scholarly journals ASSESSMENT OF VULNERABILITY IN AGRICULTURAL LAND IN FLOOD PRONE AREAS AND APPLICATION OF MOBILE SMART PHONE IN PROVIDING FLOOD HAZARD INFORMATION IN LAM RIVER BASIN (VIETNAM)

2021 ◽  
Vol 13 (2) ◽  
pp. 254-264
Author(s):  
Nguyen DUNG ◽  
◽  
Dang MINH ◽  
Bui AN ◽  
Nguyen NGA ◽  
...  
Keyword(s):  
River Basin ◽  
Agricultural Land ◽  
Flood Hazard ◽  
Smart Phone ◽  
Flood Management ◽  
Drainage Density ◽  
Slope Length ◽  
Risk Levels ◽  
High Hazard ◽  
Very High

Floods are considered to be one of the most costly natural hazards in the Lam river basin causing infrastructure damages as well as devastating the affected area and relatively high death toll. So prevention is necessary for shielding lives and properties. The flood management on the Lam River basin has been considering for many years to minimize damages caused by flooding. The flood hazard zoning map is one of the indispensable tools to provide information about hazard and risk levels in a particular area and to perform the necessary preventive and preparedness procedures. The multicriteria decision analysis based on geographic information systems is used to build a flood hazard map of the study area. The analytic hierarchy process is applied to extract the weights of six criteria affecting the areas where are prone to flooding hazards, including rainfall, slope, relative slope length, soil, land cover, and drainage density. The results showed in 91.32 % (20103.83 km2) of the basin located in the moderate hazard zones to very high hazard zones. Accordingly, this study also determined 4 vulnerability levels to agricultural land including low, medium, high, and very high. About 94% of the total area of agricultural land in the basin are classified into moderate to the very high hazard of flood vulnerability. The paper presents a method that allows flood risk areas in the Lam River basin to receive information about flood risks on a smartphone, making them more aware.

scholarly journals The Role Of Relative Slope Length In Flood Hazard Mapping Using Ahp And Gis (Case Study: Lam River Basin, Vietnam)

2020 ◽  
Vol 13 (2) ◽  
pp. 115-123
Author(s):  
Ba Dung Nguyen ◽  
Dang Tuyet Minh ◽  
Adeel Ahmad ◽  
Quoc Long Nguyen
Keyword(s):  
River Basin ◽  
Flood Hazard ◽  
Influence Factors ◽  
Drainage Density ◽  
Hazard Mapping ◽  
Gis Technology ◽  
Slope Length ◽  
Factors Affecting ◽  
Relative Slope

In addition to the five main factors affecting the formation of floods including slope, rainfall, drainage density, soil, and land cover, the relative slope length factor has also been considered to be one of the fundamental causes that contribute to flood hazard. The paper analyzes the theoretical basis for choosing the relative slope length criterion when zoning flood hazard in Lam river basin. The important role of this factor was evaluated by the results of the flood risk zoning map established by the method of integrating AHP and GIS technology in two cases: using 5 flood influence criteria and using 6 flood influence criteria. Flood hazard zoning maps for 2 cases were tested with 3 historic floods occurring on Oct 2010, Oct 2013 and Oct 2016. The results showed that the map established with six influence factors is more detailed and accurate than the one created with five factors affecting flood hazard because of the similarity with the reality of that map. The results of the study are applicable to other river basins which their geographical features are similar to characteristics the Lam river basin.

scholarly journals ASSESSMENT OF FLOOD INFLUENCE CRITERIA IN THE LAM RIVER BASIN USING A COMBINED DELPHI-AHP METHOD

2021 ◽  
Vol 13 (3) ◽  
pp. 387-396
Author(s):  
Nguyen DUNG ◽  
◽  
Dang MINH ◽  
Keyword(s):  
Land Cover ◽  
River Basin ◽  
Flood Hazard ◽  
Drainage Density ◽  
Analytic Hierarchy ◽  
Slope Length ◽  
Study Results ◽  
Baseline Information ◽  
And Control ◽  
Relative Slope

