Remote sensing and GIS techniques for the study of springs in a watershed in Garhwal in the Himalayas,India

Water has been described as the elixir of life, the source of energy that sustains life on Earth and the factor that governs the evolution and the functioning of the universe. Increased use of water in the face of the impairment of the natural environment and ecology and the drying up of springs and reduction in their discharge and those of streams in the Lesser and Outer Himalayas are the most serious problems calling for study and exploration of groundwater resources in the Himalayan region. The hilly regions of India are facing a serious water availability crisis, particularly during summer months. Viable sources of water, such as springs in the Himalayas, which are plentiful in the hills, are drying up due to rapid and unplanned developments. The present study deals with the delineation of springs in the Chandrabhaga watershed using remote sensing and GIS technologies. The study demonstrates that the coincidence of lineaments, derived from merged satellite data, and the drainage density show good correlation with the present spring locations in the Chandrabhaga watershed. The study shows also that the locations of various springs have changed since 1981, perhaps due to rapid changes in the landuse pattern in the watershed between 1981 and 1997. Besides landuse, topography, geology and geological structures are among the most influential factors affecting spring location and discharge. An integrated approach of remote sensing and GIS is proved to be an efficacious technique for the study of springs in a mountainous watershed.     

Remote sensing and GIS activities in UNESCO

The role of UNESCO is to promote international peace and security through cooperation in the fields of education, science and culture. In view of eradicating illiteracy, overcoming unsustainability of natural resources, confronting environmental problems, safeguarding historical monuments, and preserving natural and cultural heritage, UNESCO develops international research programmes and makes best possible use of new advances in technology, namely remote sensing and GIS, in order to effectively carry out activities in the framework of its programmes. Part one describes remote sensing and GIS use in international programmes such as the Man and the Biosphere (MAB) programme for biosphere reserve development and ecosystem monitoring, management and conservation; the International Hydrological Programme (IHP) for surface and ground water research management; the International Geological Correlation Programme (IGCP) for the creation of a data base on the spectral signatures of rocks and soils; and in several projects concerning ocean investigation and climate observation conducted in the framework of the Intergovernmental Oceanographic Commission (IOC). In part two constraints of using the remote sensing and GIS technology are addressed and remaining difficulties in accessing and exchanging data, training issues and costs are discussed.     

Remote sensing of coastal geomorphology to understand river migration in the Thengapatnam area,southern India

The aim of this work is to study the geomorphic processes that control river migration in the Thengapatnam coastal tract bordering the Arabian Sea in the Kanyakumari District, Tamil Nadu, southern India. Satellite image data were used to identify the geomorphic units. An attempt was made to interpret geological evidence indicative of migration of the Kuzhithura river channel. In addition, study was made of the geological evidence from the field indicative of entrenching of the channel, possibly as a result of relative uplift of the land or lowering of the mean sea level. Satellite images and information gathered from the field reveal that the river has migrated 1.5 km towards the south-east. Satellite images and Digital Elevation Models (DEMs) provide more information about the landforms that were missed out during the field survey.     

Application of remote sensing and GIS for the demarcation of groundwater potential zones of a river basin in Kerala,southwest coast of India

An integrated hydrogeological investigation has been made to delineate the groundwater‐potential zones of the Muvattupuzha river basin, Kerala, along the southwest coast of India. The basin is characterized by charnockites and gneisses of Archean age covering more than 80% of the area and the remaining by Pleistocene laterites and Miocene formation. The basin receives high rainfall, measuring 3100 mm/year. However, acute water shortage occurs during the premonsoon season and hence, a number of dug wells are made to tap the groundwater. Seasonal rainfall during NE and SW monsoons is the major source of groundwater recharge. Further, hydrogeomorphology, geology, fracture systems and the slope of the terrain also play a significant role on the movement and behaviour of the groundwater of this basin. The integration of conventional and remote sensing data has been made through geographic information system (GIS) and it is found that about 50% of the area can be identified as very good or good potential zones, whereas the remaining area falls under moderate and poor categories. Most of the Muvattupuzha sub‐basin and the western part of the Kothamangalam and Kaliyar sub‐basins are classified as good groundwater‐potential zones, although the eastern upstream part of the basin has poor groundwater potential.     

