Abstract
Groundwater constitute an important source of water for various purposes. The conventional approach for groundwater investigation are ground based survey. Keeping this in view the present study attempts to map groundwater prospect map of the Morar river basin using remote sensing, GIS and geoelectrical techniques. Geomorphological, geology, lineaments and slope map has been prepared from satellite data. All the thematic maps maps are integrated in GIS environment and classified the area in four categories of groundwater prospects from poor to excellent groundwater potential zones. For the field verification of the result obtained from the integration of thematic maps are crossed checked with resistivity survey of the area. Twenty-one vertical electrical sounding (VES) have been carried out by Schlumberger electrode configuration and found four to five layers in sub-surface set-up in study area. The resistivity of water bearing weathered / fractures shales varies from 30 to 100 ohm m. The results also verify with the bore well yield data of the area.

Introduction
Water is one of the most essential natural resources for sustaining life and it is likely to become critical scarce in the coming decades, due to continuous increase in its demands, rapid increase in population and expanding economy of the country. In view of the existing status of water resources and increasing demands of water for meeting the requirements of the rapidly growing population of the country as well as the problems that are likely to arise in future, a holistic, well planned long term strategy is needed for sustainable water resources assessment and management in India (Kumar et al. 2005). Variations in availability of water in time, quantity and quality can cause significant fluctuations in the economy of a country. Consequently the need for conservation, optimum utilization and management of this precious resource for the betterment of the economic status of the country is paramount.

Satellite remote sensing in conjunction with geographical information system (GIS) offers great potential for water resource development and management. (Krishnamurthy and Shrinivas 1995; Krishnamurhty et al. 1996; Saraf and Chaudhary 1998; Khan and Mohrana 2002; Pietronio et al. 2002; Hoffmann, 2005; Jaiswal et al. 2005; Jha and Chaudhary 2007; Hoffmann and Sander 2007). It will support in the quantification of hydrologic parameter in data collection and transmission to facilitate rapid analysis of various facet of water resources.

Number of researchers successfully used the electrical resistivity methods for groundwater prospecting in various terrains (Zohdy et al. 1974; Stewart 1986; Fittermann and Ayers 1989; Prakash et al. 1993; Ballukraya, 2001; Ayolabi, 2005; Rai et al. 2005, Idornigie et al. 2006; Shrivastava and Bhattacharya 2006; Das et al. 2007) have clearly bring out the relationship between electrical and hydraulic properties of the acquifer.

Keeping this in view, the present study attempts to delineate suitable locations for groundwater using integrated approach of the above-mentioned techniques.

Study area
The study area is located in the Gwalior district of Madhya Pradesh, India and is roughly bounded by latitudes 26 0 5’ - 26 0 25’ N and Longitude 78 0 10’ – 78 0 25’ E (Fig 1). Physiographically, the area is mainly covered by flat topography in the Northern portion while the southern portion is covered with prominent hills. The area experiences a semi-arid climate marked by extreme temperature and variability of rainfall. The duration of winter season is from November to February followed by summer from March to middle of June. The rainy season starts from middle of June to September when southeast monsoon is active while October and November are post monsoon or retreating monsoon season.

Drainage: The drainage pattern of the basin has provided quantitative description of basin geometry, which helps to understand initial slope of inequality in rock hardness. The basin is characterized by dendritic type of drainage pattern with varying density (fig 2). The high density found on the hard sandstone and shales. The total length of the basin is 479 km. and perimeter of the basin is 121.27 km. The Morar river basin is a 6th order basin with a drainage area of 405 sq.k.m. The morphometric analysis carried out under this study has revealed that the drainage density of the basin is 1. 18 km. which suggests that the area has highly permeable soil.

General geological setting
The intracratonic Gwalior basin is situated on the northwestern fringe of Bundelkhand massif. The Gwalior group of lithounits rest unconformably over Bundelkhand granite and comprise of basal arenaceous Par formation overlain by volcano-sedimentary sequence of Morar formation consisting of ferruginous shale with bands of chert, jasper and limestone. Gwalior group of rocks are similar to the Bijawar group. The sequence at Bijawar dips due south whereas at Gwalior dips due north. Vindhyan strata also show the Gwalior basin like sequence. These are dominated by quartzites at the base, ferruginous shale with chert and Jasper pointing to shallow water conditions and rapid development of basin formation followed by transgression. Gwalior group shows coarse to fine doleritic sills and dykes at the base of the Gwalior Fort. Bijawar group also shows this sequence at Mandalgarh Fort (Basu, 2007). The rocks in the study area belongs from Archaean to Precambrian group of hard rocks consisting with Sandstone, shale, Quartzite. Doleritic dykes and recent group of alluvium deposits. Granite is the basement rock of the study area.

