Prioritization of Flash Flood-Prone Areas in Small Coastal Basins around the Mediterranean Using Geomorphological Variables

The present study aims to model flash flood risk in small coastal watersheds in areas that are characterized by Mediterranean climate through extensive morphometric analysis which can prove invaluable for the investigation of flood risk, in ungauged watersheds, where flash floods are frequent. The available topographic data (EU-DEM) are analyzed through Geographic Information Systems (GIS) to produce all the secondary variables that are necessary for this morphometric analysis. Watershed prioritization techniques that are applied on geomorphological variables have proven to be an effective way of estimating the relative flash flood risk in a sub-watershed level. A series of morphometric parameters are used (bifurcation ratio, drainage frequency, drainage density, drainage texture, length of overland flow, circularity ratio, form factor, elongation ratio) which have an effect on flood risk. In small watersheds, with intermittent runoff, this effect can be different than in larger watersheds, so our methodology differs significantly from the methodology other researchers use. The compound factor is calculated by aggregating the assigned ranks of these morphometric indices and the sub-watersheds are prioritized according to their flash flood risk. The study area is located in the island of Samos, in Eastern Greece, where flood events are usual and pose a risk to villages and infrastructure around the island. The selected watershed (Imvrasos river) is divided into several sub-watersheds (W-1 to W-8) and a series of morphometric indices are calculated and evaluated through statistical procedures and by applying prioritization techniques, in order to locate the sub-basins that have the highest risk to flash floods. Sub-watersheds W-2 and W-3 (on the southern part of Imvrasos area) show the highest prioritization values, and should be prioritized for better watershed management planning.

Geo-informatics based Morphometric Analysis of a Reservoir Catchment in Shivalik Foothills of North-West India

Journal of Agricultural Engineering ◽

10.52151/jae2021581.1752 ◽

2021 ◽

Vol 58 (03) ◽

pp. 286-299

Author(s):

Mahesh Chand Singh ◽

Rohit Singh ◽

Abrar Yousuf ◽

Vishnu Prasad

Keyword(s):

Form Factor ◽

Soil Erosion ◽

Morphometric Analysis ◽

Overland Flow ◽

Infiltration Rate ◽

Elongation Ratio ◽

Alos Palsar ◽

Bifurcation Ratio ◽

Runoff Potential ◽

The present study examined 35 morphometric parameters related to stream/drainage network, catchment geometry, and relief aspects for hydrological characterization of the Thana Dam catchment using geospatial tools and techniques. The dam catchment was delineated using the high-resolution Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) Digital Elevation Model (DEM) data in ArcGIS 10.4.1 software using the Arc Hydro tools. The catchment is comprised of 4th order stream, obtained using a stream threshold value of 100 m length. The lower values of elongation ratio (0.61), circularity ratio (0.22), and form factor (0.29) indicated higher soil erosion potential, mainly due to their inverse relationship with land erodibility. Moreover, the higher values of stream frequency (15.7), drainage density (>5.0), drainage texture (7.48 km-1), and mean bifurcation ratio (4.08-6.33) indicated higher runoff potential, which would intensify the soil erosion, mainly due to their direct relationship with erodibility. Bifurcation ratio, elongation ratio, circulatory ratio, form factor, altogether indicated an elongated shape of the catchment with a fine drainage texture. The higher values of bifurcation ratio and texture ratio of the catchment also indicated severe overland flow (low infiltration rate) with a limited scope for groundwater recharge in the area, which in turn might significantly encourage the soil erosion. Overall, it was concluded that the catchment has a huge runoff potential resulting in high soil erosion due to its fine texture, impermeable subsurface material, steep slope, low infiltration rate, limited vegetation, longer duration of overland flow, and higher surface runoff. The morphometric analysis was found to be suitable for identifying catchment shape and the factors affecting hydrologic conditions and erodibility of the catchment. Thus, Geo-informatics based morphometric analysis of a reservoir catchment can be useful to study the erosion potential in relation to hydrologic (rainfall-runoff relationship) and other related land characteristics (e.g., relief, slope, infiltration rate, etc.).

