DOS in Geology

The study area covers 570 km 2 comprising of 9 sub-watersheds (Dalavayihalli, Maddalenahalli, Talamaradahalli, Puluvalli tank, Nagalamadike, Gowdatimmanahalli, Naliganahalli, Devadabetta and Byadanur) range from 49 to 75 km 2 forming part of Pennar river basin around Pavagada. The drainage network of 9 sub-watersheds was delineated using remote sensing data -Geocoded FCC of bands -2 3 4 of IRS 1 C and 1 D (LISS III+PAN merged) on 1:50,000 scale and SOI topomaps were used as reference. The morphometric analysis of 9 sub-watersheds has been carried out using GIS softwares -ArcInfo and ArcView. The drainage network shows that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream orders ranges from fourth to fifth order. Drainage density varies between 1.55 and 2.16 km/ km 2 and has very coarse to coarse drainage texture. The relief ratio range from 0.006 to 0.021. The mean bifurcation ratio varies from 3.21 to 4.88 and falls under normal basin category. The elongation ratio shows that Devedabetta sub-watershed possesses circular shape while remaining sub-watersheds mark elongated pattern. Hence from the study it can be concluded that remote sensing techniques proved to be a competent tool in morphometric analysis.

The study area is one of the watersheds of North Pennar basin, covering an area of 570 km 2 in Pavagada taluk of Tumkur district. The watershed has been subdivided into nine subwatersheds namely Dalavayihalli, Maddalenahalli, Talamaradahalli, Puluvalli tank, Nagalamadike, Gowdatimmanahalli, Naliganahalli, Devadabetta and Byadanur. These nine sub-watersheds have been evaluated to delineate groundwater potential zones based on the characteristics of geomorphic units together with slope, geology, lineaments, borewell data using Remote Sensing and Geographic Information System (GIS) techniques. Slope varies from nearly level (0-1%) to very steep (>35%). The different geomorphic units in each sub-watershed consist of denudational hills, residual hills, inselbergs, pediment inselberg complex, pediments, shallow weathered pediplains, moderately weathered pediplains and valley fills. The lineament map for each sub-watershed has been prepared and the trends were analysed with rose diagrams. The analysis of borewell locations and their yield data in association with lineaments at subwatersheds level reveals that the lineaments are acting as a pathway for groundwater movement. The integrated map comprising groundwater potential zones prepared by "Union" function using GIS indicate that valley fills and moderately weathered pediplains are very good to good, shallow weathered pediplains are good to moderate, pediment inselberg complex and pediments are moderate to poor and denudational hills, residual hills and inselbergs are poor to very poor groundwater prospect zones.

The study area is one of the watersheds of North Pennar basin, covering an area of 570 km 2 and lies between latitude 13°55′-14°17′N and longitude 77°05′-77°25′E in Pavagada area, Tumkur District, Karnataka and a small portion in Ananthpur District, Andhra Pradesh, India, forming a part of the hardrock terrain. The drainage network shows dendritic to sub-dendritic pattern and is non-perennial in nature. Poor soil cover, sparse vegetation, erratic rainfall and lack of soil moisture characterize the area for most part of the year. Recurring drought coupled with increase in groundwater exploitation results in decline the groundwater level. The entire study area has been further divided into nine sub-watersheds, namely Byadanur, Devadabetta, Talamaradahalli, Gowdatimmanahalli, Naliganahalli, Nagalamadike, Maddalenahalli, Paluvalli tank and Dalavayihalli, ranging in geographical area from 49 to 75 km 2 . It has been taken up for prioritization based on available natural resources derived from satellite images and socio-economic conditions, including drainage density, slope, water yield capacity, groundwater prospects, soil, wasteland, irrigated area, forest cover and data on agricultural labourers, SC/ST population and rainfall. On the basis of priority and weightage assigned to each thematic map, the subwatersheds have been grouped into three categories: high, medium and low priority. The prioritization results reveal that Nagalamadike, Maddalenahalli and Dalavayihalli sub-watersheds rank highest on the basis of weightage and are considered as high priority. These sub-watersheds may be taken up with development and management plans to conserve natural resources on sustainable basis with immediate effect, which will ultimately lead to soil and water conservation.

Groundwater evaluation related issues are commonly investigated by the use of distributed watershed models. These watershed models require physiographic information such as arrangement the different thematic maps of the drainage and channel network, geomorphology, structural features, slope, soil and its catchment geometric properties. Traditionally, these parameters are obtained from maps or field surveys. DEM data are digital elevation data set recording the topographic surface expression of any area (http:// www.gisdevelopment.net). Over the last two decades this information has been increasingly derived directly from digital representations of the topography . The digital representation of the topography is called a Digital Elevation Model (DEM). The automated derivation of topographic watershed data from DEMs is faster, less subjective and provides more reproducible measurements than traditional manual techniques applied to topographic maps . Digital data generated by this approach also have the advantage that they can be readily imported and analyzed by GIS. The technological advances provided by GIS and the increasing availability and quality of DEMs have greatly expanded the application potential of DEMs to many hydrologic, hydraulic, water resources and environmental investigations . Earlier investigations by different workers for the creation of DEM for watersheds elsewhere include; i) used GIS to develop a method for deriving stream-water relationships for the selection of reference site characteristics from watershed parameters derived from a DEM and data collected from the field and ii) Fels and Matson (1998) used DEMs to conduct a hydrogeomorphic land classification. In this paper, the analysis of DEMs are reviewed and discussed with respect to the derivation of topographic data in support of groundwater evaluation studies.

