Channel pattern transformation of the Burhi‐Gandak river,Bihar, India: A study based on multidata sets

The Burhi‐Gandak river is one of the major tributaries of the Ganga River in the middle Ganga basin. The river is i known to have an oscillatory character and has changed its course in Recent times. In the present study, a variety of remote sensing data combined with surface and subsurface data have been used to delineate the fluvial palaeofeatures of this river. The palaeofeatures of the Burhi‐Gandak indicate that the river has shifted from N to S over a distance of 30 km. Further, its is observed that Burhi‐Gandak river had a larger channel width and higher discharge on earlier times and was very active. On detailed examination, a past link between the now northerly flowing Baghmati and Burhi‐Gandak rivers is detected. Based on the above features, three distinct stages of migration of the river have been identified and a summary of fluvial palaeohistory is presented.     

The role of multispectral imagery in elucidation of recent channel pattern changes in middle ganga plain

The mapability of Landsat images has opened up a new potentiality for study of channel pattern changes which was earlier not so easy due to nonavailability of suitable evidences at different timespans. Middle Ganga plain covering largely the northern part of Bihar and parts of eastern Uttar Pradesh is in a slate of perpetual flux due to large scale channel migration and avulsion resulting in devastating floods. Mosaic of three Landsat images has helped to study the channel changes which have occurred since 1935. The course of the river Ganga has beeh digitised along a basal line and two dimensional coordinates are taken at as many as more than fifty sample points for studying the magnitude and direction of channel changes during 1935–1975 period. The analysis shows that the main multiple channel river Ganga is under the huge hydrostatic thrust to be shifted towards south of its basin annually at a very high rate of 100 Meter per year all along the course except at its upstream near Ghazipur and at Monghyr where the shifting is towards north. The northward bend at Monghyr may be due to the presence of the Precambrian outliers here. For the multi-and single channelld tributaries of Ganga in channel behaviour is mainly in three directions—the lower water channels in the floodplain of Ganga are shifting to the south in conformity with that of their parent stream, the tributaries in Gogra-Gandak doab are shifting towards east but the shifting of the Kosi-Mahananda group of tributaries in the eastern part of the basin is towards west These channel pattern changes thus known at the interregional scale from the Landsat images may further be integrated with the study in hydrogeomorphology and their pertinent environmental impact.     

Spatio-temporal shift of western bank of the Ganga river,Allahabad city and its implications

Ganga is one of the largest rivers of the world which supports millions of population on its banks. It is a tectonically controlled Himalayan river which also creates havoc due to perennial floods every year. Like most large river systems, it also shifts its course in the Gangetic plains in space and time. The present study measures the variable shift in a selected flood-prone stretch of the Allahabad city lying on the western bank of the Ganga river, taking into account the historical, annual to monthly data (including pre- and post-monsoon shifts) to show the ongoing changes in the river course with possible causes and futher implications. It also discusses for the first time the down stream effect of the Tehri dam on the Ganga river course after it became functional.     

Hydromorphology of a part of Azamgarh and Ghazipur districts,Uttar Pradesh

Hydrogeological studies in the Quaternary alluvial plain of a part of Azamgarh and Ghazipur districts, using air photos on scale 1:60,000 indicate the presence of five hydromorphic units namely, Alluvial upland, older alluvial plain of Mangat-Besu, older flood plain of Ganga—Gomti, youngest terrace of Ganga—Gomti and present flood plain of Ganga-Gomti. From the groundwater point of view older flood plain of Ganga—Gomti is the most promising hydromorphic unit. Abandoned channel of river Ganga offers favourable site for deep groundwater exploration with high potentiality. Chemical quality of shallow and deep aquifers is suitable for irrigation and other purposes.     

Migration behaviour of river ganga between Allahabad and Buxar using remotely sensed data

Channel migration includes any change of river channel geometry within the context of the cross-section, pattern or network in a drainage basin. To study the dynamic behaviour of a river, measurements taken with conventional ground-based instruments are time-consuming and expensive. Remote sensing techniques are capable of providing a measure of surface variability including dynamic behaviour of channels, reasonably quickly due to availability of the repetitive remotely-sensed data. These data are well suited for the assessment and monitoring of dynamic changes on the surface of the earth. In the present study Landsat MSS and TM data of winter season in the form of false colour composites (FCC) of years 1982 and 1987 were used for the delineation of river Ganga course lying between Allahabad and Buxar. The interpretation of satellite data was carried out using visual interpretation technique for the assessment of channel migration. The shift in river banks delineated from satellite data were measured with respect to river banks identified from topographical base map. The maximum shift observed in mid channel is 4. 55 km while maximum left and right banks shifts are 4.6 and 4.8 km, respectively.     

