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1.
Flood frequency analysis of river swat using Log Pearson type 3, Generalized Extreme Value,Normal, and Gumbel Max distribution methods 总被引：1，自引：0，他引：1
Muhammad Farooq Muhammad Shafique Muhammad Shahzad Khattak 《Arabian Journal of Geosciences》2018,11(9):216
In Pakistan, floods are among the most devastating and recurring natural hazards. Flood hazard assessment requires flood event magnitude and probability of occurrence. Flood frequency analysis is the most common technique used for the at-site estimation of flood recurrence magnitude. This paper evaluates four most commonly used distribution methods, i.e., Generalized Extreme Value (GEV), Log Pearson 3 (LP3), Gumbel Max, and Normal for the flood frequency and estimation of flood recurrence. Different hydrological stations data namely Khwazakhela, Chakdarra, Panjkora, and Munda Headwork located at Swat river was taken from Provincial Irrigation Department, Khyber Pakhtunkhwa. The analysis is done for 5-, 10-, 25-, 50-, and 100-year return periods by using annual maximum discharge data from 1980 to 2016 (37 yr). Three goodness-of-fit tests were applied to the fitted distributions, i.e., Kolmogorov–Smirnov, Anderson–Darling, and Chi-squared at 5% significance level. Results indicate that LP3 and GEV were ranked top two distributions at all locations while Gumbel Max and Normal were the least fitted having rank 3 and 4, respectively. Based on the goodness-of-fit ranking, LP3 was selected for the estimation of flood magnitude and return periods at Khwazakhela. Designed hydrographs based on probabilistic approach and flood 2010 hydrograph are presented for flood simulation. 相似文献
2.
Waterlogging and flood hazards vulnerability and risk assessment in Indo Gangetic plain 总被引：4，自引：2，他引：2
The recurrent flooding during monsoon and subsequent waterlogging in the northern Bihar plains and the magnitude of losses
due to these hazards indicate the continuing vulnerability of the region to flood and waterlogging. Management of floods and
waterlogging hazards in highly flood-prone regions of India, including Bihar state has been largely response oriented with
little or no attention to mitigation and preparedness. This paper presents a method for spatial, Geographic Information Systems-based
assessment of flood and waterlogging vulnerability and risk in northern Bihar plains. Multitemporal satellite data was used
to evaluate the area statistics and dynamics of waterlogging over the period from 1975 to 2008. The flood proneness is evaluated
at district level with reference to flood inundation during a period from 1998 to 2008. Census data were used to examine the
socio-economic characteristics of the region through computation of population density, cultivators, agricultural labourers,
sex ratio, children in age group 0–6 years and literates. The geohazard map derived by combining area prone to waterlogging
and flood inundation was multiplied with socio-economic vulnerability map to derive the flood-waterlogging risk map of the
region. The result shows that flood and water-logging pose highest risk to the central districts in the northern Bihar plains
with 50.95% of the total area under high and very high risk. 相似文献
3.
Urs Geiser 《Geoforum》2012,43(4):707-715
In recent years, the Swat valley in North-West Pakistan has witnessed various waves of ‘politics’. Different groups have attempted to change socio-economic conditions, each according to their clear visions of a better future. After a period of top-down attempts at modernisation by the state, development projects inspired by deliberative democracy have attempted to increase political space for ‘local people’, but failed. Swat has also witnessed agonistic politics, with the emergence of a fundamentalist social movement that constructed a radical discourse of otherisation, entering into an antagonism with the state that created war and havoc. Thus, Swat offers a challenging learning ground to reflect on practices for producing change, as well as on theoretical currents in academia. I argue that deliberative and radical theorising provide insights into the political life of Swat, but fall short analytically (missing social complexities), procedurally (favouring specific techniques of social negotiation), and normatively (due to preconceived understandings of a ‘better future’). I substantiate my argument by showing that both positions take euro-centric conceptualisation of ‘citizens’, a (modern) ‘state’, and ‘citizen/state relations’ as universals – basic conditions that are not met in the post-colonial setting of Swat. I therefore argue that our curiosity should be redirected from ontologised explanation to an analysis of actual practices of societal negotiation and the norms within which these are embedded. Such insights will make it possible for us to appreciate the enormous challenges people in Swat face in their struggle to negotiate aspirations among disparate voices and to imagine some common understanding of a ‘better future’ – challenges that go beyond what deliberative or agonistic theorising can offer. 相似文献
4.
