Impact of water demand on hydrological regime under climate and LULC change scenarios     

Satiprasad Sahoo  Anirban Dhar  Anupam Debsarkar  Amlanjyoti Kar 《Environmental Earth Sciences》2018,77(9):341

The present study focuses on an assessment of the impact of future water demand on the hydrological regime under land use/land cover (LULC) and climate change scenarios. The impact has been quantified in terms of streamflow and groundwater recharge in the Gandherswari River basin, West Bengal, India. dynamic conversion of land use and its effects (Dyna-CLUE) and statistical downscaling model (SDSM) are used for quantifying the future LULC and climate change scenarios, respectively. Physical-based semi-distributed model Soil and Water Assessment Tool (SWAT) is used for estimating future streamflow and spatiotemporally distributed groundwater recharge. Model calibration and validation have been performed using discharge data (1990–2016). The impacts of LULC and climate change on hydrological variables are evaluated with three scenarios (for the years 2030, 2050 and 2080). Temperature Vegetation Dyrness Index (TVDI) and evapotranspiration (ET) are considered for estimation of water-deficit conditions in the river basin. Exceedance probability and recurrence interval representation are considered for uncertainty analysis. The results show increased discharge in case of monsoon season and decreased discharge in case of the non-monsoon season for the years 2030 and 2050. However, a reverse trend is obtained for the year 2080. The overall increase in groundwater recharge is visible for all the years. This analysis provides valuable information for the irrigation water management framework.  相似文献   

Topo-stress based probabilistic model for shallow landslide susceptibility zonation in the Nepal Himalaya   总被引：1，自引：1，他引：0  

Ranjan Kumar Dahal  Netra Prakash Bhandary  Shuichi Hasegawa  Ryuichi Yatabe 《Environmental Earth Sciences》2014,71(9):3879-3892

While dealing with slope stability issues, determining the state of stress and the relation between driving force and resisting force are the fundamental deterministic steps. Gravitational stresses affect geologic processes and engineering operations in slopes. Considering this fact, a concept of topo-stress evaluation is developed in this research and used to produce a shallow landslide susceptibility map in a model area. The topo-stress introduced in this research refers to the shear stress induced by the gravitational forces on the planes parallel to the ground surface. Weight of the material on a slope and friction angle of the jointed rock mass are the two fundamental parameters that are considered to govern topo-stress in this study. Considering topo-stress as a main factor for initiating shallow landslides, a GIS-based probabilistic model is developed for shallow landslide susceptibility zonation. An ideal terrain in central Nepal is selected as the study area for this purpose. Two event-based shallow landslide inventories are used to predict accuracy of the model, which is found to be more than 78 % for the first event-landslides and more than 76 % for the second event-landslides. It is evident from these prediction rates that the probabilistic topo-stress model proposed in this work is quite acceptable when regional scale shallow landslide susceptibility mapping is practiced, such as in the Himalayan rocky slopes.  相似文献   

‘Indicator’ carbonaceous phyllite/graphitic schist in the Archean Kundarkocha gold deposit,Singhbhum orogenic belt,eastern India: Implications for gold mineralization vis-a-vis organic matter     

P R Sahoo  A S Venkatesh 《Journal of Earth System Science》2014,123(7):1693-1703

Carbonaceous rocks in the form of graphitic schist and carbonaceous phyllite are the major host rocks of the gold mineralization in Kundarkocha gold deposit of the Precambrian Singhbhum orogenic belt in eastern India. The detection of organic carbon, essentially in the carbonaceous phyllite and graphitized schist within the Precambrian terrain, is noted from this deposit. A very close relationship exists between gold mineralization and ubiquitous carbonaceous rocks containing organic carbon that seems to play a vital role in the deposition of gold in a Precambrian terrain in India and important metallogenetic implications for such type of deposits elsewhere. However, the role played by organic matter in a Precambrian gold deposit is debatable and the mechanism of precipitation of gold and other metals by organic carbon has been reported elsewhere. Fourier transform infrared spectroscopy (FTIR) results and total organic carbon (TOC) values suggest that at least part of the organic material acted as a possible source for the reduction that played a significant role in the precipitation of gold. Lithological, electron probe analysis (EPMA), fluid inclusions associated with gold mineralization, Total Carbon (TC), TOC and FTIR results suggest that the gold mineralization is spatially and genetically associated with graphitic schist, carbonaceous phyllite/shale that are constituted of immature organic carbon or kerogen. Nano-scale gold inclusions along with free milling gold are associated with sulfide mineral phases present within the carbonaceous host rocks as well as in mineralized quartz-carbonate veins. Deposition of gold could have been facilitated due to the organic redox reactions and the graphitic schist and carbonaceous phyllite zone may be considered as the indicator zone.  相似文献   

