This paper presents landslide hazard assessment in and around Balkhila sub-watershed of Uttarakhand, Himalaya using remote sensing data and Geographical Information System. IRS-IC LISS III, RESOURCESAT LISS-IV remote sensing data products along with Survey of India (SOI) topographical sheets accompanied by field investigations were used to generate a landslide inventory map of the study area. Such type of information on slope stability of the area could be useful for explaining the known existing landslide, helping to make emergency decisions and relieving the efforts on the avoidance and mitigation of future landslide hazards in the area.
Increasing population worldwide has put tremendous pressure on the land. Recent studies reported that many areas covered by wastelands are decreasing because parts of wastelands are being converted into arable land. It is important to identify and monitor these changes in spatial planning and management. This paper adopts a remote sensing-based identification of culturable wastelands based on seasonal vegetation changes in Vadodara district, India. Supervised classification was applied on three MODIS images of 2016-17 of 3 different seasons. Separability analysis was applied to get the best data combination for image classification. Validation was done by ground referencing and Google earth images. The composite of winter season image with NDVI and EVI performed best with an overall accuracy of 78.2% with the kappa co-efficient of 0.7580. This method opens a possibility of using digital classification for identification of culturable wastelands in the study area which are so far mapped with visual interpretations only.
The erratic nature of rainfall has increased the human dependency on surface and groundwater resources manifold. The increased pressure on surface water and groundwater resources makes hydrological drought a very important subject. The streamflow and run-off analysis are widely used methods for the quantification of hydrological drought. However, in the regions which lack perennial streams, the groundwater analysis may prove more effective for the assessment of hydrological drought rather than streamflow and run-off analysis. This study attempts to investigate the spatio-temporal patterns, frequency and intensity analysis of hydrological drought in the Marathwada region of Maharashtra state in India. The standardized water level index has been used to quantify hydrological drought. Maps have been generated to represent spatio-temporal patterns of hydrological drought. The frequency and intensity analysis of hydrological drought across seventy-six sub-districts were assessed by multiplying the frequency of each class of drought severity with its assigned weightage. The spatio-temporal assessment of hydrological drought depicts significant spatial expansion of hydrological drought during the period of 2011 to 2015. The analysis revealed that hydrological droughts of mild to the moderate category are more frequent than the severe and extreme droughts. However, there are also pieces of evidence of the severe and extreme drought occurrences in the Marathwada region, particularly more between the years 2011 and 2015.
Grain size distribution, pebble morphometry and petrographic analyses were carried out on samples collected from Mamfe Formation, Ikom-Mamfe Embayment, southeastern Nigeria to determine textural parameters, provenance and paleoenvironment. The results from grain size analysis show that mean grain size, inclusive standard deviation, graphic skewness and kurtosis yielded average values of 0.94ɸ, 1.30ɸ, 0.1, and 1.20 respectively. These results show that the sandstones have representatives of fine to coarse grain sizes; they are poorly sorted with dominance positively skewed suggesting a fluvial origin for the sediments. Bivariate analysis also infers that the sandstones were deposited in fluvial regime. The mean values of pebble morphometric parameters including elongation ratio (ER), flatness ratio (FR), maximum projection sphericity index (MPSI), oblate-prolate index (OPI) and sphericity (S) all fall within acceptable limits for fluvial deposits. The mean roundness suggests fluvial action, also indicated by the shape of the pebbles. Plots of Sphericity vs. OP index and particle form triangular diagram also indicates the pebbles were shaped predominantly by fluvial action. Petrographic study reveals quartz as the dominant framework grain, followed by feldspar and rock fragment. The sandstones are texturally and mineralogically immature. The sandstone of the Ikom-Mamfe Embayment is classified as arkosic-subarkosic arenites sourced from uplifted basement rocks and deposited in a humid climatic condition.
Kumbur River basin has been one of the biodiversity areas in India. Land use and land cover study of a particular area has been one of the most important criteria to know about the usage pattern of the environmental conditions. With every passing year, we can see a change in land use and land cover classification in the study area, a part of the Western Ghats located in Tamilnadu. In this study, an effort is made to understand the changes in land use and land cover in the study area over a period of 24 years (1990 2014). The study has been done through remote sensing tools using Survey of India map (1990) and the Landsat imageries of the study area (January, 1990, January, 2001, February, 2010 and June, 2014). The land use and land cover classification was implemented based on the supervised classification using the maximum likelihood method. Thematic maps were prepared by using GIS software. Accuracy assessment has been done for the classification by ground truth observations. The present study showed that land use and land cover of the study area has experienced a vast change between 1990 and 2014. Mainly Developed areas (built-up and agricultural land) have increased from 13% to 35% of the total area (13.9%, 20.13%, 29.4%, and 35.5% in the specified periods, respectively). Thus, proper management of the land resource is the need of the hour in the study area.