Environmental geoinformaicts of fast growing Himalaya’s foothill towns and surrounding: concept and implementation

Himalaya foothill zone have fragile geo-environment due to active tectonics and dynamic hydrological process and its associated reshaped geomorphology. Rapid urbanization and development of new colonies leads to high rate of land use change and natural resource degradation since last three decades which has been accumulating the fragility of the area. Consequently entire Himalaya foothill zone requires a comprehensive local level geo-environmental appraisal for effective sustainable development planning of the region. Keep in view this; the Ramnagar Himalayan Foothill area (RHFA) in district Nainital, Uttarakhand (India) has been selected for the case illustration. The main objective of the study was to develop a GIS database on Ramnagar environmental geo-informatics (REGI) to facilitate all the concern line departments to implement their socioeconomic developmental activities in the most suitable and safe places throughout the study area. REGI suggests, although landscape of the study area have few favorable conditions for the inhabitant (i.e. maximum proportion (92 %) of the study area enjoys sub-tropical to sub-temperate climatic conditions, easy approachable, thick vegetation cover, rich water resources) but the active tectonics and dynamic hydrological process and its associated reshaped geomorphology poses a stressed geo-environment which need to be consider to formulate a decision support system (DSS) for sustainable development planning.     

Influence of strong motion characteristics on permanent displacement of slopes

Landslides triggered by moderate to major earthquakes are a recognized seismic hazard. Arias Intensity (I _a) is a key intensity measure of the ground motion, but significant duration is widely used to define strong motion duration. We calculate Newmark’s displacements using earthquake records bracketing a broad range of Arias Intensity and significant duration employing Newmark’s rigid block method and a number of yield accelerations. Total landslide displacement increases with the increase in the energy content of the ground motion (I _a) above a threshold. Such threshold may be expressed as a function of yield acceleration of the slope regardless of the ground motion characteristics. Newmark displacement decreases with increasing duration for earthquakes with similar energy content. The wide scatter in the results converges when using formal dimensional analysis. Self-similar symmetry may facilitate the assessment of the performance of slopes during earthquakes. The mathematical framework for probabilistic determination of landslides displacement may be a useful aid to estimate the likelihood of landslide hazards provided that the geotechnical properties of the slopes are known.     

Study of mechanical properties of Vindhayan shaly rocks at elevated temperature

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.     

Forest biomass carbon dynamics (1980–2009) in western Himalaya in the context of REDD+ policy

Carbon emissions from forests have decreased in the past decade due to conservation efforts, however majority of carbon losses suffered in the past went unnoticed until the role of forests in mitigating climate change was realized. Forestry sector in developing countries is recognized as one of the largest and low cost mitigation options to address climate change. The present study was conducted to assess the multi-temporal biomass carbon mitigation in the temperate forests of western Himalaya using satellite (Landsat MSS, TM, ETM+) and forest inventory data. Forest type density mapping was done through on-screen visual interpretation of satellite data. After conducting preliminary survey in 2009, 45 quadrats (0.1 ha) were laid in six forest types for collecting field inventory data viz., diameter at breast height, tree height, slope and aspect. Biomass carbon (t ha^?1) was estimated for different forest types with different crown densities (open with 10–40% crown density and closed with >40%) using recommended regression equations, ratios and factors. A decreasing trend of carbon (145.13–134.87 mt) was observed over the period of time. Temporal biomass carbon dynamics was analyzed for REDD+ opportunities. The temporal variation of carbon observed was found to be more useful for claiming benefits under negative options (deforestation and forest degradation) of REDD+. The study doesn’t take actual conversions to CO₂ into account. However, the findings are useful in establishing baseline emissions through temporal carbon losses. Further, the study helps in identification of location specific socio-economic drivers of losses that can be used for appropriate mitigation interventions.     