Flood is represented as one of the most destructive natural hazards to humankind. Assessing and predicting floods hazard is necessary to offer appropriate solutions for flood mitigation and sustainable environmental management. It is only possible when the main criteria that contributed to creating the flood hazard are pointed out. The purpose of the current research was to choose and attribute scores to all various flood-causing factors in the Lam river basin. Firstly, the Delphi method was applied to the expertbased survey to choose six key parameters that led to the floods, including rainfall, slope, relative slope length, drainage density, land cover, and soil. Then, Analytic Hierarchy Process (AHP) approach is employed as an effective tool to obtain a better understanding of all the factors or indicator contributions in the flood process based on weight given to each of six flood influencing elements. The consistency analyses revealed that the findings were coherent and consistent with a previous study. It is also interesting to notice that rainfall and slope are the most prominent flood occurrence criteria with 45% and 25.5%, respectively. However, the influence of other factors (drainage density, relative slope length, land cover, and soil) is not visible. These parameters are assigned to the small weights and do not have a significant influence on the flood phenomenon. The study results provide baseline information, which needs to be taken into account to mitigate and control floods.

scholarly journals Flood-Prone Area Assessment Using GIS-Based Multi-Criteria Analysis: A Case Study in Davao Oriental, Philippines

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2203 ◽  
Author(s):  
Cabrera ◽  
Lee
Keyword(s):  
Flood Risk ◽  
Flood Hazard ◽  
Drainage Density ◽  
Mitigation Strategies ◽  
Risk Area ◽  
Analytic Hierarchy ◽  
Comparison Results ◽  
Prone Area ◽  
Ground Truthing ◽  
Very High

Flooding is one of the major destructive natural disasters in Davao Oriental, Philippines, and results primarily from a high incidence of typhoons and heavy rainfalls. The main objective of this study was to identify flood-prone risk areas by mapping them based on the integration of multiple indicators, including rainfall, slope, elevation, drainage density, soil type, distance to the main channel and population density. For this purpose, a GIS-based flood risk spatial assessment was conducted by using analytic hierarchy process (AHP), weights by rank (WR) and ratio weighting (RW) frameworks to determine the relative importance of each indicator against another in the province of Davao Oriental. The resulting flood-prone areas by the three methods are validated by comparing with the estimated flood map based on ground truthing points from a field survey. The comparison results show that AHP is the most appropriate method among them to assess flood hazard. The result of the AHP flood risk map shows that 95.99% (5451.27 km2) of Davao Oriental is under low and moderate flood risk. The high and very high flood risk area covers approximately 3.39% (192.52 km2) of the province, primarily in the coastal areas. Thirty-one out of the one hundred eighty-three (31/183) barangays (towns) are at a high to very high risk of flooding at current climate, calling for the immediate attention of decision-makers to develop mitigation strategies for the future occurrence of flooding in Davao Oriental.

scholarly journals Flood Inundation Mapping and Hazard Assessment for Mitigation Analysis of Local Adaption Measures in Upper Ping River Basin, Thailand

2021 ◽  
Author(s):  
Husnain Tansar ◽  
Haseeb Akbar ◽  
Rana Ammar Aslam
Keyword(s):  
River Basin ◽  
Hazard Assessment ◽  
Flood Hazard ◽  
Flood Protection ◽  
Management Approach ◽  
Flood Inundation ◽  
Adaptation Measures ◽  
High Hazard ◽  
Flooded Area ◽  
Set Up

