation measures

The Panchayati Raj Institution is a statutory body elected by the local people through a well defined democratic process with specific responsibilities and duties. It is the most appropriate institution from village to the district level. The role of Panchayats (local self governing institutions) is important in view of their proximity to the local community, universal coverage and enlisting people’s participation on an institutionalized basis. Panchayat and municipalities are local governing institutions in countries like India, have a constitutional mandate under the 73rd and 74th constitutional amendments Act. Apart from the proper implementation of different ongoing developmental programmes, the panchayat system has to play pivotal roles in respect of natural as well as man-made disaster management. In India, Particularly in West Bengal the village level Disaster Management Committee is headed by ward members of gram panchayat. The Panchayati Raj Institutions provide adequate space to the weaker section of the communities at its three levels, i.e. village, block and district. Good governance can be an instrumental feature in poverty reduction. This study was undertaken in cyclone affected areas in West Bengal to assess the role of panchayat in disaster management. The empirical study revealed that main role performed by the panchayat in respect of disaster was reconstruction of damaged houses, crop protection measures, livestock management, health and sanitation measures. Besides these broad aspects, the panchayats officials also organized health camp, involved in rescue operation, arranging temporary shelters and so on as disaster management operation. Total 60 gram panchayat officials and 150 villagers were selected randomly as respondents for the present investigation. The data were analysed into mean score, rank position and spearman correlation coefficient to achieve the objectives. The findings of the study indicated that significant differences were observed on the opinion of the villagers and officials on reconstruction of houses and health and sanitation measures. The roles performed by the local self-government in disaster management were very poor. There was absolutely lack of involvement of people’s representative. Therefore, adequate supports are suggested on these aspects from the representatives in association with higher authorities.     

Comparative analysis of two rainfall retrieval algorithms during extreme rainfall event: a case study on cloudburst, 2010 over Ladakh (Leh), Jammu and Kashmir

Natural Hazards - Intense rainfall events lead to floods and landslides in the Western Himalayas (WH). These rainfall amounts are considered comparatively moderate over the plains. These events,...     

Grain size and geochemical partitioning of heavy metals in sediments of the Damodar River – a tributary of the lower Ganga, India

 The distribution of Si, Al, Fe, Mn, Cu, Zn, Ni and Cr in different grain-size fractions and geochemical association of Fe, Mn, Cu and Zn with <63-μm size fraction of bed sediments of Damodar River has been studied. In general, concentrations of heavy metals tend to increase as the size fractions get finer. However at two sites, near mining areas, the coarser particles show similar or even higher heavy metal concentrations than finer ones. The higher residence time and/or presence of coarser particles from mining wastes are possibly responsible for higher metal content in the coarser size fractions. The chemical fractionation study shows that lithogenic is the major chemical phase for heavy metals. Fe and Mn are the major elements of the lithogenic lattice, constituting 34–63% and 22–59%, respectively, of total concentrations. Fe-Mn oxide and organic bound fractions are significant phases in the non-lithogenic fraction. The carbonate fraction is less significant for heavy metal scavenging in the present environment and shows the following order of abundance Zn>Cu>Mn>Fe. The exchangeable fraction of the Damodar sediments contains very low amounts of heavy metals suggesting poor bioavailability of metals. Received: 18 August 1998 · Accepted: 1 December 1998     

The quasi-steady-state cosmology: a study of angular size against redshift

The data on angular sizes and redshifts of ultracompact radio sources used by Jackson & Dodgson in a recent paper have been applied to the various theoretical models in the framework of the quasi-steady-state cosmology proposed by Hoyle, Burbidge & Narlikar. It is found that although acceptable fits to the data are available for the flat models, those with a negative curvature of spatial sections provide a better fit. These latter models require low densities of matter and as such do not demand too high a proportion of dark matter. A comparison is made with the work of Jackson & Dodgson and theoretical implications of the test are discussed.