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1.
The extent of saltwater intrusion in southern Baldwin County,Alabama   总被引:1,自引:0,他引:1  
Sea level rise (SLR) as a result of global warming has an impact on the increasing inundation on the coastal area. Nowadays, Semarang coastal area in Indonesia is already subject to coastal hazard due to tidal inundation and land subsidence. The impact of the inundation is predicted to be even more severe with the scenario of sea level rise. This paper concentrates on the risk assessment to the population, land use, and monetary losses as a result of coastal inundation under enhanced sea level rise. This paper uses the scenario of the depth of inundation to generate coastal inundation model using GIS-Technology. Anticipatory issues including methodology development for hazard assessment would be necessary for Semarang coastal area, and therefore, geo-information technology can be considered as a useful tool to rapidly assess the impact of the coastal hazard and evaluate the economic losses.  相似文献   

2.
Monitoring land subsidence in Semarang,Indonesia   总被引:1,自引:0,他引:1  
Semarang is one of the biggest cities in Indonesia and nowadays suffering from extended land subsidence, which is due to groundwater withdrawal, to natural consolidation of alluvium soil and to the load of constructions. Land subsidence causes damages to infrastructure, buildings, and results in tides moving into low-lying areas. Up to the present, there has been no comprehensive information about the land subsidence and its monitoring in Semarang. This paper examines digital elevation model (DEM) and benchmark data in Geographic Information System (GIS) raster operation for the monitoring of the land subsidence in Semarang. This method will predict and quantify the extent of subsidence in future years. The future land subsidence prediction is generated from the expected future DEM in GIS environment using ILWIS package. The procedure is useful especially in areas with scarce data. The resulting maps designate the area of land subsidence that increases rapidly and it is predicted that in 2020, an area of 27.5 ha will be situated 1.5–2.0 m below sea level. This calculation is based on the assumption that the rate of land subsidence is linear and no action is taken to protect the area from subsidence.  相似文献   

3.
The northern coasts of the Gulf of Mexico (GoM) are highly vulnerable to the direct threats of climate change, such as hurricane-induced storm surge, and such risks are exacerbated by land subsidence and global sea-level rise. This paper presents an application of a coastal storm surge model to study the coastal inundation process induced by tide and storm surge, and its response to the effects of land subsidence and sea-level rise in the northern Gulf coast. The unstructured-grid finite-volume coastal ocean model was used to simulate tides and hurricane-induced storm surges in the GoM. Simulated distributions of co-amplitude and co-phase lines for semi-diurnal and diurnal tides are in good agreement with previous modeling studies. The storm surges induced by four historical hurricanes (Rita, Katrina, Ivan, and Dolly) were simulated and compared to observed water levels at National Oceanic and Atmospheric Administration tide stations. Effects of coastal subsidence and future global sea-level rise on coastal inundation in the Louisiana coast were evaluated using a “change of inundation depth” parameter through sensitivity simulations that were based on a projected future subsidence scenario and 1-m global sea-level rise by the end of the century. Model results suggested that hurricane-induced storm surge height and coastal inundation could be exacerbated by future global sea-level rise and subsidence, and that responses of storm surge and coastal inundation to the effects of sea-level rise and subsidence are highly nonlinear and vary on temporal and spatial scales.  相似文献   

4.
Semarang is one of the biggest cities in Indonesia and is nowadays suffering from coastal flooding. Land subsidences, high water tide, and inadequate structural measures play important roles in the coastal inundations. Structural and non-structural methods for controlling coastal flooding including dykes, drainage systems, pump stations, polder systems, coastal-land reclamations, coastal planning and management, public education, as well as the establishment of an institutional framework for disaster management have been implemented in the Semarang coastal area. Although some improvements have been made, the current flood management system has generally failed to address a wide range of coastal inundation problems. Some improvement actions have been proposed including stakeholders involvement on the disaster mitigation. For a long period coastal management, accelerated sea level rises due to global warming should also be taken into account.  相似文献   

