Abstract

Groundwater Prospects Evaluation Based on Hydrogeomorphological Mapping Using High Resolution Satellite Images in Rishikesh Region- Uttranchal, India.

Md. Surabuddin Mondal
reachers trainee
dept. of remote sensing , Birla Institute of Technology , Mesra , Ranchi , India
Email: smondal_iit@yahoo.co.in

Dr. A C Pandey
senior lecturar
dept. of remote sensing
birla institute of technology
mesra
ranchi
india
arvindchandrap@yahoo.com

R.D. Garg
Scientist/Engineer SE
prs division
indian institute of remote sensing
4 kalidas road
dehradun
india
garg@iirs.gov.in





Groundwater Prospects Evaluation Based on Hydrogeomorphological Mapping Using High Resolution Satellite Images in Rishikesh Region- Uttranchal, India.

Md.Surabuddin Mondal*, Pandey A.C *, Minakshi Kumar**, R.D. Garg**.

* Department of Remote Sensing, Birla Institute of Technology, Mesra, Ranchi, India.
** PRS Division, Indian Institute of Remote Sensing, Dehradun, India.

Email: smondal_iit@yahoo.co.in ; arvindchandrap@yahoo.com


Abstract

Water is the most important natural resource, which forms the core of ecological system. The advent of Remote Sensing has opened up new vistas in ground water prospect evaluation, exploration and management. The study area comprised of Rishikesh township and its environs, spreading over an area of about 100 sq. km and bounded by 30o 02´ 17” to 30o 09´ 10” North latitudes and 78o 09´ 6” to 78o 20´ 40” East longitudes. It is located in the Survey of India topographical maps 53J/4 and 53 J/8 of 1:50,000 scale at the foothill zone of Lower Garhwal Himalayas with elevation ranging from 300 m to 1400 m above mean sea level. The groundwater resources of the Rishikesh region are under threat due to population pressure caused by expending tourism value of this region. This entails sustainable and judicious use of this precious resource. The ground water prospect evaluation in Rishikesh region was attempted based on hydrogeomorphological mapping on 1:50,000 scale using high resolution IRS-P6 LISS III and PAN merged satellite images. The Rishikesh region exhibits diverse hydrogeomorphological conditions where the ground water regime is controlled mainly by topography and geology. The Quaternary deposits occupying a large portion and formed by the deposition of alluvial sediments viz; sand, silt, clays, kankar, gravel and boulders are highly favourable for ground water potential. On the contrary the major lithological formations exposed in the area namely ortho-quartzite, limestone, shale, grey-wacke, siltstone, slates etc. because of their massive nature and insignificant primary porosity have relatively no water potential. The groundwater in the area occurs under unconfined water table conditions in the upper aquifers which is mainly formed of alluvium and semi-consolidated formations. In the deeper aquifer zones where the water holding formations are shales, silt and clays the ground water occurs in semi-confined to confined conditions. The major hydrogeomorphological units identified in the area have been categorized into forms of fluvial [alluvial plain (deep/shallow), flood plain (deep/shallow), palaeochannel, channel bar), denudational [Piedmont (deep/shallow), denudational hill) and structural (structural hill) origin. The main hydrogeomorphological units found in the area are alluvial plain (deep- area covered: 21.29%, shallow- 4.56%), denudational hill (25.89%), flood plain (deep- 8.68%, shallow- 9.75%), , piedmont zone (deep- 8.48%, shallow-5.95%) and structural hill (12.86%)
Alluvium plains comprising mostly loamy soil represent the youngest geomorphic landforms formed by fluvial action. Ground water prospects in alluvium plains are almost invariably found to be very good. Piedmont zone occurring in the elevation range of about 375 to 495 m above msl is characterized by moderate drainage density, high hydraulic gradient, high porosity indicate moderate ground water potential. Structural and denudational hills comprised of massive rocks like shale, slate, siltstone, quartzite, lime stone and have development of moderately steep to steep slope act as run of zones with very poor to nil ground water prospects. Areas of denudational hills characterised by prominence of major joints/ fractures patterns with wide openings may facilitate limited infiltration and form localised ground water potential. Palaeochannel, channel bars and Flood plain areas have highest possibility of occurrence of ground water due to high recharge and its composition of sand, silt, gravels making adequate porosity and permeability for high ground water yield. The Piedmont zone characterized by steep slopes, coarse sediments and deeper water levels is the main recharge area through which infiltrated water flows down the slopes. This area can be explored with deep tube wells for augmenting the groundwater resources as well as attempts of recharging the aquifers in the plains should be made. Further groundwater development in this region should be done with caution, which still have surplus groundwater for development. The study shows that the remote sensing techniques can be applied effectively for groundwater prospect evaluation.