SOME SURVEYS OF RIVERS IN CEYLON

Abstract

The city of Colombo, capital of Ceylon, is situated at the mouth of the Kelani Ganga and about 25 miles north of another considerable river, the Kalu Ganga, which enters the sea at Kalutara. Though its proximity to two of the largest of the perennial rivers of Ceylon provides some advantages of inland water transport by river craft, it also places it in the zone of periodical floods which cause damage to buildings, communications and agriculture within the city limits and over extensive areas of low-lying paddy fields and gardens beyond. Except for a spur of high land running roughly parallel to the eastern shore of the harbour through Hultsdorp, Blomendahl and Kotahena to the loop of the Kelani Ganga near its mouth, the greater part of the city is very flat and only a matter of 20 feet elevation above sea-level. On its eastern flank lies a series of connected shallow lakes, marshes and paddy fields which extend in a loop from the banks of the Kelani Ganga at Ambatalenpahala to Dehiwela on the city's southern limit; there are, in addition, canals through this area with two outlets into the sea at Wellawatta and Dehiwela. Navigable canals connect the Kelani Ganga with the Beira Lake and Colombo Harbour and, with the canals already mentioned, form a continuous waterway which, in fact, extends northwards as far as Puttalam, 80 miles from Colombo, and southwards to the Kalu Ganga and Kalutara. About half a mile east of Mount Lavinia another series of shallow lakes, marshes and paddy fields spreads its irregular shape roughly parallel to the coast through the Bolgoda Lakes to a low ridge north of the Kalu Ganga and close to its right bank. The whole of these lowlands is referred to as the Bolgoda Basin. A canal called the Kepu Ela, constructed by the Dutch during their occupation of Ceylon, passes through it to join the Kalu Ganga at Diyagama about 5 miles from the river mouth.     

Application of DEM,Remote Sensing and Geomorphic Studies in Identifying a Recent [or perhaps Neogene?] Upwarp in the Dibru River Basin,Assam, India

The Dibru river basin of Assam is investigated to examine the influence of active structure by applying an integrated study on geomorphology, morphotectonics, subsurface structure, Digital Elevation Model (DEM) using topographic map, IRS 1D LISS III, IRS P6 LISS III, SRTM, seismic and subsurface data. Seismic data reveals existence of an upwarp and an important fault in the basement around the central and eastern parts of the Dibru basin, respectively. The influence of these structures is well observed on all the younger formations inferring their active nature possibly till the Recent Period. Existence of fluvial anomalies, viz. annular drainage pattern, lineaments, abrupt changes in the direction of river course, beheaded stream and valley incision infer role of structural control on the fluvial features of this basin. Most commonly used indices for morphotectonic analysis, viz. basin elongation ratio (Re), transverse topographic symmetry (T), asymmetric factor (AF), valley floor width to valley height ratio (Vf) have been used to identify the evidences of active structures in the area. The values of Re indicated tectonically active, T indicated an asymmetric nature, AF indicated tilting and Vf indicated active incision in the Dibru basin. The DEM, profiles across the valley and superimposed longitudinal profiles of incised channel bed and valley shoulder of the Dibru clearly reveal valley incision by the river. Three large paleochannels located in different parts of the basin had their headwaters towards east at the common source, i.e. the Diyun river. These paleochannels had been resulted when their headwaters avulsed to create new rivers due to affect of the subsurface structures during Recent (or perhaps Neogene?) Period.     

Geomorphological units,their geohydrological characteristic and vertical electrical sounding response near Munger,Bihar

Geomorphological mapping through satellite remote sensing coupled with geophysical electrical resistivity survey (vertical electrical sounding) gives very useful information about spatial and depth-wise variation of aquifer’s material, respectively. The present study area broadly falls between the Ganga river and Kharagpur hills (a northern limit of Chotanagpur plateau). These hills are highly folded and consist of quartzites and phyllites of Precambrian age group In the study area, cover material above the basement is the product of weathering, colluvial and fluvial processes of different ages. Geomorphologically, study area has been categorised into different classes i.e. denudo-structural hill, buried pediment, younger alluvial plain, recent flood plain and older alluvial plain. Broadly these classes represent the general ground-water prospects, but in detail, possibility of variation in ground-water prospects cannot be ruled out. In alluvial plain (younger/older) main target for ground-water exploration is sandy horizon. Similarly in buried pediment the main target is coarse-grained weathered material with fractured basement, not the total general thickness of cover material on the basement. In the present paper, authors have tried to analyse the spatial distribution of geomorphic classes and depth-wise variation of aquifer material within the same class for determining the target horizon for further detailed investigation, using remote sensing and electrical sounding.     

