A diagnosis of groundwater quality from a semiarid region in Rajasthan,India     

N. C. Mondal  K. K. Tiwari  K. C. Sharma  S. Ahmed 《Arabian Journal of Geosciences》2016,9(12):602

A diagnosis of the groundwater quality of 70 wells sampled during two climatic regimes (dry and raining seasons) from a semiarid area in Rajasthan, India, had been carried out using standard methods. Analysis of the results for various hydrochemical parameters wherein the geological units are alluvium, quartzite and granite gneisses showed that all the parameters did not fall within the World Health Organisation’s acceptable limits for irrigation and drinking water purposes. The order of major cations and anions obtained during the dry and raining seasons are Na⁺ ? Mg²⁺ ? Ca²⁺ ? K⁺ and Cl^?? HCO₃ ^? ? SO₄ ^2?? CO₃ ^?> F^? ? NO₃ ^?, respectively. A maximum value of nitrate of 491.6 mg/l has been examined and its contamination is due to discriminated highly impacted groundwater samples by agricultural activity and small-scale urbanization. Fluoride (F^?) concentration is 6.50 mg/l as a maximum value, whereas values in about 26 % of the samples are more than the permissible limit (1.5 mg/l) for drinking water. The cumulative probability distributions of the selected ions show two individual intersection points with three diverse segments, considered as regional threshold values and highly impacted threshold values for differentiating the samples with the effects of geogenic, anthropogenic and saline water mixing. The first threshold values indicate the background hydrochemical constituents in the study area. The second threshold value of 732 mg/l for bicarbonate indicates that sandy aquifer is being dissolved during wet period, whereas NO₃ ^? concentration of more than the initial threshold value (=75 mg/l) indicates discriminated highly impacted groundwater samples by agricultural activity and urbanization in dry season. Various parameters such as soluble sodium percentage (SSP), salinity (electrical conductivity (EC)), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), Kelley’s ratio (KR), permeability index (PI), residual sodium bicarbonate (RSB) and magnesium absorption ratio (MAR) for the well samples show that, overall, 46 % of groundwater samples are not suitable for irrigation. Further, chloro-alkaline indices (CAIs) were used for distinguishing regional recharge and discharge zones whereas corrosivity ratio (CR) utilized for demarcating areas to use metallic pipes for groundwater supply. In general, groundwater quality is mainly controlled by the chemical weathering of rock-forming minerals. The information obtained represents a base for future work that will help to assess the groundwater condition for periodical monitoring and managing the groundwater from further degradation.  相似文献   

Impact assessment of climate change on future soil erosion and SOC loss     

Arun Mondal  Deepak Khare  Sananda Kundu 《Natural Hazards》2016,80(3):1515-1537

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Mapping lithology and assessing recharge characteristics in a granitic hard rock aquifer: Inference from 2D resistivity,induced polarization,tracer and moisture measurements     

Dewashish Kumar  G. B. K. Shankar  Setbandhu Mondal  V. Venkatesam  K. Sridhar  P. N. Rao  Pandith Madhnure  R. Rangarajan 《Journal of the Geological Society of India》2016,88(1):29-38

Two dimensional Electrical Resistivity Tomography (ERT) investigation along with Time Domain Induced Polarization (TDIP) investigation covering 1.6 km line were carried out at 3 natural recharge sites in a overexploited groundwater granite watershed, situated in a semi arid region in the state of Telangana, India. At these sites, shallow and/ or deep moisture influx measurements were also carried out using injected tritium tracer and neutron moisture probe. The watershed is covered by sandy loam to silt loam soil, receives an average annual rainfall of 620 mm with the pre monsoon groundwater level ranging from 8m to 29m bgl. The spot investigations were done to assess and understand the recharge process and groundwater potential in terms of resistivity/conductivity and moisture characteristics of the subsurface rock formation.  相似文献   

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   

Palaeocurrent and environmental implications from anisotropy of magnetic susceptibility (AMS): a case study from Talchir and Barakar formations,Raniganj Basin,West Bengal,India     

Saurodeep Chatterjee  Supriya Mondal  Punyotoya Paul  Pritwish Das 《Arabian Journal of Geosciences》2018,11(11):288

Oriented cylindrical cores of rock samples were collected from the Talchir and Barakar formations of the Lower Gondwana Supergroup of the Raniganj Basin exposed in and around Kalyaneshwari and Maithon areas. The cores (2.54 cm diameter and 2.2 cm height) were studied in the low field anisotropy of magnetic susceptibility (AMS) measurement to determine the nature of magnetic fabrics, to correlate it with the sedimentological characteristics and to determine the palaeocurrent patterns. The results derived from the statistical parameters (especially the q-factor), the shapes of the susceptibility ellipsoids and directional data of the AMS indicate that the magnetic fabrics within the studied units are primary (depositional) and are correlatable form the palaeoenvironmental features. The orientation of the maximum (K₁), intermediate (K₂) and minimum (K₃) susceptibility axes is dispersed on the lower hemisphere equal area diagram rather than strong clusters which is not because of secondary (tectonic) influence but due to the moderate to high-energy environment of deposition of the sediments in the studied units. Based on the q-factor (which is 0.581 for Barakar Formation and 0.565 for Talchir Formation which are both <?0.7), it is suggested the AMS indicates that the imbrication of the K₁ axis is the indicator of palaeocurrent. Also, the magnetic foliation (average value?=?1.255) exceeds the magnetic lineation (average value?=?1.107) and the shape parameter exceeds 0 in most cases pointing towards an oblate fabric. The palaeocurrent in the present study as indicated by the K₁ axis imbrication is very similar in both the units under study and is due SW. However, apart from this precise palaeocurrent direction, there exists a certain degree of randomness of the susceptibility axes which are very clear indication of corresponding depositional environments.  相似文献   