The study area is a part of Kagna river basin in the Gulburga district of Karnataka, India. It covers an area of 1320 km 2 and it has been subdivided into 4 sub-basins namely Wadi, Chitapur, Sedam and Kurkunta, which range in area from 184 to 537 km 2 . The drainage pattern of these sub-basins are delineated using Geo-coded FCC bands 2,3,4 of IRS 1C and 1D(LISS III+PAN merged) on 1:50,000 scale and Survey of India toposheets as reference. The morphometric parameters are computed using

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The study reveals that remote sensing and GIS techniques proved to be the competent tool in analysing various morphometric parameters.The drainage network of Kanamanahalli and Devaraguttahalli sub-basins were delineated using false colour composite (FCC) of IRS-1C/1D merged satellite data on 1:50,000 scale. SOI toposheets were used as reference with limited field work. The study area falls in Ponnaiyar river basin covering an area of 686 sq. km comprising two sub-basins namely Kanamanahalli and Devaraguttahalli having an area of 439 sq.km and 247 sq.km respectively in and around Malur taluk of Kolar district. The morphometric analysis of these two sub-basins shows that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream order ranges from first to sixth order. Drainage density varies between 1.57 and 1.88 km/km2 and has coarse to fine drainage texture. The relief ratio ranges from 0.0111 to 0.0117. The mean bifurcation ratio varies from 3.51 to 4.86 which fall under normal basin category. The elongation ratio shows that these sub-basins are associated with high relief and steep ground slopes.

The search for new groundwater resources is essential to sustained economic development in arid environment. The study area is part of Ponnaiyar river basin falling between N latitude of 12°48’24” to 13°07’06’ and E longitude of 77°50’30” to 78°08’15” falls in Survey of India toposheets 57 G/16, 57 H/13, 57 K/4 and 57 L/1 covering an area of 645 km2 in Kolar District, which is highly drought prone in Karnataka State, India. In the present paper, by a methodological approach based on remote sensing and GIS, drainage and hydrogeomorphological maps were prepared using the IRS-1 C & 1 D LISS-III and PAN merged satellite data and geomorphic units. Denudational hill, residual hill, inselberg, pediment inselberg complex, pediment, shallow weathered pediplain, moderately weathered pediplain and valley fill shallow were identified. The area is characterised by undulating terrain interspersed by low ranges of rocky hills. The elevation ranges from 860 m to 1127 m above MSL. The mean annual rainfall of Malur is 722.0mm. The River Dhakshina Pinakini and Markarda Halla drain the area. The streams exhibit dendritic to sub dendritic type of drainage pattern and comprise of granite and gneissic rock formations of Achaean age. On the basis of different geomorphic units, four categories of groundwater potential zones were delineated as (i) very good to good (ii) good to moderate (iii) moderate to poor, and (iv) poor to very poor.

Scientific management of the aquifers is undoubtedly is a tough task. Sustainable management of the ground water resource depends on proper understanding of the aquifers. For this, all the available data collected from various sources under different activities to be compiled and presented so as to make it handy for the administrators and user agencies to prepare ground water development and management plan. In Karnataka, the aquifer systems are classified into nine major groups depending upon their characteristics and distribution namely Banded Gneissic Complex (BGC), Basalt, Schists, Granites, Charnockites, Limestones, laterites, Sandstones and alluvium. These major aquifers are then superimposed over the state map with administrative district boundaries to arrive the district wise aquifer characteristics. Both thematic layers and corresponding data tables are presented for easy reference. Maps showing important aquifer characteristics like depth to water level-their seasonal fluctuation, decadal mean of premonsoon, postmonsoon and all season water level, over burden thickness, fracture depth, yield range, transmissivity, storativity are presented. Similarly, maps showing distribution of ground water quality such as electrical conductivity, nitrate and fluoride are compiled. Details like population density, river basins are also included. Map showing the 28 parliamentary constituencies in the state is also depicted. About 66379 sq. km (35%) of the area of the state is over-exploited. In about 12930 sq.km (7%) of the area, the stage of development has touched critical level. Keeping in view of the status, maps showing the present stage of ground water development, areas prioritized for artificial recharge, area delineated for water conservation and harvesting, area suitable for ground water development, aquifer wise ground water management plan and aquifer wise unit recharge are presented during the present exercise.

Ground water is the major source of irrigation in drought prone Ankasandra watershed which is located in parts of Tiptur and C N Halli taluks of Tumkur district of Karnataka State. The main livelihood of the people in the watershed is agriculture. The area underlain by Archaean group of rocks and important litho units are granite, gneiss, dharwar schist and dolerite dykes. The phreatic aquifer in most of the area is desaturated and groundwater is being drawn from fractured aquifer. The major crops grown under irrigation through bore wells are coconut and areacanut. The study was carried out under pilot project on aquifer mapping. To know the groundwater quality, 52 samples collected during September 2011 and chemically analysed for Hydrogen ion concentration (pH), specific conductance, calcium, magnesium, sodium, potassium, total hardness, carbonate, bicarbonate, sulphate, chloride, nitrate and fluoride. Based on the analysis, parameters like percent sodium, sodium absorption ratio (SAR) and residual sodium carbonate (RSC) were calculated. The results revealed that, with respect to electrical conductivity, it is found that about 10% of water samples fall in good category, 86% falling under permissible limit and about only 4% fall under doubtful category. In case of percent sodium analysis, about 58% fall under permissible category, 27% is under good category, 13% fall in doubtful category and 2% fall in excellent category. The SAR values ranges from 1.82 to 9.12 and reveals that all 52 water samples (100%) fall under excellent category. The RSC values shows that about 86% of water samples fall under safe category while 8% and remaining 6% fall under marginal and unsuitable type respectively. It is concluded from various methods that the groundwater quality is mostly suitable for irrigation purposes.