Computation of Watershed Parameters of Kansa Watershed in Satara Using Remote Sensing and GIS

Agropedology ◽

10.47114/j.agroped.2019.j4 ◽

2019 ◽

Vol 29 (1) ◽

Author(s):

A. P. Bowlekar ◽

Keyword(s):

Form Factor ◽

Geographical Information Systems ◽

Overland Flow ◽

Flash Flood ◽

Drainage Density ◽

Morphometric Parameters ◽

Elongation Ratio ◽

Stream Length ◽

Order Stream

In present study Kansa watershed in Satara district of Maharashtra was characterized for watershed parameters. Geographical Information Systems (GIS) and a high-resolution Digital Elevation Model (DEM) has been utilized for the estimation of morphological parameters. Several morphometric parameters have been computed and analyzed viz. linear aspects such as stream order, stream number, stream length, mean stream length, stream length ratio; areal aspects such as drainage density, stream frequency, drainage texture, elongation ratio, circularity ratio, form factor, constant of channel maintenance; relief aspects such as relief, relief ratio, relative relief, ruggedness number, length of overland flow. Impacts of morphometric parameters on flash flood characteristics have also been investigated. The presence of the maximum number of the first order segments shows that the basin is subjected to erosion and also that some areas of the basin are characterized by variations in lithology and topography. The form factor is 0.21, and the circulatory ratio is 0.42, which suggests an elongated type of catchment. Elongation ratio is 0.52, which indicates that watershed has high relief and steep slope. The estimated catchment characteristics may be useful to stimulate hydrological responses of the catchment.

Assessment of Groundwater Recharge Potential Depending on Morphologic Analysis in East of Wasit, Southeastern Iraq

Iraqi Geological Journal ◽

10.46717/igj.54.2d.11ms-2021-10-30 ◽

2021 ◽

Vol 54 (2D) ◽

pp. 138-154

Author(s):

Mohammed S. Shamkhi

Keyword(s):

Groundwater Recharge ◽

Morphometric Analysis ◽

Drainage Density ◽

Eastern Region ◽

Elongation Ratio ◽

Recharge Potential ◽

The Third ◽

Drainage Texture ◽

Elevation Model ◽

Semi Arid

Modern technologies are used for watershed management to cope with drought risks in arid and semi-arid regions. The study aimed to conduct a morphometric analysis and know potential groundwater recharge areas in the eastern region of Wasit Province. Remote sensing and GIS data were used for morphometric analysis. The morphometric analysis results adopted the Digital Elevation Model. The results of the analysis were verified by matching the results with what exists in reality. The area of the first basin was 1482.017, as it is the largest basin from the area, with a percent of 51.228% of the total area of all basins. The percentage of first-degree flows reached 83.37% in the first basin, 74.14% percent in the second basin, 75.51% in the third basin, and 75.75% in the fourth basin from all streams in each basin. The bifurcation rate (3.135-4.233), Stream frequency range values (0.543-0.332), drainage texture coarse, low drainage density that ranged between 0.986-1.14 km/km2 elongation ratio ranging from 0.348-0.624 form factor (0.095-0.316). The basins' circularity (0.105-0.238) relief value (951-112) m infiltration number value (0.369-0.535). All basins have a longitudinal shape and lead to the formation of floods and rapid currents, which exposes the region to rapid seasonal floods and the creation of flash floods that cause soil erosion and analyses the drainage intensity results. It was low, and this is an indication that the ground has high permeability. The flow frequency results indicate that the area is semi-arid and exposed to small amounts of rain and coarse drainage texture by comparing the result parameters from morphometric analysis results for each basin. The potential recharge areas of groundwater in the study area can be known, n as the analysis results showed that recharge potential occurs in all basins. The highest groundwater recharge is possible in the third basin and the lowest in the first basin. Morphometric analysis was performed by ARC-GIS(Arc-map10.4).

