Influence of physicochemical parameters on surface water quality: a case study of the Brahmani River,India

This investigation is intended to evaluate the surface water quality of Brahmani River in order to determine its uses for different purposes. The water samples were collected from the strategic locations of the river from February 2014 to July 2015 and analyzed for physicochemical parameters such as water temperature; pH; electrical conductivity (EC); dissolved oxygen (DO); total dissolved solids (TDS); major cations, e.g., Na⁺, K⁺, Mg²⁺, Ca²⁺; and major anions, e.g., F^?, Cl^?, \( {\mathrm{SO}}_4^{2-} \), \( {\mathrm{NO}}_3^{-} \), \( {\mathrm{PO}}_4^{2-} \), and alkalinity. The water quality index (WQI) being a valuable and unique rating scale to depict the overall water quality status in a single term has been employed to determine the feasibility of using the river water as a source for various activities. The parameters with higher impact on water quality were selected to derive WQI of each selected sampling station. Results showed significant deterioration in quality of water at some of the sampling stations. WQI of Brahmani River ranged from 37.87 to 62.36 which falls in the range of good to poor quality of water. Pearson’s correlation matrix was derived to find possible interrelations among water quality parameters.     

Regional flood frequency modeling for a large basin in India

The computation of flood magnitude and its likely occurrence to design different hydraulic structures are major challenges to the research community. The present study has been carried out to identify the homogeneous regions in the Mahanadi basin in Chhattisgarh part (data from 26 gauge/discharge sites) of India using conventional and clustering-based homogeneity tests and then computation and identification of probability-weighted moment and L-moment-based best regional distributions for different regions. Different simple to complex distributions like Extreme Value-I, Generalized Extreme Value, Logistic, Generalized Logistic, Generalized Pareto, Normal and Log-normal, Wakeby-4, and Wakeby-5 was used in the analysis through standardizing procedure to compute regional distributions. The best-fit distribution selected by simulating several series and compute L-kurtosis along with the L-moment ratio diagram. The homogeneity analysis confirmed that this basin can broadly be divided into two different homogeneous regions with 15 and 11 stations in the first (Region-1) and second (Region-2) regions, respectively. The GEV distribution was found best suited for Region-1 while the Generalized Pareto worked well for Region-2. To make results more convenient for field application, catchment area-based equations were converted in the form of Dicken’s or Ryve’s formulae for these regions to estimate flood quantiles of any return period.

     

Collisional Penrose process and jets in Kerr naked singularity

In this article, we investigate the possibilities of energy extraction from an over-spinning Kerr spacetime using collisional Penrose process. This phenomenon can produce a high-energy ejecta of particles under certain favourable conditions. Unlike black holes, in this case, the particles endowed with higher energy can escape to infinity. We use this model to explore various possibilities of jet formation in an over-spinning geometry. Primarily we concentrate on the energy extraction associated with collisions taking place on the off-equatorial planes and find the signature of jets from them. We also apply this formalism to a toy model which could be useful in practical astrophysical scenarios. This is motivated from the atomic model where we have considered the decay of a circular orbit because of energy extraction via Penrose mechanism.     

Grain size, geochemistry, magnetic susceptibility: Proxies in identifying sources and factors controlling distribution of metals in a tropical estuary, India

The aim of this study is to understand the various sources and factors controlling the abundance and distribution of the metals through the analyses of selected metals (iron, manganese, chromium, copper, zinc and cobalt), sand, silt, clay, organic carbon and magnetic susceptibility of the surface sediments of Zuari estuary in three different seasons. Total suspended matter (TSM) concentration and salinity of near surface and bottom waters were also measured. The study undertaken for three seasons, based on 18 selected stations all along the estuary, indicated that the concentration of most of the metals were comparatively higher during pre-monsoon than in monsoon and post-monsoon seasons. Further, along the length of the estuary, high concentrations were observed at lower middle and lower estuary and also at few stations at the upstream end. Salinity, distribution of TSM, size of the sediment, organic matter, geomorphological setup, fresh water input from land and release of industrial waste within the estuary played a role in distribution and concentration of metals. Magnetic measurements indicated the dominance of haematite like minerals and helped in understanding the source and depositional processes.     

Turbulent dissipation rates across the Summer Monsoon Current

Ocean Dynamics - During the summer monsoon, the southern Bay of Bengal (BoB) hosts a cyclonic circulation known as Sri Lanka Dome (SLD) and the swift Summer Monsoon Current (SMC), which advects...     