Remote sensing and river migration in Western India

Abstract

The art of remote sensing has opened up many vistas in the study of river migration as satellite photographs, both in their normal and digitally enhanced modes, vividly show the rivers and their migratory signatures. The rivers migrate for various reasons amongst which tectonic movement is one of the main causes. In the present study an attempt has been made to exhibit the paleochannel network of the rivers of Western India and integrate them with lineament fabric, so as to understand the Quaternary tectonics of the region. The study has shown that Western India shows considerable signs of Quaternary tectonics.     

Remote sensing techniques in estuaries and coastal zones an update

This paper reviews briefly the current state of the use of remote sensing in estuaries and coastal waters. This covers the established uses, the recent developments in relation to hyperspectral imaging systems (imaging spectrometers), interferometric SAR and lidar bathymetry. The opportunities that are expected to occur soon, as 1-m resolution space-flown systems become available, are also discussed.     

Remote sensing and GIS for an oil spill contingency plan,Ras-Mohammed,Egypt

Ras-Mohammed area located at the southern tip of Sinai, is an important and unique environment which has valuable resources that should be carefully maintained. This area is threatened by numerous anthropogenic activities. The most important risk is that associated with possible oil spills from tankers crossing the Suez canal

The main objective of this study is to prepare an oil spill contingency plan for the study area. SPOT-XS data were used to derive valuable information about the different resources of the area, especially the shallow coral reef communities

SPOT images, ground surveys and GIS analysis have enabled an accurate evaluation of environmental sensitivity. This helped to put forward a proposal of an oil spill contingency plan, in order to protect environmentally sensitive areas such as Ras-Mohammed.     

Remote sensing and active tectonics of South India

The Indian Peninsula in general and its southern part in particular has been thought to be a stable shield area and hence inert to younger earth movements and seismicities. However, in addition to fast relapsing seismicities, the studies carried out by earlier workers during the past three decades indicate possible pulsatory tectonism, at least since the Jurassics. The present study is a newer attempt to identify, analyse, and spatially amalgamate a large number of anomalies visibly displayed by the tectonic, fluvial, coastal, and hydrological systems in remote sensing and ground based datasets/observations, and to finally paint a fair picture on the active tectonic scenario of South India. The study reveals that the phenomena, viz. extensive soil erosion, reservoir siltation, sediment dump into the ocean, preferential migration of rivers, restricted marine regression, shrinkage of back waters, withdrawal of creeks, fall of groundwater table, etc., indicate two E–W trending ongoing tectonic (Cymatogenic) archings along Mangalore–Chennai in the north and Cochin–Ramanathapuram in the south. Intervening these two arches, a cymatogenic deep along Ponnani–Palghat–Manamelkudi exhibiting phenomena opposite to the above is observed. In addition, the characteristic tectonic, geomorphic, and hydrological anomalies observed in 1B satellite FCC data, as well as in the field, indicate N–S trending extensional, NE–SW sinistral, and NW–SE dextral strike slip faults. These anomalies and the tectonic features deduced thereupon, indicate that the southern part of the Indian Peninsula is tectonically active due to the northerly to north–northeasterly directed compressive force related to post collision tectonics. This active tectonic model visualized for South India gives a further clue that the whole Indian plate is whirling like a worm with alternate E–W arching and deepening, along with block and transform faulting from Cape Comorin in the south to the Himalayas in the north.     

Remote sensing and GIS for estimation of irrigation crop water demand

Satellite images supported by global positioning systems (GPS) and field visits were used to identify the cropping pattern of a large irrigation scheme in Central Asia. Two methods were used to estimate the crop evapotranspiration (ET). In the first, the ETs of the different crops were calculated from local field climatic data using the Penman–Monteith method of calculating crop water requirements as used in the Food and Agriculture Organization (FAO) CropWat programme. The satellite data were transferred to a geographical information system (GIS) and the area of each crop type was identified. Combining the two sets of data gave an estimate of ET and total evaporative water demand for each crop. ET was also calculated directly from the satellite data using a modified sensible heat flux approach (SEBAL). The Penman–Monteith approach estimated the ET to be 5.7, 3.3, 4.4 and 6.3?mm?d^?1 for cotton, mixed crop, alfalfa and rice respectively, whereas the ET estimated from the satellite data were 4.4, 3, 3.2 and 5.3?mm?d^?1, respectively. The possible causes of these differences are discussed. The FAO Penman–Monteith methodology for estimating crop water requirements is best for planning purposes but the SEBAL approach is potentially more useful for management in that it establishes the amount of water being used by the crop and can help identify where water is being wasted.     

