A new model (DRASTIC-LU) for evaluating groundwater vulnerability in parts of central Ganga Plain,India     

Fakhre Alam  Rashid Umar  Shakeel Ahmed  Farooq Ahmad Dar 《Arabian Journal of Geosciences》2014,7(3):927-937

The study area is a part of central Ganga Plain which lies within the interfluve of Hindon and Yamuna rivers and covers an area of approximately 1,345 km². Hydrogeologically, Quaternary alluvium hosts the major aquifers. A fence diagram reveals the occurrence of a single aquifer to a depth of 126 m below ground level which is intercalated by sub-regional clay beds. The depth to water level ranges from 9.55 to 28.96 m below ground level. The general groundwater flow direction is northwest to southeast. Groundwater is the major source of water supply for agricultural, domestic, and industrial uses. The overuse of groundwater has resulted in the depletion of water and also quality deterioration in certain parts of the area. This has become the basis for the preparation of a groundwater vulnerability map in relation to contamination. The vulnerability of groundwater to contamination was assessed using the modified DRASTIC-LU model. The parameters like depth to water, net recharge, aquifer media, soil media, topography, impact of vadose zone, hydraulic conductivity of the aquifer, and land use pattern were considered for the preparation of a groundwater vulnerability map. The DRASTIC-LU index is computed as the sum of the products of weights and rating assigned to each of the inputs considered. The DRASTIC-LU index ranges from 158 to 190, and is classified into four categories, i.e., <160, 160–170, 170–180, and >180, corresponding to low, medium, high, and very high vulnerability zones, respectively. Using this classification, a groundwater vulnerability potential map was generated which shows that 2 % of the area falls in the low vulnerable zone, 38 % falls in the medium vulnerable zone, and 49 % of the area falls in the high vulnerable zone. About 11 % of the study area falls in the very high vulnerability zone. The groundwater vulnerability map can be used as an effective preliminary tool for the planning, policy, and operational levels of the decision-making process concerning groundwater management and protection.  相似文献   

Structural control on landscape development of Barak Valley, northeast India     

A. Alam Laskar  P. Phukon 《Journal of the Geological Society of India》2013,81(2):232-240

The Barak Valley, comprising a contiguous region of three south Assam districts of Cachar, Hailakandi and Karimganj, represents a ridge and valley province with meridional to sub-meridional anticlinal hills and synclinal valleys. Thin skinned tectonics resulted in the deformation of Neogene clastics which is manifested in the form of a series of anticlines and synclines. These structural elements have profound control on the development of present-day landscape in Barak valley. Structurally controlled fluvial erosion produced a series of cuesta ridges and strike valleys which were further subjected to erosional dissection leading to development of numerous topographic highs. Along the northern part of Barak valley adjoining Barail range, three terrace levels stand out with topographic offsets of upto ～10 m. These terraces are linked to tectonic adjustments along Haflong-Disang Thrust that traverse along the Barail foothills. Numerous wetlands linked to fluvial activities and also isolated from the fluvial domain form a significant element of the Barak valley landscape. Some of these wetlands have their origin to tectonic activities of the region. While the trunk channel of the region follows a nearly E-W trend, all the major tributaries join it at nearly orthogonal position following the prevailing structural trend.  相似文献   

Delineation using geophysical data of the hydrocarbon bearing zone in the Begumganj structure, Hatia Trough, southern Bengal Basin, Bangladesh     

Rashed Abdullah  Delwar Hossain  M. Rafiqul Alam 《Journal of the Geological Society of India》2013,82(3):271-276

The Begumganj structure of the Hatia Trough in Bengal Basin has proved it’s hydrocarbon potentiality. Several seismic sections have been analyzed to construct different maps and to interpret subsurface geology, structure and stratigraphy. These maps reveal that the Begumganj structure is an elongated to oval shaped asymmetrical anticline having the general trend NNW-SSE. No major faults affecting the structure could have been identified. Most of the reflectors are strongly affected by channels, especially at the western flank. Based on the analysis of seismic and available well data, the only gas bearing strata at depth of 2995 m (or TWT 2.02 seconds) has been identified. The structure is interpreted as a strati-structure entrapment because shale fill channel truncated this layer on western flank and at the crestal part of the anticline. The structure probably formed after the deposition of sediments. The channel has formed after the corresponding unit cut has been deposited. The channels eroding the reservoir unit range from Late Miocene to Early Pliocene age where the anticline probably begun to form during the Pliocene. Strong increase in amplitude (bright spot), possibly associated with hydrocarbon, has been apparent on seismic lines BG 9 and BG 10. The stratigraphic succession based on the information of the wells drilled on this structure and it’s surrounding fields reveals that the lithological sequences range from Miocene to Recent age where the only proven gas producing sand zone is located in the Bhuban Formation.  相似文献   

