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1.
Atif  Salman  Umar  Muhammad  Ullah  Fahim 《Natural Hazards》2021,108(2):2357-2383

While historically significant for ancient civilizations, the Indus basin is also known for its floods and complex anthropogenic management history. Resulting from years of modifications by the pre-British era Mughal rulers followed by the post-partition division of river waters among the two neighbors, India and Pakistan, Pakistan faces severe management and financial challenges of water management. This study investigates the intricacies arising from this complicated management doctrine for the lower Indus basin. A detailed remote sensing-based analysis of the significant floods to hit the lower Indus basin since 2000 has been provided. Flood years were identified, and Moderate Resolution Imaging Spectroradiometer (MODIS) data for the years 2003, 2005, 2006, 2010, 2011, 2012, 2015, and 2016 were used to map their spatiotemporal extents. Almost all the flood water accumulated in the north is released in one river channel of the lower Indus basin. Further, the challenges were exacerbated due to the excessive rainfall in 2011 and 2012 in southeastern Sindh. A trend analysis of rainfall data shows an increase in the southern basin in the last 21 years, particularly toward the central plains and Sindh Province. The floodwater accumulated in the lower basin for as many as?~?425 days on average, stretching to?~?800 days of stagnancy in some places. The water stagnation period has been the highest in the river floodplain, highly populated and cultivated. The analyses of the current study suggest that the riverine channel has been better managed after the 2010 floods; however, the monsoon’s shift in 2011 and 2012 led to widespread disaster in low-lying regions of Sindh Province.

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2.
Pakistan has experienced severe floods over the past decades due to climate variability. Among all the floods, the flood of 2010 was the worst in history. This study focuses on the assessment of (1) riverine flooding in the district Jhang (where Jhelum and Chenab rivers join, and the district was severely flood affected) and (2) south Asiatic summer monsoon rainfall patterns and anomalies considering the case of 2010 flood in Pakistan. The land use/cover change has been analyzed by using Landsat TM 30 m resolution satellite imageries for supervised classification, and three instances have been compared, i.e., pre-flooding, flooding, and post-flooding. The water flow accumulation, drainage density and pattern, and river catchment areas have been calculated by using Shutter Radar Topography Mission digital elevation model 90 m resolution. The standard deviation of south Asiatic summer monsoon rainfall patterns, anomalies and normal (1979–2008) has been calculated for July, August, and September by using rainfall data set of Era interim (0.75° × 0.75° resolution). El Niño Southern Oscillation has also been considered for its role in prevailing rainfall anomalies during the year 2010 over Upper Indus Basin region. Results show the considerable changing of land cover during the three instances in the Jhang district and water content in the rivers. Abnormal rainfall patterns over Upper Indus Basin region prevailed during summer monsoon months in the year 2010 and 2011. The El Niño (2009–2010) and its rapid phase transition to La Niña (2011–2012) may be the cause of severity and disturbances in rainfall patterns during the year 2010. The Geographical Information System techniques and model based simulated climate data sets have been used in this study which can be helpful in developing a monitoring tool for flood management.  相似文献   

3.
Forest fire can modify and accelerate the hydrological response of Mediterranean basins submitted to intense rainfall: during the years following a fire, the effects on the hydrological response may be similar to those produced by the growth of impervious areas. Moreover, climate change and global warming in Mediterranean areas can imply consequences on both flash flood and fire hazards, by amplifying these phenomena. Based on historical events and post-fire experience, a methodology to interpret the impacts of forest fire in terms of rainfall-runoff model parameters has been proposed. It allows to estimate the consequences of forest fire at the watershed scale depending on the considered burned area. In a second stage, the combined effect of forest fire and climate change has been analysed to map the future risk of forest fire and their consequence on flood occurrence. This study has been conducted on the Llobregat river basin (Spain), a catchment of approximately 5,000 km2 frequently affected by flash floods and forest fires. The results show that forest fire can modify the hydrological response at the watershed scale when the burned area is significant. Moreover, it has been shown that climate change may increase the occurrence of both hazards, and hence, more frequent severe flash floods may appear.  相似文献   