Hydrologic behaviour of Tapi river catchment using morphometric analysis

Journal of Applied and Natural Science ◽

10.31018/jans.v6i2.480 ◽

2014 ◽

Vol 6 (2) ◽

pp. 442-450 ◽

Cited By ~ 1

Author(s):

Vishal K. Ingle ◽

A. K. Mishra ◽

A. Sarangi ◽

D. K. Singh ◽

V. K. Seghal

Keyword(s):

Remote Sensing ◽

Morphometric Analysis ◽

Remote Sensing Data ◽

Drainage Density ◽

Drainage Network ◽

Elongation Ratio ◽

Drainage Pattern ◽

River Catchment ◽

Seventh Order ◽

The study area Tapi River catchment covers 63,922.91 Sq.Km comprising of 5 five Sub-catchments: Purna river catchment (18,473.6 sq.km) Upper Tapi catchment (10,530.3 sq. km), Middle Tapi catchment (4,997.3 sq km), Girna river catchment (10,176.9 sq.km) and lower Tapi catchment (19,282.5 sq.km.). The drainage network of 5 Sub-catchments was delineated using remote sensing data. The morphometric analysis of 5 Sub-catchments has been carried out using GIS softwares – ArcMap. The drainage network showed that the terrain exhibits dendritic to sub-dendritic drainage pattern. Stream orders ranged from sixth to seventh order. Drainage density varied between 0.39 and 0.43km/ km2and had very coarse to coarse drainage texture. The relief ratio ranged from 0.003 to 0.007. The mean bifurcation ratio varied from 4.24 to 6.10 and falls under normal basin category. The elongation ratio showed that all catchment elongated pattern. Thus, the remote sensing techniques proved to be a competent tool in morphometric analysis.

Computation of Watershed Parameters of Kansa Watershed in Satara Using Remote Sensing and GIS

10.47114/j.agroped.2019.jun4 ◽

2019 ◽

Vol 29 (1) ◽

Author(s):

A. P. Bowlekar ◽

Keyword(s):

Form Factor ◽

Geographical Information Systems ◽

Overland Flow ◽

Flash Flood ◽

Drainage Density ◽

Morphometric Parameters ◽

Elongation Ratio ◽

Stream Length ◽

Order Stream

Surface Water Management and Modelling in the Sakia El Hamra Hydraulic Basin (Southern Morocco)

10.5194/egusphere-egu2020-8635 ◽

2020 ◽

Author(s):

Nafia El-alaouy ◽

Aicha Moumni ◽

Badr-eddine Sebbar ◽

Abdeljalil Gouzrou ◽

Aberrahman Lahrouni

Keyword(s):

Flash Flood ◽

Hydrological Regime ◽

Shape Index ◽

Flash Floods ◽

Drainage Density ◽

Agricultural Lands ◽

Surface Water Management ◽

Short Period ◽

Long Time ◽

Log Normal

Due to its arid to semi-arid climate, Morocco often faces significant intense rainfall periods that can generate flash floods and raging torrents causing serious damage in a very short period of time. In this context, these recent years, the watershed corresponding to the SAKIA EL HAMRA wadi has known devastating downpours and excessive heavy rains that caused severe floods in Laayoune city and its regions.The watershed of Sakia El Hamra covers an area of 82000 km2, that drains to Sakia El Hamra wadi, a stream of about 447 km long, crosses the basin in its northern part in the East-to-West direction, to discharge into the Atlantic Ocean at the outlet called Foum El Oued. This zone often experiences dangerous torrents of water and violent flash floods, specifically in the northern part of Laayoune city. For example, a flash flood has occurred at the end of October 2016. The peak flow was far in excess of the average (3000 m3/s against 410m3/s). This river flood, lasted for about 10 h, caused damage to the infrastructure and destruction of agricultural lands near Foum El Oued.The objective of this study is to investigate, through modelling, the hydrological regime of SAKIA EL HAMRA watershed to prevent the floods in the future and improve warning systems. The hydrological parameters of the watershed were determined by WMS software, namely: zone extent, perimeter, slope, basin&#8217;s average elevation, Gravelius compactness index, Horton shape index, average altitude, drainage density and concentration time.Flood flow return was simulated using the Log-normal distribution, using a long time-series of flow and maximum daily and annual precipitation data, recorded between 1985 and 2016, at the Airport station in Laayoune city. The results showed that during flash floods with known flows, water level can reach up to 13 meters, with high flow velocities flooding hundreds of hectares of surrounding plains at the northern part of the city of Laayoune and agricultural lands near Foum El Oued.