Exploring the expanding Universe and dark energy using the statefinder diagnostic   总被引：1，自引：0，他引：1  

Ujjaini Alam  Varun Sahni  Tarun Deep Saini  A. A. Starobinsky 《Monthly notices of the Royal Astronomical Society》2003,344(4):1057-1074

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Distribution functions in the statistical theory of convective MHD turbulence of an incompressible fluid     

M. S. Alam Sarker  N. Kishore 《Astrophysics and Space Science》1991,181(1):29-42

In this paper, we define a hierarchy of distribution functions for simultaneous velocity, magnetic, and temperature fields. Some properties of the constructed distribution functions such as reduction, separation, and coincidence are discussed. Equations for the evolution of one- and two-point distribution functions have been derived. Finally, a comparison of the equation for the single-point distribution function in case of zero viscosity, negligible diffusivity, and infinite electrical conductivity is made with first equation of BBGKY hierarchy in the kinetic theory of gases.On study leave from the Department of Mathematics, University of Rajshahi, Bangladesh.  相似文献   

Modeling study of growth and potential geohazard for LUSI mud volcano: East Java,Indonesia     

Bambang P. Istadi  Gatot H. Pramono  Prihadi Sumintadireja  Syamsu Alam 《Marine and Petroleum Geology》2009

The mud volcano known as LUSI first erupted in May 2006 in East Java, Indonesia. The eruption has continued for over two years, and potentially will continue for many years to come, impacting an ever larger area. An obvious and significant question is how extensive the impacted area will become in the coming years. The answer is important for planning scenarios for the relocation of people and infrastructure and for managing the environment and economy. To make such a prediction, an understanding of the geological processes controlling the mud volcanic evolution is needed.  相似文献   

Organic carbon mobilization in a Bangladesh aquifer explained by seasonal monsoon-driven storativity changes     

Britta Planer-Friedrich  Cornelia Härtig  Heidi Lissner  Jörg Steinborn  Elke Süß  M. Qumrul Hassan  Anwar Zahid  Mahmood Alam  Broder Merkel 《Applied Geochemistry》2012

Currently, the most widely accepted hypothesis to explain high As concentrations in Bangladesh groundwaters is that dissolved organic C (DOC) reduces solid Fe (hydr)oxides and mobilizes sorbed arsenate. The nature of the DOC and its release mechanism are still controversial. Based on weekly to biweekly sampling over the course of one monsoon cycle at six monitoring wells of different depths, it is proposed that storativity changes drive natural DOC release from clay–peat layers to the adjacent aquifers. With a decrease in hydraulic heads during the dry season, total mineralization and DOC concentrations increased. With the onset of the rainy season and an increase in hydraulic heads, release of clay–peat derived components stopped and vertical water displacement due to groundwater recharge from rainwater occurred, causing aquifer flushing and a decrease in total mineralization and DOC concentrations. Total As and DOC concentrations correlated over depth. However, at the depth of maximum concentrations, the As peak was observed during the rainy season. At present, the reason for this inverse seasonal trend between As and DOC is unclear. Higher mineralization or DOC concentrations could lead to increased As sorption or the increased arsenite release is a time-lag abiotic or microbial response to the DOC peak. The vulnerability of the Pleistocene aquifer towards increased As concentrations was found to be much higher than previously assumed. Though sorption capacities were determined to be higher than in the Holocene aquifer, probably due to intact Fe (hydr)oxides, long-term continuous As input from overlying clay and peat layers by the proposed seasonal storativity changes has led to increased aqueous As concentrations of 85 μg/L, considerably higher than drinking water standards. Until now, aquifer and especially aquitard and aquiclude hydraulics have not been considered sufficiently when attempting to explain As mobilization in Bangladesh.  相似文献   

Seasonal and Interannual Sea Surface Temperature Variability in the Coastal Cities of Arabian Sea and Bay of Bengal     

Tariq Masood Ali Khan  Dewan Abdul Quadir  Tad S. Murty  Majajul Alam Sarker 《Natural Hazards》2004,31(2):549-560

