Geoenvironmental impact analysis of G.B. Pant Sagar reservoir (Rihand Reservoir), U.P. and M.P.     

A M Gautam 《Journal of the Indian Society of Remote Sensing》1995,23(3):93-100

A comparison of aerial photointerpreted data around G.B. Pant Sagar (Rihand Reservoir) for pre-dam (1944) and post-dam (1967) periods and satellite imagery of 1988 shows that slope stability of the hills surrounding the reservoir has not been affected adversely as a result of impounding of the reservoir as no landslides are observed in the area in post-dam period. However, significant changes in the landuse of the area surrounding the reservoir are noticed in the post-dam aerial photographs and satellite imagery. Large areas show decrease in vegetation density as a result of deforestation while the areas bordering the reservoir show increase in vegetation density. The area under cultivation has decreased on the western side due to development of a number of coal fields in post-dam period. Improper management of coal ash disposal from a number of thermal power plants located around the reservoir is causing siltation of the reservoir.  相似文献   

A petrologic model for the constitution of the upper mantle and crust of the Koolau shield,Oahu, Hawaii,and Hawaiian magmatism     

Gautam Sen 《Earth and Planetary Science Letters》1983,62(2):215-228

A petrological model for the uppermost upper mantle and crust under the Koolau shield to a depth of about 60 km has been derived on the basis of petrology of the upper mantle and crustal xenoliths in nephelinites of the Honolulu Volcanic Series. Three main xenolith suites exist in the Koolau shield: dunites, spinel lherzolites, and garnet-bearing pyroxenites. On the basis of mineralogy, it is inferred that the dunites represent cumulates in shallow crustal tholeiitic magma chambers, the spinel lherzolites form a thick (～ 40 km) layer in the upper mantle, and the garnet pyroxenite suite occurs as veins and stringers in the spinel lherzolites at about 60 km depth.The eruption sequence in a Hawaiian volcano, i.e., tholeiite → transitional basalt → alkali basalt, is generated by partial melting of a volatile-bearing garnet-lherzolite part of a lithospheric plate as it rides over a hot spot. If the tholeiite, transitional, and alkali basalts of Hawaiian volcanoes are generated at the same depth, then the observed sequence of lavas requires replenishment of the source area with volatiles and gradual decrease of the degree of partial melting with time. Post-erosional olivine nephelinites are produced from isotopically distinct, deeper source area, which may be the asthenosphere.  相似文献   

Mapping of environs of Dharavi slums of Greater Bombay for site suitability using enhanced Landsat thematic mapper (TM) imagery     

V. Raghavswamy  N. C. Gautam  J. Krishnamurthy 《Journal of the Indian Society of Remote Sensing》1989,17(1):49-54

Slums are universal and a ubiquitous part of the urban landscape. Dharavi, the biggest slum in the whole of Greater Bombay, encompasses 4.0 sq.km. of reclaimed land with 3.50 lakh inhabitants and 75,000 hutments. Majority of the slums of Indian cities, being structurally small with high density of dwellings and uniform building material, seldom give subtle ’spectral signature’ on the satellite imagery. Here, an attempt has been made to map by visual techniques the land use of Dharavi and environs of 20 sq.km area, using optically enhanced Landsat (TM) FCC of January, 1986, on 1:25,000 sale, The study has clearly brought out the land use details, the areas undergoing reclamation, and those susceptible to hazards like floods and marine erosion. A few alternate sites, based on geomorphic attributes are suggested for resettlement of Dharavislum and their areas are also quantified. The results of the present work is a part of the project study completed for a larger area covering 150sq. kms.  相似文献   

Study of Strain Rate and Thermal Damage of Dholpur Sandstone at Elevated Temperature   总被引：1，自引：0，他引：1  

P. K. Gautam  A. K. Verma  M. K. Jha  K. Sarkar  T. N. Singh  R. K. Bajpai 《Rock Mechanics and Rock Engineering》2016,49(9):3805-3815

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Water Quality Monitoring of Tropical Ponds: Location and Depth Effect in Two Case Studies     

Gautam Mukhopadhyay  Debasis Mondal  Pinaki Biswas  Anjana Dewanji 《洁净——土壤、空气、水》2004,32(2):138-148

The variability in water chemistry of samples taken on a monthly basis (March 1999 to February 2000) from two shallow tropical ponds was studied. The effect of location and pond depth on water chemistry was also examined. The study demonstrated that intraannual variability in nutrient concentration is high. Thus, a high annual sampling frequency is required to provide representative annual mean water quality data. Routine monitoring during the monsoons is important for studies on dissolved oxygen and macrophyte growth. Significant differences were found between the topmost and bottommost points for samples of dissolved oxygen collected from the deepest part of both ponds. For nutrient analysis (nitrogen and phosphorus), sample from any location was found to be representative of the whole pond.  相似文献   

Implications of urban expansion on land use and land cover: towards sustainable development of Mega Manila,Philippines     

Mishra  Binaya Kumar  Mebeelo  Kafungwa  Chakraborty  Shamik  Kumar  Pankaj  Gautam  Arjun 《GeoJournal》2021,86(2):927-942

GeoJournal - Planning of land use and infrastructure in advance for a population that is projected to grow rapidly is highly important for its sustainable development. A correlative approach of...  相似文献   

An Analytical Solution for Predicting Transient Seepage into Partially Penetrating Ditch Drains Receiving Water from a Ponded Field     