Morphometric Analysis of Khag Micro-Watershed in North-West Himalayas of Kashmir Using GIS and Remote Sensing Techniques

International Journal of Plant & Soil Science ◽

10.9734/ijpss/2021/v33i1630533 ◽

2021 ◽

pp. 138-155

Author(s):

Rajnish Yadav ◽

Mohammad Iqbal Bhat ◽

Faisul-Ur- Rasool ◽

Shabir Ahmed Bangroo ◽

Roheela Ahmad ◽

...

Keyword(s):

Morphometric Analysis ◽

Structural Control ◽

Rainwater Harvesting ◽

Drainage Basin ◽

Drainage Density ◽

Elongation Ratio ◽

Drainage Pattern ◽

Gis And Remote Sensing ◽

North West

Morphometric analysis is of vital importance in any hydrological research and is inevitable in development and management of watershed. Using the watershed as the main unit of morphometric characterization is the most logical choice, as well as geomorphological and hydrological processes take place within the drainage basin. A critical assessment and evaluation of morphometric parameters of Khag micro-watershed was accomplished through measurement of relief, linear and aerial aspects using Geographical Information System (GIS). The watershed boundaries, aspect, slope, digital elevation model (DEM), profile graph of topography, drainage order and drainage density mapswere generated for detailed study of micro-watershed using Shuttle Radar Topographic Mission (SRTM) data. The study area was designated as fourth order basin with the drainage area of 34.32 km2 and shows dendritic drainage pattern. The total length, drainage density and mean bifurcation ratio (Rb) were found to be 38.84 km, 1.13km/km2 and 1.73, respectively. The Khag micro-watershed showed the greater Rb value, which directs a strong structural control in the runoff pattern. A decrease in the stream frequency of flow was also observed with an increase in the order of flow. The shape parameters such as circulatory ratio, elongation ratio, length of over land flow, form factor and drainage texture of Khag micro-watershed were 0.42, 0.56, 0.43 km, 0.24 and 1.66, respectively. The Khag micro-watershed is elongated in shape and dendritic in drainage pattern. This can be attributed to the fact that the lithology and structural controls are more or less uniform. Relative relief and ruggedness number were 0.065 and 2.39 and are likely to subject the micro watershed to maximum soil erosion that demands, instantaneous soil conservation measure to be taken by watershed managers for its stability and sustainability. These studies area advantageous for the planning of rainwater harvesting and the management of the catchment area.

Morphometric Analysis to Infer Hydrological Behaviour of Lidder Watershed, Western Himalaya, India

Geography Journal ◽

10.1155/2013/178021 ◽

2013 ◽

Vol 2013 ◽

pp. 1-14 ◽

Cited By ~ 34

Author(s):

Farrukh Altaf ◽

Gowhar Meraj ◽

Shakil A. Romshoo

Keyword(s):

