Discovery of lamproites near Vattikod Area, NW margin of the Cuddapah basin, Eastern Dharwar craton, southern India

A cluster of lamproite dykes are located 1 km west of Vattikod village at the NW margin of the Cuddapah basin, Eastern Dharwar craton, southern India, during the pursuit for locating primary diamond source rocks by adapting multifarious applications. These exotic rocks are emplaced along WNW-ESE to NW-SE trending fractures in the granitic rocks belonging to the Peninsular Gneissic Complex. Ten out of twelve lamproites occur near Vattikod village and one each is located in the vicinity of Marepalli and Gundrapalli villages respectively. These lamproites, though highly altered, contain microphenocrysts of altered olivine, clinopyroxene, phlogopite, leucite and sanidine and translucent to opaque, amoeboid shaped patches of glass set in a groundmass rich in carbonate, phlogopite, serpentine, and chlorite. This new cluster of lamproites constitutes a part of the recently discovered Ramadugu lamproite field. The Vattikod and Ramadugu lamproites, together with those from Krishna lamproite field and the Cuddapah basin, constitute, a wide spectrum of ultrapotassic magmatism emplaced in and around the Palaeo-Mesoproterozoic Cuddapah basin in southern India.     

Environmental flows in India: towards sustainable water management

Abstract

The strong wet and dry seasons of tropical monsoon hydrology in India necessitate development of storage and flow diversion schemes for utilization of water to meet various social and economic needs. However, the river valley schemes may cause adverse flow-related impacts due to storage, flow diversion, tunnelling and spoil disposal. There may be critical reaches in which altered flows are not able to sustain the river channel ecology and riparian environment that existed prior to implementation of the storage and diversion schemes. In the past, environmental flows in India have usually been understood as the minimum flow to be released downstream from a dam as compensation for riparian rights, without considering the impacts on the river ecosystem. Rivers in India have been significantly influenced by anthropogenic activities over the past 60 years and have great social and religious significance to the vast population. This paper explores various aspects of past, present and future environmental flow assessment (EFA) in India highlighted by case studies from rivers across the nation. It demonstrates that multidisciplinary studies requiring expertise from a range of fields are needed for EFA, and that environmental flows are necessary for aquatic ecosystems to remain in a healthy state and for the sustainable use of water resources. The major focus areas for the development of EFA research in India are the creation of a shareable database for hydrological, ecological and socioeconomic data, developing hydrology–ecology relationships, evaluation of ecosystem services, addressing pollution due to anthropogenic activities and promotion of research on EFA. At the same time, efforts will be needed to develop new methods or refine existing methods for India.

Editor D. Koutsoyiannis; Guest editor M. Acreman

Citation Jain, S.K. and Kumar, P., 2014. Environmental flows in India: towards sustainable water management. Hydrological Sciences Journal, 59 (3–4), 751–769.     

Seasonal and Monthly Variation of Vertical Structure of Temperature,Salinity and Heat Flux of the Bay of Bengal

Seasonal and monthly variations of heat flux have been investigated in this study using the Modular Ocean Model of version 3 (MOM 3) simulations and 52 years Simple Ocean Data Assimilation (SODA) products. These variations of the heat flux in different boxes of the Bay of Bengal (BOB) in different depths show the different behavior of the boxes. It is seen that the model and SODA results are comparable. The basin shows north-south variation in the surface from winter to spring whereas there is east-west variation in the mixed layer throughout the year except winter. The remote effect caused by warm water penetration from Pacific Ocean through the Strait of Malacca and coastal Kelvin waves keeps the basin warm most of the year. This article addresses the mechanisms of the seasonal variation of the vertical structure of the temperature and heat flux components.     

Rectangular tank surface aerators: scale up criteria and energy conservation

Surface aeration experiments were conducted in two types of rectangular tanks of aspect ratios i.e., length to width ratio (L/W) of 1.5 and 2 and developed simulation equations to correlate the oxygen transfer coefficient, k and power number, P₀ with a parameter governing theoretical power per unit volume X. The parameter X is defined as equal to F^4/3R^1/3, where F and R are impellers’ Froude and Reynolds numbers respectively). Results have shown that the P₀ can not be simulated singularly with either Reynolds number, R or Froude number, F, which results in scale-effects; there appears to be a need to incorporate the effects of both F and R. It was found that P⁰ is uniquely related to X for rectangular aeration tanks of both aspect ratios, however, such relationships are different depending upon the aspect ratios. It has been demonstrated that energy can be saved substantially if the aeration tanks are run at relatively higher input powers. It is also demonstrated that smaller sized tanks are more energy conservative and economical when compared to big sized tanks, while aerating the same volume of water, and at the same time by maintaining a constant input power in all the tanks irrespective of their size.     

Estimation of specific yields of individual litho-units in a terrain with multiple litho-units: A water balance approach

In a terrain with more than one litho-unit, the traditional water balance approach provides a single spatially averaged specific yield. A methodology is proposed here, which can be applied to estimate specific yields of individual litho-units in such terrains. This approach is demonstrated here considering two watersheds, which are covered partly by limestone and partly by sandstone. Watershed wise specific yields were estimated using a traditional water balance method. The specific yields thus obtained are the volume-weighted averages of the specific yields of the individual litho-units in the watersheds. Based on the volumes of aquifers desaturated and the watershed wise specific yield values, a set of two linear equations in two variables was formulated. These linear equations were solved to get the specific yields of the individual litho-units. Specific yields of sandstone (Chandarpur Group) and limestone (Charmuria Formation) units in the study area were thus estimated to be 0.004 and 0.037 respectively.     