Changing Pattern of Channel Morphology of Alaknanda River in Srinagar Valley (Garhwal Himalaya), India

The Alaknanda River is the most significant parental river of Ganga and forms an 11.5 km long and 2.5 km wide valley, locally known as the Srinagar Valley. The purpose of the present study is to highlight the recent landform changes in the Alaknanda channel course after the Kedarnath disaster, 2013. The Kedarnath flood completely changed the channel morphology of the Alaknanda river. The river changed its course at Srikot, SSB and Sriyantra Tapu with lower terraces being silted by sands at Ranihat, SSB, Bhaktiyana and Sriyantra Tapu. A new depositional terrace also formed opposite to Sriyantra Tapu. New lateral channel bars, braided channels, back swamp, rapids, pools and river souls were identified in the channel course of the river. Shifting of the channel course at Chauras still remains a serious problem for the Garhwal University Chauras Campus. About 2–5 m silt was deposited on the lower terrace at SSB, and ITI. The Srikot river bed was appended to 4.60 m. Shifting of channel course remains a serious threat to the Srinagar valley. Urbanization, sand and boulders mining, construction of dam, hydrological canal, road and settlements are the prominent example of anthropogenic activities which affect the shifting channel.     

Visual interpretation of F.C.C. satellite data for channel migration and water logging conditions along Ghaghra and Terhi rivers in part of district Gonda and Bahraich,U.P.

The conventional visual interpretation of landsat Imagery is potentially the most useful remote sensing tool for the study of channel migration & water logging conditions at different time spans; which were earlier not easy due to non availability of suitable evidences. The present study brings out, in exact terms & the extent of the utility of the false colour and black and white landsat data. The application of the false colour scanning method is also useful remote sensing tool for the study of direct & indirect hydrogeological regime by visual interpretation technique. The spectrum are favourable for detection of surface phenomenon, which is associated with the subsurface ground water environment. An area of about 3,500 Sq.Km. of U.P. along left bank of Ghaghra river and right bank of Terhi rivers have been taken for the study. The paper was designed to evaluate the fluvial action and ground water environments with the help of repetitive landsat data in ten years. The fluvial action of Ghaghra and Terhi rivers have been mainly contributing to the development of hydrogeomorphological units which have given exact references regarding fluctuation in hydrogeomorphological units and water logging with hydrological response of the ground water environment, by using landsat data of 1975 & 1984. Further the direct relationship between remote sensing measurement and physical properties of hydrogeological environments is brought out in the maps.     

Geomorphological study of Bulandshahr District (U.P.) using remotely sensed data

Remote sensing data pertaining to LANDSAT TM FCC of bands 2, 3 and 4 of 9th May 1991 and IRS-1A LISS II digital data of 3rd May 1991, have been utilized for the study of geomorphology of Bulandshahr district, U.P. Visual interpretation technique has been followed for geomorphological mapping and the area has been separated into four broadly defined geomorphic zones, namely Varahasi Older Alluvial Plain, Aligarh Older Alluvial Plain, Terrace Zone and Recent Flood Plains of Ganga and Yamuna, each characterized by its own geomorphic/landform elements discernable on remote sensing data. The Varanasi Older Alluvial Plain represents the oldest geomorphic surface occurring at highest tectonic level in the Gangetic plain. The Aligarh Older Alluvial Plain represents a palaeo-flood plain of a north flowing palaeo-drainage in the area. The Terrace zone represents the older flood plain of Ganga and its tributaries. The Recent Flood Plains of Ganga and Yamuna rivers, which get periodically inundated, constitute the youngest geomorphic surface in the study area. Digital image processing outputs, particularly ratio images have been found to be helpful in identifying certain geomorphic landforms (old/abandoned channels, scars etc.) due to greater contrast within ratio images.     

AN EXPERIMENT IN MULTISPECTRAL AIR PHOTOGRAPHY FOR ARCHAEOLOGICAL RESEARCH

The recognition of subsurface soil disturbances that have no surviving surface displacement often depends on an anomalous growth of the crop that overlies them. These disturbances are sometimes evidences of man's past activities. The very slight differentials of colour and height in growing crops are frequently difficult to record through a normal film and filter combination. In order to test the capacity of the multispectral technique, a four camera sensor was flown over archaeological sites in central southern England in the summer of 1970. Known sites were used in various geological settings, producing growth marks of differing characteristics. The sensor included the near infrared and this showed distinct advantages at the early stages of cereal growth.     

