Groundwater flow modelling of Hindon-Yamuna interfluve region, Western Uttar Pradesh     

Fakhre Alam  Rashid Umar 《Journal of the Geological Society of India》2013,82(1):80-90

The study area Hindon -Yamuna interfluve region is underlain by a thick pile of unconsolidated Quaternary alluvial deposits and host multiple aquifer system. Excessive pumping in the last few decades, mainly for irrigation, has resulted in a significant depletion of the aquifer. Therefore, proper groundwater management of Hindon-Yamuna interfluve region is necessary. For effective groundwater management of a basin it is essential that careful zone budget study should be carried out. Keeping this in view, groundwater flow modelling was attempted to simulate the behavior of flow system and evaluate zone budget. Visual MODFLOW, pro 4.1 is used in this study to simulate groundwater flow. The model simulates groundwater flow over an area of about 1345 km² with a uniform grid size of 1000 m by 1000 m and contains three layers, 58 rows and 37 columns. The horizontal flows, seepage losses from unlined canals, recharge from rainfall and irrigation return flows were applied using different boundary packages available in Visual MODFLOW, pro 4.1. The river — aquifer interaction was simulated using the river boundary package. Simulated pumping rates of 500 m³/day, 1000 m³/day and 1500 m³/day were used in the pumping well package.The zone budget for the steady state condition of study area indicated that the total annual direct recharge is 416.10 MCM and the total annual groundwater draft through pumping is of the order of 416.63 MCM. Two scenarios were considered to predict aquifer system response under different conditions. Sensitivity analysis on model parameters was conducted to quantitatively evaluate the impact of varying model inputs. Based on the results obtained from the sensitivity analysis, it was found that the model is more sensitive to hydraulic conductivity and recharge parameter. Present study deals with importance of groundwater modelling for planning, design, implementation and management of groundwater resources.  相似文献   

Fresh-water lenses and practical limitations of their three-dimensional simulation     

F. Ghassemi  K. Alam  K. Howard 《Hydrogeology Journal》2000,8(5):521-537

Fresh-water lenses are the major sources of water supply in many atoll islands in the Pacific and Indian Oceans, particularly in dry seasons. Several two- and three-dimensional models are currently available for the simulation of atoll-island aquifers; however, 2D models cannot include 3D spatial variability of material properties, they must simplify the boundary conditions, and they cannot correctly simulate pumping wells. In an attempt to overcome these difficulties, a 3D model, SALTFLOW, was adopted for the simulation of Home Island in the Indian Ocean. This exercise required a discretisation on the order of a few metres and time steps of a few hours requiring significantly high CPU times. High CPU demand proved to be a difficult challenge but cannot be considered a serious practical limitation with today's advanced computers. The exhaustive data demands of the model (e.g., 3D distributions of hydraulic conductivity, porosity, dispersivities, and spatial and temporal variations of recharge and extraction rates) proved to be more problematical. Although the Home Island data set is unusually comprehensive by any standards, nonetheless the quality and quantity of the available data proved inadequate to meet the calibration needs of a highly karstic aquifer system. The Home Island modeling demonstrates the practical limitations of 3D models. It raises the concern that our ability to develop computer codes capable of simulating complex systems now exceeds our ability to supply the input data necessary for reliable calibration. Finally, the paper demonstrates the importance of the transient calibration in reliable simulation of various management options and emphasises that transient calibration should be considered as an integral part of any similar 2D or 3D modeling. Electronic Publication  相似文献   

Estimating the maximum impact force of dry granular flow based on pileup characteristics     

XIAO Si-you  SU Li-jun  JIANG Yuan-jun  MEHTAB Alam  LI Cheng  LIU Dao-chuan 《山地科学学报》2019,(10)

The maximum normal impact resultant force(NIRF)is usually regarded as the sum of the static earth pressure of the dead zone and the dynamic impact pressure of the flowing layer.The influence of the interaction between the flowing layer and dead zone on the impact force is ignored.In this study,we classified two impact models with respect to the pileup characteristics of the dead zone.Then,we employed the discrete element method to investigate the influences of the pileup characteristics on the impact force of dry granular flow on a tilted rigid wall.If the final pileup height is equal to the critical value,the maximum NIRF can be estimated using a hydrostatic model,because the main contribution to the maximum NIRF is the static earth pressure of the dead zone.If the final pileup height is less than the critical value,however,the particles in the dead zone are squeezed along the slope surface by the impact ofthe flowing layer on the dead zone,and because of shear effects,the flowing layer causes an entrainment in the dead zone.This results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope angle.As such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum NIRF.Impact models will benefit from further study of the components and distribution of the impact force of dry granular flow.  相似文献   

