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1.
Alfios is the biggest river of the Peloponnese and the ninth longest river in Greece. It drains an area of almost 2575 km2 in Western Peloponnese and discharges at Kiparissiakos Gulf. Due to its extent, the Alfios basin presents complex physiography and geomorphology. During the last 50 years, major direct human activities have had an important impact on the river network shape and on the valley floor morphology. The most important human activities were the channel straightening caused by meander cut-offs in 1950, the construction of two dams: the Ladonas dam in 1955 and the Flokas dam in 1968 and the illegal in-stream gravel extraction that started in the 1960s and continues until today. As a result, the Alfios riverbed has presented very rapid vertical and horizontal (lateral) erosion and significant changes to its network shape. The drainage network follows a straighter course, the number of meanders has been reduced and the seventh order branch is deeply incised. Besides the morphological impacts to the river network shape there are also serious economic damages caused by human activity. During the winter of 1999, the Flokas dam bridge was closed for a long period due to damages at its foundation caused by the heavy rain and illegal gravel extraction. Transportation between the villages in the area became extremely difficult and time consuming and the cost of the repairs was estimated at 500 000 euros. In this study, there is an effort to map the network shape transformation for the period 1977–2000 using multitemporal and multisensor satellite images. One Landsat MSS image, three Landsat TM images, two Landsat ETM images, and one Terra ASTER image have been orthorectified and processed in order to cover the specific period. Principal Component Analysis (PCA) method and Geographical Information System (GIS) techniques have been applied to map the changes in the Alfios River channel. The drainage network straightening and the cut-off of five big meanders were detected and mapped. These changes occurred between 1986 and 2000. 相似文献
2.
黄河携带大量泥沙入海,河口三角洲覆盖20~50m厚的沉积层。沉积层的自然压实导致该地区的地表沉降。此外,黄河三角洲油气资源的开发和地下水的开采也加速地表的下陷。InSAR作为一种有效的空间大地测量工具,可以提供几十公里范围内的高精度地表形变场。时序InSAR技术在多幅雷达影像组成的干涉网络基础上,识别永久散射体(PS)等雷达回波信噪比高的像素。与传统的InSAR技术相比,时序InSAR技术削弱雷达影像去相干效应的影响,实现长期的形变序列提取。文中利用两组雷达影像:19幅ERS卫星1992年12月至1996年1月的SAR影像,17幅ENVISAT卫星2003年5月至2008年3月的SAR影像。影像主要覆盖山东省东营市及其周边部分区域。结果显示,东营地区存在每年15mm以上的地表沉陷,该地区的地表沉降与油气开采活动有关。 相似文献
3.
郑州-兰考区域性隐伏断裂的发现及其意义 总被引：1，自引：0，他引：1
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。 相似文献
4.
2019-06-14,河源市源城区东江大桥第三跨第二桥墩以及第四跨第三桥墩出现了垮塌,此次事故造成了人员伤亡和重大经济损失。为了分析此次灾害事故发生发展的成因,本研究获取了Sentinel-1A雷达卫星2018年12月至2019年6月的历史影像数据,基于时序InSAR技术手段处理得到了该监测时间段内的历史形变信息。研究成果显示该桥梁在此数据获取时间段处于相对稳固状态,并无明显的形变特征趋势。通过对事发桥梁进行实地观测,结合了各类研究资料推断该桥梁垮塌的成因机理为突发因素,例如物体撞击或者水流的冲刷造成。文中研究成果可以为今后桥梁类基础设施的监测预警工作提供应用实践。 相似文献
5.
Change of river channel and bank erosion of the burhi dihing river (assam), assessed using remote sensing data and gis 总被引：1，自引：0，他引：1
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. 相似文献
6.
M M Jana 《Journal of the Indian Society of Remote Sensing》1997,25(2):105-111
River basin management and development are most important for utilising and conserving the water resources in any region where the average annual rainfall is highly fluctuating, the North Bengal is one of such region. Though there are a large number of rivers having a large catchment area in the hills and carry a huge amount of water during rainy season but they are completely dry in winter and summer. The upper part of majority of river basins arc highly sensitive to water erosion and land slides due to deforestation, intensive cultivation, increased settlements in sloping and erosion prone areas. So, floods in the rainy season and droughts in summer months are frequent features in North Bengal. In view of this proper management and effective conservation of land and water resources is necessary to develop the region. An integrated river basin management consisting soil conservation, afforestation, flood control, and adoption of suitable cropping pattern is essential for economic development of North Bengal. 相似文献
7.
Hassan M. Fadul Ahmed A. Salih Imad-eldin A. Ali Shinobu Inanaga 《International Journal of Applied Earth Observation and Geoinformation》1999,1(3-4)
The problems and impact of gully erosion along the Atbara River (Sudan), situated in semi-arid and arid environments, were investigated. The total gross area of gullied land and the loss of arable land by gully erosion were estimated. Multi-date sets of panchromatic aerial photographs and Landsat images (TM) were selected to represent two sites in the arid (New Halfa) and semi-arid (Showak town) zones along the Atbara River. Photo interpretation was conducted using physiographic and element methods. The interpretations detected the effects of water action in different climatic zones on geology, lithology, vegetation and land use. The results showed that the traditional rainfed agriculture has accelerated gully erosion in the semi-arid rather than in the arid zone. The progressive rate of gully erosion in the semi-arid zone resulted in loss of arable land at about 13.4 km2 yr-1 and 9.8 km2 yr-1 in the periods 1985–1987 and 1987–1990, respectively. The study provided data on the monitoring and mapping of gully erosion along the Atbara River and its tributaries. 相似文献
8.