The rocks of the area divided into two formation the older Par formation and younger Morar Formation. This group of rocks are overlain by upper Vindhyans which are the youngest rocks in the region. On the basis of interpretation of satellite data, field work and published geological map of the region , the geological map of the study area has been prepared (Fig.3). Data used and methodology

Different data products required for the study includes are …

• Fussed data of IRS – ID Pan and LISS – III satellite imagery of path 97 and row 53 from National Remote Sensing Agency (NRSA) Hyderabad.
• The Survey of India topographical maps include 54 J/ 3, 54 J/ 4, 54J/7 and 54 J/ 8.
• Geological Quadrangle map.
• Resistivity data.
• Field Survey data

The IRS-ID PAN and LISS – III satellite imageries are georeferenced using the ground control points with SOI toposheets as a reference and further merged to obtain a fused, high resolution output in Erdas Imagine 8.6 Image processing software. For understanding the dynamic phenomenon and preparation of thematic maps such as drainage, geology, and geomorphological map of the terrain are generated by applying various digital image processing techniques, which involved contrast stretching, edge enhancement, principal component analysis for the interpretation of the features.

A drainage density and lineament density map generated by using the spatial analysis tool of ARC GIS 9.0 software. Slope map of the area prepared from the SRTM data of the area.

24 vertical electrical sounding (VES) were carried out throughout the study area using Schlumberger method of electrode configuration. In Schlumberger configuration the two outer current electrodes (AB) and two inner potential electrode (MN) are aligned in a straight line. The sounding data of the area is plotted by using the IPI2WIN resistivity data plotting software. Results and discussion Geomorphological and slope analysis In the present study, various land forms have been delineated on the basis of their tone, texture, pattern, size, shape and association and categorized under three types – denudational structural and depositional land forms. The various hydrogeomorphololgical units delineated from satellite data are presented in (fig 4) and (table 1) with their ground water potential.

The hydrogeomorphological units identified are alluvial plain, valley fills, pediplains, buried pedipain, pedimonts and residual hills.

Linear contrast stretching, high pass filters for spatial enhancement and histogram equalization techniques were applied on IRS – ID data for the interpretation of geomorphic features. Principal Component Analysis (PCA) was also applying for the discrimination of geomorphic units.

Slope map was prepared from SRTM data. Most of the area having flat topography accept the southern portion, which is as hilly terrain having steep slope. Finally slope map was prepared using ARC GIS software and the entire are classified into four groups as very gentle slope (0 0 – 3 0), gentle slope (3 0 – 10 0), moderately steep (10 0 – 20 0) and very steep (> 25 0) as shown in (fig 5) A high slope region causes more runoff and less infiltration and thus have poor groundwater prospects compared to the low slope region.

Lineament density
The mapping of linear features on various types of mps or remotely sensed data is one of the keys to understanding groundwater occurrence in hard rock area. In the present investigation, 3 *3 high pass directional convolutions under spatial enhancement techniques were used for the lineament mapping of the study area by using the Erdas Imagine image processing software. Two major systems of joints striking between NW-SE and SW –NE were observed in granitic rock of the area. Some sedimentary structures were also observed during field survey like ripple marks, cross beddings and horizontal stratifications in sandstones and shales. The major trends of lineaments follow the above mentioned joint systems as observed in the lineament map prepared from the satellite data. The lineament density map (Figure 6) was prepared with the help of spatial analysis tool of ARC GIS software and classified into three zones as low, medium and high lineament density values. Most of the lineaments are accentuated into clusters including high and medium lineaments density zones in the northwestern, northeastern and southeastern portions of Morar river basin. However, some small clusters of medium lineament density zones are also found in south-central and southwestern marginal portions as well as along the southeastern boundary of the basin.

