Origin of kondakarla lake in Visakhapatnam district,Andhra Pradesh

Kondakarla lake is the largest natural fresh water lake in Visakhapatnam district. The lake is thought to have been formed in stages. There might have been in the past a ‘U’ shaped rim of hills enclosing a basin with a minor drainage system. With the reduction of hills in relative relief, the drainage got obliterated because of excessive deposition of alluvium leaving a gently sloping piedmont and a central shallow depression. An old course of the Sarada river entered the lake and there are evidences in field indicating the old course having got in and got out of the lake, in the absence of a few geomorphic units along the foot-slopes of the hills. These geomorphic units appear to have been removed by the swerving meander loops of the old course. Again, there are a series of four sandy islands in the lake, the configuration and disposition of which indicate deposition in the inside of the meander loops as point bar deposits, while the old course migrated towards southeast of the basin. The lake is thought to have been farmed in the gently sloping basin partially deepened perhaps by migrating course of tha Sarada river. Aggradation at the northestern part besides cutting off of the meander loop, has created a barrier of low relief resulting in a narrow long basin of internal drainage. Neither the structural trend of the hills nor any other features indicate synclinal or anticlinal troughs, ruling out any structural origin for this lake.     

Morphometry of the meghadrigedda watershed, Visakhapatnam district, Andhra Pradesh using GIS and resourcesat data

Resourcesat-I data is to provide continuity in operational remote sensing with its enhanced capabilities in the field of land and water resources management. Using GIS tools and image processing techniques are to identify the morphological features and water resources of the Meghadrigedda watershed. The morphometric parameters such as linear aspects and aerial aspects of six sub-watersheds of the watershed were determined and are computed. The drainage pattern is mainly dendritic type. The six sub-watersheds are elongated in shape. The Meghadrigedda reservoir supplies around 8 million gallon/day of water to the needs of Visakhapatnam city for domestic and industrial purpose. Most of the water tanks of the area have been silted and subjected to unauthorized occupations. Twelve recharge pits were located to excavate silted water tanks. To improve the ground water levels, thirteen suitable sites were identified for the construction of check dams in the Meghadrigedda watershed.     

Assessment of Fragmentation and Disturbance Patterns in Eastern Ghats: A Case Study in R.V. Nagar Range,Visakhapatnam District,Andhra Pradesh,India

At present the biodiversity in Eastern Ghats is threatened by loss of habitats, exploitation and unscientific management of natural resources, forest fire, biological invasion and other anthropogenic pressures. In this context, we have assessed the forest cover changes, fragmentation and disturbance in the R.V. Nagar Range of Eastern Ghats region, Andhra Pradesh using satellite remote sensing and GIS techniques. Satellite data of IRS-1A LISS II of 1988 and IRS-P6 LISS III of 2006 were assessed for forest cover changes in 1 sq.km grid and generated as Sensitivity Index map. Further the road and settlement buffer of 1000 m was generated to represent Threat Index map. From 1988 to 2006, the forest cover had a total cover loss of 35.2 sq.km and increase in scrub cover by 7.2%. Over all change analysis from 1988 to 2006 with reference to forest cover indicates, negative changes (loss of forest area) accounted for 48.1 sq.km area and positive changes (gain of forest) for an area of 12.1 sq.km of area. The results of the change detection using multi-date satellite imagery suggest degradation in forest cover over two decades, which necessitates the conservation measures in this range with high priority.     

Hydromorphogeology and Remote Sensing applications for groundwater exploration in agnigundala mineralised belt, Andhra Pradesh, India

Hydromorphogeological studies have been carried out around Agnigundala mineralised belt (longitude 70°.39′ - 16°.51′ and latitude 16°.2′ - 16°.15′) using remote sensing IRS-IB and SPOT data for ground water exploration. Based on erosional and depositional characters of various geomorphic units like Hills (Structural and denudational) Pediment, Buried pediment, plains and valley fills have been identified in various lithologies like granite, granite gneiss, biotite schist, phyllite,. quartzite and dolomite. The acclamations of individual geomorphic units through visual interpretation are verified from field data. The groundwater potentials of the individual geomorphologic units have been evaluated to obtain a complete hvdrogcological picture of the area. The field data have further helped in quanlifying various geomorphological units with reference to their potential for ground water occurrence.     