Abstract Annual monsoon flooding phenomena have caused disastrous impacts on the Upper Ping River basin and its inhabitants over the years. The existing administration set-up for flood mitigation and adaptation measures lacks effective utilization of locally available resources for complete flood protection. This study addressed this gap by flood hazard assessment at a lower administration scale (sub-district level) and performance evaluation of local adaptation measures was performed. 1D and 2D hydrodynamic models were developed and calibrated against observed discharge and water level (1D) and flood extent (2D), respectively. Flood inundation and hazard maps were reproduced and categorized into different classes based on defined critical depths for 2, 5, 10, 25, 50 and 100 years return periods. A maximum flood inundated area of 996.9 km2 (3.94% of total basin area) was simulated in a 100-year return period. The flood hazard results represent that the largest flooded area categorized under “high hazard”, followed by “very high hazard” and “low hazard” categories, and least flooded area was classified under “medium hazard” category. The current administration set-up for flood adaptation and mitigation needs to update based on an integrated flood management approach to improve its effectiveness for future flood protection.

Flood risk management under climate change: a hydro-economic perspective

2018 ◽  
Vol 18 (5) ◽  
pp. 1832-1840 ◽  
Author(s):  
Rohini P. Devkota ◽  
Tek Maraseni
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Flood Hazard ◽  
Methodological Approach ◽  
Extreme Rainfall ◽  
Developed Countries ◽  
Flood Management ◽  
Policy Implications ◽  
Extreme Rainfall Events ◽  
Management Plans

Abstract Most developing countries, like Nepal, are expected to experience the greatest impact of climate change (CC) sooner and on a greater magnitude than other developed countries. Increase in the magnitude and frequency of extreme rainfall events is likely to increase the risk of flooding in rivers. The West Rapti River basin is one of the most flood prone and also one of the most dynamic and economically important basins of Nepal. This study elicits the willingness to pay (WTP) from the local people in the basin to reduce risks from possible floods due to CC. The WTP for flood mitigation in different flood hazard zones and flood scenarios were determined using referendum method and a face to face questionnaire survey. From a total of 720 households across all flood zones, a stratified randomly selected sample of 210 households was surveyed. The sample included households from a range of socio-economic backgrounds. The average WTP varied by flood hazard zone and within each zone, by CC-induced flood scenarios. The average WTP of respondents was highest for the critical flood prone zone, followed by moderate and low flood prone zones. Similarly, within each zone, the average WTP increased with increasing flood magnitudes due to CC. The variation of average WTP of respondents in different flood prone zones and scenarios indicate different levels of perceived severity. Moreover, the introduction of the concept of ‘man-day’ or ‘labour-day’ in WTP research is a novel and applicable methodological approach, particularly in the South Asian region. The findings of this study are useful for policy implications for the design of participatory flood management plans in the river basin.

scholarly journals Estimation of soil loss by the USLE model in a mountain basin in the south of Santa Catarina state, Brazil

2020 ◽  
Vol 24 ◽  
pp. e20
Author(s):  
Lucas Kister Amaral ◽  
Sabrina Baesso Cadorin ◽  
Álvaro José Back ◽  
Fernanda Dagostin Szymanski ◽  
Claudia Weber Corseuil
Keyword(s):  
River Basin ◽  
Soil Loss ◽  
Rainfall Erosivity ◽  
Intense Rainfall ◽  
Slope Length ◽  
Control Practice ◽  
Runoff Potential ◽  
Shallow Soils ◽  
The Impact ◽  
Very High