9.
《International Journal of Digital Earth》2013,6(3):258-270
Abstract Land use and land cover change, perhaps the most significant anthropogenic disturbance to the environment, mainly due to rapid urbanization/industrialization and large scale agricultural activities. In this paper, an attempt has been made to appraise land use/land cover changes over a century (1914–2007) in the Neyyar River Basin (L=56 km; Area = 483.4 km2) in southern Kerala – a biodiversity hot spot in Peninsular India. In this study, digital remote sensing data of the Indian Remote Sensing satellite series I-D (LISS III, 2006–2007) on 1:50,000 scale, Survey of India (SOI) toposheet of 1914 (1:63,360) and 1967 (1:50,000) have been utilized to map various land use/land cover changes. Maps of different periods have been registered and resampled to similar geographic coordinates using ERDAS Imagine 9.0. The most notable changes include decreases in areas of paddy cultivation, mixed crops, scrub lands and evergreen forests, and increases in built-up areas, rubber plantations, dense mixed forests, and water bodies. Further, large scale exploitation of flood plain mud and river sand have reached menacing proportions leading to bank caving and cut offs at channel bends. Conservation of land and water resources forms an important aspect of ecosystem management in the basin. 相似文献
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12.
“削山填沟造地”等岩土工程在湿陷性黄土沟壑地区屡见不鲜,掌握填方区沉降情况具有重要意义。本文收集了2017年11月—2020年12月获取的56景TerraSAR-X StripMap模式影像,利用时序InSAR技术监测了陕北某湿陷性黄土填方地基工程的沉降信息,并与2017年11月—2020年12月期间监测区3个水准点的沉降测量结果比对。结果表明,在填方区地表以沉降为主,在挖方区地表以抬升为主,研究区存在有1处较为明显的地表沉降情况,位于填挖边界线附近填方区内,形变速率范围为-40~-20 mm/a,最大形变速率达-49.9 mm/a,累计量为-151.6 mm,时序InSAR形变结果和实地水准结果吻合性较好,垂直方向形变速率中误差为1.8 mm/a,表明时序InSAR技术在湿陷性黄土填挖方区变形监测中具有较好的应用价值。 相似文献
13.
2017年以来，以四川茂县新磨村高位垮塌、金沙江白格滑坡为代表的重大地质灾害多次发生，呈现出隐蔽性强、突发性高、破坏力大等特点，难以早期发现。值得注意的是，尽管地质灾害防治工作已在全国大范围开展并受到国家层面的高度重视与支持，但绝大部分灾害仍发生于全国现有地质灾害隐患点分布以外的区域。对这些人迹罕至、人不能至且观测条件苛刻的地区的重大隐患进行有效早期识别，是当前地质灾害防治工作尚需解决的难题和重要任务。在总结合成孔径雷达干涉测量（interferometric synthetic aperture radar，InSAR）技术特点与其应用局限的基础上，从光学遥感、InSAR、激光雷达等综合遥感测量的角度提出了以“形态、形变、形势”（三形）为观测内容、以定性识别灾害隐患位置、定量监测灾害体变形幅度、依靠综合遥感动态监测数据提升隐患识别能力的技术思路。对未来工作提出了若干建议与思考，以期服务于重大地质灾害隐患综合判断与早期识别工作。 相似文献
14.
江苏省海岸线演变及地质灾害遥感分析 总被引：3，自引：0，他引：3
江苏省漫长的海岸曾经历了大淤大蚀的沧桑变化。现代海岸仍经常受到侵蚀崩岸、岸滩淤涨以及沿岸泥沙流的袭扰破坏。沿岸港口建设、交通航运及滩涂围垦等也不时受到危害,成为江苏海岸带特有的地质灾害。 相似文献
15.
本文对地理国情监测的具体案例,某尾矿库监测实施过程中主要技术进行了详细的描述。通过静态GPS测量方法完成了尾矿库控制测量工作,按国家统一坐标系解算了尾矿库基础控制点、监测点等坝体要素的三维坐标,并和尾矿库监测点的原始独立三维坐标进行对照、比较,根据不同高程基准坝体高差变化、尾矿库设计高度等坝体数据进行综合分析,绘制高程标注图。研究结果为尾矿库安全运行提供了准确、可靠的监测数据及相关合理建议。 相似文献
16.
