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Assessment of spatio-temporal waterline changes of a reservoir: A case study of Ujjani wetland, Maharashtra, India
1-13Views:242The Ujjani reservoir is an artificial inland wetland and a potential Ramsar site in Maharashtra, India. The present study investigates the changes in the surface water area over time using remote sensing imageries (LANDSAT, LISS-III, Sentinel 2 series) for four decades (1981 to 2021) and the normalized difference water index (NDWI). The study reveals that the overall mean amount and rate of decrease in the surface water area are estimated at 20.50% (44.31 + 30.38 km2) and 0.75% year-1 (1.62 + 1.36 km2year-1), respectively. Furthermore, multiple correlation matrix analysis shows a strong positive correlation between surface water area and rainfall while a weak negative correlation with mean annual temperature (TMAX). Thus, indicating rainfall as the principal factor in inducing changes to the surface water area of the Ujjani wetland. However, the study also finds that the impact of the dramatic rise in population growth and anthropogenic activities in the form of overexploitation and land encroachments for agriculture are gradual but significant cursors to wetland degradation. Hence, the study recommends periodic monitoring, management, and conservation of wetlands, by employing stringent policies and effective technological measures.
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Human induced conservation in the natural islets. Status of vertebrate diversity in the selected sacred forests of Kerala India
41-47Views:101Sacred forests are conserved based on religious aspects. Regional differences are visible among sacred groves in their management policies, temple construction, landscapes, and religious beliefs. This study analyzed whether there is any relationship between vertebrate species diversity and the management policies adopted by respective owners. To examine this, twenty sacred groves were selected. The vertebrates, such as birds, reptiles, amphibians, and mammals were surveyed, which lasted up to 2 years. Specific methodologies, such as point count for bird survey and visual encounter surveys for other vertebrates, were followed. To analyze the management policies adopted by the respective owners, nine parameters were considered, and each parameter was given a score for all the study sites. 135 species of vertebrates were recorded, and their species diversity is estimated by using the Shannon Wiener Index. To estimate the association between the management policies and species diversity, the scores of each parameter for all the sacred groves were summed and correlated with the Shannon‒Wiener index. A positive correlation between these factors obtained indicated that the management policies taken by the owners influenced the species conservation.
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Specific features of NDVI, NDWI and MNDWI as reflected in land cover categories
194-202Views:1813The remote sensing techniques provide a great possibility to analyze the environmental processes in local or global scale. Landsat images with their 30 m resolution are suitable among others for landcover mapping and change monitoring. In this study three spectral indices (NDVI, NDWI, MNDWI) were investigated from the aspect of land cover types: water body (W); plough land (PL); forest (F); vineyard (V); grassland (GL) and built-up areas (BU) using Landsat-7 ETM+ data. The range, the dissimilarities and the correlation of spectral indices were examined. In BU – GL – F categories similar NDVI values were calculated, but the other land cover types differed significantly. The water related indices (NDWI, MNDWI) were more effective (especially the MNDWI) to enhance water features, but the values of other categories ranged from narrower interval. Weak correlation were found among the indices due to the differences caused by the water land cover class. Statistically, most land cover types differed from each other, but in several cases similarities can be found when delineating vegetation with various water content. MNDWI was found as the most effective in highlighting water bodies.
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Rock mass rating in Bükk Mts., N Hungary based on petrophysical parameters and parting conditions
161-168Views:296In the region of Bánkút and Ómassa, Bükk Mountains the strength of the rocks of 29 outcrops was studied based on Rock Mass Rating (RMR). Strength of the rock masses showed no correlation with the material of the Formations they exposed, however, correlation between the orientation of valleys and ridges and the location of the most deformed rocks and thus that of the rock masses with poorest qualification could be observed.