Asadullah Kazi 《Natural Hazards》2014,70(1):839-864
5.
受洪水补给来源和阿尔泰山山势影响,阿勒泰地区洪水发生时间比新疆其他以高山永久积雪和冰川融水补给为主的河流偏早。因此,从认识洪水特性、预防洪水灾害角度出发,对阿勒泰地区洪水发生机制、时空分布和变化特点进行分析研究是很有必要的。利用阿勒泰地区各主要河流1960~2011年历年洪峰、冬季和汛期降水、气温和700hPa高空温度资料,对洪水发生机制、时空分布和变化特点进行分析。结果表明:(1)本区洪水类型有融雪型洪水、融雪与降水混合型洪水和暴雨型洪水;(2)洪水与冬季积雪和汛期气温、降雨有关;(3)汛期过程相对短,主汛期发生时间以5月下旬至6月中旬期为主;(4)洪水挟沙能力强,汛期含沙量占年含沙量近90%;(5)暴雨洪水多发生于阿勒泰地区的中东部区域河流上;(6)全区洪水具有同步性,洪水年际变化相对小。 相似文献
6.
Different techniques have been used to discuss the existence of significant relation between the El Nino Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). Various studies present their interaction and influence on the natural disasters (i.e. drought, flood, etc.) over large parts of the globe. This study uses a Markov chain method to investigate the relation between the ENSO and IOD for the period of 62 years (1950–2011) and aggregates their influence on the occurrence of floods in Pakistan. Both data sets show similarities in the formation of transition matrices and expected number of visits from one state to another. The strong values of 2-dimensional correlation and high self-communication of the transition states confirm the existence of a possible relation between ENSO and IOD data. Moreover, significant values of dependency and stationary test endorse the applicability of the Markov chain analyses. The independent analysis shows that strong events of both data sets are co-occurred in the same flood years. During the study period maximum number of floods was observed during summer monsoon season. However, further analysis shows that after 1970, Pakistan observed the highest percentage of floods occurred per year during El Nino, Non-ENSO and positive IOD years. These observations and results demonstrate that climate variability especially ENSO and IOD should be incorporated into disaster risk analyses and policies in Pakistan. 相似文献
7.
The peculiar rainfall pattern in Indiarenders the country highly vulnerable to floods. Forty million hectares of land, roughlyone-eighth of the country's geographical area, is prone to floods. Each year, floods cause extensive damage to life and property, losses being exacerbated by rapid population growth, unplanned development and unchecked environmental degradation. The country has been tackling the problem through structural and non-structural measures. While non-structural measures like flood forecasting aim at improving the preparedness to floods by seeking to keep people away from floodwaters, structural measures involve the construction of physical structures like embankments, dams, drainage channels, and reservoirs that prevent floodwaters from reaching potential damage centres. Almost 48% of the vulnerable area has been provided with reasonable protection, though floods continue to cause widespread losses year after year. This paper examines the incidence of floods and the trends in consequent losses in the eastern region of the country – one of the most vulnerable – with the objective of studying the efficacy of flood protection measures in the region. Based on a simple regression exercise for three highly vulnerable states in the region, the paper argues that flood protection measures have been inadequate in controlling losses and reducing vulnerability. Regressions for the three states over the period 1971 to 1996 indicate that the level of protection is an insignificant explanatory variable in explaining the number of people (adjusted for increases in density) affected by floods; while area affected, as an indicator of the intensity of floods remains the main loss-determining factor. 相似文献
8.
分期设计洪水标准计算方法研究 总被引：3，自引：0，他引：3
针对水库分期设计和调度运用所涉及的分期情况下如何定义水库防洪标准,以及如何在不突破水库防洪标准的前提下合理确定分期设计洪水标准等关键问题,本文基于概率论中独立事件的概率组合原理,提出了水库分期运用情况下的水库防洪标准的等价表达形式,并以一个水库作为分析案例,在确保水库分期运用情况下的等价防洪标准不突破水库防洪标准的前提下,分别确定了各个分期设计洪水标准以及相应的汛限水位。 相似文献
9.