Knowledge on the interaction of active structures is essential to understand mechanics of continental deformation and estimate the earthquake potential in complex tectonic settings. Here we use Sentinel-1A radar imagery to investigate coseismic deformation associated with the 2016 Menyuan (Qinghai) earthquake, which occurred in the vicinity of the left-lateral Haiyuan fault. The ascending and descending interferograms indicate thrust-dominated slip, with the maximum line-of-sight displacements of 58 and 68 mm, respectively. The InSAR observations fit well with the uniform-slip dislocation models except for a larger slip-to-width ratio than that predicted by the empirical scaling law. We suggest that geometric complexities near the Leng Long Ling restraining bend confine rupture propagation, resulting in high slip occurred within a small area and much higher stress drop than global estimates. Although InSAR observations cannot distinguish the primary plane, we prefer the west-dipping solution considering aftershocks distribution and the general tectonic context. Both InSAR modelling and aftershock locations indicate that the rupture plane linked to the Haiyuan fault at 10 km depth, a typical seismogenic depth in Tibet. We suggest that the earthquake more likely occurred on a secondary branch at a restraining bend of the Haiyuan fault, even though we cannot completely rule out the possibility of it being on a splay of the North Qilian Shan thrusts. 相似文献
17.
Water and suspended sediment fluxes are considered during the period 2000–2008 in a region including the full Amazon River from the confluence of the Negro River to Santarém, the end part of the Solimões River, and the lower part of the Madeira River. Three types of data are used: water discharge estimated from field measurements, and suspended sediment obtained from field measurements and derived from MODIS satellite data. A generalized least square method including a propagating term is developed in order to propagate the signal upward and downward the river. The approach is introduced and tested. Several experiments are considered in order, first, to estimate the ability to propagate the signal from stations located before the confluences of Negro and Madeira Rivers to stations located on the Amazon River; second to investigate the possibility to propagate the signal along the Amazon River which dynamics is coupled with floodplains dynamics; and third to produce optimal solutions of water and sediment fluxes. For each experiment, the influence of field and satellite data is compared. The approach is efficient in the upper part of the region of study where the Solimões, the Negro and the Madeira Rivers meet and fails in the lower part of the region where interactions between Amazon River and floodplains play an important role on the fluxes’ dynamics. The optimal experiment includes in situ and satellite data from all the stations available and is used to analyse the recent evolution of suspended sediment flux along the Amazon River and its interaction with the large coupled floodplains. A high accumulation rate is observed during the 2000–2002 period, followed by decreasing rates until 2005 and by increasing values in 2006 and 2007. Our results suggest that floodplains extending along a river reach of 390 km-long between Itacoatiara and Óbidos trap about 15% of the suspended sediment flux passing at Óbidos. The simulated deposition rate is of about 0.3 Mt km−1 yr−1 corresponding to an accretion rate of about 27 mm yr−1. 相似文献
18.
河流谷坡工程地质环境评价是水电工程的前期工作,直接关系到工程的选址、建设规模和水利资源的充分利用。 本文利用现有航空遥感资料,对四川雅砻江中游的鲜水河口至官地河段,约510 km河流谷坡的物理地质现象进行了判读,运用数理统计和工程地质综合分析的方法,对该河流区段的工程地质环境进行了评价,并对其发展趋势进行了预测,为该地区丰富的水利资源的开发利用提供了决策依据;对于区域工程地质环境评价,尤其是基础工作薄弱、自然条件恶劣、地面工作难以开展的高山峡谷地区的河流谷坡工程地质环境评价和发展趋势预测提出了新的方法。 相似文献
19.
Swades Pal 《国际地球制图》2019,34(10):1055-1074
Punarbhaba river of Indo-Bangladesh has experienced hydro-ecological alteration after installation of Komardanga dam in 1992 and consequently wetland and inundation areas have undergone into transformation. The present work intends to explore the impact of flow attenuation on contemporary and upcoming flood extent and flood plain wetlands. In post-dam condition, average and maximum flows are attenuated by 36 and 41%, respectively, and as a result the active flood prone area is squeezed considerably by 39.72%. Average flood water depth is also reduced by 37.87% (4.45metre) after flow modification. Due to shrinkages of flood prone areas, wetland area is also reduced from 215.70 to 90.40 km2 and larger part of the present wetland area is under stress and critical state. Predicted flood prone areas in next 25 years will be 328.91 km2 and consequently 65.63 km2 wetland areas may further be under hydro-ecological threats. Release of ecological flow is essential to restore and preserve the wetland. 相似文献
20.
Study of drainage pattern of Jharia Coalfield (Bihar), India, through Remote Sensing technology 总被引：2，自引：0，他引：2
V K Srivastava 《Journal of the Indian Society of Remote Sensing》1997,25(1):41-46
Study of drainage pattern of Jharia Coalfield as observed on IRS-IA LISS II image shows that the region is drained by 11 streams with general flow direction to north east to south east and ultimately joining to trunk river Damodar. The perennial river Damodar flows from west to east and approximately marks the southern limit of the famous Jharia Coalfied. The average stream length in the region varies from 15 km to 110 km with average hasin area from 10 km2 to 150 km2. The general pattern is essentially a coarse dendritc with very gentle (0 to 1%) to sluggish stream flow condition over a gentle sloping (1 to 3%) topographic surface characteristic of old age streams in matured erosion terrain (Paleo-pediplain). 相似文献