Water erosion is a factor of soil degradation that is triggered by the impact of raindrops originated by intense rainfall disaggregating the soil, followed by the carrying of particles by surface runoff. In the erosion process, in addition to soil loss, nutrients, fertilizers, and pesticides are carried resulting in water courses and water pollution. Erosion can have a major impact on agricultural production, when soil use and management techniques are not used. Therefore, this study aimed to evaluate the soil loss in the Malacara river basin, which is a sub-basin of the Mampituba river basin characterized by a contrasting relief, with high altitudes in the escarps of Serra Geral and floodplain. The method used for the development of this research was the application of the Universal Soil Loss Equation (USLE). USLE soil loss estimation requires the following factors: rainfall erosivity (R), soil erodibility (K), slope length (L), slope steepness (S), soil use and management (C), and erosion control practice factor (P). The estimated rainfall erosivity was 5,754.2 MJ mm ha-1 h-1 year-1. Erodibility was determined for the soils present in the basin, highlighting a high value for gleysoil. The topographic factor (LS) showed values from 0 to greater than 20, which corresponds to the low to very high runoff potential. The floodplain showed lower runoff rates, while for the locations close to the enclosed valleys in the Malacara canyon, the runoff potential varied from high to very high. The soil use and management factors and conservation practices (CP) obtained a maximum value of 0.404, corresponding to the exposed soil; the second most representative class was agricultural areas, with a value of 0.145. The soil loss in the Malacara river basin varied from 0 to more than 200 t ha-1 year-1. In fact, 87.38% of the area presents a degree of sheet erosion normal to slight and, only 2.94% of the area has a high or very high degree of erosion. Moreover, due to the relief characteristics with shallow soils and intense rainfall in mountainous basins, knowing and understanding soil losses due to erosion is crucial for the adequate management of water resources in river basins. 

scholarly journals Groundwater Prospect Zonation Using Frequency Ratio Model For Banganga River Basin, India

2019 ◽  
Vol 8 (6) ◽  
pp. 806-814
Keyword(s):  
River Basin ◽  
Drainage Density ◽  
Groundwater Potential ◽  
Groundwater Prospect ◽  
Land Use Land Cover ◽  
Well Location ◽  
High Zone ◽  
Gis Methods ◽  
The Right ◽  
Very High

Groundwater prospective Zonation mapping and its reasonable improvement are a significant perspective in Banganga River Basin. In the present investigation, the groundwater imminent zones were depicted by receiving a recurrence proportion (FR) model Land use land cover, Geomorphology, Geology, Drainage Density, Lineament Density Aquifer, Slope, well location and water level were the Thematic layers considered for groundwater prospective Zonation mapping. There are 157 spring wells situated in the investigation Study area, of which all wells were considered for evolution rate and staying absolute wells considered for predict rate in the FR model. The last groundwater prospective map was characterized into five zones as Very Low, Low, Medium, High and Very high. Finally, appropriate destinations for Groundwater revitalize for practical groundwater the board were distinguished. The locales were chosen based on profundity of groundwater level, wellspring of spring great areas and inclination from regular spring to select invigorate wells.Groundwater Prospective zone ranging from 2.8068 to 12.3712. It classified into five prospective classes Very low classes cover 904.62 sq km, low zone covers 1220.76 sq km, medium zone covers 1821.46 sq km, High zone covers 2145.55sq km and very High zone covers 2687.57 sqkm.Areas with steeply inclined limestone terrains and younger tough rocks had moderate to weak groundwater potential. The groundwater is mostly not appropriate in the research region for consumption but may be used for irrigation under unique circumstances, on the basis of the chemical analysis. The general findings show that using remote sensing and GIS methods provides strong method for developing groundwater and developing the right exploration scheme.

Flood hazard zoning in Ngan Sau, Ngan Pho river basin, Ha Tinh province using GIS and analytical hierarchical process

2021 ◽  
Vol 66 (1) ◽  
pp. 198-212
Author(s):  
Minh Dang Thi Tuyet
Keyword(s):  
Flood Hazard ◽  
Hazard Analysis ◽  
Drainage Density ◽  
Gis Technology ◽  
Slope Length ◽  
Hazard Zoning ◽  
Hazard Zone ◽  
Gis Environment ◽  
High Flood ◽  
Reliable Methods

