Harjeet Kaur

Application of geospatial technologies for multi-hazard mapping and characterization of associated risk at local scale

ABSTRACT In this study multi-hazard risk assessment is carried out in Arithang ward, one of the major wards within Gangtok Municipal Corporation, with the objectives of (a) landslide and earthquake hazard mapping of Gangtok city with analytical hierarchy process (b) vulnerability mapping in Arithang ward and (c) semiquantitative and semiqualitative risk analysis. Landslide hazard zonation (LHZ) depicts that very high and high hazard zone occupies 6% and 17% of the Gangtok city whereas 60% and 18% of area falls under medium and low hazard category respectively. With respect to seismic hazard susceptibility 13% and 22% of area falls under very high and high category respectively. Semiquantitative risk analysis reveals that majority of the residential buildings are concentrated in low earthquake and landslide hazard zone followed by 39% and 35% within medium class. Only 0.6% and 7% of residential buildings are found in high earthquake and landslide hazard zones. Bamboo and wood made buildings are found to cluster within very high class of landslide hazard. About 61% of multistoried buildings are placed within low zone of LHZ. Risk analysis reveals that buildings at the eastern and western part of Arithang ward come under high risk with respect to earthquake and landslide.

Comparative evaluation of various approaches for landslide hazard zoning: a critical review in Indian perspectives

The progress of geospatial technique can help to minimise the losses as it emerges as a powerful technique for mapping landslide hazard zonation. Different researchers use different methods for landslide hazard assessment. But, there is not a single method which has been universally accepted for effective assessment of landslide hazard. In Indian subcontinent, 12.6% of land area is susceptible to landslide hazard and the estimated total economic damage due to landslide hazard is 4,500,000US

Comparative evaluation of water quality zonation within Dwarka River Basin, India

. This review article represents the temporal development of different methodologies towards landslide hazard zonation up to a recent year and their advantages and disadvantages. The review indicates that mostly three methods i.e., knowledge driven, data driven and physical based method are followed among which, knowledge driven and bivariate analysis are mostly used during last decade but from the twenty-first century onwards multivariate statistical modelling is mostly popularised as it gives the most accurate result of landslide hazard zonation in comparison to other methods. Geospatial modelling of landslide susceptibility is useful for monitoring, mapping and formulating proper management plans that will be helpful for future landslide mitigation measures.

Sensitivity analysis and mapping the potential groundwater vulnerability zones in Birbhum district, India: A comparative approach between vulnerability models

ABSTRACT This study evaluates the thematic representation of drinking water quality of 211 habitations along the Dwarka River Basin (DRB), West Bengal, India. The dominant water type is Ca–Mg–HCO3. Statistical analysis of the spatial dataset indicates a clustering pattern (with a nearest-neighbour ratio of 0.368 and Z score of 29.774). Two different techniques, spatial interpolation of water quality index (WQI) and composite water quality index (WQIC) of physico-chemical constituents, were implemented to compare their performance. The WQIC indicates approximately 11.68% of the total study area is at non-permissible levels, whereas the normal WQI technique predicts about 1.64% of the area is in non-permissible zones. Spatial water quality zonation by means of the overlay technique was superior to the conventional WQI technique in precisely distinguishing the characteristics of the permissible area with respect to even a single WHO recommended water quality parameter.

Geochemical and geostatistical appraisal of fluoride contamination: An insight into the Quaternary aquifer

Abstract The assessment of groundwater vulnerability is essential especially in developing areas, where agriculture is the main source of the population. In the present study, four different overlay and index method, namely, DRASTIC, modified DRASTIC, pesticide DRASTIC and modified pesticide DRASTIC are implemented with a view to identifying the most appropriate method that predicts the vulnerable zone to groundwater pollution. Sensitivity analysis reveals that net recharge is the most influential parameter of the vulnerability index. Cross comparison of model output shows the highest similarity of 97% is observed between drastic and modified drastic while the maximum difference in models prediction of 49% is observed between modified drastic and pesticide drastic. Reported nitrate concentrations in groundwater are considered for validation of model-generated final output map. The prediction power of the models are assessed using success and prediction rate method and it highlights DRASTIC model as the most suitable model with 89.69% and 84.54% of the area under area under the curve (AUC) for success and prediction rate respectively.

Assessment of groundwater potential zones using multi-influencing factor (MIF) and GIS: a case study from Birbhum district, West Bengal

Fluoride (F-) in groundwater poses a severe public health threat in the Dwarka River Basin (DRB) of West Bengal, India, where many cases of fluorosis have been reported. This research evaluates the spatial distribution patterns of major cations and anions, delineates zones of high F- concentrations within alluvial sediments of the DRB, and identifies both the sources and the geochemical processes responsible for the release of F- to groundwater. A total of 607 groundwater samples were collected from shallow and deep tube wells located within the DRB, encompassing an area of 435 km2 and including 211 villages. Fluoride levels range from 0.01 to 10.6 mg/L, and high concentrations (>1.5 mg/L) are restricted to isolated areas within the basin (occurring within nine of the villages and comprising 4.3% of the samples collected). The high-fluoride areas are characterized by mostly Na-HCO3 type groundwater, where the abundance of cations and anions are Na+ > Ca2+ > Mg2+ > K+ and HCO3- > Cl- > SO42- > F- > NO3- > Br-, respectively. Analyses of the groundwater geochemistry and sediment mineralogy suggest that fluoride is released to groundwater primarily through the hydrolysis of albite and biotite; however, the resulting alkaline conditions are also favorable for release of fluoride from weathered biotite and clay minerals through anion exchange (OH- in groundwater replacing F- within the mineral structure). Multiple linear regression models show that fluoride concentrations can be predicted from the measures of other dissolved constituents with a high degree of accuracy (R2 = 0.96 for high fluoride samples and R2 = 0.8 for low fluoride samples).