Rameshwar Bali

Drainage morphometry of Himalayan Glacio-fluvial basin, India: hydrologic and neotectonic implications

Morphometric analysis, being widely used to assess the drainage characteristics of the river basins, has been found to be a useful tool to delineate the glacial till covered overburden material as well as to identify areas prone to flash floods in present studies. A number of parameters including the stream frequency, drainage density and drainage texture suggest that the unconsolidated, unstratified and highly permeable glacially deposited overburden till material facilitates the infiltration of snowmelt and rainwater in the Pindari glacio-fluvial basin, Eastern Kumaun Himalaya, India. Likewise, other till overburden covered glacial and proglacial areas of Higher Himalayan regions have been contributing to the groundwater budget. The shape parameters further suggest that the sub-basins with higher form factor are more prone to flash floods. Besides this, the anomalies in the morphometric parameters have been found to be a useful tool to delineate zones of active tectonics in such areas.

Integration of remote sensing and electrical sounding data for hydrogeological exploration - a case study of Bakhar watershed, India.

Abstract A geographical information system (GIS) was used for the integration of hydrological data acquired using remote sensing and geoelectrical techniques to understand the groundwater condition of Bakhar watershed, Mirazpur District, UP, India. Indian remote sensing IRS-1D, LISS—III data were used to prepare a geomorphological and lineament map of the Bakhar watershed. Vertical electrical sounding (VES) was carried out in different geomorphic units, and ranges of electrical resistivity values were assigned to the different formations by calibrating electrical resistivity with borehole data. Based on these, a subsurface resistivity map and an aquifer thickness map were prepared. Several layers were superimposed using GIS techniques. Each theme was assigned a weight, depending on its influence on groundwater recharge. Each class or unit in the map was assigned a knowledge-based rank from one to four, depending on its significance in storage and transmittance of groundwater, and these were then multiplied by the layer weighting to produce a score. Based on these scores, the watershed was categorized into different groundwater potential zones. The results indicate that the eastern and northern parts of the study area have very good groundwater potential to meet the demands of water for irrigation and domestic purposes, whereas the southern region has poor groundwater potential zones. Such integrated analysis has not been attempted so far in this region for hydrogeological investigation.

Neotectonic Control on the Geomorphic Evolution of the Gangotri Glacier Valley, Garhwal Himalaya

Abstract The paper records evidences of neotectonic activities in the Gangotri glacier valley that are found to be responsible for the present-day geomorphic set-up of the area since the last phase of major glaciation. Geomorphological features indicate the presence of a large glacier in the valley in the geological past. Prominent planar structures present in the rocks were later on modified into sets of normal faults in the present-day Himalayan tectonic set-up giving rise to graben structures. The block nearest the snout is traversed by the NW-SE trending Gaumukh fault. A number of terraces mark the entrenchment of Bhagirathi River in this part. The contrasting drainage morphometric parameters of two sides of the valley and asymmetric recessional patterns of the tributary glaciers further document movement along the fault. The distribution and orientation of debris fans also seem to be controlled by neotectonic activity. The neotectonic activity that followed the process of deglaciation has brought the glacially carved, wide U- shaped valley in contact with the present-day fluvially incised narrow and relatively deep valley. The wider segments have become sites of active deposition of glacially eroded debris. The low gradient and excessive filling has resulted in the river attaining a braided nature in these segments.

Impact of Anthropocene Vis-à-vis Holocene Climatic Changes on Central Indian Himalayan Glaciers

Systematic palaeoclimatic study of the glacio-lacustrine sediments using multiproxy data in Pindari glacier area, Central Himalaya has helped in better understanding of the climatic fluctuations since the last 7 Ka. The palynological data supported by the environmental magnetic parameters suggests that the climate of the Pindar valley was cold and dry during 7 ka BP followed by five different vegetational shifts. The studies further suggest that since the last 300 yr BP, the climate has been warm and moist. It has to be ascertained weather the present phase of warming as inferred from the current phase of deglaciation is anthropogenic or is the continuation of the warm period that was initiated prior to the anthropocene time around 300 years B.P.