4.
A geomorphologic and morphometric analysis was performed to determine the characteristics of the de La Flecha river basin, located in the southwest of San Juan province (31°50′S, 68°57′W), Precordillera of San Juan. The drainage networks were derived from shuttle radar topographic mission (SRTM), satellite imageries (Landsat TM and Spot image) and field works. The paper also addresses a preliminary evaluation of the flood hazard responsible for severe damage to people and infrastructure in the downstream region. The study area covers about 300 km2, comprising of six sub-watersheds, ranging from 31.7 to 81.8 km2. The irregular morphology of the basin and the diversity of alluvial deposits found along the de La Flecha river allow the authors to infer that it is in an active tectonic environment with strong lithological and structural controls. One feature common to all analyzed sub-basins is their elongated shape, which allows for a rapid concentration of water that intensifies the power of the flash floods. The drainage network in the different sub-basins has, in general, two predominant patterns; one is parallel to sub-parallel to the headers and foothill areas; and the other, in the alluvial zone, is divergent. Los Berros, Cañada Honda and Media Agua towns, located downstream of the basin, are the most affected by flash floods coming from the mountainous area.  相似文献   

5.
Pakistan is exposed to numerous hazards, but the problem of recurrent floods has been causing massive losses to lives and other properties. Swat valley is no exception to it. In this paper, an attempt has been made to analyse the causes and associated socio-economic impacts of floods on the Swat valley, Pakistan. Swat valley falls in the Hindukush region, North-west-Pakistan. The valley has been studied with special reference to its physical and socio-economic environment. Similarly, three-sample villages were also randomly selected from the active floodplain for micro-level analysis. The sample villages include Ningolai, Delay and Ghureijo. All the three-sample communities are located on the right bank of river Swat. This area is located in the active flood zone of Swat valley. The analysis revealed that in the study area, floods occur during summer season, which is mainly caused by heavy rainfall as well as rapid melting of snow and glacier. Besides these, there are some floods intensifying factors, which accelerate intensity of floods and enhance resultant damages in the valley. It was found that during flood season, water overflows the natural levees and trigger tremendous loses to housing, agricultural land, standing crops and other properties. The flood-related Government Departments have only implemented limited structural mitigation measures. However, in addition to structural measure, land-use zoning and flood abatement strategies would largely help in reducing the adverse consequences of this recurrent phenomenon.  相似文献   

6.
Debris flow is one of the most serious and frequent geological disasters that occur in the Loess Plateau. The outbreak of a debris flow is sudden, ferocious, swift, and destructive. The characteristics and mechanism of debris flow were explored in this study via survey, numerical simulation, and simulation analysis in a Loess Plateau area (Huangling County, Shaanxi Province, China). Numerical models and formulas corresponding to the occurrence and movement mechanism were established based on the HEC-RAS, HEC-GeoRAS, and SWAT results. The range of debris flow deposition was determined through capturing the debris flow free surface. A hydrological model and critical rainfall threshold were determined in order to provide technical support for debris flow forecasting in the Loess Plateau. The results suggest that 10-year floods do not submerge any portion of the basin. One village area was affected by the 100-year flood (total area of 0.648 km2) while four villages areas were submerged by the 1000-year flood (total area of 1.39 km2). The method presented here may provide a reliable scientific basis for mitigating loss due to debris flow hazards.  相似文献   

