scholarly journals Flood Modeling Assessment: A Case of Bishnumati River

2020 ◽  
Vol 20 (1) ◽  
pp. 31-37
Author(s):  
Noor Dangol

Flood, a common water induced disaster of a monsoon season, is the recurring phenomenon in Nepal. To study this disaster, different flood modelling had been conducted for different river basins following different modelling tools. This study describes the technical approach of probable flood vulnerability and hazard analysis of Bishnumati river catchment and analyze the result with previous study done for the same study area. The method adopted for previous study in 2009 was adopted in this study as well in order to compare the results. One dimensional hydraulic model HEC-RAS with HEC GeoRAS interface in co-ordination with Arc GIS was applied for the analysis.. Hazard maps, landuse vulnerability maps of various return periods (10 Yrs, 20Yrs, 50Yrs and 100Yrs), were prepared in ArcGIS. The results of flood frequency analyzed by WECS/ DHM method showed discharges of 445 m³/s, 541m³/s, 648m/s, 725 m³/s for 10, 20, 50 and 100 years return period floods. The primary data of the study showed most of the flooding area had water depth greater than 3m. The assessment of the flood inundated area showed that large percentage of vulnerable area lied in built up areas followed by barren land.

2009 ◽  
Vol 9 (3) ◽  
pp. 751-766 ◽  
Author(s):  
A. M. Youssef ◽  
B. Pradhan ◽  
A. F. D. Gaber ◽  
M. F. Buchroithner

Abstract. Geomophological hazard assessment is an important component of natural hazard risk assessment. This paper presents GIS-based geomorphological hazard mapping in the Red Sea area between Safaga and Quseir, Egypt. This includes the integration of published geological, geomorphological, and other data into GIS, and generation of new map products, combining governmental concerns and legal restrictions. Detailed geomorphological hazard maps for flooding zones and earth movement potential, especially along the roads and railways, have been prepared. Further the paper illustrates the application of vulnerability maps dealing with the effect of hazard on urban areas, tourist villages, industrial facilities, quarries, and road networks. These maps can help to initiate appropriate measures to mitigate the probable hazards in the area.


2021 ◽  
Vol 15 (2) ◽  
pp. 221-234
Author(s):  
Crina Radu ◽  
Andreea Beteringhe ◽  
Marius Andrei Raduc

The study aims to analyze the vulnerability of floods and their impact in the Giulești-Sârbi area, the marginal northwestern neighborhood of Bucharest. The location of the accumulation lake has hydrological importance for the studied area. The anthropogenic dam is one of the susceptible sources of floods, but the most inefficiency of the sewage system is the actual principal cause, which frequently flows back when there are significant increases in rainfall. The motivation for choosing the study is represented by the vulnerability of the Giulești-Sârbi area and by the lack of a study on flood vulnerability and frequency in the area. A questionnaire was also applied locally, some of the results being presented in this paper. The main objectives of the study refer to the spatialization at the street level of the vulnerability of floods and their following impact. It also compares the vulnerability of floods after two key periods: before and after the construction of the dam, respectively 1980 and 2020 – for the comparison and evolution of terrain changes. The problem was also analyzed by the vulnerability related to the slope, land use and geological characteristics. The results show that the Giulești-Sârbi neighborhood is still susceptible to floods. The most affected streets are those from the southeastern part of the neighborhood and punctually to the NW. On the other hand, the application of the questionnaire shows that the southernmost street (Răsadniței Street) did not register problems as often as the current hazard maps from the rowater.ro source for which the highest vulnerability was expected to show. The areas indicating problems according to the questionnaires and Romanian Waters National Administration maps largely coincide with the results of the vulnerability maps resulting in this paper. The main solution that can reduce the effect of flood vulnerability is the modernization of the sewage system.


2014 ◽  
Vol 11 (5) ◽  
pp. 5463-5485 ◽  
Author(s):  
J. Herget ◽  
T. Roggenkamp ◽  
M. Krell

Abstract. There is no doubt, that the hazard assessment of future floods especially under consideration of the recent environmental change can be significantly improved by the consideration of historic flood events. While flood frequency inventories on local, regional and even European scale are already developed and published, the estimation of their magnitudes indicated by discharges is still challenging. Such data are required due to significant human impact on river channels and floodplains though historic flood levels cannot be related to recent ones or recent discharges. Based on own experiences from single local key studies the general outline of an approach to estimate the discharge of the previous flood based on handed down flood level and topographic data is presented. The model for one-dimensional steady flow is based on the empirical Manning equation for the mean flow velocity. Background and potential sources of information, acceptable simplifications and data transformation for each element of the model-equation are explained and discussed. Preliminary experiences on the accuracy of ±10% are documented and potential approaches for the validation of individual estimations given. A brief discussion on benefits and limitations including a generalized statement on alternative approaches closes the review presentation of the approach.


