Groundwater prospects evaluation based on hydrogeomorphological mapping using high resolution satellite images: A case study in Uttarakhand

Water is the most important natural resource which forms the core of the ecological system. The advent of remote sensing has opened up new vistas in groundwater prospect evaluation, exploration and management. The groundwater resources of the study area, Rishikesh region of Garhwal Himalayas, are under threat due to population pressure caused by expanding tourism in this region. This entails sustainable and judicious use of this precious resource. The groundwater prospect evaluation in Rishikesh region has been attempted based on hydrogeomorphological mapping of the area consisting of thematic maps of hydrogeomorphology, geology, drainage, lineament, slope and relief using high resolution IRS-1C LISS III and PAN merged satellite images. The Rishikesh region exhibits diverse hydrogeomorphological conditions where the groundwater regime is controlled mainly by topography and geology. A probability-weighted approach has been applied during overlay analysis in ArcMap GIS environment. The overlay analysis allows a linear combination of weights of each thematic map with respect to ground water potential. Good groundwater prospects dominate in the area with more than 50% of the study area showing moderate to excellent potential. The study shows that the remote sensing and geoinformatics techniques can be applied effectively for groundwater prospect evaluation.     

Aid of remote sensing in mapping geofractures of environmental significance in Tamil Nadu

Geofractures play a crucial role in environmental degradation and environmental pollution. Such geofractures were interpreted using LANDSAT and IRS 1A imagery and integrated with seismic, erosion and groundwater-chemistry data. The study shows that mostly the N-S and NE-SW trending fractures are prone to seismicity and pollutant migration while NE-SW and WNW-ESE trending faults are prone to soil erosion. The study further shows that mostly the Quaternary fractures/lineaments and the Quaternary reactivated Precambrian fractures are having a dominant control over such phenomena. On the basis of such studies, suggestions are made to take adequate care while dealing with such regions for resource exploitation and developmental purposes.     

Geoinformatic Modeling of Groundwater Resource Mapping of Shear Zone Regions- A Case Study on Attur Valley,Tamil Nadu,India

The general tendency of mapping groundwater resource using remote sensing and Geographic Information System (GIS) techniques involve assigning higher weightage to geomorphology. But this cannot be used as a thumb rule everywhere, especially an area where many ductile and brittle zones are prevalent. The influence of texture and structure of sheared rocks might play a control over retaining and permitting groundwater to flow. Attur valley is characterized by the presence of many shear zones and faults and hence the rocks are highly fissile within the shear zones. The present study tries to establish a new ranking and weightage scheme and hence a new spatial model for groundwater resource mapping in shear zone area like Attur Valley. This spatial model can be verified with field data such as water level data, pump test and resistivity data.     

Geology and geomorphology of Cumbum valley and Varushanadu hills,Madural district,Tamil Nadu through remote sensing

The Varushanad hills forms the eastern offshoot of the Western Ghats and the Cumbum valley divides the Varushnad hills from the Western Ghats. Investigations were carried out in about 1700 sq Km comprising the Cumbum valley and the Varushanad hills of the Western Ghats situated in Periakulam Srivalliputhur and Usilampatti taluks of Tamil Nadu on the geological and geomorphological aspects. Remote sensing techniques were used and limited field checks were made. Visual interpretation of aerial photographs on 1:60,000 scale was carried out for identifying the geomorphological features, drainage pattern and lithology. Digital analysis of the Landsat computer compatible tape (CCT) path-row 154–053 was also carried out to delineate major lithological variations. Major lineaments were also mapped from the Landsat imagery and false colour composite. The rock types of the Cumbum valley and the Varushanad hills are mainly charnockites, granite gneiss and pink granites which have been deformed by folds and faults. The various geomorphological units of the area are ridges, valleys, bazada zone and pediment zone of mountain complex. Resources evalution studies on the potential zone of ground water and possible construction materials were also discussed.     

Integrated remote sensing and GIS study for hydrogeomorphological mapping and delineation of groundwater potential zones in Khallikote block,Ganjam district,Orissa

The present study attempts to delineate different groundwater potential units using remote sensing and geographic information system (GIS) in Khallikote block of Ganjam disrict, Orissa. Thematic maps of geology, geomorphology, land use and land cover, drainage density, lineament density, slope and DEM (digital elevation model) were prepared using the Landsat Thematic Mapper data in 3 spectral bands, band 7 (mid-infrared light), band 4 (near-infrared light), Band 2 (visible green light). Relationship of each layer to the groundwater regime has been evaluated through detailed analysis of the individual hydrological parameters. The SMCE (Spatial Multi-Criteria Evaluation) module in ILWIS (Integrated Land and Water Information System) supports the decision-making process for evaluating the ground water potential zones in the area. The study shows that more than 70% of the block is covered by medium to excellent category having good ground water potential.     