The Upper Middle Rhine Valley, granted the status of a World Heritage site, is well known for its unique inner narrow valley
of Quaternary age with its historical legacy of numerous medieval castles and old towns. Less known is that this has always
been a risk area of floods and gravitative mass movements. Up to the recent past, mainly ice floods caused enormous damage.
The inhabitants of the valley were well aware that they lived in a risk area, but they had learned to handle the flood hazard.
With the demise of ice floods over the last 40 years, due to climate change and because of the additional heating of the river
water by power plants, the awareness of flood hazards has been much diminished, in contrast to that of potential damage by
rockfalls and landslides which were also much feared in the past, though at the local level only. Still in the people’s memory
is the Kaub catastrophe of March 10, 1876, when 28 persons were killed by a landslide. Nowadays, even minor rockfalls are
a major threat, as they will affect the much-used traffic lines on both banks of the river, in particular the railroads. Therefore,
since 2002, on behalf of German Rail (Deutsche Bahn, DB), all problematic slopes have been protected by costly steel-ring nets, although they are an aesthetic problem by UNESCO
standards. The feeling of absolute safety created among the public is only subjective, though, as planners are well aware
of. Moreover, the impact of modern climate change on slope stability is nearly unknown. Therefore, it is still necessary to
develop a risk map for the narrow valley, with emphasis on gravitational hazards. 相似文献
10.
Causes and extent of environmental impacts of landslide hazard in the Himalayan region: a case study of Murree, Pakistan 总被引：2，自引：2，他引：0
Pakistan is located at the cross-roads of plate boundaries, experiencing multiple hazards of earthquake, flood, drought, water-logging, salinization and recurrent landslides. This paper examines the causes and environmental impacts of frequently occurring landslide hazards in the Murree area of Pakistan??s Himalayan region. These are wide ranging in nature and in terms of the damage that result. The area under research was divided into eight blocks and randomly data collected. It was observed that landslides mostly occur along the road network and disturbed slopes. Immature geology, a wide variation in climate and degradation of the natural resource-base were found to be some of the causal factors responsible for the landslide hazards. During the past three decades, rapid expansion of urban zones contributed to the changing vulnerability of the area. The analysis revealed that a large majority of the households (75%) in the area have been directly or indirectly affected by landslide hazards. Damages to already scarce agricultural land, infrastructure and other properties are each year a regular and escalating phenomenon. Landslide size, frequency and consequent costs of damage have increased considerably. 相似文献
11.
The Melfa River is a torrent of the intramontane Lower Liri Valley, which has been a difficult barrier to cross since ancient times. It is dry and can be forded during the summer, but it experiences high floods during rainy reasons, with recurrent disruption of bridges. In Iron Age and early Roman times, fords and bridges were located near the confluence of the river with the valley plain, servicing the ancient Via Pedemontana. Later, faster routes with bridges were moved toward the flatter central area of the valley. There, Romans selected a crossing through wide braided reaches, taking advantage of fording, but consistently losing low lying, long bridges. Traces of one and possibly two such bridges remain along what was the Via Latina, from Fregellae to Aquino. For such bridges, the Romans used relatively strong piers, probably linked with readily detachable (by floods) and replaceable, wooden, flat roadways. The strategy of Medieval and Modern civilizations was instead to bridge the river in a more permanent way, with arches across the nearby deep gorges whose banks are composed of stable calcareous conglomerates and sandstones. 相似文献
12.