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Urban vegetation classification with high-resolution PlanetScope and SkySat multispectral imagery
66-75Views:812In this study two high-resolution satellite imagery, the PlanetScope, and SkySat were compared based on their classification capabilities of urban vegetation. During the research, we applied Random Forest and Support Vector Machine classification methods at a study area, center of Rome, Italy. We performed the classifications based on the spectral bands, then we involved the NDVI index, too. We evaluated the classification performance of the classifiers using different sets of input data with ROC curves and AUC values. Additional statistical analyses were applied to reveal the correlation structure of the satellite bands and the NDVI and General Linear Modeling to evaluate the AUC of different models. Although different classification methods did not result in significantly differing outcomes (AUC values between 0.96 and 0.99), SVM’s performance was better. The contribution of NDVI resulted in significantly higher AUC values. SkySat’s bands provided slightly better input data related to PlanetScope but the difference was minimal (~3%); accordingly, both satellites ensured excellent classification results.
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Population an land cover dinamics of Sundarbans impact zone is Bangladesh
1-13Views:343Sundarbans is the largest mangrove forest of the world that lies in Bangladesh and India. This paper examined the correlation among population dynamics of Sundarbans impact zone (SIZ) from 1974 to 2011; impact of climate change on the forest; and changes in land cover of the forest from 1973 to 2010. Population size of SIZ was increased by 1.6 times between 1974 and 2011, whereas decreased by 2% during 2001 to 2011. During 1973 to 2010, water bodies, barren land and vegetated land reduced by 7.35%, 49.56% and 15.92% respectively; while grass land increased by 228.14% during the same period. But both population size and vegetated land declined during 2001 and 2011. This was due to the landfall of two severe cyclones in 2007 and 2009 through Sundarbans which resulted thousands of human casualties and out migration, and destruction of the forest. In addition, anthropogenic interventions like low flow from Ganges River and policy constraints also contributed to the demolition of Sundarbans. Thus, population growth, climate change and anthropogenic interventions are playing a decisive role to the depletion of forest resources from the Sundarbans mangrove forest.
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Integrated approach for lineament extraction in assessing groundwater potential: a case study in the highlands of Eritrea
1-14Views:156Groundwater exploration is crucial for sustaining ecosystems and human activities, particularly in semi-arid regions like the highlands of Eritrea. This study evaluates the effectiveness of manual and automated lineament extraction methods for identifying geological structures indicative of groundwater potential. Using a 30-meter resolution SRTM digital elevation model (DEM), we generated hillshade images and extracted lineaments manually by ESRI ArcGIS and automatically with MATLAB's edge detection algorithms, including Canny, Sobel, Prewitt, Roberts, Approximate Canny, and Laplacian of Gaussian (LoG). Our findings reveal significant differences between the manual and automated methods. Directional analysis showed that manually identified lineaments primarily followed NE-SW and NW-SE directions. Among the automated methods, Canny, Approxcanny, and Prewitt exhibited similar directional trends. Lineament density maps indicated high-density areas in the western and northern parts of the study area for both manual and automated methods. The LoG algorithm showed the highest correlation (0.8561) with the manual method, suggesting it as a reliable alternative for lineament mapping, contributing to more efficient groundwater exploration in semi-arid regions.
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Urbanization induced land use/land cover change and its impact on land surface temperature in Bhubaneshwar city, India
43-62Views:250The study was conducted in Bhubaneswar City, the capital of the Indian state of Odisha. The impact of the increase in surface temperature on the city was studied by retrieving LST, Normalized Difference Vegetation Index (NDVI), and Normalized Difference Vegetation Index (NDBI) values of Bhubaneswar using Landsat 5 and Landsat 8 data for 2001, 2011, and 2021. The surface urban heat island (SUHI) effect was also studied to identify temperature changes and hotspots in the city. There was a rise of 3.93℃ and 1.55℃ in the maximum and minimum LST in Bhubaneshwar city from 2001 to 2021. The heating effect of the built-up and cooling effect of vegetation was ascertained through correlation analysis between LST and NDBI (positive) and between LST and NDVI (negative). The results of this study will help the government and urban planners to identify heat stress and vulnerable areas, thereby contributing to better monitoring and future planning of the city. Thus, this will lead to efficient heat strategies and action plans such as developing green spaces in and around the city.