Urban citizenship in the global south: Critical reflections on the tactics and counter-tactics of the urban poor     

Redento B. Recio  Erich Wolff  Ashraful Alam  Sanjeev Routray  Eric Gaisie  Adriana Marin-Toro  Ishita Chatterjee  Nabanita Islam 《New Zealand geographer》2023,79(1):46-53

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An assessment of the potential impact of climate change on rice farmers and markets in Bangladesh     

Ashrafun Nahar  Jeff Luckstead  Eric J. Wailes  Mohammad Jahangir Alam 《Climatic change》2018,150(3-4):289-304

Bangladesh, the sixth largest rice producer in the world, has been identified as high risk from the effects of climate change. Many of the adverse impacts of climate change such as land inundation and changes in weather patterns and CO₂ levels will impact the agricultural sector. This study develops a partial-equilibrium multi-regional farm household model of Bangladesh rice and non-rice agricultural markets to quantify the impacts of climate change on consumption, production, prices, and farmers’ welfare. The model is calibrated to the Bangladesh rice market using Household Income and Expenditure Survey data. The model is simulated to analyze the impact of land reduction and productivity decline resulting from climate change. The results show that the decline in production in the coastal and northern regions offsets the production increase in the central and eastern regions, and the simulation predicts that total rice production for Bangladesh falls by about 2%. As total rice consumption falls and imports rise, the net effect leads to a rise in the rice price by 5.71% and a decline in farmers’ welfare. Sensitivity analysis shows that more- (less-) effective abatement technology could play a key role in mitigating (exacerbating) the price and welfare effects. The model predicts that many farmers in regions directly impacted by climate change could leave farming in search of off-farm work. Thus, the government can ease this transition by promoting urban development to provide more job options and technical training for farmers.  相似文献   

A long-term trend in precipitation of different spatial regions of Bangladesh and its teleconnections with El Niño/Southern Oscillation and Indian Ocean Dipole     

Ahmed  Md. Kawser  Alam  Mohammad Samsul  Yousuf  Abu Hena Muhammad  Islam  Md. Monirul 《Theoretical and Applied Climatology》2017,129(1-2):473-486

A long-term (1948 to 2012) trend of precipitation (annual, pre-monsoon, monsoon, and post-monsoon seasons) in Bangladesh was analyzed in different regions using both parametric and nonparametric approaches. Moreover, the possible teleconnections of precipitation (annual and monsoon) variability with El Niño/Southern Oscillation (ENSO) episode and Indian Ocean Dipole (IOD) were investigated using both average and individual (both positive and negative) values of ENSO index and IOD. Our findings suggested that for annual precipitation, a significant increasing monotonic trend was found in whole Bangladesh (4.87 mm/year), its western region (5.82 mm/year) including Rangpur (9.41 mm/year) and Khulna (4.95 mm/year), and Sylhet (10.12 mm/year) and Barisal (6.94 mm/year) from eastern region. In pre-monsoon, only Rangpur (2.88 mm/year) showed significant increasing trend, while in monsoon, whole Bangladesh (3.04 mm/year), Sylhet (7.17 mm/year), and Barisal (6.94 mm/year) showed similar trend. In post-monsoon, there was no significant trend. Our results also revealed that the precipitation (annual or monsoon) of whole Bangladesh and almost all of the spatial regions did not show any significant correlation with ENSO events, whereas the average IOD values showed significant correlation only in monsoon precipitation of western region. The individual positive IODs showed significant correlation in whole Bangladesh, western region, and its two divisions (Rajshahi and Khulna). So, in the context of Bangladesh climate, IOD has the more teleconnection to precipitation than that of ENSO. Our findings indicate that the co-occurrence of ENSO and IOD events may suppress their influence on each other.

