Remote sensing and geophysical studies for groundwater exploration in Osmania University campus, Hyderabad, India: A case study

With the increasing resolution of satellite sensors, it is possible to fruitfully exploit the special advantages of image analysis for a wide range of geological environments. With this view, a LISS-III and PAN merged image of the 1600 acre (approximately 6.5 sq km) Osmania University (OU) campus taken from IRS-ID in the month of May (a fairly representative month in terms of minimum annual drainage/vegetation cover) was acquired. The image was then digitally processed and visually interpreted for potential groundwater resource regions. Since occurrence of groundwater in crystalline rocks, the host rocks for the entire Hyderabad region, is generally associated with secondary porosity, the accent was on determining and establishing lineaments of considerable surface extent. This was then augmented with maps of subsurface features as obtained from geophysical studies for the southern part of 0 U campus and available bore well/open well information. Subsequently, information from the three sources was integrated for a better understanding of the geological situation and the interrelationship of its various constituents to determine possible locations of groundwater resources. The significant findings comprised the identification of three major dykes, two running E-W and the third running NE-SW. A major N-S linear exposure of granitic rocks, as also several criss-crossing fractures in the southern side of the campus, along with the prevailing drainage pattern for the entire campus area were mapped. Based on these findings and supporting geophysical/hydrogeological data, a geological/lithological map of Osmania University campus was prepared and prospective groundwater zones have been identified.

Comparative geomorphometric approach to understand the hydrological behaviour and identification of the Erosion prone areas of a coastal watershed using RS and GIS tools

Assessment of the geomorphometric parameters using Remote Sensing (RS) and Geographic Information System (GIS) tools forms an important part in routing the runoff and other hydrological processes. The current study uses a geospatial model based on geomorphometric parameters for the categorization of surface runoff and identification of the erosion-prone areas in the watershed of the Kuttiyadi River. The 4th order Kuttiyadi river is dominated by a dendritic to semi-dendritic drainage pattern in the subwatersheds. The linear aspect of the subwatersheds indicates towards the presence of permeable surface and subsurface materials with uniform lithology. The aerial and relief aspects of the subwatersheds shows fine drainage texture, gentle slopes, delayed peak flow, flatter hydrograph, and large concentration time which shows that subwatersheds are quite capable of managing flash floods during storm events. The estimated values of surface runoff (Q) and sediment production rate (SPR) are range from 2.13 to 32.88 km2-cm/km2 and 0.0004–0.017 Ha-m/100km2/year respectively and suggest that Subwatershed 1 (SW1) will generate more surface runoff and is prone to soil erosion followed by subwatershed 2 (SW2) in comparison to other subwatersheds. This paper aims to fill the knowledge gap regarding categorization of flow and erosion dynamics in a coastal river watershed. We believe that our work may work help in providing the crucial information for decision-makers and policymakers responsible for establishing suitable policies and sustainable land use practices for the watershed.

Morphometric and Sub-Watershed Analysis of Taraka Watershed, H.D. Kote Taluk, Mysuru District, Karnataka, India using Remote Sensing and GIS Techniques

The current research work is an attempt to study of drainage area covering 429 sqkms comprising of 10 sub-watersheds they are namely Heggadadevanakote, Budanuru, Kodasige, Yedenhundi, Sunkadakatte, Nagarahole, Muruganahalli, Heggadapura, Kalhalla, Sarathihole. The research area has strong structural control shows that the 10 sub-basins named as the normal category. Different parameters of morphometric were used, Arc-Info and Arc -View GIS software was used to analysis the morphometric parameters and drainage characteristics, Sub-basin have been delineated by drainage pattern. The drainage pattern suggesting very coarse to coarse texture and the density explains the texture of drainage is related to coarse as geomorphic development their late youth stage and values suggest that Form factor, Circulatory ratio, Sub-basins are circular to elongated in shape.

Risk Factors and Clinical Outcome in Hemorrhagic Intracranial Dural Arteriovenous Fistulas After Endovascular Treatment

Purpose The purpose of this study was to analyze the risk factors of hemorrhage in DAVFs and the factors that influence the clinical outcome of hemorrhagic intracranial DAVFs after endovascular treatment. Methods We reviewed the records of patients with hemorrhagic intracranial DAVFs who received endovascular embolization from December 1996 to April 2015. We analyzed the risk factors of hemorrhage and emphasized the drainage pattern and the classification of drainage location. We also analyzed the factors that influence clinical outcomes such as the patient's age and the time interval between hemorrhage and treatment.Results A total of 32 patients were included in this study. Twenty-seven (84.4%) had engorged medullary veins (EMVs), and 24 (75%) of the hemorrhagic DAVFs had dorsal epidural drainage. Twenty-five (78.1%) had complete occlusion on post-procedural angiography. A significant difference (p=0.0054) of the modified Rankin Scale after treatments between the groups who received treatment within or exceeding 14 days after diagnosis. Conclusions Regional EMVs and dorsal epidural drainage patterns are risk factors in the prediction of hemorrhage in intracranial DAVFs. Patients who received early treatment within 14 days after hemorrhage could have a better clinical outcome.