Impact of tsunami on aquaculture farms along the nagapattinam coast zone,Tamil Nadu,India

The tsunami waves triggered by underwater earthquake with a focal depth of 30 km near the Sumatra Island distressed the entire coast of Tamil Nadu. The worst affected coastal region is Nagapattinam, particularly from Nagoore to Vailankanni. The impact of tsunami had multidimensional effect, killing most of the fishermen communities, devastating the coastal huts and damaging the coastal aquaculture resources. The present study has been carried out to find the impact of tsunami on the aquaculture small farmland owners along the coast using pre (December 18, 2004) and post January 6, 2005) IRS P6 data. The study includes the extent of damage caused to the farms by saltwater intrusion; sand inundation, total destruction of farms. The results indicate that, there have been incredible damage caused to the farmers beyond recovery in short span of time.     

Remote sensing based agricultural drought assessment in Palar basin of Tamil Nadu state,India

Agricultural drought has been a recurrent phenomenon in many parts of India. Remote sensing plays a vital role in real time monitoring of the agricultural drought conditions over large area, there by effectively supplementing the ground mechanism. Conventional drought monitoring is based on subjective data. The satellite based monitoring such as National Agricultural Drought Assessment and Monitoring System (NADAMS) is based on the crop condition, which is an integrated effect of soil, effective rainfall, weather, etc. Drought causes changes in the external appearance of vegetation, which can clearly be identified (by their changed spectral response) and judged using satellite sensors through the use of vegetation indices. These indices are functions of rate of growth of the plants and are sensitive to the changes of moisture stress in vegetation. The satellite based drought assessment methodology was developed based on relationship obtained between previous year’s Normalised Difference Vegetation Index (NDVI) profiles with corresponding agricultural performance available at district/block level. Palar basin, one of the major river basins in Tamil Nadu state was selected as the study area. The basin covers 3 districts, which contain 44 blocks. Wide Image Field Sensor (WiFS) of 188m spatial resolution from Indian Remote Sensing Satellite (IRS) data was used for the analysis. Satellite based vegetation index NDVI, was generated for Samba and Navarai seasons in the years 1998 and 1999. An attempt has been made to estimate the area under paddy. It was also observed that, there was reduction in the crop area as well as vigour in the vegetation in both Samba and Navarai seasons in 1999 when compared with 1998. Drought severity maps were prepared in GIS environment giving blockwise agricultural water deficiency status.     

Hydrogeomorphological mapping in ground water exploration using remotely sensed data — a case study in keonjhar district, orissa

Identification of fractures/lineaments and hydrogeomorphic units is prerequisite for undertaking ground water exploration and development in any terrain. Use of satellite remote sensing techniques coupled with aerial photo-interpretation greatly aid in planning ground water exploration, and pin pointing well sites In this study, airborne and space borne data was used for qualitative evaluation of ground water resources and a critical appraisal of such study in combination with hydrogeological and hydrogeophysical techniques for ground water exploration and development in Keonjhar district of Orissa. The study area has been divided into various geomorphic units based on visual interpretation of Landsat (TM) false colour composite on. 1:2,50,000 scale and the ground water potential of each of the units is qualitatively assessed. Digital image processing techniques such as principal component analysis and brightness index were used for generating classified outputs. The features like valley fills, pediments ete appeared clearly on the classified image. Directional filtering brought out minor fractures/lineaments crisply. The study has revealed the significance of different hydrogeomorptuc units and lineaments in Controlling ground water potential of the area. The findings were corroborated by resalts of drilling and resistivity soundings.     

Flood intensity and land evaluation in the Cauvery delta,Tamil Nadu,applying modern remote sensing techniques

An area of about 7500 km² covering Cauvery delta has been studied from airphotos (1:60,000), Landsats (1:250,000) and survey of India topographic sheets (1:50,000) with a view to delineate various landforms, soils, land use, hydromorphic units, drainage, and flood intensity of the delta. The delta is composed of mainly ancient channels, delta p ains, fossil islands, levees, beach ridges, mangroves marshes and coastal dunes. The various soil types are clayey soils, silty soils, silty loams, sandy loams, coastal sands and alkaline clays. Paddy and sugarcane are dominant crops. The old channels are found to be zones of high ground water potential. The growth of delta seems to be from south to north with twelve abandoned meander lobes and three delta fronts with gradual influx of material into Bay of Bengal. The old rivet courses lying parallel to the present active Coleroon river in third stage of the growth of the delta seem to be severely affected by floods. Moderate to low growth is noticeable in the second stage of the of the delta. The oldest river course which debouched into Bay of Bengal near Adirama-patnam is less affected by floods. The delta plains, fossil islands, disturbed ridges and beach ridges are unaffected. Basing on landforms, soils, land use, hydrogeomorphology and flood intensity the land capability of the delta has been evaluated. About seven classes of land are interpreted.     