Data Integration: All the thematic maps such as Geology, geomorphology, lineament density, and slope (3 to 6) with their individual classes were prepared from satellite data and through field survey. In the present study, each thematic map is overlaid two at a time to generate a composite map. Thus, each layer representing a particular theme is overlaid on other theme to find the intersecting polygon. By applying this method, a new map showing the integrated map of two thematic maps is obtained, over this composite map a third map is overlaid and so on, so that a final composite map is obtained.

In the final composite map and each polygon is given suitable weightage, according to their importance with respect to other classes in the same thematic layer. Finally, all the polygons are reclassified into four categories of groundwater prospect from poor to excellent groundwater zones in the study area.

Interpretation of resistivity Data
A Vertical Electrical Resistivity (VES) survey at 24 locations using Schlumberger method of electrical resistivity techniques were undertaken to find out the aquifer characteristics of the area (Singh, 2009). The combination of all type of curves recorded in the study area indicate the presence of multilayered inhomogenous formation. In the above classified curve types, A and H type curves indicate the presence of three layers followed by combination of curves (AK, HA, KH, QH) indicating the four layer sub-surface medium. The interpretation of resistivity data of the present investigation of Morar river basin has been carried out using IPI2WIN software program version 3.0.1.a7.01.03 prepared and distributed by Geoscan M. Ltd, Moscow, Russia. This software helps in interactive semi-automated interpretation of the field data.

On the basis of resistivity survey, 4 or 5 geo-electrical sub-surface layers setup is found in the study area. The top layer is predominantly clay/ clay with Kankar with resistivity varying from 2- 30 Ohm-m its thickness varies between 2 m to 40 m, next layer is highly weathered zone of Morar Shales and sandstone with a resistivity between 30 – 100 Ohm-m its thickness varies between 5 m to 50 m, the third layer is semi-weathered zone of hard and compact Shale with resistivity varying from 100 – 300 Ohm-m its thickness varies between 0 m to 48 m, forth layer is bedrock with hard and compact dolerite dykes and hard compact shales with resistivity value > 300 Ohm-m (Table 2). Resistivity values obtained from interpretation of VES were correlated with litholog data. The principle aquifer and water bearing formations are characterized by weathered & jointed shales of study area with resistivity ranging from 30 to 100 Ohm-m. low resistivity value ( 2 to 30 Ohm-m) are better water bearing aquifers, while higher resistivity value (> 300 Ohm-m) are poor water bearing aquifers.

Surface layers are mainly composed of alluvial plain (sand, silt and clays) which is the major groundwater prospect at upper level in the study area as they show low resistivity values.

Validity Test
The groundwater potential map (Figure 7) generated through GIS integration and resistivity value was also checked against the yield data for the validity of model developed. The groundwater potential zones generated through this model revealed that the excellent potential zones are located in the alluvial plain, which coincides with field observation of bore wells yield data collected from the villages viz. Rithora Kalan, Sohli, Bahadurpur, Dungutina, Lakshmangarh, Baretha, Padampur, Rora etc. The bore wells give yield 3000 to 3500 LPH in these zones. Good groundwater potential zones are found in the villages viz. Singhwani, Girongi, Malanpur, Kheriya Mirdha etc with a yield of 800 – 900 LPH followed by the University campus, IITM campus, Mohanpur and Pintopark which come under moderate zones having an yield of 600 – 700 LPH and the locations Maharajpur and Londra come under the poor zones with yielding capacity varying from 300 – 400 LPH.

Conclusion
Remote sensing and GIS approach has successfully used in the present investigation to obtain a detailed evaluation of groundwater conditions of an area.The integrated maps were classified into four groundwater potential zones from excellent to poor. Based on the geomorphological mapping, lineament density and resistivity data, the following broad conclusion can be drawn.

• The present study brings out the close relationship among the geomorphic, geologic, hydrogeologic and geophysical parameters of groundwater. The ground water potential zones are also verifying with bore wells yield data of the study area. The comparison shown that the groundwater potential zones are in agreement with the bore wells yield data.
• The above study has demonstrated the capabilities of using remote sensing, geoelectrical data and GIS for demarcation of groundwater potential zones, especially in diverse geological setup. This gives more realistic groundwater potential map of an area which may be used for any groundwater development and management plan.

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