Remote sensing of regional yield assessment of wheat in Haryana,India

Regional estimates of crop yield are critical for a wide range of applications, including agricultural land management and carbon cycle modelling. Remotely sensed images offer great potential in estimating crop extent and yield over large areas owing to their synoptic and repetitive coverage. Over the last few decades, the most commonly used yield–vegetation index relationship has been criticized because of its strong empirical character. Therefore, the present study was mainly focused on estimating regional wheat yield by remote sensing from the parametric Monteith's model, in an intensive agricultural region (Haryana state) in India. Discrimination and area estimates of wheat crop were achieved by spectral classification of image from AWiFS (Advanced Wide Field Sensor) on‐board the IRS‐P6 satellite. Remotely sensed estimates of the fraction of absorbed photosynthetically active radiation (fAPAR) and daily temperature were used as input to a simple model based on light‐use efficiency to estimate wheat yields at the pixel level. Major winter crops (wheat, mustard and sugarcane) were discriminated from single‐date AWiFS image with an accuracy of more than 80%. The estimates of wheat acreage from AWiFS had less than 5% relative deviation from official reports, which shows the potential of single‐date AWiFS image for estimating wheat acreage in Haryana. The physical range of yield estimates from satellites using Monteith's model was within reported yields of wheat for both methods of fAPAR, in an intensive irrigated wheat‐growing region. Comparison of satellite‐based and official estimates indicates errors in regional yields within 10% for 78% and 68% of cases with fAPAR_M1 and fAPAR_M2, respectively. However, wheat yields in general are over‐ and underestimated by the fAPAR_M1 and fAPAR_M2 methods, respectively. The validation with district level wheat yields revealed a root mean square error of 0.25 and 0.35 t ha^?1 from fAPAR_M1 and fAPAR_M2, respectively, which shows the better performance of the fAPAR_M1 method for estimating regional wheat yields. Future work should address improvement in crop identification and field‐scale yield estimation by integration of high and coarse resolution satellite sensor data.     

Stratification of forest density and its validation by NDVI analysis in a part of western Himalaya,India using Remote sensing and GIS techniques

This study deals with the assessment of the status of forest density in the Kangra district of Himachal Pradesh, western Himalaya. A classified forest map of the area with an accuracy of 88.17% was produced using the hybrid classification method in Erdas Imagine. An IRS 1D LISS III satellite image was used for mapping and classification. Forest density was calculated in the ArcGIS environment by overlaying a mesh of uniform resolution cells (500 m×500 m) on a classified forest map. The forest density value of each cell was later used for the preparation of forest density contours. The forest density output was verified by Normalized Difference Vegetation Index (NDVI) analyses. The forest cover of the study area was found to be 34.3%. Baroh area had the highest (45.87%) forest density and Baijnath (18.65%) the lowest. Central and western regions of the district showed high‐value forest density contours (>50%). The derived NDVI values were compared against the forest density classes for assessing the accuracy of the results obtained. A positive correlation (r = 0.99) between NDVI values and forest density confirms the accuracy of the results.     

Remote sensing and GIS applications of surface and near-surface hydromorphological features in Darfur region,Sudan

Groundwater modelling and mapping in a region partly inaccessible using traditional techniques is practically very difficult, and time and cost consuming. However, integration of remote sensing and GIS enables more reliable mapping and analysis of hydromorphological elements such as palaeolakes. In the present study, a set of automated morphometric techniques of fitting a bivariate quadratic surface in a moving window of size 3 × 3 was used and modified to map and analyse hydromorphological elements in northwestern Sudan. Geomorphometry results indicate that the palaeodrainage network incision and depressions may have received most of the rainwater during late Quaternary wet phases. The results revealed that of the total 2000 km² coverage of the unnamed depression, about 49.6% was classified as accumulation zone with a recharge area of about 992 km², while the Wadi Fesh Fesh and Oyo depressions were shown to have the smallest areas of accumulation zone, approximately 31.3% and 37.3%, respectively. Validation of the methods was made by comparing trends and textural features from a Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) with 30 m spatial resolution Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEM and 0.6 m spatial resolution Quickbird images and geological maps of the study area. The maps obtained showed a strong correlation, indicating that the proposed methods are very efficient tools for regional mapping and analysing hydromorphological elements in arid regions and remote and inaccessible regions.     