5.
The focus of this study is investigation of land subsidence in Semarang city Indonesia with the use of Interferometry Synthetic Aperture Radar (InSAR) of ALOS–PALSAR satellite. We processed 22 ascending SAR images during January 2007 to January 2009 plus two descending SAR images acquired on 6 June 2006 and 17 June 2007. The time series analysis of interferometry was performed by using 12 pairs of interferogram relative to 21 January 2007 and 8 pairs of interferogram relative 24 January 2008. The topographic phase contribution was removed using the 3-arcsec (90 m) Shuttle Radar Topography Mission (SRTM), Digital Elevation Model (DEM). We performed precision baseline estimation to vanish the fringes from baseline effect between master and slave data. In order to investigate the contribution of horizontal movement in our analysis, we constructed two interferograms of ascending orbit and descending orbit. The time series results exhibited that the area is subsiding continuously without a significant seasonal effect during January 2007 to January 2009. The land subsidence observed from InSAR data is approximately up to 8 cm/year. Three cross sections on image displacement show the extreme land subsidence occurred especially along the coastal area and lowland area where this area is considered as industrial with high-density settlements, consuming a lot of groundwater, and land is changed from agriculture and cultivation purposes to industrial estates and house. Our result also shows a consistency with historical pattern of subsidence measured by leveling data. The results highlight the potential use of InSAR measurements to provide better constraints for land subsidence in Semarang city Indonesia.  相似文献   

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8.
Geomorphological zoning for flood inundation using satellite data   总被引:3,自引:0,他引:3  
The authors investigated geomorphological features on the central plain of Thailand utilizing satellite remote sensing data and made geomorphological land classification map showing flood-stricken area. Land classification maps showing flood-striken area tell us former flood inundation area, such as inundation depth, inundation width, flood flow course and flood direction, as well as estimating of the features of flooding. Thus map is useful for planning of flood control works.We classified land form units in the central plain of Thailand as following; delta, tidal flat, lagoon, mud spit, back marsh, natural levee, fan and former river course and so on. After that, the principal component analysis is applied to Landsat TM data and gives good results for photo interpretation of land form units and we transfer geomorphological land classification map to make zoning map of flood risk for the purpose of evaluating the flood damages.  相似文献   

9.
Natural hazards in Central Java Province,Indonesia: an overview   总被引:2,自引:0,他引:2  
Central Java Province, Indonesia, suffers from natural hazard processes such as land subsidence, coastal inundation, flood, volcanic eruption, earthquake, tsunami, and landslide. The occurrence of each kind of natural hazard is varied according to the intensity of geo-processes. It is necessary to learn from the historical record of coastal inundation, flood, volcanic eruption, earthquake, tsunami, and landslide hazards in Central Java Province to address issues of comprehensive hazard mitigation and management action. Through the understanding about the nature and spatial distribution of natural hazards, treatments can be done to reduce the risks. This paper presents the natural hazard phenomena in Central Java Province and provides critical information for hazard mitigation and reduction.  相似文献   

10.
This paper demonstrates the decisive role of natural preconditions on the formation of large late Holocene sea ingressions in peaty coastal plains along the North Sea’s southern shores. Geological and archaeological evidence shows that these sea ingressions (expansion of new tidal systems) were mainly caused by land subsidence, which occurred due to intensified agricultural use of artificially drained peatlands since the Late Iron Age (250–12 BC). This made the coastal plain sensitive to storm-surge ingression through weak spots, e.g., at the location of existing creeks, in the coastline.Using The Netherlands as a case study, we show that natural preconditions (i.e., the geological setting at the time of ingression) played a key role in the pacing and extent of tidal area expansion. Ingressive tidal systems eventually reached most far inland in coastal segments with wide peaty back-barrier plains. In contrast, sea ingression formation was hampered in coastal segments with well-developed natural ingression-protecting geomorphic features (e.g., beach-barriers, supratidal levees). Feedback mechanisms, such as additional peat subsidence by loading of sediment imported into the new tidal area, caused further tidal volume increase and created accommodation space for tidal deposits. These combined effects caused irreversible sea ingression over large areas that consequently became unsuitable for habitation for many centuries.Improved understanding of such sea-ingression mechanisms and their facilitating conditions are essential for the assessment of the sensitivity of many densely populated coastal plains, which experience major human-induced subsidence, eventually leading to coastal plain drowning.  相似文献   