随着长江上游梯级水库的陆续建成投运，三峡水库的水文情势和功能需求与设计条件相比发生了显著变化，仍维持固定的汛限水位运行已不能适应新形势需求。本文通过辨析三峡水库设计阶段汛限水位的设置条件，挖掘流域洪水特性和洪水遭遇规律，论证三峡水库汛期运行水位动态控制的可行性。结果表明：① 三峡水库设计推求的汛限水位145 m的适用条件是应对流域性大洪水，而流域性洪水发生概率小且特征明显，可以通过水文水情分析提前预判。② 根据流域洪水类型、洪水分期和遭遇规律，预判发生区域性大洪水时，三峡水库6月初至梅雨期结束汛限水位按145 m设置，从梅雨期结束后逐渐提高水位，8月20日后过渡到155 m。③ 在考虑上游水库群联合调度和气象水文预报的配合下，正常年份三峡水库汛期运行水位可在155 m上下浮动，并考虑提前蓄水。④ 三峡水库汛期运行水位动态控制，不会增加防洪风险和库区淤积风险，对中下游江湖关系和水文情势有利，可显著提高发电、航运、生态保护和供水等综合利用效益。 相似文献
13.
随着长江上游梯级水库的陆续建成投运，三峡水库的水文情势和功能需求与设计条件相比发生了显著变化，仍维持固定的汛限水位运行已不能适应新形势需求。本文通过辨析三峡水库设计阶段汛限水位的设置条件，挖掘流域洪水特性和洪水遭遇规律，论证三峡水库汛期运行水位动态控制的可行性。结果表明:①三峡水库设计推求的汛限水位145 m的适用条件是应对流域性大洪水，而流域性洪水发生概率小且特征明显，可以通过水文水情分析提前预判。②根据流域洪水类型、洪水分期和遭遇规律，预判发生区域性大洪水时，三峡水库6月初至梅雨期结束汛限水位按145 m设置，从梅雨期结束后逐渐提高水位，8月20日后过渡到155 m。③在考虑上游水库群联合调度和气象水文预报的配合下，正常年份三峡水库汛期运行水位可在155 m上下浮动，并考虑提前蓄水。④三峡水库汛期运行水位动态控制，不会增加防洪风险和库区淤积风险，对中下游江湖关系和水文情势有利，可显著提高发电、航运、生态保护和供水等综合利用效益。 相似文献
14.
The study examines the relationship between poverty and forest cover degradation in rural areas of Pakistan. The area selected for the study District Upper Dir is a rural and relatively backward region located in northwestern Pakistan, in Khyber-Pakhtunkhwa province. The study area is undergoing severe deforestation and natural disasters in the recent past. The study consists of two stages, in first stage the traditional Geographical information system image was used to analyze the spatial–temporal situation of the surroundings. In the second stage, well-designed questionnaire was used to collect the primary information from 420 randomly selected households of research areas. A multidimensional poverty index has been used to measure the poverty profile of the population. It has been found that 55% households were below the poverty line. Almost, 95% households are using wood for cooking purposes. High dependence on natural resources causes forest cover degradation while burning off too much wood causes CO2 emission and leads to environmental degradation. A major portion of population is living on steeply sloped areas with certain risks. It is found that frequency of flash flood is 53% and agricultural land (54%) is at high risk and often flows with flash floods. It is concluded that there is strong correlation between multidimensional poverty and forest cover degradation which leads to climate and environmental risks.
相似文献15.
This article attempts to analyse the nature, magnitude and causes of 2010 disastrous flood that seriously affected the province of Khyber Pakhtunkhwa (KPK), Pakistan. Pakistan is famous for its summer floods, but the flood of 2010 is considered to be the century’s worst. It has broken all the previous records in terms of discharge, damages and amount of rainfall occurred. Most of the meteorological stations have received rainfall above normal. Data for this study were collected both from primary and secondary sources. A total 150 questionnaires were filled in from the flood victims. However, secondary data were obtained from the Pakistan Meteorology Department, Flood Forecasting and Warning Centre, Federal Flood Commission, Provincial Disaster Management Authority, National Disaster Management Authority, Surface Water Hydrology Department and Provincial Irrigation and Drainage Authority. The analysis reveals that heavy and prolonged rainfall for four consecutive days (27–30 July) was the major cause of 2010-flood. In addition to this, the development of unusual low pressure zone over the northern Pakistan, aggradations of river bed, rapid deforestation, ponding back of river by motorway, blocking of bridges by tree trunks and subsequent bursting of temporary dams have played their role in causing the disastrous flood in almost all the rivers of KPK. This has inflicted terrible damages to human lives, standing crops, housing, infrastructure and other properties. 相似文献
16.