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Landscape shape index, as a potencial indicator of urban development in Hungary
78-88Views:541The study of settlement shape, morphology and structure is a classic topic of urban geography. Since the 1960s multiple shape indices have been developed. Urban patterns were then compared with geometric forms or, alternatively their temporal changes were tracked and analysed. In the current study we adapted the landscape shape index (LSI) to analyse the historical shape development of eight Hungarian cities. The LSI is capable to demonstrate the functional and mutual relationship between the developed area and their immediate physical and natural environment. Over the past 230 years the land area of the studied cities has increased manifold for several reasons: on average, an areal increase of 10.4 to 24.5 was observed for the eight settlements, while their perimeter increased by 8.8 to 30.3 times. Simultaneously with their size growth, the studied cities are characterized by an increasingly fragmented and dissected ground plans. Consequently, due to the longer border between the developed areas and the adjacent natural zones, urban areas have become increasingly sensitive to environmental effects over the past century, while mutual ecological and environmental interactions has also considerably increased between the adjoining zones. In general, cities of hilly and low-mountain areas had the highest LSIs, whereas cities located on relatively flat grounds had comparatively low LSIs. We also investigated the rank correlation of the historical change of LSI of the studied settlements. Cities of high positive correlations (> 0.9) were classified into two major categories. Miskolc, Pécs, Szeged and Kecskemét belonged to the group of higher LSIs, whereas Székesfehérvár and Nyíregyháza fell into the class of medium LSIs and the third category included Debrecen and Győr, cities of low (< 0.9) LSIs. Based on the temporal trends of the LSIs, our results provide applicable information for decision makers in order to monitor, manage and track their investments, city management policies and infrastructural development strategies.
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Examination of the heavy metal uptake of carrot (daucus carota) in different soil types
56-70Views:182In this paper the heavy metal uptake of carrot (Daucus carota) is studied in sample areas with different soil types. Our aim is to examine how the different soil types possessing different characteristics affect the heavy metal uptake and distribution in the plant. Correlation analyses were carried out in order to determine which of the total heavy metal concentrations and soil characteristics (pH, CaCO3-content, humus content, granulometric composition) play the most important role in the uptake of the Co, Cu, Fe, Ni, Mn, Zn and in the metal distribution in the examined plant. Soil and plant samples were collected from 5 different Hungarian areas in July, 2008. In the cases of soils with different soil characteristics, the examined plants are supposed to give varied physiological responses. During the examination we proved that the genetic type and the heavy metal content of the soil do not significantly affect the heavy metal uptake of carrot. The granulometric composition of the soil has the most considerable effect but this factor only affects the rate of the metal uptake in 50% of the examined heavy metals (Ni, Mn, Zn).
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Quantitative Morphometric Analysis of Streams in Extreme Humid Areas: A Case Study of the Um-Mawiong River Basin, Mawsynram, Meghalaya
59-75Views:221Quantitative morphometric analysis of the drainage system is essential to characterising a watershed, as all the hydrologic and geomorphic processes occur within the watershed. Consequently, this plays a crucial role in understanding the geo-hydrological attributes of a drainage basin to the terrain feature and its flow patterns, thus enabling the estimate of the incidence of infiltration and runoff and other related hydrological characteristics of a watershed, which strongly impacts natural resource conservation. The study area selected is the Um-Mawiong River basin in Mawsynram, Meghalaya. The basin shows a dendritic pattern that highlights the homogeneity in the texture of the basin. Results suggest that the stream frequency of the basin is 19.10 km², suggesting a faster surface runoff and less infiltration. In addition, it has an Elongation ratio of 0.75 indicating an elongated basin shape. The current study demonstrates that the implementations of GIS techniques are trustworthy, efficient, and capable of managing extensive databases for managing river basins. The present study tries to analyse the linear, areal and relief aspects of the basin using a GIS environment and manipulated for different calculations. The analysis reveals that the total number of stream segments and length are maximum in first-order streams and decrease as stream order increases. The drainage density exhibits a high degree of positive correlation, i.e., 0.87, with its frequency suggesting an increase in stream population concerning increasing drainage density and vice versa.