7.
Knowledge of Himalayan cryosphere seems to be an outstanding requirement for assessment of glacier storage, water balance analysis, planning of water resources and flood hazard monitoring. A stepwise approach through mapping glaciers and glacial lakes using satellite remote sensing data and investigating potential glacial lake outburst flood (GLOF) hazards was adopted for the three Hindukush, Karakoram and Himalayan (HKH) ranges of Pakistan. The findings of the study revealed 5,218 glaciers in the cryosphere of HKH ranges. The cumulative glacial cover of over 15,000 km2 contains ice reserves of about 2,738 km3. About 46 % of the Karakoram glaciers are contributing 77 % to the total glacial cover and 87 % to the cumulative ice reserves of the country. The 33 % Himalayan glaciers and 21 % Hindukush glaciers contribute only 3 and 10 % ice reserves, respectively. Among 2,420 glacial lakes identified in the three HKH ranges, 52 were classified as critical lakes that can pose GLOF hazard for the downstream communities. Most of the potential hazardous lakes lie in the Karakoram and Himalayan ranges, the monitoring of which is crucial to reduce high risk of future floods hazard in this fragile mountain ecosystem of the Himalayan region.  相似文献   

8.
Hydrological parameters are among the widely used parameters in assessing flood risk. On the other hand, anticipated flood damages, in case of flooding, are estimated with the help of expected losses in areas nearer to the watercourse. The major source of almost every-year flooding in Pakistan is the Indus River system that comprises the major rivers of Pakistan. We first use observed data to construct simulated data models based on various probability distributions namely normal, lognormal, Weibull, largest extreme value, gamma-3, and log-Pearson type-3 distributions and thereby compute probable maximum flood. Secondly, we perform log-Pearson type-3 analysis with and without historic adjustment on the observed data series of 17 years to forecast floods with return periods T of 2, 5, 10, 25, 50, 100, and 200 years. We also categorize the river structures based on the risk of flooding. Lastly, we estimate risk of flood damages in terms of expected losses based on observed data. The present study reveals that the log-Pearson type-3 distribution is relatively better for estimating probable maximum flood. We use exceedence probability to assess the risk of flooding in the various structures of the said rivers. The analysis shows that flood damages in Pakistan may be reduced by increasing the design capacity of the structures and also by giving awareness to people about the flood-generating factors.  相似文献   

9.
This work analyzes various morphometric characteristics of the Colangüil river basin in order to evaluate flash flood hazards. Such high-water events pose a risk to the similarly named small village located at the basin’s foot area. For this purpose, the basin is divided into seven sub-basins and some basic measurements (surface, perimeter, basin length, river beds, elevations and slope of the main river bed, and of a number of minor river beds) are calculated. These measurements permit to predict approximately the behavior of the basin in the presence of a series of theoretical rainstorms that may generate unusual runoff volumes that make up such flash floods.  相似文献   

10.
Mahmood  Shakeel  Hamayon  Kiran 《Natural Hazards》2021,106(3):2825-2844
Natural Hazards - Pakistan is exposed to hydro-meteorological and geological hazards. Flood is one of the hydro-meteorological hazards, and so far 25 major floods have occurred in Indus River...  相似文献   

11.
Subansiri?CRanganadi Doab (confluence country), located in Lakhimpur district, Assam, is one of the worst flood-affected areas in Brahmaputra valley. The Doab is well populated, and land around these rivers is extensively used for cultivation. As means of flood protection, embankments were constructed in the 1950s along the banks of both the rivers. On the other hand, these rivers are dynamic in terms of banklines and other forms of channel changes. Progressive migration of bankline, due to erosion, results in loss of cultivable land. Moreover, it causes breaches in the embankments increasing the severity of flood in the Doab. This paper attempts to study the changes in the banklines of two major rivers in the floodplains of the Subansiri?CRanganadi Doab during 1997?C2009 in the context of the riverine hazards it brings to the floodplain dwellers. The shift of the banklines in Subansiri?CRanganadi Doab, downstream of North Lakhimpur, has been estimated using IRS LISS imageries of 1997 and 2009 in GIS environment. The river Subansiri during the study period has migrated westward and has widened substantially resulting in erosion of an area of ~19.137?km2. For Ranganadi, the total area that has been eroded due to channel changes is ~0.897?km2. The channel changes are mainly due to concave bank erosion associated with high stages of flow. Channel widening in Subansiri and Ranganadi in the study area during the decades of 1990s and 2000 has led to frequent breaches in the embankments. Lateral erosion and inundation due to embankment failure are the most dominant facets of riverine hazards in the study area as these lead to loss of livelihood. Therefore, it is necessary to incorporate geomorphic changes in formulating flood management programmes.  相似文献   