Drainage Basin Morphometry Analysis in Parts of South Shillong Plateau, Meghalaya: Implications for Landscape Development

The Shillong Plateau is characterized by multiple phases of deformation and number of prominent sets joints/fracture system. The Southern Shillong Plateau unlike the northern part is highly dissected by the scarp faces which are mostly erosional. The area is characterized by deep incising river networks which cuts across many lithological units. To understand the factors influencing the drainage characteristic of the area and landscape development, the present study has been done in context of morphometry, geomorphology and geology of the drainage basin. Fifteen sub basins of 4th order have been selected from the Um Sohrynkew River basin. Drainage morphometry, indices of active tectonism, geology and tectonics and landform features have been worked out for better evaluation of drainage characteristics. The study area forms part of the Meghalaya Precambrian province of upper Proterozoic age. The southern border of the Shillong Plateau is demarcated by Dauki (Also known as Dawki) fault which is a prominent structural lineament. It consists of at least four E-W trending normal faults with occasional reversal. The segment of the Dauki fault in the study area is believed to be active. The present study focuses on the drainage network and the landscape development of the study area where a very strong relationship has been observed between the lithology and structure together with the tectonic activity influencing the drainage pattern in the area.

GIS & Remote Sensing Based Morphometric Parameters and Topographic Changes of the Lower Orashi River in Niger Delta

In watershed hydrology, the morphometric features of a river basin are vital to examine the lower Orashi River basin morphological and hydrological aspects, as well as its flood potential, based on their morphometric characteristics using remotely sensed SRTM data that was analyzed with ArcGIS software. The areal, linear, and relief aspects of the Orashi River basin were examined as morphometric parameters. The lower Orashi river basin, according to the findings, has a total size of 625.61 km2 and a perimeter of 307.98 km, with a 5th order river network based on Strahler categorization and a dendritic drainage pattern. Because of low drainage density, the drainage texture is very fine, the relief is low, and the slope is very low. Bifurcation ratio, circularity ratio, drainage density aspect ratio, form factor, and stream frequency values indicate that the basin is less elongated and would produce surface runoff for a longer period, while topographic changes show that the river is decreasing with depth in the land area at about the same elevation as a result of sand deposited due to lack of maintenance by dredging, which implies that the basin is morphometrically elevated and sensitive to erosion and flooding. To understand geohydrological features and to plan and manage watersheds, morphometric analysis based on geographic information systems and remote sensing techniques is beneficial.

Existence of a continental-scale river system in eastern Tibet during the late Cretaceous–early Palaeogene

The establishment of continental-scale drainage systems on Earth is largely controlled by topography related to plate boundary deformation and buoyant mantle. Drainage patterns of the great rivers in Asia are thought to be highly dynamic during the Cenozoic collision of India and Eurasia, but the drainage pattern and landscape evolution prior to the development of high topography in eastern Tibet remain largely unknown. Here we report the results of petro-stratigraphy, heavy-mineral analysis, and detrital zircon U-Pb dating from late Cretaceous–early Palaeogene sedimentary basin strata along the present-day eastern margin of the Tibetan Plateau. Similarities in the provenance signatures among basins indicate that a continental-scale fluvial system once drained southward into the Neo-Tethyan Ocean. These results challenge existing models of drainage networks that flowed toward the East Asian marginal seas and require revisions to inference of palaeo-topography during the Late Cretaceous. The presence of a continent-scale river may have provided a stable long-term base level which, in turn, facilitated the development of an extensive low-relief landscape that is preserved atop interfluves above the deeply incised canyons of eastern Tibet.

Status Quo of a CO2-Assisted Steam-Flooding Pilot Test in China

It is challenging to enhance heavy oil recovery in the late stages of steam flooding. This challenge is due to reduced residual oil saturation, high steam-oil ratio, and lower profitability. A field test of the CO2-assisted steam flooding technique was carried out in the steam-flooded heavy oil reservoir in the J6 block of the Xinjiang oil field (China). In the field test, a positive response to the CO2-assisted steam flooding treatment was observed, including a gradually increasing heavy oil production, an increase in the formation pressure, and a decrease in the water cut. The production wells in the test area mainly exhibited four types of production dynamics, and some of the production wells exhibited production dynamics that were completely different from those during steam flooding. After being flooded via CO2-assisted steam flooding, these wells exhibited a gravity drainage pattern without steam channeling issues, and hence, they yielded stable oil production. In addition, emulsified oil and CO2 foam were produced from the production well, which agreed well with the results of laboratory-scale tests. The reservoir-simulation-based prediction for the test reservoir shows that the CO2-assisted steam flooding technique can reduce the steam-oil ratio from 12 m3 (CWE)/t to 6 m3 (CWE)/t and can yield a final recovery factor of 70%.