11.
Tidal marsh (re)creation on formerly embanked land is increasingly executed along estuaries and coasts in Europe and the USA, either by restoring complete or by reduced tidal exchange. Ecosystem functioning and services are largely affected by the hydro-geomorphologic development of these areas. For natural marshes, the latter is known to be steered by feedbacks between tidal inundation and sediment accretion, allowing marshes to reach and maintain an equilibrium elevation relative to the mean sea level. However, for marsh restoration sites, these feedbacks may be disturbed depending on the restoration design. This was investigated by comparing the inundation-elevation change feedbacks in a natural versus restoration site with reduced tidal exchange in the Scheldt estuary (Belgium). This study analyzes long-term (9 years) datasets on elevation change and tidal inundation properties to disentangle the different mechanisms behind this elevation-inundation feedback. Moreover, subsequent changes in sediment properties that may affect this feedback were explored. In the restoration area with reduced tidal exchange, we found a different elevation-inundation feedback than on natural marshes, which is a positive feedback on initially high sites (i.e., sediment accretion leads to increasing inundation, hence causing accelerating sediment accretion rates) and a gradual silting up of the whole area. Furthermore, there is evidence for the presence of a relict consolidated sediment layer. Consequently, shallow subsidence is less likely to occur. Although short-term ecological development of the tidal marsh was not impeded, long-term habitat development may be affected by the differences in hydro-geomorphological interactions. An increase of inundation frequency on the initially high sites may cause inhibition of habitat succession or even reversed succession. Over time, the climax state of the restoration area may be different compared to natural marshes. Moreover, sediment-related ecosystem services, such as nutrient and carbon burial, may be positively influenced because of continuing sedimentation, although flood water storage potential will decrease with increasing elevation. Depending on the restoration goals, ecosystem trajectories and delivery of ecosystem services can be controlled by adaptive management of the tidal volume entering the restoration area.  相似文献   

12.
Analysis of remote images, elevation surveys, stratigraphic cross-sections, and hydrocarbon production data demonstrates that extensive areas of wetland loss in the northern Gulf Coast region of the United States were associated with large-volume fluid production from mature petroleum fields. Interior wetland losses at many sites in coastal Louisiana and Texas are attributed largely to accelerated land subsidence and fault reactivation induced by decreased reservoir pressures as a result of rapid or prolonged extraction of gas, oil, and associated brines. Evidence that moderately-deep hydrocarbon production has induced land-surface subsidence and reactivated faults that intersect the surface include: (1) close temporal and spatial correlation of fluid production with surficial changes including rapid subsidence of wetland sediments near producing fields, (2) measurable offsets of shallow strata across the zones of wetland loss, (3) large reductions in subsurface pressures where subsidence rates are high, (4) coincidence of orientation and direction of displacement between surface fault traces and faults that bound the reservoirs, and (5) accelerated subsidence rates near producing fields compared to subsidence rates in surrounding areas or compared to geological rates of subsidence. Based on historical trends, subsidence rates in the Gulf Coast region near producing fields most likely will decrease in the future because most petroleum fields are nearly depleted. Alternatively, continued extraction of conventional energy resources as well as potential production of alternative energy resources (geopressured-geothermal fluids) in the Gulf Coast region could increase subsidence and land losses and also contribute to inundation of areas of higher elevation.  相似文献   

13.
北京地下水系统演化与地面沉降过程   总被引:2,自引:0,他引:2  
采用地下水动态监测网、GPS监测网数据、气象监测数据与SAR数据、GIS等技术相结合,建立地下水系统演化与地面沉降过程模型,系统分析了北京地区地下水降落漏斗区地面沉降的形成过程。研究表明:降雨量呈逐年下降趋势,地下水开采量随之增大;平原区地下水位呈下降趋势,间接导致了地下水降落漏斗和地面沉降的形成演化。地面沉降对地下水降落漏斗的响应模式存在着季节与年际差异性,时空分布上存在不均匀性,最大地面沉降速率约为41.43 mm/a;揭示了地下水降落漏斗与地面沉降漏斗空间展布特性存在一致性,但并非完全吻合。  相似文献   