12.
Flood risk assessment of River Indus of Pakistan   总被引：1，自引：1，他引：0  
Annual flood peak discharges is widely used in risk assessment. Major sources of flooding in Pakistan are River Jhelum, River Chenab, River Kabul, and upper and lower parts of River Indus. These rivers are major tributaries of the River Indus System which is one of the most important systems of the world and the greatest system of Pakistan. River Indus is the longest river of Pakistan containing seven gauge stations and several barrages, and it plays a vital role in the irrigation system and power generation for the country. This paper estimates the risk of flood in River Indus using historical data of maximum peak discharges. On the basis of our analysis, we find out which dam/barrage reservoir need to be updated in capacity, and whether there are more dams/barrages needed.  相似文献   

13.
This paper deals with the presentation of a flood warning system (GFWS) developed for the specific characteristics of the Guadalhorce basin (3,200 km2, SE of Spain), which is poorly gauged and often affected by flash and plain floods. Its complementarity with the European flood alert system (EFAS) has also been studied. At a lower resolution, EFAS is able to provide a flood forecast several days in advance. The GFWS is adapted to the use of distributed rainfall maps (such as radar rainfall estimates), and discharge forecasts are computed using a distributed rainfall–runoff model. Due to the lack of flow measurements, the model parameters calibrated on a small watershed have been transferred in most of the basin area. The system is oriented to provide distributed warnings and fulfills the requirements of ungauged basins. This work reports on the performance of the system on two recent rainfall events that caused several inundations. These results show how the GFWS performed well and was able to forecast the location and timing of flooding. It demonstrates that despite its limitations, a simple rainfall–runoff model and a relatively simple calibration could be useful for event risk management. Moreover, with low resolution and long anticipation, EFAS appears as a good complement tool to improve flood forecasting and compensate for the short lead times of the GFWS.  相似文献   

14.
Flood mapping requires the combination and integration of geomorphological and hydrological-hydraulic methods; however, despite this, there is very little scientific literature that compares and validates both methods. Two types of analysis are addressed in the present article. On the one hand, maps of flood plains have been elaborated using geomorphological evidence and historical flood data in the mountainous area of northwestern Spain, covering an area of more then 232 km2 of floodplains. On the other hand, a hydrometeorological model has been developed (Clark semidistributed unit hydrograph) in the Sarria River basin (155 km2, NW Spain). This basin is not gauged, hence the model was subjected to a goodness-of-fit test of its parameter (curve number) by means of Monte Carlo simulation. The peak flows obtained by means of the hydrological model were used for hydraulic modeling (one-phase, one-dimensional and steady flow) in a 4 km2 urban stretch of the river bed. The delineation of surface areas affected by floods since 1918, as well as those analyzed subsequent to the geomorphological study, reveals a high degree of reliability in the delineation of the flooded areas with frequent recurrence intervals (<50 years). If we compare these flooded surface areas with the estimate obtained by the hydrological-hydraulic method we can see that the latter method overestimates the extent of the surface water by 144% for very frequent recurrence intervals (>10 years) and underestimates it as the recurrence interval increases, by up to 80% less floodplain for exceptional events (>500 years). Finally, a management map is put forth combining the most reliable results available by integrating both methods. Originally presented at the Sixth International Conference on Geomorphology.  相似文献   