The geology and structure of the area south of Gani,Kurnool District,Andhra Pradesh — a study based on remotely sensed data

Geological investigations in the area south of Gani, Kurnool District, Andhra Pradesh, were carried out with the help of aerial Photographs and multiband satellite imageries. The rocks of the Cuddapah Group and the Kurnool Group are exposed in the area under study. The Gani-Kalava anticline and the ENE-WSW trending Kalava fault are the important structural features of the area. The anticlinal structure could be better studied using the aerial photographs, while the fault is clearer on the imagery. Small scale folds involving the Cuddapahs and the Kurnools along the northern limb of the fold could be mapped using the aerial photographs. The Gani-Kalava anticline is a post-Kurnool structure, formed by movement along the Kalava fault and in the first instance the minor folds appear to be drags on the northern limb. However, certain structural and stratigraphic relations suggest that the folding in the Cuddapahs may be a pre-Kurnool phenomenon.     

Application of lineament density and hydrogeomorphology to delineate groundwater potential zones of Baghmundi block in Purulia District, West Bengal

Groundwater being a valuable resource in today’s world needs proper evaluation and management for overall development within the region for its judicious use. The Baghmundi Block of Purulia district, West Bengal is within the hard rock terrain of Ayodhya hills and Matha Protected forest. The groundwater in this region is confined within the fracture zones and weathered residuum. Hydrogeomorphologically, the entire area is classified into following categories such as - i) Very shallow weathered pediment, ii) Moderately weathered pediment, iii) Valley fills, iv) Erosional gullies, v) Lateritic Upland and vi) Accumulation gullies. The hydrogeomorphic map of the area prepared by Department of Science and Technology, Govt. of West Bengal has been digitized for the present study. The lineament map has been prepared from the satellite imagery. The lineament map has also been digitized for the present study. From this the lineament density contour map has been prepared. An integrated remote sensing and Geographic Information System (GIS) based methodology has been used for the delineating Groundwater potential zones in the study area. Here the Geomorphology and Lineament density maps are overlaid following the Weighted Index Overlay Method, which delineates groundwater potential zones.     

Assessment of groundwater potential zones using GIS technique

A case study was conducted to find out the groundwater potential zones in Kattakulathur block, Tamil Nadu, India with an aerial extent of 360.60 km². The thematic maps such as geology, geomorphology, soil hydrological group, land use / land cover and drainage map were prepared for the study area. The Digital Elevation Model (DEM) has been generated from the 10 m interval contour lines (which is derived from SOI, Toposheet 1:25000 scale) and obtained the slope (%) of the study area. The groundwater potential zones were obtained by overlaying all the thematic maps in terms of weighted overlay methods using the spatial analysis tool in ArcGIS 9.2. During weighted overlay analysis, the ranking has been given for each individual parameter of each thematic map and weights were assigned according to the influence such as soil −25%, geomorphology − 25%, land use/land cover −25%, slope − 15%, lineament − 5% and drainage / streams − 5% and find out the potential zones in terms of good, moderate and poor zones with the area of 49.70 km², 261.61 km² and 46.04 km² respectively. The potential zone wise study area was overlaid with village boundary map and the village wise groundwater potential zones with three categories such as good, moderate and poor zones were obtained. This GIS based output result was validated by conducting field survey by randomly selecting wells in different villages using GPS instruments. The coordinates of each well location were obtained by GPS and plotted in the GIS platform and it was clearly shown that the well coordinates were exactly seated with the classified zones.     