Identification and characterization of marine geohazards in the deep water eastern offshore of India: constraints from multibeam bathymetry,side scan sonar and 3D high-resolution seismic data

The eastern offshore of India covers a vast stretch of sedimentary tract fed by major rivers like Ganges, Brahmaputra and Mahanadi in the north, Krishna and Godavari in the center, and Cauvery and Palar in the south, which led to variations in shelf-slope characteristics, degree of slope and hence slope instability. The structure as well as seismic attribute maps prepared from multibeam bathymetry and high-resolution 3D seismic data set has been analyzed to identify various geohazards in the deep water offshore regions of the east coast of India. These can be categorized as slope instability, slope canyons, shallow gas, mass transport complexes, sediment waves, gas hydrates, gas chimney, mud volcanoes and shallow faults. The slope instability is primarily related to rapid sedimentation by the active river systems while the other geohazards are often developed in association with shallow gas flows and leakages. The bottom simulating reflectors (BSRs) identified in the seismic sections indicate the presence of gas hydrates. Rapid sedimentation, BSR formation, dissolution and expulsion of water as well as gas and their subsequent vertical migration are responsible for the formation of shallow gas-related hazards. The results from the above analysis are of immense help in minimizing the risk of shallow hazards during exploration, drilling and subsurface installation activities along the eastern Indian offshore.     

Groundwater arsenic contamination in Ganga–Meghna–Brahmaputra plain, its health effects and an approach for mitigation

The authors’ survey of the Ganga–Meghna–Brahmaputra (GMB) plain (area 569,749 km²; population >500 million) over the past 20 years and analysis of more than 220,000 hand tube-well water samples revealed groundwater arsenic contamination in the floodplains of the Ganga–Brahmaputra river (Uttar Pradesh, Bihar, Jharkhand, West Bengal, and Assam) in India and the Padma–Meghna–Brahmaputra river in Bangladesh. On average, 50 % of the water samples contain arsenic above the World Health Organization guideline value of 10 μg/L in India and Bangladesh. More than 100 million people in the GMB plain are potentially at risk. The authors’ medical team screened around 155,000 people from the affected villages and registered 16,000 patients with different types of arsenical skin lesions. Arsenic neuropathy and adverse pregnancy outcomes have been recorded. Infants and children drinking arsenic-contaminated water are believed to be at high risk. About 45,000 biological samples analyzed from arsenic-affected villages of the GMB plain revealed an elevated level of arsenic present in patients as well as non-patients, indicating that many are sub-clinically affected. In West Bengal and Bangladesh, there are huge surface water in rivers, wetlands, and flooded river basins. In the arsenic-affected GMB plain, the crisis is not over water scarcity but about managing the available water resources.     

Impact Assessment of GIS Based Land Resource Inventory Towards Optimizing Agricultural Land Use Plan in Dandakaranya and Easternghats Physiographic Confluence of India

GIS based land resource inventory (LRI) with fine resolution imagery is considered as most authentic tool for soil resource mapping. Soil resource mapping using the concept of soil series in a smaller scale limits its wide application and also its impact assessment for crop suitability is controversial. In this study, we attempted to develop LRI at large scale (1:10,000 scale) at block level land use planning (LUP) in Dandakaranya and Easternghats physiographic confluence of India. The concept of land management unit was introduced in this endeavour. The impact assessment of LRI based LUP was exercised to develop efficient crop planning with best possible management practices. The study area comprised six landforms with slope gradient ranging from very gentle (1–3%) to steep slopes (15–25%). The very gently sloping young alluvial plains occupied maximum areas (19.95% of TGA). The single cropped (paddy) land appears to dominate the land use systems (40.0% of TGA). Thirty three landscape ecological units were resulted by GIS-overlay. Eighteen soils mapping units were generated. The area was broadly under two soil orders (Inceptisols and Alfisols); three great group (Haplaquepts, Rhodustalfs and Endoaquepts) and ten soil series. Crop suitability based impact assessment of LRI based LUP revealed that average yield of different crops increased by 39.2 and 14.5% in Kharif (rainy season) and Rabi (winter) seasons respectively and annual net returns by 83.4% for the cropping system, compared to traditional practices. Productivity and net returns can be increased several folds if customized recommended practices are adopted by the farmers. Informations generated from the study emphasized the potentiality of LRI towards optimizing LUP and exhibited an ample scope to use the methodology as a tool to assess in other physiographic regions in India and abroad.