Lasafam Iturrizaga 《GeoJournal》2005,62(3-4):1-47
At least six devastating glacial floods occurred in the Karambar valley in the 19th and 20th century. Previously mainly the
Karambar glacier was considered as the origin of these outburst floods. However, in this project more detailed investigations
revealed that up to eight more tributary glaciers could have dammed the Karambar valley in historical and prehistorical times.
The ice-dammed lakes reached an approximate length of up to about 5 km and more. The dense concentration of the glacier dams
along a horizontal distance of only 40 km results in a complex interfingering of lake basins and flooded valley sections.
In the individual flood events were probably involved almost synchronously the drainage of at least two lakes resulting in
a lake outburst cascade.
The Karambar case study highlights the characteristic geomorphological landforms of the glacier dams, their lake basins and
the geomorphological impact of the outburst floods. The abundant occurrence of unconsolidated sediments mantling the valley
flanks caused a high sediment load and enhanced the erosion potential of the flood. The erosion cliffs of sediment cones,
up to 100 m high, wash limits along the slopes and longitudinal bars in the gravel floors are main characteristics of the
flood landscape. Secondary temporary lake formations (back water ponding) during the flood events in consequence of blockages
of the ice- and sediment-loaden flood masses occurred at many locations in the narrower valley sections and lasted for several
days. Additionally, debris flows in-between the glacier dams have dammed temporarily the Karambar valley. On the basis of
losses of settlement area and eye-witness reports, the extent, erosion rates and characteristics of the 1905 flood event could
be reconstructed. In order to warn the villagers living downstream, the Karambar people established an early warning fire
system (Puberanch) from Sokther Rabot to Gilgit which was operated until 1905. The reconstructed Karambar flood chronology represents one of
the longest records for this region and provides also information on historical and recent glacier oscillations, especially
on exceptional glacier advances. At present, the Chateboi glacier seals the Karambar valley over a distance of 4 km. An outburst
flood would have disastrous impacts to the human infrastructure as the settlement areas expanded to the flood plains in the
last decades. 相似文献
17.
Historical glacier-dammed lakes and outburst floods in the Karambar valley (Hindukush-Karakoram) 总被引：1，自引：0，他引：1
Lasafam Iturrizaga 《GeoJournal》2005,63(1-4):1-47
At least six devastating glacial floods occurred in the Karambar valley in the 19th and 20th century. Previously mainly the Karambar glacier was considered as the origin of these outburst floods. However, in this project more detailed investigations revealed that up to eight more tributary glaciers could have dammed the Karambar valley in historical and prehistorical times. The ice-dammed lakes reached an approximate length of up to about 5 km and more. The dense concentration of the glacier dams along a horizontal distance of only 40 km results in a complex interfingering of lake basins and flooded valley sections. In the individual flood events were probably involved almost synchronously the drainage of at least two lakes resulting in a lake outburst cascade. The Karambar case study highlights the characteristic geomorphological landforms of the glacier dams, their lake basins and the geomorphological impact of the outburst floods. The abundant occurrence of unconsolidated sediments mantling the valley flanks caused a high sediment load and enhanced the erosion potential of the flood. The erosion cliffs of sediment cones, up to 100 m high, wash limits along the slopes and longitudinal bars in the gravel floors are main characteristics of the flood landscape. Secondary temporary lake formations (back water ponding) during the flood events in consequence of blockages of the ice- and sediment-loaden flood masses occurred at many locations in the narrower valley sections and lasted for several days. Additionally, debris flows in-between the glacier dams have dammed temporarily the Karambar valley. On the basis of losses of settlement area and eye-witness reports, the extent, erosion rates and characteristics of the 1905 flood event could be reconstructed. In order to warn the villagers living downstream, the Karambar people established an early warning fire system (Puberanch) from Sokther Rabot to Gilgit which was operated until 1905. The reconstructed Karambar flood chronology represents one of the longest records for this region and provides also information on historical and recent glacier oscillations, especially on exceptional glacier advances. At present, the Chateboi glacier seals the Karambar valley over a distance of 4 km. An outburst flood would have disastrous impacts to the human infrastructure as the settlement areas expanded to the flood plains in the last decades. 相似文献
18.