2017 ◽  
Vol 13 ◽  
pp. 52-57
Author(s):  
Susheel Dangol

Flood is one of the striking water induced disaster that hits most of the part of the world. In Nepal also it is one of the serious disasters which affect the study describes the technical approach of probable flood hazard analysis. Segment of Balkhu River within the Balkhu catchment of area 44.37 km2 from Kirtipur gorge to Bagmati confluence was taken as area of study. The total length of the study segment was 5485.89 m. One dimension HEC-RAS (Hydrologic Engineering Center-River Analysis System) model was used for the analysis. The study shows that higher flood depth increases and low flood depth decreases with increase in intensity of flood. Also, huge area of barren land area is affected by flood and few percentage of settlement area is affected by flood indicating the damages to the human lives. Huge area of barren land indicates that in future human lives are more prone to disasters as those lands have gone through planning for future settlement.Nepalese Journal on Geoinformatics -13, 2014, Page: 52-57


2011 ◽  
Vol 11 (4) ◽  
pp. 1141-1151 ◽  
Author(s):  
I. Poretti ◽  
M. De Amicis

Abstract. In the Lombardy Region, as in many other contexts all over the world, hazard maps do not have a precise legislative confirmation. Despite this, they are necessary to support several institutional activities, and among these, local urban planning. An approach to hazard analysis and mapping that fits the Lombardy Region legislative framework is presented here that introduces a level of experimental modelling, making use of SOBEK 1-D–2-D as a tool for hydrodynamic simulations. A stretch of 17 km of the Adda river in Valtellina has been modelled, referring to twelve scenarios characterised by different temporal probabilities, and comprising the main sources of uncertainty. The results were compared with available local hydraulic studies, and combined to obtain two complementary flood hazard maps which could usefully support urban planning. Advantages and drawbacks of this modelling approach, together with considerations related to flood hazard mapping are discussed.


Geosciences ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 24 ◽  
Author(s):  
Mohamed Saber ◽  
Karim I. Abdrabo ◽  
Omar M. Habiba ◽  
Sameh A. Kantosh ◽  
Tetsuya Sumi

Urban growth, extreme climate, and mismanagement are crucial controlling factors that affect flood vulnerability at wadi catchments. Therefore, this study attempts to understand the impacts of these three factors on the flash flood vulnerability in different climatic regions in Egypt. An integrated approach is presented to evaluate the urban growth from 1984 to 2019 by using Google Images and SENTINEL-2 data, and to develop hazard maps by using a rainfall-runoff-inundation model (RRI). Annual rainfall trend analysis was performed to evaluate the temporal variability trend. The hazard maps that were created were classified into three categories (low, medium, and high) and integrated with the urban growth maps to evaluate the impacts on the flood-vulnerable areas. The results show a significant increase in urban growth resulting in an increase of prone areas for flood hazards over time. However, the degree of this hazard is mainly related to growth directions. Mismanagement affects urban growth directions in both planned and unplanned growth, whether by loss of control over unplanned growth or by deficiencies in approved plans. The rainfall analysis showed that there is no explicit relationship to increases or decreases in the flood vulnerable areas. An urban planning approach is recommended for risk reduction management based on a comprehensive study considering such factors.


2020 ◽  
Vol 20 (6) ◽  
pp. 1639-1661
Author(s):  
Khalid Mahmood ◽  
Naveed Ahmad ◽  
Usman Khan ◽  
Qaiser Iqbal

Abstract. Probabilistic seismic hazard analysis of Peshawar District has been performed for a grid size of 0.01∘. The seismic sources for the target location are defined as the area polygon with uniform seismicity. The earthquake catalogue was developed based on the earthquake data obtained from different worldwide seismological networks and historical records. The earthquake events obtained at different magnitude scales were converted into moment magnitude using indigenous catalogue-specific regression relationships. The homogenized catalogue was subdivided into shallow crustal and deep-subduction-zone earthquake events. The seismic source parameters were obtained using the bounded Gutenberg–Richter recurrence law. Seismic hazard maps were prepared for peak horizontal acceleration at bedrock level using different ground motion attenuation relationships. The study revealed the selection of an appropriate ground motion prediction equation is crucial for defining the seismic hazard of Peshawar District. The inclusion of deep subduction earthquakes does not add significantly to the seismic hazard for design base ground motions. The seismic hazard map developed for shallow crustal earthquakes, including also the epistemic uncertainty, was in close agreement with the map given in the Building Code of Pakistan Seismic Provisions (2007) for a return period of 475 years on bedrock. The seismic hazard maps for other return periods i.e., 50, 100, 250, 475 and 2500 years, are also presented.


2017 ◽  
Vol 14 ◽  
pp. 20-24
Author(s):  
Susheel Dangol ◽  
Arnob Bormudoi

Flood is one of the striking water induced disaster that hits most of the part of the world. In Nepal also it is one of the serious disasters which affect the human lives and huge amount of property. The increase of population and squatter settlements of landless people living at the bank of the river has tremendous pressure in encroachment of flood plain making them vulnerable to the flood damage. The study describes the technical approach of probable flood vulnerability and flood hazard analysis. Bishnumati catchment was taken as area of study. One dimension model of HEC-RAS with HEC-GeoRAS interface in co-ordination with ArcGIS was applied for the analysis. Analysis shows that the flood area increases with flood intensity. Higher flood depth increases and lower flood depth decreases with increase in intensity of flood. Inundation of huge area of urban land indicates that in future human lives are more prone to flood disaster. Thus, the study may help in future planning and management for future probable disaster.Nepalese Journal on Geoinformatics, Vol. 14, 2015, page: 20-24


2014 ◽  
Vol 46 (1) ◽  
pp. 22 ◽  
Author(s):  
Dewi Susiloningtyas ◽  
Mennopatria Boer ◽  
Luky Adrianto ◽  
Fredinand Julianto

This paper was based on primary data from Lombok squid fishermen communities. The presence of fishermanmigrants in fishing activities at salura island is very important for their livelihood. The purpose of this study wasdetermined the catch in different season influenced by the duration time of migration and fishing assets. Fishing assetsdescribed of number of fishing gear, number of boat, and number of engine. Duration time described are length of stayat located of migration and frequency of migration. Data were analyzed by regression statistic analysis. The results is thatfishing assets of fishing gear have influenced to cacth both on east monsoon and west monsoon season. Then lengthof stay at the destination of migration affect the catch too, when the squid are abundant in the east monsoon season.


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