Environmental evaluation of medchal taluk,Andhra Pradesh using aerial photographs

The human interaction with nature in the form of improper exploitation and unplanned utilisation of natural resources has caused a lot of environmental imbalance in nature. The aerial photographs and other repetitive orbital remote sensing data provide valuable information in identification and surveying of such environmentally imbalanced zones. In this study the aerial photographs were used in identifying such vulnerable areas and some remedial measures are suggested for the planned exploitation of natural resources without damaging the environment.     

Spatial and Temporal Variation of Groundwater Level and its Relation to Drainage and Intrusive Rocks in a part of Nalgonda District,Andhra Pradesh,India

Drainage and lineaments play an important role in the flow of groundwater. The objective of this study is to assess the groundwater level and its relation to drainage and lineaments in a hard rock region of a part of Nalgonda district, Andhra Pradesh, southern India. The region predominantly comprise of granites and gneisses. Groundwater level was measured in 42 representative wells in this study area from March 2008 to January 2010 once in every two months. Observed groundwater levels were compared with drainage and dyke density. Groundwater level fluctuation in low drainage density region is generally greater than those in moderate and high drainage density regions. The dykes do not act as barriers for groundwater flow as they are highly weathered. The quantity and flow of groundwater in this region is predominantly controlled by drainage density, intensity of weathering and presence of fractures. Thus the study indicate that the drainage density play a major role in groundwater level fluctuation and as the dykes are weathered, they do not affect the groundwater flow in this shallow unconfined aquifer.     

Integration of thematic maps through GIS for identification of groundwater potential zones

The remote sensing data combined with Geographical Information System (GIS) technique has been proved to be very efficient in identification of groundwater potential of any area. In the present paper, IRS 1 A, LISS II data has been used to identify the groundwater potential zones by integrating various thematic maps generated on 1:50,000 scale. These maps are integrated after assigning weight factors to the identified features in each thematic map depending upon their infiltration capacities and the groundwater potential zones in Bhamini mandai (developmental block) of Srikakulam district, Andhra Pradesh are demarcated. The area of investigation has been classified into seven groundwater potential zones. The present results show that integration of all attributes provides more accurate results in groundwater potential zones identification.     

Groundwater prospects in a developing satellite township of Andhra Pradesh, India, using remote sensing techniques

Geomorphologic map prepared, using the remote sensing techniques and conventional methods, has been used to assess groundwater prospects in a developing satellite township of Visakhapatnam Metropolitan Complex. Andhra Pradesh, India. The geomorphic units delineated are denudational, fluvial and coastal. The study indicates that the fluvial and rolling plains are promising zones for groundwater occurrence. The denudational landforms are not considered as groundwater potential zones, whereas the groundwater occurring in the coastal plain is not suitable for any use, because of its brackish nature.     

Delineation of groundwater potential zones using remote sensing and GIS-based data-driven models

The rapid increase in human population has increased the groundwater resources demand for drinking, agricultural and industrial purposes. The main purpose of this study is to produce groundwater potential map (GPM) using weights-of-evidence (WOE) and evidential belief function (EBF) models based on geographic information system in the Azna Plain, Lorestan Province, Iran. A total number of 370 groundwater wells with discharge more than 10 m³s^?1were considered and out of them, 256 (70%) were randomly selected for training purpose, while the remaining114 (30%) were used for validating the model. In next step, the effective factors on the groundwater potential such as altitude, slope aspect, slope angle, curvature, distance from rivers, drainage density, topographic wetness index, fault distance, fault density, lithology and land use were derived from the spatial geodatabases. Subsequently, the GPM was produced using WOE and EBF models. Finally, the validation of the GPMs was carried out using areas under the ROC curve (AUC). Results showed that the GPM prepared using WOE model has the success rate of 73.62%. Similarly, the AUC plot showed 76.21% prediction accuracy for the EBF model which means both the models performed fairly good predication accuracy. The GPMs are useful sources for planners and engineers in water resource management, land use planning and hazard mitigation purpose.     

