Spatial Technologies in Deriving the Morphotectonic Characteristics of Tectonically Active Western Tripura Region,Northeast India

Employing integrated remote sensing and GIS technology the western most part of Tripura region (Northeast India) and adjoining Bangladesh region has been investigated in the light of its geomorphological characteristics. Nature of fold ridges, several streams and the respective drainage basins are well depicted in satellite images and digital elevation model providing meaningful information. Quantitative parameters such as stream sinuosity, drainage basin asymmetry, basin elongation ratio have been computed. Main rivers of the study area, namely the Gomti and Khowai follows extremely meandering path and crosses through the transversely faulted anticlinal ridges. Fluvial anomalies viz. shift in stream channel and the abandoned meandering loops have been inferred and mapped. The Haora river in the study area exhibits northward shift in some part. Development of drainage system towards north and south from the drainage divide along the latitude 23°45^′N indicated up arching of the region which is also corroborated by the extracted topographic profiles. It has been observed that several tributary streams have gone dry and agricultural fields are developed along the dried up stream. These derived parameters remained useful to understand the nature of topographical modification attributed to the possible tectonic activity.     

The shift of ravi river and the geomorphological features along its course in amritsar and gurdaspur districts of punjab

Satellite remote sensing technique can be effectively utilised in mapping and monitoring the river course changes and associated geomorphological features. Ravi river, flowing along the Indo-Pakistan border, has been in the limelight for its repeated flood havoc during monsoon and abrupt encroachment at some places in the Indian territory, where it was not flowing earlier. This river, meandering in zig-zag fashion along the International boundary in Amritsar and Gurdaspur districts of Punjab, poses perennial threats to the nations’s economy due to extensive destruction happening every year. An attempt has been made to map the shift of this river and the associated geomorphological features along its course using the Indian Remote Sensing Satellite data (IRS-IA and IB LISS-IIFCC) of the period 1991–1993 and the Survey of India topographic sheets of the period 1972–1973. The study shows that there has been drastic changes in the course of Ravi during a span of 20 years due to human activities along its course. The river has shifted its course considerably towards India since its topography is against it. River training structures/bundhs, built by the neighbouring country, across and very near to the earlier river course has been the main reason for this drastic shifting. It is estimated that such massive structures could turn the river course towards India by atleast 1 to 5 km in the border districts of Punjab. This shifting of Ravi along international border poses a serious threat to the Nation’s defence system.     

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.     

Erosion study of a part of Majuli River-Island using remote sensing data

Majuli, the world’s largest river island, is situated in mid of river Brahmaputra in Assam. River Brahmaputra flows in highly braided channels most of them are transient in nature, being submerged during high monsoon flows and changing drastically their geometry and location. Majuli island, home of about 1.3 million people is endangered because of the erratic behavior of the river. In this study, an attempt has been made to observe the trends of erosion in a small part of Majuli island, the area near Kaniajan village in south Majuli- a stretch of about 11 km, using satellite data of 1991, 1997 and 1998. Image processing of digital data has been done in ILWIS software. Supervised for delineation of river from land and then change detection analysis has been done to find out changes in river course from 1991 to 1997 and further from 1997 to 1998. Erosion and deposition maps of the area have been prepared and the erosion of island is measured at various sections at 1 km interval. Erosion of 1900 ha has been observed during the period of six years from 1991 to 1997 and 845 ha during the period of one year from 1997 to 1998.     

Meandering valley of Karjan-Terav rivers in district broach,Gujarat

Karjan river is an important tributary of Narmada in Gujarat. Along with one of its own tributaries, called Terav it has carved a “meandering valley” across the block faulted rldge and valley Deccan Trap topography, south of Narmada. Karjan originates at Bardipada, which is much nearer to Tapti river than Narmada and in the initial stretches its channel is consequent to faults and fractures. However, before emerging on to the alluvial plain in north it has a sinuous valley. With confines of this valley the present stream channel wanders back and forth and has incised deep into various Deccan Trap flows. The geometry of such meanders shows that this is an symmetric meandering valley. The valley as such is an antecedent one in which the present stream channel is ur.derfit and ingrown. Natural fluvial processes, accelerated by dynamic rejuvenation of the area and wetter climatic phases during Pleistocene and Holocene seem to have carved this meandering valley and integrated the drainage.     