Gautam Barua  Ratan Sarmah 《Acta Geophysica》2016,64(1):149-205

A transient analytical model is worked out for predicting seepage from a ponded field of infinite extent to a network of equally spaced ditch drains in a homogeneous and anisotropic soil underlain by an impervious barrier at a finite distance from the surface of the soil. The solution can account for finite width and finite level of water in the ditches, finite penetration of the drains in the soil, and also a variable ponding field at the surface of the soil. The study highlights the fact that the transient state duration of a partially penetrating ponded drainage scenario may be considerable should the drains be dug in a lowly conductive soil with a high storage coefficient, particularly if the underlying impervious layer lies at a large distance from the bottom of the ditches and the separation between the adjacent ditches is also large at the same time.  相似文献   

Study of mechanical properties of Vindhayan shaly rocks at elevated temperature     

Manish Kumar Jha  A. K. Verma  Pradeep Kumar Gautam  Anil Negi 《Journal of the Geological Society of India》2017,90(3):267-272

Shale is an important rock due to its suitability for different engineering and scientific applications. Elevated temperature may cause major deformation or damage in shale rock and it may be of irreversible in nature. Such damage have adverse effect on the physicomechnical properties of shale rock. The uniaxial compressive strength and tensile strength of two shales (upper Vindhyan basin, India) have been estimated at elevated temperature using point load strength index method. The rock samples have been analyzed at various temperatures starting from room temperature to 900 °C. The effect of elevated temperature on the physicomechanical properties and their influence on the uniaxial compressive strength has been studied in detail. Damage induced, in both shale have been estimated using compressional wave velocity. The analysis of the experimental result shows that the uniaxial compressive strength decreases from 63.45 to 18.45 MPa and 60.94 to 22.22 MPa, for Jhiri and Ganurgarh shale respectively. Tensile strength of shales have been also estimated. The value of tensile strength decreases from 3.65 to 1.05 MPa and 3.46 to 1.26 MPa respectively for Jhiri and Ganurgarh shale. Multivariate regression analysis has been carried out to obtain the correlation between physicomechanical properties and uniaxial compressive strength of Jhiri and Ganurgarh shale.  相似文献   

Groundwater arsenic contamination and its health effects in India   总被引：2，自引：0，他引：2  

Dipankar Chakraborti  Mohammad Mahmudur Rahman  Bhaskar Das  Amit Chatterjee  Dipankar Das  Biswajit Nayak  Arup Pal  Uttam Kumar Chowdhury  Sad Ahmed  Bhajan Kumar Biswas  Mrinal Kumar Sengupta  Md. Amir Hossain  Gautam Samanta  M. M. Roy  Rathindra Nath Dutta  Khitish Chandra Saha  Subhas Chandra Mukherjee  Shyamapada Pati  Probir Bijoy Kar  Adreesh Mukherjee  Manoj Kumar 《Hydrogeology Journal》2017,25(4):1165-1181

During a 28-year field survey in India (1988–2016), groundwater arsenic contamination and its health effects were registered in the states of West Bengal, Jharkhand, Bihar and Uttar Pradesh in the Ganga River flood plain, and the states of Assam and Manipur in the flood plain of Brahamaputra and Imphal rivers. Groundwater of Rajnandgaon village in Chhattisgarh state, which is not in a flood plain, is also arsenic contaminated. More than 170,000 tubewell water samples from the affected states were analyzed and half of the samples had arsenic >10 μg/L (maximum concentration 3,700 μg/L). Chronic exposure to arsenic through drinking water causes various health problems, like dermal, neurological, reproductive and pregnancy effects, cardiovascular effects, diabetes mellitus, diseases of the respiratory and gastrointestinal systems, and cancers, typically involving the skin, lungs, liver, bladder, etc. About 4.5% of the 8,000 children from arsenic-affected villages of affected states were registered with mild to moderate arsenical skin lesions. In the preliminary survey, more than 10,000 patients were registered with different types of arsenic-related signs and symptoms, out of more than 100,000 people screened from affected states. Elevated levels of arsenic were also found in biological samples (urine, hair, nails) of the people living in affected states. The study reveals that the population who had severe arsenical skin lesions may suffer from multiple Bowens/cancers in the long term. Some unusual symptoms, such as burning sensation, skin itching and watering of eyes in the presence of sun light, were also noticed in arsenicosis patients.  相似文献   

Hydraulics of a partially penetrating well with skin zone in a confined aquifer     

Gautam Barua  S.N. Bora 《Advances in water resources》2010

A steady/quasi-steady model is developed for predicting flow into a partially penetrating well with skin zone in a confined aquifer overlying an impervious layer. The model takes into account flow through the bottom of the wellbore, finite skin thickness and finite horizontal and vertical extent of the aquifer. Moreover, the solution can be easily extended to include the mixed-type boundary condition at the well face, where a Dirichlet in the form of a specified hydraulic head and a Neumann in the form of zero flux coexist at the same time at different portions of the well face. The validity of the proposed solution is tested by comparing a few results obtained from the developed model with corresponding results obtained by analytical and numerical means. The study shows that, among other factors remaining constant, both the horizontal and vertical extent of an artesian aquifer, thickness of the skin zone, bottom flow and conductivity contrast of the skin and formation zones, play an important part in deciding flow to a well dug in the aquifer, and hence these factors must be considered while analyzing the problem. The model proposed here can be used to estimate skin thickness as well as hydraulic conductivities of the skin and formation zones of a well with skin zone in an artesian aquifer underlain by an impervious layer by utilizing pumping test data falling in the steady or quasi-steady state of a typical pumping test. As the proposed solution is of a general nature in the sense that it can handle, apart from partial penetration and bottom flow, the finite size skin zone and finite horizontal and vertical extent of an artesian aquifer together with the mixed-type boundary condition at the well face, it is hoped that the predictions coming out of the model will be more realistic than those obtained using solutions developed with more stringent assumptions.  相似文献