Hydrogeologic framework of the Deccan terrain of the Koyna River basin, India     

Pradeep K. Naik  Arun K. Awasthi  A. Anand  Prakash C. Mohan 《Hydrogeology Journal》2001,9(3):243-264

The Koyna River basin in India drew the attention of geoscientists after an earthquake (magnitude 7) in 1967. Since then, detailed geological, tectonic, and seismic investigations of this river basin have been carried out by several workers. However, very little study has been done on its hydrogeological framework. The present work aims at filling this gap. Basalts, laterites, alluvium, soils, and talus deposits form shallow unconfined aquifers, with transmissivity of 27–135 m²/d and a regional specific yield of 0.012. In shallow basaltic aquifers, the lower part of the highly weathered and highly jointed horizon above, and the poorly weathered and highly jointed horizon below, form the most potential zone for groundwater occurrence. Well yields in the deeper basaltic aquifers are directly related to the occurrence of lineaments, whereas at a shallower level they are related to geomorphic features. Spring discharges are highly dependent on their source aquifers and areas of recharge. They have a mean winter discharge of 46 m³/d and a summer discharge of 28 m³/d. Chemically, groundwaters are dominated by alkaline earths (Ca²⁺, Mg²⁺) and weak acids (HCO₃ ^–, CO₃ ^–); they are calcium-bicarbonate type (53%) and calcium-magnesium-bicarbonate type (27%) at shallower levels; and calcium-magnesium-bicarbonate type (29%), sodium-bicarbonate type (24%), calcium-bicarbonate type (19%), and calcium-magnesium-sodium-bicarbonate type (19%) in deeper aquifers. The Koyna River basin is characterized by both scarcity and abundance of groundwater. In the water-scarce areas in the dissected plateaus, artificial recharge of aquifers through construction of several recharge structures at suitable locations is highly recommended. In the water-abundant areas in the central valley, on the other hand, expanded consumptive use of water resources is encouraged. Electronic Publication  相似文献   

Estimation of surface runoff potential of a watershed in semi-arid environment — A case study     

Dilip G. Durbude  B. K. Purandara  Arun Sharma 《Journal of the Indian Society of Remote Sensing》2001,29(1-2):47-58

An accurate assessment of run-off through aerial rainfall is a basic concept in most of the rainfall-runoff models, particularly conceptual models which emphasis a complete water balance. The run-off measurements by gauging can only be regarded as an index of rainfall and restrict our ability to successfully model the rainfall-runoff process. To overcome some of these problems, remote sensing satellite data are of immense use, particularly in mountainous and desert areas. Therefore in the present study, a typical watershed from a drought hit Banswara district of Rajasthan has been analysed using IRS-1B-LISS II satellite imagery for estimating the run-off potential under different geomorphic set-up. The run-off potential was estimated using SCS method based on the satellite data in conjunction with ground truth information collected during field visit. The results indicated that the soil and water conservation measures in the watershed would improve the existing water potential and storage capacity of the study area. Based on the study eight check dams and five lift irrigation schemes are proposed.  相似文献   

A Rulebase physiographic characterization of a drought prone watershed applying remote sensing and GIS     

P. S. Arun  R. Jana  M. S. Nathawat 《Journal of the Indian Society of Remote Sensing》2005,33(2):189-201

Efficient micro-watershed management needs characterization of it to optimize natural resources, which is especially important in drought prone areas. In the present study micro-watersheds of Gandheshwari tributary in Chotta-Nagpur Plateau are characterized based on physiographic properties towards agricultural potentiality. An algorithm interpolating elevation values using an empirical formula is proposed to obtain an improved Digital Elevation Model (DEM). IRS LISS-Ill Satellite data is used to acquire important parameters like landuse/ landcover and drainage. Image processing techniques like edge enhancement, edge detection, and principal components analysis are used for improving lineament detection. For characterization of watershed landform analysis using physiographic parameters is done in Geographic Information System (GIS). Detailed drainage network obtained from satellite image, the improved DEM and other GIS layers of land based information are used to delineate micro-watersheds. The Agricultural 1-lydrologic Response Units (AHRU) targeting agricultural use of the land are derived by overlaying the delineated parameters and are grouped into thirty response units based on their agricultural potential. Micro-watersheds are characterized based on the dominant Al-IRU giving spatial information about agricultural suitability, emphasizing availability and scarcity of water so that respective water conservation practices can be improved to use the potential AHRU.  相似文献   

Assessment of groundwater pollution due to tannery industries in and around Dindigul, Tamilnadu, India     