14.
为了研究地面沉降的时空分布模式、机理机制,选择北京典型沉降区——潮白河冲洪积扇为研究区,采用PS-InSAR技术、莫兰指数及地理探测器,分析了研究区地面沉降的空间异质性特征,探测了不同特征下的地面沉降的主要驱动因素。结果表明:2017-01—2019-01研究区内地面沉降时空分布特征以一般沉降为主,沉降速率为[-133,3] mm/a,最大累积沉降量为261 mm,呈北部轻微、中部较严重、南部较轻的分布状态,其中,严重、极严重等级地面沉降主要分布在中游顺义后沙峪东部等地区及中下游交界地带的潞城镇;不同地区地面沉降呈现不同的空间异质性特征,即不均匀地面沉降分布特征明显,中游、下游均表现为低—低集聚;不同分布特征下地面沉降主要驱动因素不同,中游地区主要驱动因素为第二承压水水位变化和可压缩层厚度,下游主要驱动因素为浅层地下水水位变化和第一承压水水位变化。莫兰指数能够有效分析地面沉降空间异质性,识别集聚特征;地理探测器可以探明沉降空间异质性成因,获得其主要驱动因素。  相似文献   

15.
基于时序InSAR技术的常州市地面沉降监测与分析   总被引:1,自引:0,他引:1       下载免费PDF全文
城市地面沉降不仅会对居民生命安全造成影响,而且也会给当地的社会经济造成损失。常州市位于长江三角洲地面 沉降区,也是我国经济最发达的地区之一。因此地面沉降监测是常州市掌握地面沉降的动态,为防灾减灾提供决策依据的 重要举措。本文采用SBAS InSAR 方法对2012-2013 年23 景TerraSAR-X 高分辨率雷达影像数据进行了地表形变的反演,获 取了该时间段常州地区年均沉降速率和时序地表累积形变图。结果表明,在整个观测期间,常州市呈现出“全区基本保持 稳定,武进区局部沉降严重”的特点。为此,我们利用PS-InSAR 技术对武进区的地面沉降进行了重点监测,发现该区多条 重要交通线路存在不同程度的地面沉降。最后我们结合历史监测结果和水文地质背景,揭示了常州地区近50 年地面沉降的 时空变化特征和规律。综合分析表明,地下水全面禁采后研究区地面沉降的确得到了有效控制,沉降速率减缓,甚至出现 了回弹。而武进地区的地面沉降虽然也在减缓,但仍然存在明显的地面沉降,一些重要交通线路的周边沉降已超过安全阈 值,有必要在常规监测的同时,对这些沉降严重的区域进行重点监测,并建立预警预报机制,在城市基础设施选址和规划 时提供决策依据。  相似文献   

16.
Most urban agglomerations located in the Mumbai coastal region in India are vulnerable to flooding due to increasing frequency of the short-duration heavy rainfall, by virtue of their location at foothills on one side and tidal variations on the other side. Steep slopes in the catchment ensure fast runoff and tidal variation adds to backwater effect in the drainage system, which together are favorable for flooding. The present study simulates the flood inundation due to heavy rainfall and high-tide conditions in a coastal urban catchment within Mumbai region with detention pond. Overland flow is modeled using a mass balance approach, which can adapt to hilly slopes and smoothly accommodate detention pond hydraulics. Dynamic wave channel routing based on finite element method captures the backwater effects due to tidal variation, and raster-based flood inundation model enables direct use of digital elevation model. The integrated model is capable of simulating detention pond hydraulics within the raster flood model for heavy rainfall events. The database required for the model is obtained from the geographical information system (GIS) and remote sensing techniques. Application of the integrated model to literature problems and the catchment of the study area for two non-flooding events gave satisfactory results. Further, the model is applied to an extreme rainfall event of July 26, 2005, coinciding with high-tide conditions, which revealed vulnerability of the area to flooding despite of an existing detention pond. A sensitivity analysis on the location of detention pond indicated that catchment response can be better governed by relocating the detention pond to upstream of existing detention pond especially when heavy rainfall events are becoming frequent.  相似文献   