15.
The tannery effluents discharged by the existing units on either side of the Palar river at Ambur town (known for tannery industry), has resulted in vertical and lateral spread of pollution. The study area of 55.3 km2 is situated on a granitic terrain of Archaean age with undulating topography and hillocks. The shallow aquifers, in flood plain and valley fills of the river are highly polluted (with EC: 15340 μS/cm) by tannery effluents making groundwater unfit for any use, hence the local population (20000) face health hazards and shortage of potable water. Hydrogeological, geophysical and in-situ groundwater quality measurement were carried out to demarcate fresh groundwater zones and to delineate lateral and vertical extent of pollution. The results show, brackish aquifer was characterized by low order of resistivity (<20 Ω-m) with a thickness of 8.5 to 28 m located in the flood plains, valley fills, and partially in hard rock formations, whereas the fresh water aquifer resistivity varying from 23 to 216 Ω-m in hard rock. Further, these results were correlated with the water quality data and Ground Penetrating Radar (GPR) signals. The integrated studies revealed that pollution due to tannery effluents has spread over an area of 33.4 km2 (60.4 %) on either side of the river and only a small area of 21.9 km2 (39.6 %) was identified as fresh groundwater zone, which has to be conserved and exploited in sustainable manner for future generations.  相似文献   

16.
The main objective of the study was to assess the integrated multiple hydrological hazards and their environmental and socio-economic risks in Himalaya through geographical information system (GIS) and database management system (DBMS). The Dabka Watershed constitutes a part of the Kosi Basin in the Kumaun Lesser Himalaya has been selected for the case illustration. The Dabka DBMS is constituted of three GIS modules, that is, geo-informatics, hydro-informatics and hazard-informatics. Through the integration and superimposing of these modules prepared Hydrological Hazard Index to identify the level of vulnerability for existing hydrological hazards and their socio-economic and environmental risks. The results suggested that geo-environmentally most stressed barren land areas have high rate of runoff, flood magnitude, erosion sediment load and denudation during rainy season particularly in the month of August (i.e., respectively, 84.56 l/s/km2, 871.80 l/s/km2, 78.60 t/km2 and 1.21 mm/year), which accelerates high hazards and their socio-economic and environmental risks, whereas geo-environmentally least stressed dense forest areas experience low rate of stream runoff, flood magnitude, erosion sediment load and denudation in the same season and month (i.e., respectively, 20.67 l/s/km2, 58.12 l/s/km2, 19.50 t/km2 and 0.20 mm/year) comparatively have low hazards and their socio-economic and environmental risks. The other frazzled geo-environment that also found highly vulnerable for natural hazards and their risks is agricultural land due to high stream runoff, flood magnitude, erosion sediment load and denudation rates (i.e., respectively, 53.15 l/s/km2, 217.95 l/s/km2, 90.00 t/km2 and .92 mm/year). This makes it necessary to take up an integrated and comprehensive sustainable land use policy for the entire Himalaya region based on the scientific interpretation of the crucial linkages between land use and hydrological hazards, that is, floods, erosion, landslides during rainy season and drought due to dry-up of natural springs and streams during summer season. The study would help the village, district and state development authority to formulate decision support system for alternate planning and management for the Himalaya region.  相似文献   

17.
Dwarka River Basin is one of the fluoride affected river basin in Birbhum, West Bengal. In the present research work, various controlling factors for fluoride contamination in groundwater i.e., geology, aquifer type, groundwater table, soil, rainfall, geomorphology, drainage density, land use land cover, lineament and fault density, slope and elevation were considered to delineate the potential fluoride contamination zones within Dwarka River Basin in Birbhum. Assigning weights and ranks to various inputs factor class and their sub-class respectively was carried out on the basis of knowledge driven method. Weighted overlay analysis was carried out to generate the final potential fluoride contamination zones which are classified into two broad classes i.e., ‘high’ and ‘low’, and it is observed that major portion of the study area falls under low fluoride contamination category encompassing 88.61% of the total area which accounts for 759.48 km2 and high fluoride contaminated region accounts for 11.40% of the total study area encompassing an area of about 97.67 km2. Majority of high fluoride areas fall along the flood plain of Dwarka River Basin. Finally, for validation 197 reported points within Dwarka having fluoride in underground water are overlaid and an overall accuracy of 92.15% is observed. An accuracy of 83.21% and 84.24% is obtained for success and prediction rate curve respectively.  相似文献   