The sea surface temperature (SST) variations play a veryimportant role in the genesis and maintenance of meteorological and oceanographic processessuch as monsoon depressions and subsequent floods, large-scale sea level fluctuationsand genesis of tropical cyclones. Many low lying coastal regions of South Asia are adjacentto river deltas and have large population. The dense population, poor economy and severalother socio-economic factors make these areas most vulnerable to the impact of climate change.Variability of sea surface temperature (SST) is importantas the duration and intensity of SST provide the basis for studies related to climatic changescenario. In this study an attempt has been made to estimate the recent SST trends in the coastalwaters of some cities, which lie on the Arabian Sea and Bay of Bengal. The annual andinterannual variability has also been studied. The SST variations have then been linkedwith the El Nino and La Nina events.The NOAA-NASA Pathfinder Advanced Very High Resolution Radiometer (AVHRR) SST fields from 1985-1998, created in the Jet Propulsion Laboratory(JPL), USA are used in this study. Here the quality of data is an important factor toobtain reliable estimates of Sea Surface Temperature (SST) trends and other related parameters.However, this is not possible with the conventional type data, due to low quality as wellas sparse data in the region. Though the satellite based SST climatologies have shorterobservation lengths, they can provide reliable estimates of recent SST variability overa large oceanic areas with sparse or no data.Increasing trend of SST is observed throughout all theseasons in the northern Arabian Sea extending from Oman to Karachi and Mumbai and furthersouth to Salalah and Colombo. However, in coastal islands stations further south ofIndia such as at Colombo the increment is not significant. Though the increasing trend in SSTduring winter is not significant, nevertheless it shows the increasing influence of coldspells on this Island. An interesting situation has been observed in the Bay of Bengal. On anaverage, increasing trends in the annual SST were observed in Visakhaputnam. But at thestations located in the northeastern part of Bay of Bengal, namely Hiron Point and Cox'sBazar reverse conditions are observed. In the Southern Bay of Bengal variations in SST isnot significant which reflects in the SST analysis of Chennai and Port Blair stations. Locationof these stations at lower latitudes (near by equator) probably is the reason for this insignificantchange. It has been found that the interannual mode of SST variations dominate the linear SSTtrends which is characterized by the El Nino Southern Oscillations (ENSO) scale cycle.  相似文献   

Clay mineralogy of archaeological soil: an approach to paleoclimatic and environmental reconstruction of the archaeological sites of the Paharpur area,Badalgacchi upazila,Naogaon district,Bangladesh   总被引：1，自引：0，他引：1  

A. K. M. Masud Alam  Shucheng Xie  Dilip Kumar Saha  Sifatul Quader Chowdhury 《Environmental Geology》2008,53(8):1639-1650

A geo-archaeological examination was carried out in and around the Paharpur area, Badalgacchi upazila of Naogaon District in the north-western part of Bangladesh. Clay mineralogy and global paleo-temperature curves were used to determine the paleoclimatic and depositional environmental conditions of the Holocene archaeological soils (Barind clay residuum) of the Paharpur archaeological spot. Clay mineralogical data show that the dominant clay mineral is illite with subordinate amounts of kaolinite and chlorite. The high illite and low kaolinite content implies a marine or estuarine deposit. The clay mineral ratio log diagram, constructed by plotting the 7–10°Å integrated intensity ratios versus depth, supports this assumption. The presence of illite, together with quartz and feldspar, suggests high detrital input under generally cool to temperate and dry climates. Chlorite is another common by-product of weathering reactions with low hydrolysis, which is typical for cool to temperate and dry climates. The results suggest the existence of a marine–estuarine influence under a generally cool to temperate and dry climates around Paharpur and the surrounding region throughout the Pala dynasty around mid-century 700 a.d. to early 1100 a.d. Furthermore, this observation is consistent with the global paleo-temperature curves.  相似文献   

Long-term trend analysis of water table using ‘MAKESENS’ model and sustainability of groundwater resources in drought prone Barind area,NW Bangladesh   总被引：1，自引：0，他引：1  

ATM Sakiur Rahman  Md. Kamruzzama  Chowdhury Sarwar Jahan  Quamrul Hasan Mazumder 《Journal of the Geological Society of India》2016,87(2):179-193

In Bangladesh, agriculture plays a major role in the national economy. In the drought prone Barind area in NW Bangladesh, cropping intensity has increased almost double since late eighties of last century (from 1985) because of the introduction of groundwater irrigation. Long-term behavior of groundwater table (GWT) in the drought prone Barind area has been studied using MAKESENS model in the wake of massive installation of tube-wells. The study reveals that the maximum and minimum depths to GWT during 1991-2010 show on average declining trend of 4.51 m and 4.73 m. The long-term prediction for the period of 2020-50 assuming the current rate of groundwater withdrawal is that the declining trend will be 1.16 to 1.59 and 1.07 to 1.82 times more for maximum and minimum groundwater depths respectively in comparison to the present. The rigorous exploitation of groundwater for irrigation, decreasing rainfall and surface geological attributes lead towards declining trend of GWT. This will hamper the country’s food security and ultimately threaten its socio-economic sustainability. So the appropriate strategies for the management of groundwater resource on a sustainable basis should be the priority for maintaining agricultural productivity.  相似文献