Spatial Distribution of Shear Wave Velocity for Late Quaternary Alluvial Soil of Kanpur City,Northern India     

Sambit?Prasanajit?Naik  Nihar?Ranjan?PatraEmail author  Javed?N.?Malik 《Geotechnical and Geological Engineering》2014,32(1):131-149

Empirical correlation between standard penetration resistance (SPT-N) and shear wave velocity measured by seismic downhole techniques are prepared of the alluvial soil of quaternary age for the Kanpur city. The Kanpur city is having seismic threat from Himalaya and it falls in seismic zone III according to seismic zones of India. Standard penetration test as well seismic downhole test has been carried out up to 30 m at twelve different locations of Kanpur city. The measured SPT-N values and shear wave velocity values are used to develop empirical correlation between SPT-N and shear wave velocity. The proposed correlations have been compared with the existing regression equations by various other investigators. It is found that the proposed correlation exhibit good performance (10 % error bar). Also the measured shear wave velocity has been used to prepare spatially distributed contour map of 50, 75 and 100 m/s using ArcGIS-9 software. It is observed that the shear wave velocity values for the northern part of Kanpur city vary from 125 to 825 m/s. In southern part, it is varying from 125 to 500 m/s where as in the central part of the city the shear wave velocity varies from 125 to 375 m/s. The eastern part of the city also shows some variation in shear wave velocity which ranges from 250 to 625 m/s. The western part of the city shows the variation of shear wave velocity from ≤125 to 500 m/s. The soil type of the study area are classified as per NEHRP and new Italian O.P.M.C classification system as B, C and D type soil with having site period of 0.1–0.9 s and Poisson’s ratio varying from 0.1 to 0.4.  相似文献   

The great 1950 Assam Earthquake revisited: Field evidences of liquefaction and search for paleoseismic events   总被引：1，自引：0，他引：1  

D.V. Reddy  P. Nagabhushanam  Devender Kumar  B.S. Sukhija  P.J. Thomas  Anand K. Pandey  R.N. Sahoo  G.V. Ravi Prasad  K. Datta 《Tectonophysics》2009,474(3-4):463-472

Extensive field investigations were carried out for the first time in the meizoseismal area of the great 1950 Assam Earthquake aimed at exploring the paleoseismic history of the NE Indian region through documentation of liquefaction features and radiocarbon (¹⁴C) dating. Trenching at more than a dozen locations along the Burhi Dihing River valley and within the alluvial fans adjoining the Brahmaputra and Dibang Rivers resulted in the identification of more than a dozen very prominent liquefaction features (sand dykes, sills, sand blows etc.) as evidences of large to great earthquakes. ¹⁴C dating of the organic material associated with some of the features indicates a paleoseismic record of about 500 yrs archived by the sediments in this region. Compelling geological evidence(s) of the great 1950 earthquake are well constrained by ¹⁴C dating. Out of the two historically reported seismic events (1548 AD and 1697 AD) from this region, ¹⁴C dating could constrain the 1548 AD event though not distinctly. Further studies using combined ¹⁴C and OSL dating may better constrain the seismo-chronology of the study region.  相似文献   

Depositional history,processes and mechanism of early Miocene sediments of Upper Assam Basin     