Impact of Climate Change on Runoff of the Major River Basins of India Using Global Circulation Model (HadCM3) Projected Data

The effects of climate change on hydrological regimes have become a priority area for water and catchment management strategies. The terrestrial hydrology driven by monsoon rainfall plays a crucial role in shaping the agriculture, surface and ground water scenario in India. Thus, it is imperative to assess the impact of the changing climatic scenario projected under various climate change scenario towards the hydrological aspects for India. Runoff is one of the key parameters used as an indicator of hydrological process. A study was taken up to analyse the climate change impact on the runoff of river basins of India. The global circulation model output of Hadley centre (HADCM3) projected climate change data was used. Scenario for 2080 (A2 scenario indicating more industrial growth) was selected. The runoff was modeled using the curve number method in spatial domain using satellite derived current landuse/cover map. The derived runoff was compared with the runoff using normal climatic data (1951–1980). The results showed that there is a decline in the future climatic runoff in most of the river basins of India compared to normal climatic runoff. However, significant reduction was observed for the river basins in the eastern region viz: lower part of Ganga, Bahamani-Baitrani, Subarnrekha and upper parts of the Mahanadi. The mean projected runoff reduction during monsoon season (June–September) were 18 Billion Cubic Meter (BCM), 3.2 BCM, 3.5 BCM and 5.9 BCM for Brahmaputra-Barak Subarnrekha, Subarnarekha and Brahmini-Baitrani basin, respectively in comparison to normal climatic runoff. Overall reduction in seasonal runoff was high for Subarnrekha basin (54.1%). Rainfall to runoff conversion was high for Brahmaputra-Barak basin (72%), whereas coefficient of variation for runoff was more for Mahanadi basin (1.88) considering the monsoon season. Study indicates that eastern India agriculture may be affected due to shortage of surface water availability.     

Synergistic Application of Optical and Radar Data for Archaeological Exploration in the Talakadu Region,Karnataka

Talakadu is a well known historic place situated on bank of the river Cauvery in Mysore district of Karnataka. The place is close to concave side of a prominent meander where large amount of sand has accumulated. It is believed that after construction of a reservoir upstream, sand was exposed to wind action burying the structures of Ganga dynasty and other later kingdoms. A number of buried sites have been identified by archaeological excavations conducted so far. Presently the area forms sand dunes with thick plantation cover. Analysis of RADAR data (fine beam RADARSAT and ENVISAT ASAR) led to identifying a hitherto unknown buried channel through the Old Talakadu town adjoining the excavated archaeological sites. The study suggests that RADAR penetration through the plantation canopy seems to have occurred as observed by comparing with corresponding optical data of LISS-IV. Below the canopy, sand and shrubs on top of the channel (topographically low area) are acting as smooth surface providing dark tone on radar imagery. During field validation GPS was extensively used to navigate through the forest canopy and locate the buried channel, excavated archaeological sites as well as other anomalous patterns. Synergistic application of optical (RESOURCESAT-1 LISS-IV and CARTOSAT-1 & 2) and radar (fine beam RADARSAT and ENVISAT ASAR) data led to identifying remote sensing based guides for archaeological exploration. Integration of known archaeological sites with the identified anomalous patterns was done in GIS environment. This study adds on to the knowledge base of the site and compliments already known information and suggested new areas for further archaeological exploration.     

Polarization of reflected light as a function in remote sensing of sea state

Polarizaton characteristics of completely diffuse light reflected from a wind roughened sea surface and its total reflectance are studied for various wind speeds on the assumption that distribution of wave slopes around their mean is Gaussian. The angular distribution of diffuse reflectance and polarization status of reflected light are also estimated with a view to exploring possibilities of using these parameters for remote sensing of sea state from a satellite, aircraft or an observation tower. The efficiency of Brewster’s angle technique in eliminating reflected light from the sea surface radiance for remote sensing of subsurface material is examined for non flat sea surface in the light of these results. the results show that the diffuse light reflected from the sea surface contains information on the sea state in the form of its status of polarization and can be used as an observational tool in remote sensing of sea state. The scope and limitations of the method proposed are discussed.     

On the origin of Renuka Lake

Aerial photo-interpretation supported by field study of the Renuka Lake area in Himachal Pradesh brings to light some evidences on the origin of the Lake. Contrary to the belief that it is of glacial origin, evidences support the view that this lake basin is a part of a former river valley. The evaluation of morphological features leading to the above conclusion is discussed.     