Study of tectonics in relation to the seismic activity of the Dalvat area,Nasik District,Maharashtra, India using remote sensing and GIS techniques

Well‐documented geological data (from both field and satellite) in the Deccan Volcanic Provinces (DVP) in and around the Dalvat region, Nasik District, India has been analysed by Geographic Information System (GIS) techniques and reported in this paper so as to relate the geology and structures with recent seismicity. It has been the belief among earth scientists that the Deccan Traps in Maharashtra, India is tectonically stable as the region attained solidity long ago. However, recent activity in the study area altered this concept and it is now accepted that seismic activity is still continuing on a mild scale. As such, the need has arisen to take into consideration historical as well as recent geological data to study in detail the tectonic setup in the Deccan Traps.

Using the well‐known relationship between the shear zone, lineaments, and geomorphology, and incorporating these with tectonic events, an attempt has been made to explore the geology and structures in and around the Dalvat region. Field observations and signatures on remote sensing data show that there is evidence of fault traces in the form of shear zones and slickensides in the Deccan Traps near the Kosurde, Dhanoli, Chikhli, and Manchandar villages of the Nasik District. The study has further been incorporated with seismic density data. Magnitudes of 3.9 were recorded as the maximum micro‐epicentres, and they fell on the shear fractures detected in the area of study.

In order to identify seismically vulnerable areas, seismic hazard zonation (SHZ) mapping has been carried out. Different data layers, including structural, lithological, geomorphological, drainage, and soil have been visually interpreted, scanned, and rectified. A rose diagram of the lineaments shows trends in the NNE–SSW to NS falling on major seismic zones of the study area, showing weaker zones beneath the surface. Raster images were digitized for conversion to a vector coverage using ERDAS 8.6. and ArcGIS 8.3. The ordinal scale (qualitative) relative weighting rating technique was used to give a seismic hazard index (SHI) value to delineate various seismic hazard zones; namely very low, low, moderate, high, and very high.     

Remote sensing and GIS for detecting changes in the aquatic vegetation of a rehabilitated lake

Remote sensing and geographical information system (GIS) methods combined with ground estimations were used to assess the effects of rehabilitation on the aquatic vegetation of a shallow, eutrophic lake in Finland. Aerial photograph interpretation was used to study the distribution of aquatic vegetation before (1953, 1996) and after (2001) rehabilitation in 1997. A digital elevation model was derived to relate the change in the aquatic vegetation to water depth. In addition, changes in the biomass of the most abundant species of the lake, Common Club-rush (Schoenoplectus lacustris), were studied by means of a regression analysis relating the ground estimations to the reflectance values (R ²=0.889, p@lt;0.001). The results indicated that the objective of the rehabilitation--to stop the overgrowth process--has at least temporarily been achieved. After rehabilitation the most noticeable change had taken place in the area covered by floating-leaved vegetation. Greater proportional changes in the aquatic vegetation areas had occurred in the deep rather than in the shallow areas. A decrease in biomass of Common Club-rush was estimated to be 30% due to rehabilitation. The use of remote sensing and GIS provided valuable information on temporal and spatial changes in the aquatic vegetation, and the methods could be applied more extensively for lake monitoring purposes.     

Neotectonic analysis of Mendha river basin,Rajasthan, India

Abstract

The study presented here examined the tectonically active Mendha River basin, Rajasthan, India. Landsat TM data in bands 2, 3 and 4 were used in this study. The neotectonic features were extracted through the digital analysis of the principal component (PC) and directional filtered images. However, the regional view of the study area was examined through the false colour composite (FCC). A map of the neotectonic features was generated by incorporating the limited field observations and this yielded the extensions of the neotectonic features.     

Delineation of groundwater recharge sites using integrated remote sensing and GIS in Jammu district,India

With the increasing demands for water due to increasing population, urbanization and agricultural expansion, groundwater resources are gaining much attention, particularly in the Kandi region of Jammu district, which faces acute shortages of drinking water throughout the year. Groundwater development programmes need a large volume of data from various sources. This study used integrated remote sensing and geographic information system (GIS) techniques to provide an appropriate platform for convergent analysis of multidisciplinary data and decision making for artificial recharge to groundwater. Thematic maps were constructed using merged Linear Imaging Self Scanner (LISS)‐III and Panchromatic (PAN) remote sensing data and aquifer parameter thematic layers were prepared from conventional field data. The thematic layers of the aquifer parameters were integrated and a map showing the potential zones for artificial recharge to groundwater was generated. By superimposing the drainage network map over this artificial recharge zone map, and also considering the terrain conditions for artificial recharge, suitable sites for replenishing groundwater in the study area were identified.     