17.
Huangpu River floodplain is historically vulnerable to flooding due to its location in the path of tropical cyclones, low elevation, relatively flat topography, rapid changes in sea level and fast rate of land subsidence due to urbanization. This paper presents a scenario-based study that investigates the fluvial flood potentials in the Huangpu River floodplain. Flood scenarios with return periods of 50, 100, 200, 500 and 1,000 years were designed to cover the probable situations. Further, a flood inundation model (FloodMap) that tightly couples a river flow model with a 1D solution of the full form of the St. Venant equations and a 2D floodplain flow model was used to predict the river flow and inundation extents. Flood characteristics obtained from the simulations were used in the exposure analysis to determine the spatial distribution of susceptible land uses under different scenarios. Results suggest that overtopping inundation mainly occurs within 1–2 km of the banks of the Huangpu River, with larger inundation extent predicted in the upper and middle reaches of the channel, a result of varying protection levels from relatively rural upstream to high urbanized floodplain in the vicinity of the middle reaches.  相似文献   

18.
Remote sensing imagery can be an invaluable resource to quantify land change in coastal wetlands. Obtaining an accurate measure of land change can, however, be complicated by differences in fluvial and tidal inundation experienced when the imagery is captured. This study classified Landsat imagery from two wetland areas in coastal Louisiana from 1983 to 2010 into categories of land and water. Tide height, river level, and date were used as independent variables in a multiple regression model to predict land area in the Wax Lake Delta (WLD) and compare those estimates with an adjacent marsh area lacking direct fluvial inputs. Coefficients of determination from regressions using both measures of water level along with date as predictor variables of land extent in the WLD, were higher than those obtained using the current methodology which only uses date to predict land change. Land change trend estimates were also improved when the data were divided by time period. Water level corrected land gain in the WLD from 1983 to 2010 was 1 km2 year−1, while rates in the adjacent marsh remained roughly constant. This approach of isolating environmental variability due to changing water levels improves estimates of actual land change in a dynamic system, so that other processes that may control delta development such as hurricanes, floods, and sediment delivery, may be further investigated.  相似文献   

19.
Evaluation of coastal inundation hazard for present and future climates   总被引:2,自引:1,他引:1  
Coastal inundation from hurricane storm surges causes catastrophic damage to lives and property, as evidenced by recent hurricanes including Katrina and Wilma in 2005 and Ike in 2008. Changes in hurricane activity and sea level due to a warming climate, together with growing coastal population, are expected to increase the potential for loss of property and lives. Current inundation hazard maps: Base Flood Elevation maps and Maximum of Maximums are computationally expensive to create in order to fully represent the hurricane climatology, and do not account for climate change. This paper evaluates the coastal inundation hazard in Southwest Florida for present and future climates, using a high resolution storm surge modeling system, CH3D-SSMS, and an optimal storm ensemble with multivariate interpolation, while accounting for climate change. Storm surges associated with the optimal storms are simulated with CH3D-SSMS and the results are used to obtain the response to any storm via interpolation, allowing accurate representation of the hurricane climatology and efficient generation of hazard maps. Incorporating the impact of anticipated climate change on hurricane and sea level, the inundation maps for future climate scenarios are made and affected people and property estimated. The future climate scenarios produce little change to coastal inundation, due likely to the reduction in hurricane frequency, except when extreme sea level rise is included. Calculated coastal inundation due to sea level rise without using a coastal surge model is also determined and shown to significantly overestimate the inundation due to neglect of land dissipation.  相似文献   

20.
Situated at the junction of land and sea, coastal salt marshes are very sensitive to global environmental changes. Existing numerical models simulating the vertical growth of coastal salt marshes are under the conditions of low suspended sediment concentration (SSC), but under high SSC, such as in the Jiangsu coast of China, the models need to be refined. In this paper, based on the mass balance principle, a refined zero-dimensional time-stepped model is applied after considering the average suspended sediment concentration (ASSC). The statistical results of in situ observation data show that there is an obvious positive linear relationship between ASSC and maximum inundation height, and an obvious positive exponential one between inundation time and inundation height. Using the short-term measurement values for the input parameters and incorporating the above-mentioned relationship between SSC and inundation height, the sedimentation rates are calculated, and the results are similar to previous data. In addition, some factors and hydrodynamic processes that were ignored or simplified could influence the calculated value.  相似文献   

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