Physical Habitat Assessment of River Denwa Using GIS Techniques

Physical habitat of any aquatic ecosystem is an integral part upon which the biological structures of resident communities are built. Degradation of the physical habitat has serious consequences on aquatic communities and is among the leading causes of stream impairment worldwide. Therefore, a sound habitat assessment approach is necessary to assess the condition of running water and to determine if habitat degradation is responsible for any degradation in biological condition. The present study was focused on Physical Habitat Assessment of Denwa River, a sub tributary of river Narmada in central India, for generating a Habitat Suitability map. The Denwa River originates from Satpura ranges in central India and flows through entire Pachmarhi plateau supporting a diversity of habitats for aquatic flora and fauna. A survey was carried out to assess the physical characteristic of Denwa river (84 kms) from its origin to the confluence point of Tawa Denwa river. Six reaches have been identified in study area on the basis of their physiographic conditions. For Habitat Assessment measurement, Rapid Bioassessment Protocols for Stream and Wadeable rivers by United States Environmental Protection Agency (USEPA, 841-B-99-002) have been used. Seven parameters from this protocol have been chosen for physical characterization. GIS techniques have been used to develop a Habitat Suitability Map of the study area based on scores to illustrate its suitability to support aquatic life. The present paper discusses in detail the suitability of the different reaches of the River Denwa for supporting the aquatic biodiversity.     

从遥感信息看连云港西海堤工程的隐患

位于黄海西海岸中部的连云港是重要的万吨级商港。港池外有连岛作为海上屏障。为了扩大 吞吐能力, 拟建造连按陆地与连云岛西端长达6700m的西海堤, 以期防淤防浪。 多时相遥感图像动态分析显示, 连云港东侧河口外航道不断西移, 河口异重流也向西飘移, 表明该区存在着自东向西的沿岸流。美国陆地卫星MSS图像上沿岸流自废黄河口一带流向连云港 地区的特征也很清晰, 并对侵蚀岸产生的大量泥沙携在连云港一带的特征也有明显显示。 连云港地区原来存在绕连岛右旋的流场。西海堤未建前, 泥沙尚可顺利通过港池。西海堤的 建成, 则破坏了现有流场, 阻断泥沙流, 将导致大量泥沙在港池内消能落淤, 对港口造成危害。     

New findings on the course of river sarasvati

Numerous studies have been carried out during last 20-25 years by different agencies to trace the courses of palaeo river Sarasvati. Varying number of courses of river Sarasvati have been suggested by the different workers in the north-western region. Taking advantage of the developments in satellite/ sensor and digital image processing technologies an attempt has been made to rediscover the course of river Sarasvati and solve the controversy regarding its exact course, in the sand covered Thar desert region. Data available from a variety of ground investigations carried out by different agencies working in this area have been analyzed in support of confirmation of palaeo channels, along the courses mapped under the present study. The results indicate that the river Sarasvati had its course through river Ghaggar and did not drain along the Aravalli hills. Also it did not shift its course drastically and continuously from east to west, as suggested by earlier workers. The image anomalies indicate that river Sarasvati flowed parallel to the river Indus as an independent river system (closer to the north-western Indian border) and did not flow through present course of river Nara. The findings raise the doubt that ‘Rise along Delhi-Hardwar ridge’ as suggested by earlier workers was the main cause for west-ward shift of Sarasvati river and ultimate drainage desiccation in the northwestern region. The analysis indicates towards rise in Himalayas/ Siwaliks and consequent displacements in the Siwaliks and its foot hills region (in the form of Yamuna and Satlej tear faults) as the main cause for drainage desiccation and disappearance of river Sarasvati.     