Free-convective flow of non-Newtonian fluid with heat sources

An analytical study is performed to examine the effects of temperature-dependent heat source on free-convective flow of non-Newtonian fluid (Walters's liquidB). The expression for the velocity field has been obtained by the Laplace transform technique. The influence of the various parameter entering into the problem is extensively discussed.     

Cylindrically symmetric inhomogeneous universe with electromagnetic field in string cosmology

Cylindrically symmetric inhomogeneous string cosmological model in presence of electromagnetic field is investigated. We have assumed that F ₂₃ is the only non-vanishing component of F _ij . To get the deterministic solution, it has been assumed that the expansion (θ) in the model is proportional to the eigen value σ ¹ ₁ of the shear tensor σ ⁱ _j . The physical and geometric aspects of the model are also discussed.      

Quantifying land use/land cover spatio-temporal landscape pattern dynamics from Hyperion using SVMs classifier and FRAGSTATS®

This study aims to quantify the landscape spatio-temporal dynamics including Land Use/Land Cover (LULC) changes occurred in a typical Mediterranean ecosystem of high ecological and cultural significance in central Greece covering a period of 9 years (2001–2009). Herein, we examined the synergistic operation among Hyperion hyperspectral satellite imagery with Support Vector Machines, the FRAGSTATS^® landscape spatial analysis programme and Principal Component Analysis (PCA) for this purpose. The change analysis showed that notable changes reported in the experimental region during the studied period, particularly for certain LULC classes. The analysis of accuracy indices suggested that all the three classification techniques are performing satisfactorily with overall accuracy of 86.62, 91.67 and 89.26% in years 2001, 2004 and 2009, respectively. Results evidenced the requirement for taking measures to conserve this forest-dominated natural ecosystem from human-induced pressures and/or natural hazards occurred in the area. To our knowledge, this is the first study of its kind, demonstrating the Hyperion capability in quantifying LULC changes with landscape metrics using FRAGSTATS^® programme and PCA for understanding the land surface fragmentation characteristics and their changes. The suggested approach is robust and flexible enough to be expanded further to other regions. Findings of this research can be of special importance in the context of the launch of spaceborne hyperspectral sensors that are already planned to be placed in orbit as the NASA’s HyspIRI sensor and EnMAP.     

Influence of the mean period of ground motion on the inelastic dynamic response of single and multi degree of freedom systems

This paper focuses on examining the effects of frequency content of the ground motion on the inelastic demands imposed on both single degree of freedom (SDF) and multi degree of freedom (MDF) steel‐framed systems. A detailed literature review is conducted to identify the indicator that best represents the frequency content of ground motion. The mean period (T_m) of ground motion is selected owing to its ability to distinguish between various spectral shapes of ground motion, and its relationship with magnitude, distance and site characteristics. Inelastic displacement demands on SDF systems for target ductility levels are first studied in the light of T_m, using a suite of 128 ground motion records. The study is then extended to MDF systems with the help of incremental dynamic analysis by employing the same ground motion ensemble to assess the influence of T_m on various engineering demand parameters. The results obtained indicate that, for SDF systems, the amplification of displacements occurs when the period ratio between elastic period (T_e) and T_m is lower than unity. For MDF systems, the results demonstrate that the influence of higher modes on the base shear and maximum storey drift profile becomes more pronounced, as T_m approaches the higher mode periods of the structure. These observations, for both SDF and MDF systems, tend to be more evident for higher levels of inelasticity. The significance of the results, with particular reference to European seismic design procedures, is highlighted. Copyright © 2010 John Wiley & Sons, Ltd.     

Variation of δ18O, δD and 3H in karst springs of south Kashmir,western Himalayas (India)

Water samples were collected from cold and warm karst springs for stable isotopes (δ¹⁸O and δD) and ³H from SE of Kashmir valley (western Himalayas) to distinguish the sources of recharge and infer their recharge areas. The spring water samples were most depleted in heavier isotopes in May (average δ¹⁸O: ?8.87‰ and δD: ?50.3‰) and enriched in September (average δ¹⁸O: ?7.58‰ and δD: ?48.1‰). The depleted ¹⁸O and ²H of spring waters bear the signatures of winter precipitation while as the enriched ¹⁸O and ²H of spring waters bear the signature of summer rainfall. D‐excess and ³H corroborate with the stable isotope results that the spring flow in spring season (May) and autumn (September) is dominantly controlled by the melting of winter snowmelt and summer rainfall, respectively. The results showed that unlike δD, the δ¹⁸O value in the karst spring waters decreases in January suggesting δ¹⁸O shift. The spring water samples also fall above the Local Meteoric Water Line and Global Meteoric Water Line indicating the δ¹⁸O shift due to interaction of groundwater with the host carbonate rocks during its traverse. The mean elevation of the recharge areas of the springs using δ¹⁸O and δD tracers was also estimated. Copyright © 2014 John Wiley & Sons, Ltd.