M. Sahoo  K. D. Gogoi 《Journal of the Geological Society of India》2009,73(4):575-585

A detailed analysis of depositional history of Miocene sediments and various effects which are governed for creation of accommodation space as well as the processes of sedimentation inherent to the depositional system at that period is described in this work. The early Miocene clastic sediments are deposited in prograding environment where sediment supply exceeds the accommodation space available. The accommodation space created due to basin subsidence and source area upliftment due to local and regional tectonic activity in the basin. In the early Miocene time, the Assam shelf major transgression occurred and several minor transgression followed. There was wide spread deposition of the fluvial Tipam sandstones. In Miocene time due to thrust loading and flexure subsidence, accommodation space was created for deposition of the sediments. The Tipam Sandstone is deposited by cyclic deposition of fining upward sequence in a fluvial to brackish water environment of braided river processes. The mechanism of braided rivers is also discussed in which it laterally expanded, leaving sheet like or wedge — shaped deposits of channel and bar complexes preserving only minor amounts of flood plain material.  相似文献   

Cyclic sedimentation of the Karharbari Formation (Damuda Group), Talchir Gondwana basin, Orissa     

Rabindra Nath Hota  Madhusmita Sahoo 《Journal of the Geological Society of India》2009,73(4):469-478

The cyclic arrangement of lithofacies of the Karharbari Formation of the Damuda Group from a part of the Talchir Gondwana basin has been examined by statistical techniques. The lithologies have been condensed into five facies states viz. coarse-, medium-, fine-grained sandstones, shale and coal for the convenience of statistical analyses. Markov chain analysis indicates the arrangement of Karharbari lithofacies in form of fining upward cycles. A complete cycle consists of conglomerate or coarse-grained sandstone at the base sequentially succeeded by medium-and fine-grained sandstones, shale and coal at the top. The entropy analysis categorizes the Karharbari cycles into the C-type cyclicity, which is essentially a random sequence of lithologic states. Regression analysis undertaken in the present study indicates the existence of sympathetic relationship between total thickness of strata (net subsidence) and number and average thickness of sedimentary cycle and antipathic relationship between number and average thickness of sedimentary cycle. These observations suggest that cyclic sedimentation of the Karharbari Formation was controlled by autocyclic process by means of lateral migration of streams activated by intrabasinal differential subsidence, which operated within the depositional basin and the channels carrying coarse grade clastic sediments, which make the cycles thicker, tend to be more common in the areas of maximum subsidence. Clastic sediments issued from the laterally migrating rivers interrupted the cyclic sedimentation of the Karharbari Formation in many instances.  相似文献   

Evaluation of geotechnical properties of overburden dump for better reclamation success in mining areas     

Shivesh Kishore Karan  Adarsh Kumar  Sukha Ranjan Samadder 《Environmental Earth Sciences》2017,76(22):770

Coal-mining activities are precursors to land degradation, a part of which is directly related to the generation of huge quantity of overburden (OB) material. The problem of managing OB is mitigated through reclamation, which is directly associated with the geotechnical properties of these dumps. The main objective of this study was to assess the potential of an alternative management plan of OB by analyzing physical properties of these dumps. This alternative management plan of OB could enhance reclamation success by fostering conditions conducive for vegetation growth. This is especially required in old mining areas, where salvaging of topsoil was not done, and as a result, reclamation was affected. For the present study, 12 representative OB samples were collected from two open-cast coal mines (OCP-A and OCP-B) of Bastacolla area in Jharia Coalfield, Dhanbad, India. The samples were analyzed for different geotechnical properties. The results revealed that optimization of these parameters could help in enhancing the reclamation success of the area. From land-use classification, it was observed that about 242 ha of the study area was OB dump; if these areas are reclaimed successfully, then they can act as a potential source of carbon sequestration, and furthermore, they will improve the esthetics and the overall environmental quality at these degraded areas.  相似文献   

Mesonic stiff fluid distribution in five dimensional Bianchi type space time     

G. Mohanty  R. R. Sahoo 《Astrophysics and Space Science》2008,314(1-3):1-6

In this paper, we have constructed mesonic stiff fluid cosmological models in five dimensional LRS Bianchi type-I and Bianchi type-VI₀ space times in general theory of relativity. Some physical and geometrical properties of the models are discussed.  相似文献   

Anisotropic string cosmological models in Lyra’s geometry     

G. Mohanty  R. R. Sahoo 《Astrophysics and Space Science》2008,315(1-4):167-173

In this paper, we constructed some five dimensional LRS Bianchi type-I string cosmological models based on Lyra geometry and studied some physical and geometrical properties of the models.  相似文献