18.
Glacial lake outburst flood (GLOF) is a powerful natural phenomenon that is very active in the Karakoram and Himalayas. This paper presents a case study from Gupis Tehsil in northern areas of Pakistan that is exposed to GLOFs from nine different glacial lakes in its upper catchment areas. Khukush Lake being the largest of all the glacial lakes has been studied and a flood attenuation model has been created for the whole Gupis Tehsil. This lake covers almost 2.2 km2 of surface area, and its calculated volume is 2.6 × 104 m3. In case of its outburst, the peak flow discharge is calculated to be 7,642 m3/s. The catchment area which contributes water and debris to the lake is 170 km2. This lake is dammed by a glacial moraine, which is not strong enough to sustain the pressure for a longer period of time. Other factors that are reducing the reliability of the dam are the secondary hazards which are in direct contact with the lake, and in case of their reactivation, they can put severe impacts on the dam. There are eight potential sites of the snow avalanche activity where debris along with snow may fall directly into the lake producing a strong wave. This strong wave of water will increase the pressure on the dam and ultimately will increase the probability for its outburst. The presense of water springs towards the downstream side of the natural dam also indicate the presence of hidden channels passing through the dam which may weaken the shear strength of the dam. Almost 24 villages settled along either sides of the Gupis River are critically studied for the expected flood from Khukush Lake. With few exceptions, almost 20–25 % area of all the villages will be affected from this flood.  相似文献   

19.
Extreme sea-level events (e.g. caused by storm surges) can cause coastal flooding, and considerable disruption and damage. To understand the impacts or hazards expected by different sea levels, waves and defence failures, it is useful to monitor and analyse coastal flood events, including generating numerical simulations of floodplain inundation. Ideally, any such modelling should be calibrated and validated using information recorded during real events, which can also add plausibility to synthetic flood event simulations. However, such data are rarely compiled for coastal floods. This paper demonstrates the capture of such a flood event dataset, and its integration with defence and floodplain modelling to reconstruct, archive and better understand the regional impacts of the event. The case-study event comprised a significant storm surge, high tide and waves in the English Channel on 10 March 2008, which resulted in flooding in at least 37 distinct areas across the Solent, UK (mainly due to overflow and outflanking of defences). The land area flooded may have exceeded 7 km2, with the breaching of a shingle barrier at Selsey contributing to up to 90 % of this area. Whilst sea floods are common in the Solent, this is the first regional dataset on flood extent. The compilation of data for the validation of coastal inundation modelling is discussed, and the implications for the analysis of future coastal flooding threats to population, business and infrastructure in the region.  相似文献   

20.
In arid and semiarid areas, the only surface and groundwater recharge source is the runoff generated through flash floods. Lack of hydrological data in such areas makes runoff estimation extremely complicated. Flash floods are considered catastrophic phenomena posing a major hazardous threat to cities, villages, and their infrastructures. The objective of this study is to assess the flash flood hazard and runoff in Wadi Halyah and its sub-basins. Integration of morphometric parameters, geo-informatics, and hydrological models has been done to overcome the challenge of scarcity of data.Advanced Spaceborne Thermal Emission and Reflection (ASTER) data was used to prepare a digital elevation model (DEM) with 30-m resolution, and geographical information system (GIS) was used in the evaluation of network, geometry, texture, and relief features of the morphometric parameters. Thirty-eight morphometric parameters were estimated and have been linked together for producing nine effective parameters for evaluation of the flash flood hazard in the study basin.Flash flood hazard in Wadi Halyah and its sub-basins was identified and grouped into three classes depending on nine effective parameters directly influencing the flood prone areas. Calculated runoff volume of Wadi Halyah ranges from 26.7 × 106 to 111.4 × 106 m3 with an inundation area of 15 and 27 km2 at return periods of 5 and 100 years, respectively. Mathematical relationships among rainfall depth, runoff volume, infiltration losses, and rainfall excess demonstrate a strong directly proportional relationships with correlation coefficient of about 0.99.  相似文献   

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