Snow cover area variability assessment in the upper part of the Satluj river basin in India

In high-altitude areas, snow cover plays a significant role in mountainous hydrology. Satluj, which is a snow-fed river, is a part of the Indus River system in the western Himalayas. Snow cover area (SCA) variability in this river basin affects the spatio-temporal flow availability and avalanche events. Keeping this in mind, the present study focuses on SCA variability and its relationship with various topographical features such as elevation, slope and aspect. The study has been carried out in the upper part of the Satluj River Basin on the basis of MODIS Terra (MOD10A2) data from 2001 to 2014. It has been noticed that the average annual SCA in this part of the Satluj River Basin varies from 44 to 56% with an average of about 48% of the total basin area of 16, 650 km². Further, snow accumulation and depletion curves have been suggested for assessing the SCA in the study area.     

Assessment of floodplain landuse and channel morphology within meandering reach of the Talar River in Iran using GIS and aerial photographs

Abstract

The main objective of this study is to investigate and monitor the landuse and morphological changes in the floodplain part of the Talar River, northern parts of Iran. In the present study, the aerial photographs have been used to produce landuse maps of the floodplain for three periods including 1968, 1994, and 2013. The quantitative analysis of the produced landuse maps showed that the floodplain has undergone substantial landuse changes. Moreover, the sediment bar and the beach area have been decreased about 97 and 90%, respectively, during the 45-year period. Substantial increases of 192 and 622% have been observed for orchards and residential areas, respectively. On the other hand, not only the forest and riparian vegetation were decreased but also the average width of river was decreased about 25.5 m. In addition, flow length of the study reach increased about 8 m. The RNCI was about ?0.7 m per year indicating sedimentation process. During the period of 1968–2013, Caspian Sea has retreated about 150 m and the delta of Talar River was changed. This study showed that morphological actions during first 26 years (1968–1994) were the stable and last 19 years had the change period, especially sedimentation (bar).     

黄河银川平原段河道演变的遥感监测与研究

 在遥感调查和监测的基础上，结合第四纪地质资料，对黄河银川平原段的河道演变过程进行了系统研究，对主要的河流改道原因进行了分析。研究表明： 黄河银川平原段在早更新世初期形成，此后，自西向东不断迁移； 在中晚更新世发展壮大，到全新世形成了银川平原的主体，并留下了明显的古河道遗迹； 到了现代，河道逐步变窄，向东迁移的趋势未变且速度依然很快。     

A Geospatial Approach to Understand the Dynamics of Shifting Cultivation in Champhai District of Mizoram,North-East India

The dynamics of crop-fallow rotation cycles of shifting cultivation has been poorly understood in northeastern part of the country although it is one of the major land use systems in the hilly states of this region. The present study was conducted to understand the dynamics of shifting cultivation through the use of Landsat time-series data from 1999 to 2016 in Champhai district of Mizoram. We mapped the current jhum fields and abandoned areas of each imagery of the study period and performed a post classification comparison to assess the crop-fallow rotation cycle/jhum cycle. The chrono-sequential change of slash and burn area over the past 17 years showed a decreasing trend with the greater part of the shifting cultivation area being occupied by 2nd year crop fields, covering 48.81% of total jhum land. On average, 114.46 km² area were annually slashed for current jhum, out of which 33.41% continued with current jhum 2nd year cropping and only 3.27% of jhumias continued with 3rd year cropping. The shifting cultivation patches were mostly confined to moderately steep slopes (15°–30°). East facing aspect was mostly preferred and North facing aspect was least preferred. During the study period, 10 years jhum cycle covered the maximum area followed by 9 years and 11 years jhum cycle. The end result of this study proved that the prevalent jhum cycle in Champhai district is 8–11 years with a fallow period of 6–9 years.     