Structure and its impact in Uthangarai and Thirthamalai region, Tamil Nadu, India using remote sensing technique

The Uthangarai-Thirthamalai region in Dharmapuri district is a typical Precambrian tract in Tamil Nadu. IRS-1C satellite imagery was used for interpreting folds, faults, fractures and lineaments, in this region. As interpreted from the satellite imagery, there are five major structural domains, which control the Ponnaiyar, Pambar, Vaniyar and Kovilar river courses and other drainage pattern in this region. Presence of fault rock, epidotization and sympathetic fractures along such folds and faults reveals the intensity of tectonism in this sector. The interpreted lineaments have been classified into five major groups on the basis of their geometry and orientation. From the rose diagram, it is inferred that the NNW-SSE trending lineaments are fall in major frequency domain. The springs observed near Hanumanthirtham and Thirthamalai region could be structurally originated. The geomorphology interpreted from the satellite data has shown significant morphological expression of folds, faults and lineaments. The geophysical data have been analysed and correlated with intensity of weathering by fractures and lineaments.     

Effect of deforestation on landslides in Nilgiris district — A case study

Landslides in the Nilgiris are mainly due to rainfall, but human intervention in the form of deforestation and plantation has turned this into a calamity. Our study in the Nilgiris district of Tamilnadu help of the Global Land Cover Facility data reveals that there is a drastic reduction in forest cover and human interventions in the form of unplanned tea estates has resulted in the loss of natural ecosystem of Nilgiris which is causing massive and frequent landslides.     

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.     

Geology amd drainage analysis of the area between peram-balur and padalur in the Trichinopoly District,Tamil Nadu

Photogeological studies of the area shows the presence of four major lithological groups as : 1. Precambrian basement made up of granitic gneisses and Charnockites, 2. The Utatur Group of rocks, 3. The Trichinopoly Group of rocks and 4. The Ariyalur Group of rocks. Some prominant lineaments roughly trending in NE-SW direction are seen. These lineaments represent the traces of the reactivated faults in the basemeht. The photogeological studies were supplemented by morphometric analyses. It is seen that the drainage in lower order basins is controlled by structure, i.e. by the strike of the rocks and faults in the basement. The higher order streams apparently follow the direction of regional gradient.     

Groundwater potential in the hard rock terrain of western ghats: A case study from Kottayam district,Kerala using resourcesat (IRS-P6) data and GIS techniques

The present study was aimed to identify and delineate the groundwater potential areas in parts of Western Ghats, Kottayam, covering the upper catchment of Meenachil river. The study area is composed rocks of Archaean age and Charnockite dominated over others. The information on lithology, geomorphology, lineaments, slope and land use/land cover was generated using the Resourcesat (IRS P6 LISS III) data and Survey of India (Sol) toposheets of scale 1:50,000 (surveyed in 1969) and integrated them with raster based Geographical Information System (GIS) to identify the groundwater potential of the study area. Thus, a GIS-based model which takes account of local condition/variations has been developed specifically for mapping groundwater potential. On the basis of hydrogeomorphology, three categories of groundwater potential zones namely good, moderate and poor were identified, and delineated. The high potential zones correspond to the fracture valleys, valley fills, pediments and denudational slope, which coincide with the low slope and high lineaments density areas. The low zone mainly comprise structural hills and escarpments and these act as run-off zones. The derived panchayath-wise groundwater potentiality information could be used for effective identification of suitable locations for extraction of potable water for rural populations.     

Land transformation in Punjab — A case study of Kapurthala district

The map showing the extent of salt affected and sand dune soils was prepared at 1:50,000 scale using Landsat TM data for March 1987 and compared with the soil map of Kapurthala district based on 1965 aerial photographs and semi detailed survey of the district during 1975–76. The study revealed that in a span of 22 years (1965 to 1986) the area of sand dunes decreased from 22.7 per cent to 2.3 per cent and that of salt affected soils from 20.95 per cent to 4.38 per cent respectively as a consequence of reclamation of salt affected soils and clearing and levelling of sand dunes. Salt affected soils after reclamation have been brought under paddy-wheat rotation. Whereas sand dunes after clearing and levelling, have been brought under wheat or wheat -rice/fodder/oilseed crops.     