Retrieval and validation of soil moisture from FRS-1 data set of radar imaging satellite (RISAT-1)

In this work, we estimated soil moisture (SM) by using dielectric constant properties of soil with radar backscattering coefficient (bc) from simulated annealing techniques of RISAT-1 (radar imaging satellite, based on synthetic aperture radar (SAR) technique) data. We examined the performance of simulated annealing in retrieving SM where the vegetation cover is not very high (NDVI ≈ 0.35 for wheat-dominated area on January 19, 2013).To overcome the land surface model limits on SM estimation accuracy, point measurement spatial coverage limits, and microwave remote sensing spatial-temporal sampling limits, we reduced uncertainties through a combination of these approaches. Near-surface SM measurements from the 5.35-GHz (C-band) channels of RISAT-1 were collocated against ground-truth data (collected during the flight time of RISAT-1 over the study area), to establish SAR-SM relationships for FRS-1(circular horizontal (RH) and circular vertical (RV)) data set of RISAT-1. Comparison with the limited ground-based point (total 24 points) measurements of SM content exhibited a net improvement when near-surface SM observations were assimilated. Comparison of the SM derived from the sigma naught (σ ⁰) (of RISAT-1 data set FRS-1) using the inversion algorithm with the observed measurements (using time domain reflectometry) of SM showed root mean square error of 0.24, nRMSE = 0.03, R-RMSE = 0.38, MAE = 0.63, NRMSE = 1.02, NSE = 1, d = 0.87, r ² = 0.65, and RMSE% = 12.79 for RH polarized image while RV polarized image failed each statistical test for predicting good SM with respect to the observed SM. The ability to extract additional information comes at the expense of including more measurements, especially at frequencies lower than the L-band. This approach is therefore intended for future space-borne systems.     

Groundwater arsenic contamination and its health effects in India

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.     

Combining geomatics and conventional methods for monitoring forest conditions under different governance arrangements

Introduction Assessment and systematic resource condition monitoring are essential components of long-term planning and management of forest resources. These requirements can be fulfilled using different methods and techniques. Traditionally, when the primary objective of forest management was tim- ber production, sample-based forest inventories were the sole method of determining forest condi- tions. Aerial photographs were frequently used for forest cover mapping during the third quarter of …     

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

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.     

Integration of magnetism and heavy metal chemistry of soils to quantify the environmental pollution in Kathmandu, Nepal

Abstract Soil profiles of the Kathmandu urban area exhibit significant variations in magnetic susceptibility (χ) and saturation isothermal remanence (SIRM), which can be used to discriminate environmental pollution. Magnetic susceptibility can be used to delineate soil intervals by depth into normal (< 10^?7 m³/kg), moderately enhanced (10^?7–< 10^?6 m³/kg) and highly enhanced (≥ 10^?6 m³/kg). Soils far from roads and industrial sites commonly fall into the ‘normal’ category. Close to a road corridor, soils at depths of several centimeters have the highest χ, which remains high within the upper 20 cm interval, and decreases with depth through ‘moderately magnetic’ to ‘normal’ at approximately 30–40 cm. Soils in the upper parts of profiles in urban recreational parks have moderate χ. Soil SIRM has three components of distinct median acquisition fields (B_1/2): soft (30–50 mT, magnetite‐like phase), intermediate (120–180 mT, probably maghemite or soft coercivity hematite) and hard (550–600 mT, hematite). Close to the daylight surface, SIRM is dominated by a soft component, implying that urban pollution results in enrichment by a magnetite‐like phase. Atomic absorption spectrometry of soils from several profiles for heavy metals reveals remarkable variability (ratio of maximum to minimum contents) of Cu (16.3), Zn (14.8) and Pb (9.3). At Rani Pokhari, several metals are well correlated with χ, as shown by a linear relationship between the logarithmic values. At Ratna Park, however, both χ and SIRM show significant positive correlation with Zn, Pb and Cu, but poor and even negative correlation with Fe (Mn), Cr, Ni and Co. Such differences result from a variety of geogenic, pedogenic, biogenic and man‐made factors, which vary in time and space. Nevertheless, for soil profiles affected by pollution (basically traffic‐related), χ exhibits a significant linear relationship with a pollution index based on the contents of some urban elements (Cu, Pb, Zn), and therefore it serves as an effective parameter for quantifying the urban pollution.