Praveen K. Thakur Sreyasi Maiti Nanette C. Kingma V. Hari Prasad S. P. Aggarwal Ashutosh Bhardwaj 《Natural Hazards》2012,61(2):501-520
Vulnerability assessment of natural disasters is a crucial input for risk assessment and management. In the light of increasing
frequency of disasters, societies must become more disaster resilient. This research tries to contribute to this aim. For
risk assessment, insight is needed into the hazard, the elements at risk and their vulnerabilities. This study focused on
the estimation of structural vulnerability due to flood for a number of structural elements at risk in the rural area of Orissa,
India (Kendrapara), using a community-based approach together with geospatial analysis tools. Sixty-three households were
interviewed about the 2003 floods in 11 villages and 166 elements at risk (buildings) were identified. Two main structural
types were identified in the study area, and their vulnerability curves were made by plotting the relationships between flood
depth and vulnerability for each structural type. The vulnerability ranges from 0 (no damage) to 1 (collapse/total damage).
Structural type-1 is characterized by mud wall/floor material and a roof of paddy straw, and structural type-2 is characterized
by reinforced cement concrete (RCC) walls/floor and a RCC roof. The results indicate that structural type-1 is most vulnerable
for flooding. Besides flood depth, flood duration is also of major importance. Houses from structural type-1 were totally
collapsed after 3 days of inundation. Damage of the houses of structural type-2 began after 10 days of inundation. 相似文献
19.
Duane G Froese Derald G SmithJohn A Westgate Thomas A AgerShari J Preece Amanjit SandhuRandolph J Enkin Florence Weber 《Quaternary Research》2003,60(1):50-62
Recurring glacial outburst floods from the Yukon-Tanana Upland are inferred from sediments exposed along the Yukon River near the mouth of Charley River in east-central Alaska. Deposits range from imbricate gravel and granules indicating flow locally extending up the Yukon valley, to more distal sediments consisting of at least 10 couplets of planar sands, granules, and climbing ripples with up-valley paleocurrent indicators overlain by massive silt. An interglacial organic silt, occurring within the sequence, indicates at least two flood events are associated with an earlier glaciation, and at least three flood events are associated with a later glaciation which postdates the organic silt. A minimum age for the floods is provided by a glass fission track age of 560,000 ± 80,000 yr on the GI tephra, which occurs 8 m above the flood beds. A maximum age of 780,000 yr for the floods is based on normal magnetic polarity of the sediments. These age constraints allow us to correlate the flood events to the early-middle Pleistocene. And further, the outburst floods indicate extensive glaciation of the Yukon-Tanana Upland during the early-middle Pleistocene, likely representing the most extensive Pleistocene glaciation of the area. 相似文献
20.
Alejandro Dussaillant Wouter Buytaert Paul Carling Claudio Meier Fabián Espinoza 《Natural Hazards》2010,54(2):469-481
Five similar glacial-lake outburst floods (GLOFs) occurred in April, October, December 2008, March and September 2009 in the Northern Patagonia Icefield. On each occasion, Cachet 2 Lake, dammed by the Colonia Glacier, released circa 200-million m3 water into the Colonia River. Refilling has occurred rapidly, such that further outbreak floods can be expected. Pipeflow calculations of the subglacial tunnel drainage and 1D hydraulic models of the river flood give consistent results, with an estimated peak discharge surpassing 3,000 m3 s?1. These floods were larger in magnitude than any flood on record, according to gauged data since 1963. However, geomorphological analysis of the Colonia valley shows physical evidence of former catastrophic outburst floods from a larger glacial-lake, with flood discharges possibly as high as 16,000 m3 s?1. Due to potential impacts of climate change on glacier dynamics in the area, jökulhlaups may increase future flood risks for infrastructure and population. This is particularly relevant in view of the current development of hydropower projects in Chilean Patagonia. 相似文献