四川三星堆遗址多源遥感研究

运用遥感考古技术，通过对卫星和航空遥感图像的处理、解译及相互映证，对三星堆的古河道、古城池进行了全面调查，发现了马牧河由南往北的多期古河道及一些未曾被发现的古城遗址，得出三星堆古城池分为内外二层的结论。     

Change of river channel and bank erosion of the burhi dihing river (assam), assessed using remote sensing data and gis

The Burhi Dining river flows in a meandering course for about 220 km through alluvial plains of Assam including a short rocky and hilly tract in between. Sequential changes in the position of banklines of the river due to consistent bank erosion have been studied from Survey of India topographic maps of 1934 and 1972, and digital satellite data of 2001 and 2004 using GIS. Two broad kinds of changes have been observed, e.g. alteration of direction of flow due to neck cut-off and progressive gradual change of the meander bends that accounts for translational, lateral, rotational, extensional and other types of movement of the meander bends. Study of bankline shift due to the bank erosion has been carried out for the periods 1934–1972, 1972–2001, 2001–2004 and 1934–2004 at 13 segments spaced at 5′ longitude interval (average 15 km) as the river course trends nearly east to west. The amounts of the bank area lost due to erosion and gained due to sediment deposition are estimated separately. The total area eroded in both banks during 1934–1972 was more (26.796 km²) as compared to sediment deposition (19.273 km²), whereas total sediment deposition was more (34.61 km²) during 1972-2001 as compared to erosion (23.152 km²). Erosion was again more in 2001–2004 (7.568 km²) as compared to sediment deposition (2.493 km²). During the entire period (1934–2004) of study the overall erosion on the both banks was 31.169 km² and overall sediment deposition was 30.101 km². The highest annual rates of bank erosion as well as bank building of the river are 21055.47 m²/km in 2001–2004 and 9665.81 m²/km in 1972-2001, respectively. Similarly the highest average annual rates of erosion as well as sediment deposition in both banks are observed during 2001–2004 and 1972–2001, respectively. The hard rocks of the hilly tract situated in between result in development of entrenched meandering and this tract has suffered minimum bank erosion.     

A geological cum geomorphological framework of haryana and adjoining areas for landuse appraisal using landsat imagery

The state of Haryana and the adjoining areas are covered to a large extent by Quaternary sediments of alluvial/aeolian origin. An attempt has been made to study this area and classify the various geomorphic zones and a geological-cum geomorphological map of the area has been prepared based on MSS Landsat Imagery on 1:1 million. The geological set-up of the area comprises the sub-Himalayan system of rocks, mostly belonging to Siwalik Group which are exposed in the northeastern extremity and adjoining parts. In the south and southwestern corner of Haryana bordering the state of Rajastan, older rocks belonging to Delhi Supergroup are exposed. In between lies the vast stretch of Quaternary sediments of aliuvial/aeolian origin. The different geomorphic units recognised include 1) High structural hills, 2) Moderate structural cum denudational hills, 3) Low structural-cum-denudational hills, 4) Older and younger piedmont zones, 5) Flood plain, 6) Older Alluvial surface, 7)Aeolian zone, 8) Transitional zone & 9) Upland tract. Except the river Yamuna flowing along the eastern boundary of the State, the only other stream is the Ghagghar. A well-defined palaeo-channel of the Ghagghar is clearly picked up on the imagery. This river appears to be structure controlled and flows along well-defined tectonic lines. The southerly to southeasterly direction of flow of the river Yamuna indicates a basement high. The topographical low passing through Delhi-Rohtak-Hissar and Sirsa appears to coincide with basement high and the gradual shift in the drainage system indicates some neotectonic activity in the region. The most important ecological problem of the state of Harayana is the rapid desertification due to migration of dunal sands in the south and southwestern parts. Other environmental problems related to landuse are the salt efflorescence, waterlogging, unscientific stone quarrying, etc. It is felt that geomorphic maps generated should be utilised for regional land-use planning and restoration of the eco-balance in the State.     