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Rock mass rating and Kinematic analysis for slope stability investigation of Utari dam,Lalitpur district,Uttar Pradesh     

M. E. A. Mondal  Tariq Siddique  Mohammad Alam  M. Masroor Alam 《Journal of the Geological Society of India》2016,87(4):463-468

Rock mass characterization of Utari dam in Lalitpur district of Uttar Pradesh was done to identify different stability classes of rock mass. For better stability of Utari dam, foundation conditions were carefully studied by detailed field investigations of the site supplemented by laboratory tests. During feasibility and preliminary stages, rock mass characterization of slopes was conducted to identify the vulnerable zones of failure. Rock mass characterization was done by compilation of information obtained from intact rock as well as from rock mass to determine its grade and long term slope stability of the site. On the basis of Rock Mass Rating (RMR) and Geological Strength Index (GSI) slope stability is identified which lies under good quality rock mass. Kinematic analysis was conducted to find out the probability for different types of structurally controlled slope failure. Microscopic analyses were conducted to identify the degree of chemical alteration of feldspar. Clay formation by sericitization along joint planes is harmful for the stability of dam structure. Remedial measures must be taken to reduce the extent of chemical alteration. Granitoids at dam site forms a compact and stable foundation consisting of four sets of joints in which two sets were prominent which are dipping on the upstream side of the dam which reveals good condition on the dam site as leakage from reservoir will be minimum and least up-thrust on the dam structure.  相似文献   

SMR geomechanics and kinematic analysis near Rasulpur,Fatehpur Sikri,Uttar Pradesh   总被引：1，自引：0，他引：1  

M. E. A. Mondal  Tariq Siddique  Bulbul Mondal  M. Masroor Alam 《Journal of the Geological Society of India》2016,87(5):623-627

Slope stability of mine slopes is often associated with safety and economics during excavation. Sandstone is excavated from Rasulpur area of Fatehpur Sikri in Uttar Pradesh for the purpose of crushed, decorative and dimension stones. In the present paper an attempt has been made to characterize the rock slope faces into different stability classes. Characterization is based on geological and geotechnical parameters recorded on the outcrop during field investigation and supplemented by geomechanical properties by the laboratory test for strength of the rock intact. SMR Geomechanics classification is used to identify the stability class and remedial measures are also suggested to reduce any possible hazard. Kinematic analysis of slope was also investigated to determine the probability of any possible structurally controlled failure. On the basis of SMR Geomechanics calculations slope under investigation lies under good stability class i.e. 2a and 2b. Installation of nets during excavation can be done and for better safety spot and systematic rock bolting can be done. Kinematic study reveals that toppling failures may occur, special care must be given to the joint set which can trigger toppling failure.  相似文献   

A Review of the Bentong-Raub Suture vis-à-vis New Insight of the Tectonic Evolution of Malay Peninsula,South East Asia     

Aftab Alam KHAN  Mustaffa Kamal SHUIB 《《地质学报》英文版》2016,90(5):1865-1886

Genesis of the so‐called Bentong‐Raub Suture of Malay Peninsula does not fit to the model of subduction‐related collision. It has evolved from transpression tectonics resulting closure and exhumation of the inland basin which underwent extensive back‐arc extension during Triassic. Crust having similar thickness (average ～35 km) below entire Malay Peninsula nagate collision of two separate continental blocks rather supports single continental block that collided with South China continental block during Permo‐Triassic. Westward subduction of intervening sea (Proto South China Sea) below Malay Peninsula resulted in widespread I‐ and S‐Type granitization and volcanism in the back‐arc basins during Triassic. Extensive occurrence of Permo‐Triassic Pahang volcanics of predominantly rhyolitic tuff suggest its derivation from back‐arc extension. Back‐arc extension, basin development and sedimentation of the central belt of the peninsula continued until Cretaceous. A‐Type granite of metaluminous to peraluminous character indicates their emplacement in an intraplate tectonic setting. Malay Peninsula suffered an anticlockwise rotation due to the rifting of Luconia–Dangerous Grounds from the east Asia in the Late Cretaceous–Early Tertiary. Extensive ductile and brittle deformation including crustal segmentation, pull‐apart fracturing and faulting occurred during the closure and exhumation of the basins developed in the peninsula during Late Cretaceous–Early Tertiary. Crustal shortening in the central belt of the peninsula has been accomodated through strike‐slip displacement, shearing and uplift.  相似文献   

Assessing factors affecting drought,earthquake, and flood risk perception: empirical evidence from Bangladesh     

Mallick  Javed  Salam  Roquia  Amin  Ruhul  Islam  Abu Reza Md. Towfiqul  Islam  Aznarul  Siddik  Md. Nur Alam  Alam  G. M. Monirul 《Natural Hazards》2022,112(2):1633-1656

Natural Hazards - Understanding household disaster risk perception is crucial to formulate and apply disaster risk reduction strategies. Using survey data from 300 households from three highly...  相似文献