Study of landforms,land use and land units of a part of Krishna district,Andhra Pradesh,from aerial photographs

Utilising aerial photographs as the chief source of information an attempt has been made to study the land units, land use, land capability and limitations in relation to geomorphology of an area of about 350 sq. kms. in Krishna district of Andhra Pradesh. Besides identifying major individual landforms, the area is divided into four geomorphic environments each characterised by dominant landform pattern and relief. Each form and unit is described. Nine types of land units based on amount of slope and six land use classes were chosen after preliminary interpretation and a reconnaissance field check. The estimated range in slope is given for each land unit. The land’s capability and limitations are brought out from consideration of landforms, land units (slopes), nature of soil and water resources. Soil samples were collected from each geomorphic unit and analysed. The results are presented in the form of 3 maps and 2 tables, which may be of use for planning and development of the area.     

Evaluation of groundwater potential zones using Remote Sensing data in upper Vaigai river basin,Tamil Nadu,India

The area of upper Vaigai river basin covering parts of Madurai and Theni Districts, in Tamil Nadu, faces acute water scarcity and chronically drought prone. The groundwater resources in the area have not been fully exploited. The present investigation has been made to evaluate the potential zones for groundwater targeting using IRS - ID LISS III geocoded data on 1:50,000 scale. The geology, geomorphology, lineament tectonic maps are generated and integrated to evaluate the hydrogeomorphological characteristics of the upper Vaigai river basin and demarcate the groundwater potential zones. A number of geomorphic units have been observed. Out this the more groundwater prospective units are buried pediment medium, buried pediment deep, flood plain, bajada and lineament and intersection of lineaments. Non potential areas like pediment, pediment inselberg, shallow pediment and pediplain were identified.     

Application of photo-interpretation and remote sensing techniques for integrated survey of Anantapur district,Andhra Pradesh

Multi-disciplinary integrated studies were carried out in the drought prone, backward district of Anantapur, for an appraisal of its natural resource and environmental potential, by applying the photointerpretation and remote sensing techniques. Shortage of land and water resources are identified as the major constraints for developmental planning. The natural resources and the potential available for development are documented in various thematic maps. The landuse pattern for agriculture and forestry is mainly controlled by the lithological and morphological units. It is surmised, that with the new source for groend water identified along linement and fracture zones, there is scope for augmenting and uplift the land use and crop-pattern, and this helps to upgrade the socio-economic condition of the district.     

Remote sensing and GIS study of the Ravipadu gabbro pluton,Prakasam alkaline province,Andhra Pradesh,India

Geospatial themes namely geology, topography and classified satellite image of the area in and around Ravipadu gabbro pluton (RGP), Prakasam alkaline province, Andhra Pradesh has been studied. The geological map of co-magmatic suite of RGP predominantly exposes olivine gabbro followed by olivine norite, troctolite and anorthosite. Graphic portrayal of the attributes such as mineralogical (modal) and chemical compositions of rocks of RGP is supplemented in the map display. The topography reveals that the terrain is flat and that it underwent differential erosion thereby exposing the deeply eroded RGP flanked on the North and South by two hilly mounds composed of cordierite-garnet gneiss (metapelite). Digital analysis of satellite image (IRS-1D) of the Ravipadu area, based on the spatial and spectral characteristics producing a classified image superposing on the vectorised geological map of the gabbroic body on a spatially referenced base, reveal a near perfect match of the two digital data products.     

Photogeological mapping in parts of Cuddapah basin Kurnool and Prakasam Districts of Andhra Pradesh