This paper introduces the AHP method integrated with GIS technology to provide information for flood hazard analysis in the Ngan Sau and Ngan Pho river basins. The factors ìnluencing the occurrence of floods in a study area include slope, rainfall, drainage density, soil, relative slope length, and land cover. These data are used for establishing a flood hazard zone map in a GIS environment. The obtained results indicate that the two main causes of flooding are rainfall and slope with weights of 45% and 25.5%, respectively. The resultant map has shown about 82.78% of the total catchment area is having a high and very high probability of flood and areas under high flood hazard only covers 17.22% of the study area. The validation of the flood hazard zone map was conducted based on flood evens in the field. The results showed that the AHP technique and GIS are reliable methods for the assessment of the flood hazard potential, specifically in spare-data regions.

scholarly journals Evaluation and validation of flood hazard zoning using Analytical Hierarchy Process and GIS: A case study of Lam River basin (Vietnam)

2021 ◽  
Vol 66 (4) ◽  
Author(s):  
Ba Dung Nguyen ◽  
◽  
Quynh Nga Nguyen ◽  
Thi Lan Pham ◽  
Thi Le Le ◽  
...  
Keyword(s):  
Natural Disasters ◽  
River Basin ◽  
Analytical Hierarchy Process ◽  
Negative Impact ◽  
Flood Hazard ◽  
Gis Technology ◽  
Slope Length ◽  
The People ◽  
Hazard Zoning ◽  
Hierarchy Process

In recent years, the Lam river basin had suffered various forms of natural disasters such as floods, inundations, windstorms, tornadoes, etc. Among all these, the flood has proved to be the greatest threat to the people and the socio-economic development in the basin. Moreover, it is very frequent as compared to other natural disasters. In view of the fact that such disastrous floods are still occurring in the basin, it becomes a necessity to determine the causes and analyze the components affecting flood. This is important in order to develop an early flood warning system and thus minimize the negative impact of flood in the Lam river basin on the people and the facilities. In this paper, the Analytical Hierarchy Process (AHP) analysis method integrated with GIS technology is used to map flood risk zones in the Lam river basin. The parameters used for the analysis are the main causes affecting the floods. In addition to the 5 most commonly used factors such as slope, rainfall, land cover, soil, and drainage density, this study also includes a new factor - relative slope length to compute a more rigorous and reliable model. The results were compared with the two more methods of flood hazard zoning in the same study area: the method of the main flood caused factor analysis and the method of inheriting, data analyzing, and processing. The results were also validated by the historical flood data of three years 2010, 2013, and 2016.

scholarly journals Geo-hydrological hazard and risk zonation of Banganga watershed using GIS and remote sensing

2001 ◽  
Vol 23 ◽  
Author(s):  
Motilal Ghimire
Keyword(s):  
Agricultural Land ◽  
Hydrological Processes ◽  
Hazard Map ◽  
Risk Map ◽  
Risk Zone ◽  
Hazard Zone ◽  
Hazard And Risk ◽  
High Hazard ◽  
Vulnerability Map ◽  
Very High

The present study attempts to analyse the terrain elements and geo-hydrological processes operating on the Banganga watershed in western Nepal. The paper also assesses the hazard and risk to the land use, land cover, and settlements. The Banganga watershed is highly rugged, steep, and fragile. Based on GIS, a geo-hydrological hazard map, a vulnerability map, and a risk map were prepared. In the study area, the geo-hydrological processes are active and intense during the monsoon season. Instabilities are generally found on steep slopes with high relative relief, in areas underlain by the Siwaliks, and along the fault zones. The mass movements are more frequent on slopes covered by dense to moderately dense forest than on the agricultural land. The socio-economic significance of the hazard in the watershed is considerably high. About 8% of the agricultural land lies in the very high and high hazard zones. Similarly, 18 house s are located in the very hazard zone. 93 houses in the high hazard zone, 211 in the moderately high hazard zone, and the rest of 2,185 houses in the moderate and low hazard zones. The risk map generated by combining the hazard map and vulnerability map shows 14% of the area under the very high and high risk zones, 38% under the moderate risk zone, and 48% under the low risk zone.

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