郑州-兰考区域性隐伏断裂的发现及其意义

 黄河下游郑州京广铁桥—兰考段河道穿行于华北平原济源—开封凹陷,南邻太康隆起。该河段为著名的地上悬河,属典型的游荡型河床,河流地质作用以强烈侧蚀南岸为特征。遥感、物探综合解译首次发现在河道南岸存在一东西向郑州—兰考区域性隐伏深大断裂带,该断裂带的发现,从河流地质作用特征与基底新构造活动关系方面解释了该段黄河发生、发展和演化机理,解释了河床“小尺度游荡,大尺度呈直线状延伸” 的河道地貌特征和“河流强烈侧蚀南岸”的河流地质作用特征,对黄河下游河道防洪、治理具有重要意义。     

Deposition and genesis of alluvial soils in the Indo-Gangetic Alluvial Plain Muzaffarnagar (U.P.)

The area under study forms a part of the Indo-Gangetic Alluvial Plain, in Muzaffar Nagar District (Uttar Pradesh). To understand the relation of stratigraphy and geogenesis on one hand, and landscape and pedogensis on the other hand, the study was undertaken through a 40 km. long E-W. Cross-section of the area, with augering upto a depth of five metres or more, Aerial photographs (1:25,000) were used for delineating the major land forms and selection of cross-section and observations sites. Care was taken to cover all the main physiographic units occuring in the survey area. Four distinct depositional phases in Upper Alluvial Plain and two in Lower Alluvial Plain by Ganges, while first braided and then meandering have been recognized. Soil were classified according to Soil Taxonomy (1975), being Inceptisols and Alfisols in the Upper Alluvial Plain and Entisols in the Lower Alluvial Plain.     

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.     

京九铁路北段沿黄地区地震灾害与区域构造活动性遥感评价

黄河下游黄泛平原是我国东部地震高发区之一,涉及地震Ⅶ级烈度区带48万km²,Ⅷ级烈度区带4.5万km²,历史地震统计资料表明,华北地区自1812年以来即进入地震活跃期,地震活动呈现出向华北南部黄泛区集中的趋势。京九铁路进入黄泛区以后,在山东聊城斜穿聊兰发震断裂带达200余km,在河南台前,横跨地上悬河——黄河现代河道,历史上该地曾有地震引发黄河决溢泛滥的记录,因此,地震活动及其诱发的黄河水患,是京九铁路及其沿线地区的不稳定因素之一。所以该地应以防御震害及水患为目的,加强防御体系的建设,避免二次灾害的发生。     

Mass Balance Estimation of Dokriani Glacier in Central Indian Himalaya Using Remote Sensing Data

Dokriani Glacier is regarded as one of the important glaciers of Bhagirathi River basin, which fed river Ganges. The length of the glacier is about 4.6 km, and snout elevation is about 4028 m m.s.l. The mass balance of this glacier was calculated using field-based measurements for few years during 1994 to 2000. However, due to remote and poor accessibility, the field-based measurements could not continue; thus, remote sensing-based methods become useful tool to estimate the long-term mass balance of the glacier. In this study, glacier mass balance has been determined using accumulation area ratio (AAR) method. Remote sensing data sets, e.g. Landsat TM, ETM?+?and OLI, have been used to estimate AAR for different years from 1994 to 2014. An attempt has also been made to develop a mathematical relationship between remote sensing-derived AAR and field-observed mass balance data of the glacier. Further, this relationship has been used to estimate mass balance of the glacier for different years using remote sensing-derived AAR. Estimated mass balance was validated from ground-observed mass balance for few years. The field-observed and remote sensing-derived mass balance data are compared and showed high correlation. It has been observed that AAR for the Dokriani Glacier varies from 0.64 to 0.71. Mass balance of the glacier was observed between ??15.54 cm and ??50.95 cm during the study period. The study highlights the application of remote sensing in mass balance study of the glaciers and impact of climate change in glaciers of Central Indian Himalaya.