Mapping of groundwater potential zones in the Musi basin using remote sensing data and GIS

The objective of this study is to explore the groundwater availability for agriculture in the Musi basin. Remote sensing data and geographic information system were used to locate potential zones for groundwater in the Musi basin. Various maps (i.e., base, hydrogeomorphological, geological, structural, drainage, slope, land use/land cover and groundwater prospect zones) were prepared using the remote sensing data along with the existing maps. The groundwater availability of the basin is qualitatively classified into different classes (i.e., very good, good, moderate, poor and nil) based on its hydrogeomorphological conditions. The land use/land cover map was prepared for the Kharif season using a digital classification technique with the limited ground truth for mapping irrigated areas in the Musi basin. The alluvial plain in filled valley, flood plain and deeply buried pediplain were successfully delineated and shown as the prospective zones of groundwater.     

Drought assessment and monitoring through remote sensing and GIS in western tracts of Tamil Nadu,India

Drought is an insidious hazard of nature and is considered to be the most complex but least understood of all natural hazards. Large historical datasets are required to study drought and these involve complex interrelationships between climatological and meteorological data. Rainfall is an important meteorological parameter; the amount and distribution influence the type of vegetation in a region. To analyse the changes in vegetation cover due to variation in rainfall and identify the land-use areas facing drought risk, rainfall data from 1981 to 2003 were categorized into excess, normal, deficit and drought years. The Advanced Very High Resolution Radiometer (AVHRR) sensor's composite dataset was used for analysing the temporal and interannual behaviour of surface vegetation. The various land-use classes – crop land (annual, perennial crops), scrub land, barren land, forest land, degraded pasture and grassland – were identified using satellite data for excess, normal, deficit and drought years. Normalized Difference Vegetation Indices (NDVIs) were derived from satellite data for each land-use class and the highest NDVI mean values were 0.515, 0.436 and 0.385 for the tapioca crop in excess, normal and deficit years, respectively, whereas in the drought year, the groundnut crop (0.267) showed the maximum. Grassland recorded the lowest value of NDVI in all years except for the excess year. Annual crops, such as groundnut (0.398), pulses (0.313), sorghum (0.120), tapioca (0.436) and horse gram (0.259), registered comparatively higher NDVI values than the perennial crops for the normal year. The Vegetation Condition Index (VCI) was used to estimate vegetation health and monitor drought. Among land-use classes, the maximum VCI value of 92.1% was observed in onions for the excess year, whereas groundnut witnessed the maximum values of 78.2, 64.5 and 55.2% for normal, deficit and drought years, respectively. Based on the VCI classification, all land-use classes fall into the optimal or normal vegetation category in excess and normal years, whereas in drought years most of the land-use classes fall into the drought category except for sorghum, groundnut, pulses and grasses. These crops (sorghum 39.7%, groundnut 55.2%, pulses 38.5% and grassland 38.6%) registered maximum VCI values, revealing that they were sustained under drought conditions. It is suggested that the existing crop pattern be modified in drought periods by selecting the suitable crops of sorghum, groundnut and pulses and avoiding the cultivation of onion, rice and tapioca.     

Remote sensing data analysis for mapping active faults in the northwestern part of Kangra Valley,NW Himalaya,India

Aerospace data show morphological features indicative of two prominent active faults to the northwest of the Kangra valley, the meizoseismal zone of the 1905 Kangra earthquake (M 7.8). Topographical features indicative of long‐term uplift/deformation during the Holocene and cumulative slip along these faults reflect the manifestation of normal faulting. The south‐side‐up behaviour of these two faults is in contrast to the general north‐side‐up movement along the Main Boundary Thrust (MBT). The newly identified faults suggest that the fault scarps have developed because of large‐magnitude earthquakes in the past, preceding the known 1905 Kangra earthquake. The study also demonstrates that valuable geomorphological and structural inferences associated with active tectonics are possible using high‐resolution satellite data for the tectonically complex terrain of the Himalaya.     

Monitoring snow area and depth with integration of remote sensing and GIS

Abstract

This article reports recent progress in monitoring snow area and snow depth over the U.K. using NOAA AVHRR data. A series of transportable programmes have been developed and updated for data calibration and navigation. The establishment of a database registered to the British National Grid enables the generation of subsequent thematic overlays for any selected area. Results of snow area mapping and estimation have been validated by means of high-resolution Landsal TM data and data from U.K. Meteorological Office Snow Survey Reports. Assignment of snow depth values has also been attempted. The integration of remote sensing and GIS has facilitated the work, and will be further deployed.