N. C. Mondal  V. K. Saxena  V. S. Singh 《Environmental Geology》2005,48(2):149-157

The overexploitation of groundwater in some parts of the country induces water quality degradation. The untreated industrial effluents discharged on the surface causes severe groundwater pollution in the industrial belt of the country. This poses a problem of supply of hazard free drinking water in the rural parts of the country. There are about 80 tanneries operating in and around Dindigul town in upper Kodaganar river basin, Tamilnadu, India. The untreated effluents from the tanneries have considerably affected the quality of groundwater in this area. To assess the extent of groundwater deterioration, a detailed analysis of groundwater quality data has been carried out. The concentration of cations such as Calcium (Ca²⁺), Magnesium (Mg²⁺), Sodium (Na⁺) and Potassium (K⁺), and anions such as Bicarbonate (HCO₃^–), Sulphate (SO₄^2–), Chloride (Cl^–) and Nitrate (NO₃^–) in the groundwater have been studied. Apart from these constituents, pH, electrical conductivity (EC), total dissolved solid and total hardness (TH as CaCO₃) were also studied. The correlation of these constituents with the EC has been carried out. The highest correlation is observed between EC and chloride with a correlation coefficient of 0.99. Progressive reduction in correlation coefficients for Mg²⁺, (Na⁺ + K⁺), Ca²⁺ and SO₄^2– are observed as 0.91, 0.87, 0.86 and 0.56, respectively. It is found that the quality of groundwater in the area under investigation is deteriorated mainly due to extensive use of salt in the leather industries.  相似文献   

Hydrochemistry of reservoirs of Damodar River basin, India: weathering processes and water quality assessment     

Abhay Kumar Singh  G. C. Mondal  P. K. Singh  S. Singh  T. B. Singh  B. K. Tewary 《Environmental Geology》2005,48(8):1014-1028

Water samples collected from the six reservoirs of Damodar River basin in pre- and post-monsoon, have been analysed, to study the major ion chemistry and the weathering and geochemical processes controlling the water composition. Ca, Na and HCO₃ dominate the chemical composition of the reservoir water. The seasonal data shows a minimum concentration of most of the ions in post-monsoon and a maximum concentration in pre-monsoon seasons, reflecting the concentrating effects due to elevated temperature and increased evaporation during the low water level period of the pre-monsoon season. Water chemistry of the reservoirs strongly reflects the dominance of continental weathering aided by atmospheric and anthropogenic activities in the catchment area. Higher concentration of SO₄ and TDS in Panchet, Durgapur and Tenughat reservoirs indicate mining and anthropogenic impact on water quality. The high contribution of (Ca+Mg) to the total cations, high concentration of dissolved silica, relatively high (Na+K)/TZ⁺ ratio (0.3) and low equivalent ratio of (Ca+Mg)/(Na+K) suggests combined influence of carbonate and silicate weathering. Kaolinite is the possible mineral that is in equilibrium with the water, implying that the chemistry of reservoir water favours kaolinite formation. The calculated values of SAR, RSC and sodium percentage indicate the ‘excellent to good quality’ of water for irrigation uses.  相似文献   

A General Relativistic Calculation of Boundary Layer and Disc Luminosity for Accreting Non-magnetic Neutron Stars in Rapid Rotation     

Arun V. Thampan  & Bhaskar Datta 《Monthly notices of the Royal Astronomical Society》1998,297(2):570-578

We calculate the disc and boundary layer luminosities for accreting rapidly rotating neutron stars with low magnetic fields in a fully general relativistic manner. Rotation increases the disc luminosity and decreases the boundary layer luminosity. A rapid rotation of the neutron star substantially modifies these quantities as compared with the static limit. For a neutron star rotating close to the centrifugal mass shed limit, the total luminosity has contribution only from the extended disc. For such maximal rotation rates, we find that well before the maximum stable gravitational mass configuration is reached, there exists a limiting central density, for which particles in the innermost stable orbit will be more tightly bound than those at the surface of the neutron star. We also calculate the angular velocity profiles of particles in Keplerian orbits around the rapidly rotating neutron star. The results are illustrated for a representative set of equation of state models of neutron star matter.  相似文献   

Geodynamic evolution and crustal growth of the central Indian Shield: Evidence from geochemistry of gneisses and granitoids     

M. Faruque Hussain  M. E. A. Mondal  T. Ahmad 《Journal of Earth System Science》2004,113(4):699-714

The rare earth element patterns of the gneisses of Bastar and Bundelkhand are marked by LREE enrichment and HREE depletion with or without Eu anomaly. The spidergram patterns for the gneisses are characterized by marked enrichment in LILE with negative anomalies for Ba, P and Ti. The geochemical characteristics exhibited by the gneisses are generally interpreted as melts generated by partial melting of a subducting slab. The style of subduction was flat subduction, which was most common in the Archean. The rare earth patterns and the multi-element diagrams with marked enrichment in LILE and negative anomalies for Ba, P and Ti of the granitoids of both the cratons indicate interaction between slab derived melts and the mantle wedge. The subduction angle was high in the Proterozoic. Considering the age of emplacement of the gneisses and granitoids that differs by ∼ 1 Ga, it can be assumed that these are linked to two independent subduction events: one during Archaean (flat subduction) that generated the precursor melts for the gneisses and the other during the Proterozoic (high angle subduction) that produced the melts for the granitoids. The high values of Mg #, Ni, Cr, Sr and low values of SiO₂ in the granitoids of Bastar and Bundelkhand cratons compared to the gneisses of both the cratons indicate melt-mantle interaction in the generation of the granitoids. The low values of Mg#, Ni, Cr, Sr and high values of SiO₂ in the gneisses in turn overrules such melt-mantle interaction.  相似文献   