Using NHDPlus as the Land Base for the Noah-distributed Model

The National Elevation, Hydrography and Land Cover datasets of the United States have been synthesized into a geospatial dataset called NHDPlus which is referenced to a spheroidal Earth, provides geospatial data layers for topography on 30 m rasters, and has vector coverages for catchments and river reaches. In this article, we examine the integration of NHDPlus with the Noah-distributed model. In order to retain compatibility with atmospheric models, Noah-distributed utilizes surface domain fields referenced to a spherical rather than spheroidal Earth in its computation of vertical land surface/atmosphere water and energy budgets (at coarse resolution) as well as horizontal cell-to-cell water routing across the land surface and through the shallow subsurface (at fine resolution). Two data-centric issues affecting the linkage between Noah-distributed and NHDPlus are examined: (1) the shape of the Earth; and (2) the linking of gridded landscape with a vector representation of the stream and river network. At mid-latitudes the errors due to projections between spherical and spheroidal representations of the Earth are significant. A catchment-based "pour point" technique is developed to link the raster and vector data to provide lateral inflow from the landscape to a one-dimensional river model. We conclude that, when Noah-distributed is run uncoupled to an atmospheric model, it is advantageous to implement Noah-distributed at the native spatial scale of the digital elevation data and the spheroidal Earth of the NHDPlus dataset rather than transforming the NHDPlus dataset to fit the coarser resolution and spherical Earth shape of the Noah-distributed model.     

Planform analysis of Hooghly river metamorphosis using multidate satellite data

Conventional techniques of monitoring both long-term and short-term changes in river morphology is time consuming and expensive. Remote sensing with its synoptic and temporal capability is an effective tool to study river metamorphosis. The present study is carried out in lower Ganga basin where Hooghly river is an important river contributing sediment to this vast fertile plain. A time series planform analysis is carried out between 1971 to 1991 period. Thematic maps generated from Landsat MSS and IRS-IA LLSS-I satellite data for 1986 and 1991 period respectively is compared with 1971 topographic maps. The migratory character of paleocourse of Hooghly river is deciphered through the paleochannels, oxbow takes and meander scars deciphered from satellite imagery. The shortterm river metamorphosis like cut-offs, bar migration and point bar accretion morphology are mapped and compared with 1971 topographic maps. The critical zone with respect to cut-offs and future channel migration are identified for river stabilization work.     

The solani-ganga interfluve; an application of remote sensing technique on soil resource mapping for agricultural planning

The area of the Solani-Ganga interfluve, which lies between 29°16′N to 30°15′N latitude and 77°45′E to 78°15′E longitude was undertaken for the present study using LANDSAT imagery of band 5 and 7 and the false colour composite on the scale of 1:250,000 in combination with aerial photographs (1:25,000). Major geomorphic units, e.g., Siwalik Hills. Solani-upper alluvial plain, Solani lower alluvial plain, ‘Tarai’ and Ganga alluvial plain were delineated on LANDSAT and colour composite. Sample areas selected from LANDSAT were studied on aerial photographs in details and soil physiography relationship was developed. The soils on Siwalik hills are classified as Orthents. The soils of the pledmont plain and the recent terraces of Solani river and its tributaries were Psamments, Orthents, Fluvents, Orchrepts and Aquepts. The soils of upper alluvial tract of the Ganga plain is mostly Ustalfs with inclusion of Aqualfs, while the strong hydromorphic Tarai tract consists of partly Aquepts, Ochrepts (cultivated) and partly of Aquolls, Ustolls and Ustalfs (under forest). The present study aims to pin point the nature of soil relief relationship with the help of LANDSAT imagery and aerial photographs and diagnose the intensity of the depletion of soil resources (by prevailing factors like swift run off of biykderfed torrents, fast-flow of ground water, soil creep, mass wasting) through field studies and then treat them with ecological dose of soil conservation. For agronomic development of the region, it is worked out that the present crop-combination and crop-rotation systems should be slightly modified according to its ecosystem to prevent the depletion of soil nutrients.     

等高线与水网数据集成中的匹配及一致性改正

等高线作为地势起伏与地形凹凸特征的表达,与水网表达有着密切的约束关系。在空间数据库集成与匹配中,由于来源不同,这两种数据往往出现不一致,导致水网"爬坡"现象。针对该问题提出一种等高线与水网匹配及一致性改正方法,利用Delaunay三角网模型在等高线基础上通过弯曲分析提取地形特征,基于河流分布与谷地走势的相关性,建立水网与等高线间的匹配关系,进而识别两者间的一致性。在此基础上利用仿射变换等几何方法完成一致化操作,包括水网移位匹配等高线和等高线移位匹配水网。