Hydrological Investigations In Gangetic Basin Using Remote Sensing And Basement DEM

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Hydrological Investigations In Gangetic Basin Using Remote Sensing And Basement DEM - A Case Study

4.0 Landform Analysis
Regional and local geomorphology is well depicted by satellite images. Based on the remote sensing keys, the area has been divided into five major geomorphic units with their associated landforms.

Recent flood plain of Ken and its tributaries containing point bars, channel bars and sand bars.
Ken alluvial surface comprising of palaeo channels, menader cutoffs, meander scrolls.
Stable alluvial remnants with dense vegetation.
Ravinous tract along Ken and its tributaries.
Low structural-cum denudational hills.

Various morphological features in the study region identified in the image are shown in Fig. 2.

Figure 2 Hydrogeomorphological map of the study area
5.Groundwater Potential
The gemorphological study of the area alongwith the reconstructed palaeosurface topography has shown that the area holds promose for future development of groundwater. ON this basis, following conclusions are made,

The area is almost plain except some isolated granitic hillocks and the part of natural levees, point bars and flood plain. It is made up of unconsolidated deposits of Indogangetic alluvium of recent age comprising clay, silt, Kankar, sand and their admixtures of various grades.
About more than one-third of the Banda area is covered by prominent features such as, meander scroll, abandoned channels, natural levee, flood plain, point bar deposits and rest is covered by stable alluvial remnants.
Alluvial plain area is hydrogeologically a potential region for the development of groundwater resources.
Point bar area is much better and promising for the development of groundwater works depending upon location and suitability in respect f flood recurrence.
Although food plain area if self is a highly moistures contained installation of permanent and heavy groundwater structures is not recommended due to frequent flood hazards.

Topographic depressions in the basement and their lateral extent can be correlated with t he geometry of buried channels to enable a complete understanding of the aquifer geometry.

6.Conclusions
This study has established that remote sensing and GIS techniques can be successfully applied for the regional investigations of the groundwater recharge zones. It may be indicated that the most remarkable areas of groundwater availability correspond to the commonly occurring depressions in the bedrock. The subsurface morphology of the basin and the tectonics are the factors which influenced the sedimentation pattern and guided the channels of Yamuan rive system. These depressions domed the site of intensive deposition of coarse gravel and coarse sand due to rapid erosion of the material from adjacent regions and subsequent transportation to the favorable sits. The low gradient of near surface water table, thin sand bed beneath a thick clay layer the Banda region and the related discharge from the neighboring areas resulting in an immigration of groundwater and an increased amount of dissolved salts towards the Ken graben area have all contributed to the groundwater salinity in the northern part of the study area. This problem willfurhte aggravate with time as more salt will accumulate with inflow of groundwater in the future. But I n the southern part of the study area the salinity problem is not encountered due to presence of thick sand below the upper clay horizon and a relatively steeper gradient of water table around Naranini 'mini gradben' region.

Acknowledgement
Authors are grateful to the officials of Central Groundwate Board, Northern Region, India, for providing the access to their library for the ground truth and borethole data.

Reference

AHMAD, S.M., 1984, Hydrogeological investigation for augmenting water supply in drogutht affected areas of Banda District U.P., India Report of the Central Groundwater Board, India.
BAJPAI, V.N. and GOKHALE, K.V.G.K., 1986, Hydrogeological characterists of marginal Gangetic alluvial plain in Uttar Pradesh. Journal of Geological Society of India, 28,pp9-20.
BHATTACHARYA, S.C. 1984, Report on Systematic Hydrogeological Surveys in part of Hamirrpur,, Banda and Fatehpur District of U.P., India. Report of the Central Groundwater Board, India.
GAUTAM, A.M. 1990, Application of IRS-1A Data for Delineating Buried Channels in Southern Part of Allahabad District of Uttar Pradesh , Journal of the Indian Society of Remote Sensing, Vol. 18, No 3, 1990, pp 52-55.
MURTY, C.D. and SRIVASTAVA, J.B. 1990, Feasibility report for drilling of tube wells for augmentation of water supply to Banda city, U.P., India Report of the Remote Sensing Application Centre, U.P. India.