A paleolimnological record of Holocene climate and environmental change in the Temagami region,northeastern Ontario   总被引：3，自引：0，他引：3  

Robert?E.?A.?Boudreau  Jennifer?M.?Galloway  R.?Timothy?PattersonEmail author  Arun?Kumar  Frederick?A.?Michel 《Journal of Paleolimnology》2005,33(4):445-461

The Arcellacean (Thecamoebian) fauna was assessed in five Holocene sediment cores obtained from James and Granite lakes in the Temagami region of northeastern Ontario. In addition, palynological analysis was carried out on two of these cores, one each from James and Granite lakes. The first indication of postglacial colonization by plants was the appearance of rare Cupressaceae pollen, dated to 10,800 yr BP. Plant diversity began to increase by 10,770 yr BP when Pinus spp. and Larix migrated into the area. The first appearance of arcellaceans occurred after 9650 yr BP in assemblages dominated by Centropyxis constricta and opportunistic Centropyxis aculeata. High abundances of charophytes in the cores until 8800 yr BP indicated that macroalgae were proliferating at this time. This deposition is interpreted to have occurred during the draining of an ice-marginal lake following the retreat of the Laurentide Ice Sheet. Based on pollen analysis, warmer conditions associated with the Holocene Hypsithermal prevailed in the area from 6250 to 4115 yr BP. The stable, open Great Lakes – St. Lawrence type forest that developed here at the beginning of the Hypsithermal continues to prevail to the present. The periodic colonization of the lake by beavers (Castor canadensis) acted as a control on water-level and eutrophication through the Holocene. Evidence of eutrophication was indicated in the core samples by the abundance of high levels of the alga Pediastrum and the arcellacean Cucurbitella tricuspis. Eutrophication periodically developed when beavers dammed a site, causing the rate of flow in drainage streams to slow and stagnant conditions occurred. When the site became depleted of the nearby trees, which were preferred by beaver (Betula, Alnus and Populus), the dam would be abandoned, causing the water-level to drop. Stagnant conditions were reduced as flow levels increased, reducing eutrophication and resulting in recovering forest stands. In addition, the lowering water levels would result in encroachment of the forest along the lake shore. This cycle occurred many times in the history of this lake as indicated by fluctuations in the size of arcellacean populations.  相似文献   

Climate drift of AMOC,North Atlantic salinity and arctic sea ice in CFSv2 decadal predictions     

Bohua Huang  Jieshun Zhu  Lawrence Marx  Xingren Wu  Arun Kumar  Zeng-Zhen Hu  Magdalena A. Balmaseda  Shaoqing Zhang  Jian Lu  Edwin K. Schneider  James L. Kinter III 《Climate Dynamics》2015,44(1-2):559-583

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Regional crop water use assessment using Landsat-derived evapotranspiration     

Arun Bawa  Gabriel B. Senay  Sandeep Kumar 《水文研究》2021,35(1):e14015

Reliable information on water use and availability at basin and field scales are important to ensure the optimized constructive uses of available water resources. This study was conducted with the specific objective to estimate Landsat-based actual evapotranspiration (ETa) using the Operational Simplified Surface Energy Balance (SSEBop) model across the state of South Dakota (SD), USA for the 1986–2018 (33-year) period. Validated ETa estimations (r² = 0.91, PBIAS = −4%, and %RMSE = 11.8%) were further used to understand the crop water-use characteristics and existing historic mono-directional (increasing/decreasing) trends over the eastern (ESD) and western (WSD) regions of SD. The crop water-use characteristics indicated that the annual cropland water uses across the ESD and WSD were more or less met by the precipitation amounts in the area. The ample water supply and distribution have led to high rainfed and low percentage of irrigated cropland (~2.5%) in the state. The WSD faced greater crop-water use reductions than the ESD during drought periods. The landscape ETa responses across the state were found to be more sensitive than precipitation for the drought impact assessments. The Mann Kendall trend analysis revealed the absence of a significant trend (p > 0.05) in annual ETa at a regional scale due to the varying weather conditions in the state. However, about 12% and 9% cropland areas in the ESD and WSD, respectively, revealed a significant mono-directional trend at pixel scale ETa. Most of the pixels under significant trend showed an increasing trend that can be explained by the shift in agricultural practices, increased irrigated cropland area, higher productions, moisture regime shifts, and decreased risk of farming in the dry areas. The decreasing trend pixels were clustered in mid-eastern SD and could be the result of dynamic conversion of wetlands to croplands and decreased irrigation practices in the region. This study also demonstrates the tremendous potential and robustness of the SSEBop model, Landsat imagery, and remote sensing-based ETa modelling approaches in estimating consistent spatially distributed evapotranspiration.  相似文献