Battered minipile response to low-frequency cyclic lateral loading in very dense sand     

Mondal  Sanchari  Disfani  Mahdi M. 《Acta Geotechnica》2022,17(9):4033-4050

Acta Geotechnica - This experimental study investigates the response of vertical and battered minipiles to two-way symmetrical low-frequency (0.1&nbsp;Hz) cyclic lateral loading. Laboratory...  相似文献   

Monitoring dual-season hydrological dynamics of seasonally flooded wetlands in the lower reach of Mayurakshi River,Eastern India     

Debabrata Mondal  Swades Pal 《国际地球制图》2018,33(3):225-239

The seasonally flooded wetlands are often neglected due to their ephemeral and erratic appearance and small size, however, their hydro-ecological importance, socio-economic values are equivalent to the permanent wetlands. Using dual-season Landsat multi-spectral imagery, this study highlights a comprehensive monitoring of the hydrological dynamics of wetlands in the lower reach of the Mayurakshi River at a 14-year temporal resolution with the seasonal mode of 1987–2014 time frames. Our results demonstrate the seasonal and periodic hydrological variability of water presence frequency (WPF) in six wetland complexes defined for this study. The Hijal, Ghambira and Maldah wetland complexes are highly affected by the change of WPF, while Dwarka complex is relatively stable. The assessment of WPF change analysis showed that the method is proficient in identifying stable and physically vulnerable wetland patches and absolute loss of wetland inundation frequency resulting from various anthropogenic causes like regulation of river, dry farming practices and other integrated developmental works. The outcome of our study provides a robust basis for the fundamental hydrological and ecological studies and helpful for the conservation and management of seasonally flooded wetland resources in the tropical monsoon climate.  相似文献   

Study of spectral signatures for exploration of Bauxite ore deposits in Panchpatmali,India     

P. Suman Babu  Amit K. Bhattacharya 《国际地球制图》2015,30(5):545-559

Spectral analysis technique has been utilized to identify the Bauxite mineral occurrences in Panchpatmali, Orissa, India. Spectral processing of Landsat ETM+ data has been carried out by converting the digital data from quantized and calibrated values to reflectance values. Minimum noise fraction transformation is used to determine the inherent dimensionality of reflected Landsat ETM+ data, to segregate noise in the data, and to reduce the computational requirements for subsequent processing and interactively to locate pure pixels within the data-set, projecting n-dimensional scatterplots. Spectral processing results are displayed in the form of images corresponding to each group of pixels (endmembers). Mixed tune matched filtering method has been applied on Landsat ETM+ images which gave three score (abundance) images for three different classes (endmembers) such as Bauxite, vegetation and soil. Further, mineralized zones are identified using image fusion of ERS-2 SAR and Landsat ETM+ data using intensity-hue-saturation technique.  相似文献   

Role of panchayat (Local self-government) in managing disaster in terms of reconstruction,crop protection,livestock management and health and sanitation measures     

Debabrata Mondal  Sarthak Chowdhury  Debabrata Basu 《Natural Hazards》2018,94(1):371-383

The Panchayati Raj Institution is a statutory body elected by the local people through a well defined democratic process with specific responsibilities and duties. It is the most appropriate institution from village to the district level. The role of Panchayats (local self governing institutions) is important in view of their proximity to the local community, universal coverage and enlisting people’s participation on an institutionalized basis. Panchayat and municipalities are local governing institutions in countries like India, have a constitutional mandate under the 73rd and 74th constitutional amendments Act. Apart from the proper implementation of different ongoing developmental programmes, the panchayat system has to play pivotal roles in respect of natural as well as man-made disaster management. In India, Particularly in West Bengal the village level Disaster Management Committee is headed by ward members of gram panchayat. The Panchayati Raj Institutions provide adequate space to the weaker section of the communities at its three levels, i.e. village, block and district. Good governance can be an instrumental feature in poverty reduction. This study was undertaken in cyclone affected areas in West Bengal to assess the role of panchayat in disaster management. The empirical study revealed that main role performed by the panchayat in respect of disaster was reconstruction of damaged houses, crop protection measures, livestock management, health and sanitation measures. Besides these broad aspects, the panchayats officials also organized health camp, involved in rescue operation, arranging temporary shelters and so on as disaster management operation. Total 60 gram panchayat officials and 150 villagers were selected randomly as respondents for the present investigation. The data were analysed into mean score, rank position and spearman correlation coefficient to achieve the objectives. The findings of the study indicated that significant differences were observed on the opinion of the villagers and officials on reconstruction of houses and health and sanitation measures. The roles performed by the local self-government in disaster management were very poor. There was absolutely lack of involvement of people’s representative. Therefore, adequate supports are suggested on these aspects from the representatives in association with higher authorities.  相似文献   

The Effects of Solar Eclipse of August 1, 2008 on Earth’s Atmospheric Parameters     

Syam Sundar De  B. K. De  B. Bandyopadhyay  B. K. Sarkar  Suman Paul  D. K. Haldar  S. Barui  Asim Datta  Syam Sundar Paul  Nikhilesh Paul 《Pure and Applied Geophysics》2010,167(10):1273-1279

Several experiments were undertaken at Kolkata (latitude: 22°34′N, longitude: 88°30′E) on the solar eclipse day of August 1, 2008 to observe the effects of the solar eclipse on Fair Weather Field (FWF) and VLF amplitude and phase. The experimental results presented here show significant deviations of the observed parameters from their normal values, as they are determined by the average of the records obtained on 5 days adjacent to the day of the solar eclipse.  相似文献