Morphometric Analysis ◽

Western Himalaya ◽

Drainage Density ◽

Vital Role ◽

Integrated Analysis ◽

Mountain Range ◽

Drainage Pattern ◽

Entire Study ◽

Drainage Patterns ◽

West Lidder River, in the Northwest Greater-Himalayan mountain range, is the major source of irrigation and drinking water supplies for the Kashmir Valley with a population of seven million people. The major source of water for the whole Lidder River is snow and icemelt emanating from its two subcatchments East Lidder and West Lidder. Snowmelt significantly contributes to the evolution of drainage patterns in this area. Quantitative morphometry plays a vital role in routing the snowmelt and other hydrological processes. Morphometric analysis of the West Lidder River catchment was carried out using geospatial technique. The outcome revealed that the entire study area has uniform lithology and is structurally permeable. The high drainage density of all subwatersheds indicate more surface runoff. The morphometric analysis also indicates that the area is more prone to weathering due to very-coarse to coarse drainage texture. All the subwatersheds showed dendritic to subdendritic drainage pattern. An immense control of structure on the drainage in some subwatersheds is indicated by their high bifurcation ratios. Circulatory and elongation ratios show that the subwatersheds have elongated to circular shapes. From the integrated analysis of the morphometric parameters, important hydrologic behaviour of 17 subwatersheds could be inferred.

Flash flood in Arau watershed, West Sumatera: a mitigation study

MATEC Web of Conferences ◽

10.1051/matecconf/201822903002 ◽

2018 ◽

Vol 229 ◽

pp. 03002 ◽

Cited By ~ 2

Author(s):

Irfan Pramono ◽

Endang Savitri

Keyword(s):

Land Cover ◽

Flash Flood ◽

Soil Depth ◽

Daily Rainfall ◽

Heavy Rain ◽

Flash Floods ◽

Drainage Density ◽

Antecedent Soil Moisture ◽

Natural Dam ◽

Maximum Daily Rainfall

Flash flood often occurs in West Sumatera. In spite of heavy rain, flash floods are also caused by the landslide in the riverside that blocks the river as a natural dam. The natural dam can be broken at any time, depending on storage capacity. Flash flood occurs when the dam is broken. The aim of the research is to mitigate flash floods based on parameters influencing flood and landslide. The research was conducted in Arau watershed, West Sumatera. Parameters that have a direct proportion of floods are maximum daily rainfall, watershed shape, river gradient, drainage density, slope, and land cover. Parameters influencing landslides are antecedent soil moisture, slope, geologic type especially fault line, soil depth, and land cover. GIS is used to analyze the factors influencing flood and landslide spatially. The results show that more than 50% of the Arau watershed are slightly high and high vulnerability due to its natural condition. Furthermore, the locations of fault, especially in the riverside, should be noticed because this location could become a natural dam causing flash flood. In order to reduce flash flood impact, the natural dam should be opened as soon as possible.

Catchment delineation and morphometric analysis using geographical information system

Water Science & Technology ◽

10.2166/wst.2015.303 ◽

2015 ◽

Vol 72 (7) ◽

pp. 1168-1175 ◽

Cited By ~ 3

Author(s):

Manoj Kumar ◽

Rohitashw Kumar ◽

P. K. Singh ◽

Manjeet Singh ◽

K. K. Yadav ◽

...

Keyword(s):

Information System ◽

Geographical Information System ◽

Morphometric Analysis ◽

Water Conservation ◽

Drainage Density ◽

Morphometric Parameters ◽

Vegetative Cover ◽

Elongation Ratio ◽

Drainage Pattern

The geographical information system (GIS) has emerged as an efficient tool in delineation of drainage patterns of watershed planning and management. The morphometric parameters of basins can address linear, areal and relief aspects. The study deals with the integrated watershed management of Baliya micro-watersheds, located in the Udaipur district of Rajasthan, India. Morphometric analysis in hydrological investigation is an important aspect and it is inevitable in the development and management of drainage basins. The determination of linear, areal and relief parameters indicate fairly good significance. The low value of the bifurcation ratio of 4.19 revealed that the drainage pattern has not been distorted by structural disturbance. The high value of the elongation ratio (0.68) compared to the circulatory ratio (0.27) indicates an elongated shape of the watershed. The high value of drainage density (5.39 km/km2) and stream frequency (12.32) shows that the region has impermeable subsoil material under poor vegetative cover with a low relief factor. The morphometric parameters of relief ratio (0.041) and relative relief (0.99%) show that the watershed can be treated using GIS techniques to determine the morphometric presence of dendritic drainage pattern, with a view to selecting the soil and water conservation measures and water harvesting.