Geomatics Based Analysis of Predicted Sea Level Rise and its Impacts in Parts of Tamil Nadu Coast,India

The coastal zones around the world are very densely populated and hence heavily packed with related infrastructures. So, the territorial nations have obvious apprehensions against the IPCC SRES (Intergovernmental Panel on Climate Change, Special Report on Emission Scenario) predicted sea level rise, as it would cause flooding of the low lying coasts and also other related chains of environmental endangers. This has driven these nations to initiate research studies in multiple directions for scientifically evaluating the phenomenon and impacts of sea level rise using all possible technologies including the Geomatics which possesses unique credentials in geosystem mapping. But certain advanced virtues available with Geomatics technology are yet to be capitalized deservingly in this. In addition, almost all the earlier studies have focused only on the impacts of sea level rise (SLR) and not on the predicted shift of high tide line (HTL) and the related inter tidal activities, which would cause a series of environmental disaster. Hence, the present research study was undertaken in a test site of 750 km² in central Tamil Nadu coast to visualize the areas prone to submergence due to predicted SLR and areas prone to environmental disasters/degradation viz. erosion, deposition, salination of agricultural lands, pollution of aquifers, etc. due to predicted shift of HTL, using digital elevation models derived from SRTM data (Shuttle Radar Topographic Mission), geomorphology and land use/cover maps interpreted using IRS P6 LISS IV satellite data. The paper narrates the certain newer concepts and methodologies adopted in the study and the results.     

Groundwater vulnerability assessment based on modified DRASTIC model: a case study in Changli County,China

Groundwater vulnerability assessment has been regarded as the initial step to understand and evaluate the susceptibility of the subsurface to contamination. As one of the most widely used models, the DRASTIC has been applied worldwide. However, problems associated with the model, such as the subjectivity in rating and weighting schemes, have led to modified versions of this model for better representing the vulnerability of the aquifer. In this study, a modified DRASTIC model was formulated by adjusting the rating and weighting scores based on Wilcoxon rank-sum test and Analytic Hierarchy Process. The modified model was then applied to the evaluation of groundwater vulnerability in Changli County, China in a GIS environment. The validity of the model was verified by analysing the correlation coefficient between the vulnerability index and the nitrate concentration. The results revealed that the modified DRASTIC model presents stronger correlation with the nitrate contamination than the traditional DRASTIC model.     

Glacial mapping using landsat thematic mapper data: A case study in parts of gangotri glacier, NW himalaya

Glacial mapping is difficult and hazardous because of the remoteness and inaccessibility of the terrain. In this context, remotely-sensed data from satellites provide valuable information on glaciers and the associated landforms. It is important to note that judicious selection of spectral bands is critical in mapping the glacial features. Glacial landforms in parts of Gangotri glacier, NW Himalaya, have been delineated using selected bands of Landsat Thematic Mapper Data. Digital image processing of Landsat data has helped in identifying the major features of the Gangotri glacier such as accumulation and ablation zones, and glacial moraines. The study shows that Thematic Mapper bands 4, 5 and 7 are more useful in snow mapping because of their distinct spectral discriminability in identifying the glacial features.     

Modeling sprawl of unauthorized development using geospatial technology: case study in Kuantan district,Malaysia

Abstract

The paper explores a framework combining remote sensing and GIS-cellular automata (CA) concepts aimed at improving the modeling of unauthorized land use sprawl. Remote sensing data have been used in urban modeling and analysis, the use of high-resolution remote sensing data in assessing unauthorized development is quite unexplored. This work has demonstrated systematic combination utilization of geospatial analyses tools to acquire a new level of information to enable urban modeling and sprawl analysis in assisting urban sustainable management. In this study, Kuantan city, Malaysia was selected in simulation of the unauthorized land use with CA concept for a period of 15 years (2000–2015), with main input time-series land use observation from 1995 to 2005. The 2000 and 2005 land use input was also used as calibrated and test assessment of the simulation. The results show excellent agreement between in-situ changes of the unauthorized land use classes and the corresponding simulated classes within the same periods. In conclusion, CA model can lead to new levels of understanding of how urban areas grow and change as in view of digital earth aspiration.     

Assessing image processing techniques for geological mapping: a case study in Eljufra,Libya

Various image processing techniques were experimented with in this study to evaluate their efficiency for geological mapping in the Eljufra area of northwest Libya. Remote sensing data including multi-spectral optical Landsat Enhanced Thematic Mapper (ETM+), Synthetic Aperture Radar (ERS-2 SAR) and Digital Elevation Models (DEMs) extracted from the Shuttle Radar Topography Mission (SRTM) data were used to trace different lithological units as well as extracting geological lineaments in the study area. The study area is located in an arid environment mostly devoid of any vegetation. Most lithological and structural units are distinguishable based on their topographic form and spectral properties. Fusion of ETM+ and ERS-2 images was experimented with to further identify lithological units. Shaded relief techniques were implemented to enhance terrain perspective views and to extract geological lineaments. The results discriminated different rock units and modified formation boundaries and revealed new geological lineaments. Nine rock units were identified and plotted in the new geological map defined by the new boundaries. The dominant lineaments tend to run in the NNW-SSE and NNE-SSW directions. Analysis and interpretation of the lineaments provided information about the tectonic evolution of the study area.