An area of 2500 sq. Km. has been covered by photogeological mapping with selected field checks which forms a part of Cuddapah basin in the Kumool and Prakasam Districts of A.P. The rocks exposed in the area belong to the Cumbum and Bairankonda Formations of Cuddapah Super Group. They occur more or less as an alternating sequence. These formations are bound on the east by Dharawar gneisses and on the west by Nandyal Shales. The Bairankonda Formation is predominantly arenaceous with quartzite as the main member, being easily identifiable in the aerial photographs by its characteristic topography, coarse drainage, light grey tone etc. The Cumbum Formation is mainly argillaceous with slate/phyllite as the main member, intercalated with minor quartzite band and is expressed on the photographs in dark tone with dendritic to sub-parellel drainage and occurs relatively at lower elevations, mostly in plains. The Dharwar (Archaean) gneisses underlying the vast plains in the east are recognised by the sandy nature of soil and by the thrusted contact of this unit with the Bairankondas. The Nandyal Shales occupying the large cultivated area in west have a darker tone and a dendritic drainage pattern. They are Upper Kurnool in age. All the litho-units have undergone pre-Kurnool deformation resulting into plunging/doubly plunging antiforms and synforms trending NNE-SSW and a few shear zones and faults. Due to severe deformation a very prominant foliation has developed in the Cumbum unit. Groove lineation has also been developed in the hinge portions of major folds. The magmatic activity in these formations has been witnessed with the emplacement of reibeckite syenite and Kimberlite plugs and veins. Geomorphologically the area may be divided into two prominant units namely (i) Denudational landforms comprising (a) hills, ridges, inselbergs, bornhardts and hogbacks on Bairankonda quartzites and phyllites (b) pediment and dissected pediment on Cumbum Shales and Dharwar gneisses and (ii) Depositional landforms such as (a) alluvial fans and colluvial fans (b) alluvial valley fills along river courses and (c) sand dunes in Dharwar gneisses.     

Delineation of ground water potential zones in a hard Rock Terrain of Bargarh District, Orissa using IRS data

In the present paper, various groundwater potential zones for the assessment of groundwater availability in a hard rock terrain have been delineated with the help of hydrogeological parameters using satellite IRS- 1B-LISS-II digital data. Area selected for this study is a part of Bargarh district, Orissa, India covering an area of about 680 square km. Satellite data has been used to prepare geological-cum-lineaments, geomorphological, landuse and drainage maps. The various thematic maps have been integrated with the help of Geographic Information System to demarcate the poor to excellent groundwater potential zones. Weightage has been given to various groundwater controlling factors to the total groundwater potential in each segment of study area. Subsequently, several sites were selected and pumping tests carded out in the area. The results show that among others, lineaments as well as drainage density are the most important contributory factors in the groundwater potential of various geomorphic units in the area of investigation.     

Terrain analysis of Panna District,Bundelkhand, Madhya Pradesh,using LANDSAT imagery

Visual interpretation of LANDSAT imagery in bands 6 and 7 covering Panna district, Bundelkhand, Madhya Pradesh was carried out for terrain analysis and present land use. The physiographic units viz. hills and hill ranges, escarpments, ridges, table-land, pediment, piedmont plain and sub-units of second order were identified and delineated using inter pretation elements. Area of each unit and sub-unit is calculated and presented in the table showing extent, tone, texture, shape and land use. Land use in relation to physiographic units is also described in the paper and shown in the form of small scale map. Visual interpretation technique helps in broad terrain analysis on scale 1:1 million. This information could be used for making a rapid resource inventory.     

Identification of Groundwater Potential Zones Using Remote Sensing Techniques In and Around Guntur Town, Andhra Pradesh, India

The area in and around Guntur Town in Andhra Pradesh faces an acute water problem. It represents plain land and gentle slope responsible for infiltration and groundwater recharge. Adequate groundwater resource is reported to be available in the investigated area. It has not been properly exploited. The present investigation is, therefore, undertaken to assess groundwater favourable zones for development and exploration with the help of geomorphological units and associated features. The identified units and features by remote sensing technology with the integration of conventional information and limited ground truths are shallow weathered pediplain (PPS), moderately weathered pediplain (PPM), deeply weathered pediplain (PPD), residual hill (RH) and lineaments (L). The results show that the PPD, PPM and PPS are good, moderate to good and poor to moderate promising zones, respectively for groundwater prospecting. The RH is a poor geomorphological unit in respect to prospective zone as groundwater resource. However, adequate recharge source of groundwater can be expected surrounding the RH, as it acts as surface run-off zone. Lineaments parallel to the stream courses and intersecting-lineaments are favourable indicators for groundwater development. They can also be utilized to augment groundwater resource.