Geomorphometric Approach Research Articles

A Multivariate Geomorphometric Approach to Prioritize Drought Prone Sakri Basin for Land and Water Resource Management

A Multivariate Geomorphometric Approach to Prioritize Drought Prone Sakri Basin for Land and Water Resource Management

Flood Vulnerability Assessment Across Alaknanda River Basin using GIS-based Combined Analysis of Geomorphometric Approach and MCDM-AHP

Abstract Floods are one of the most devastating natural disasters, causing land destruction, economic loss, and massive disruptions to humans. The present study was conducted in the Alaknanda river basin with medium to high drainage density and stream frequency. The flood vulnerable zones (FVZ) are identified using geomorphometric analysis, and flood vulnerability zones are identified through analytical hierarchy processes (AHPs). Three factors, such as linear, relief, and aerial, have been used in the geomorphometric analysis of the Alaknanda basin. The weights were assigned on a scale of 1 for flood-induced factors such as slope (0.386), rainfall (0.192), drainage density (0.129), LULC (0.096), geology (0.077), soil (0.064), and DEM (0.055) have been determined using 7×7 decision matrix of multi-criteria decision making- analytical hierarchy processes (MCDM-AHP) model accounting for their varying importance from high to low priorities. A consistency ratio (CR) of 0.083 (less than 0.1) signifies the acceptance of the weights derived in the case. The high shape index, form factor, and rotundity factor indicate the basin allows quick drainage of surface runoff with a lesser time of concentration; as a result, sharp peaks of the hydrograph will be obtained at the outlet of the basin. However, most of the basin area is under the moderate vulnerability category, while the entire river banks along the valley are the most vulnerable. Additionally, a small-scale sociological study indicates that for a population that resides close to highly susceptible locations, temporary relocation is the most common strategy.

Intraspecific Population Variability in Goldstripe Ponyfish, Karalla daura Sampled along the Pakistan Coast Based on Geo-Morphometric Approach

Intraspecific Population Variability in Goldstripe Ponyfish, Karalla daura Sampled along the Pakistan Coast Based on Geo-Morphometric Approach

A multi-scale geomorphometric approach to semi-automated classification of seabed morphology of a dynamic and complex marine meander bend

Seabed geodiversity comprises abiotic seabed structures and functions that form valuable natural resources, foundation for benthic habitats and marine ecosystems, and requires knowledge based, sustainable management. Geomorphological mapping involves delineation of surface features based on form, material composition and formative processes. We present an approach that applies methods of scale analysis and geomorphometric classification to characterize seabed morphology and interpretation of geomorphic units in a dynamic and complex marine meander bend. Seabed morphology was delineated using the morphometry as template supported by the DEM and associated surface derivatives. The seabed morphology served as input to an interpretation of geomorphic units applying a fluvial classification scheme in channelized marine settings. We demonstrate the potential of using a (semi-) automated morphometric classification scheme to support the characterization of high-resolution seabed morphology based on descriptive definitions and the potential of translating a fluvial classification scheme in channelized marine settings.

Comparative geomorphometric approach to understand the hydrological behaviour and identification of the Erosion prone areas of a coastal watershed using RS and GIS tools

Assessment of the geomorphometric parameters using Remote Sensing (RS) and Geographic Information System (GIS) tools forms an important part in routing the runoff and other hydrological processes. The current study uses a geospatial model based on geomorphometric parameters for the categorization of surface runoff and identification of the erosion-prone areas in the watershed of the Kuttiyadi River. The 4th order Kuttiyadi river is dominated by a dendritic to semi-dendritic drainage pattern in the subwatersheds. The linear aspect of the subwatersheds indicates towards the presence of permeable surface and subsurface materials with uniform lithology. The aerial and relief aspects of the subwatersheds shows fine drainage texture, gentle slopes, delayed peak flow, flatter hydrograph, and large concentration time which shows that subwatersheds are quite capable of managing flash floods during storm events. The estimated values of surface runoff (Q) and sediment production rate (SPR) are range from 2.13 to 32.88 km2-cm/km2 and 0.0004–0.017 Ha-m/100km2/year respectively and suggest that Subwatershed 1 (SW1) will generate more surface runoff and is prone to soil erosion followed by subwatershed 2 (SW2) in comparison to other subwatersheds. This paper aims to fill the knowledge gap regarding categorization of flow and erosion dynamics in a coastal river watershed. We believe that our work may work help in providing the crucial information for decision-makers and policymakers responsible for establishing suitable policies and sustainable land use practices for the watershed.

Using geomorphometric approach to investigate spatial pattern and intensity of erosional dissection in a block-faulted topography (Orlickie-Bystrzyckie Mountains, Central Europe)

The paper presents an attempt to recognize areas of enhanced erosional dissection, based on a combined analysis of several geomorphometric variables and using four different approaches (rank-based, cold and hot spot analysis, k-means clustering of ‘raw’ data, and k-means clustering of local measures of spatial autocorrelation). The study area includes the Orlickie-Bystrzyckie Mountains Block (OBMB), which is a block-faulted range within the Sudetes Mountains, Central Europe, typified by fault-generated range fronts, remnant planation surfaces and topographic ramps due to large-scale tilting. Geology is diverse, with basement rocks and sedimentary cover, and the relevant timescale is late Cenozoic. Morphometric variables derived from a LiDAR-based DEM include contour length, standard deviation of elevation, median valley depth and standard deviation of curvature, and are considered to account for various morphometric signatures of erosional dissection. While deriving compound measures of dissection, three grid cell sizes were considered. Within the OBMB several areas were identified as erosionally dissected to a considerable degree. Their spatial pattern is complex and reflects several factors simultaneously. Differential uplift appears as the main trigger, but the erosional response varies, depending mainly on the size of runoff contributing area – itself related to the pattern of uplift, and the distance from the margins of elevated areas. Lithology (bedrock resistance to erosion) seems to play a subordinate role. We also discuss various issues related to the procedures themselves, pointing out their advantages and limitations. Procedural setups proposed in this paper are not site-specific and may be used in various topographic and geological settings.

Volume estimation of soil stored in agricultural terrace systems: A geomorphometric approach

High-resolution topographic (HRT) techniques allow the mapping and characterization of geomorphological features with wide-ranging perspectives at multiple scales. We can exploit geomorphometric information in the study of the most extensive and common landforms that humans have ever produced: agricultural terraces. We can only develop an understanding of these historical landform through in-depth knowledge of their origin, evolution and current state in the landscape. These factors can ultimately assist in the future preservation of such landforms in a world increasingly affected by anthropogenic activities. From HRT surveys, it is possible to produce high-resolution Digital Terrain Models (DTMs) from which important geomorphometric parameters such as topographic curvature, to identify terrace edges can be extracted, even if abandoned or covered by uncontrolled vegetation. By using riser bases as well as terrace edges (riser tops) and through the computation of minimum curvature, it is possible to obtain environmentally useful information on these agricultural systems such as terrace soil thickness and volumes. The quantification of terrace volumes can provide new benchmarks for soil erosion models, new perspectives to stakeholders for terrace management in terms of natural hazard and offer a measure of the effect of these agricultural systems on soil organic carbon sequestration. This paper presents the realization and testing of an innovative and rapid methodological workflow to estimate the anthropogenic reworked and moved soil of terrace systems in different landscapes. We start with remote terrace mapping at large scale and then utilize more detailed HRT surveys to extract geomorphological features, from which the original theoretical slope-surface of terrace systems were derived. These last elements were compared with sub-surface information obtained from the excavations across the study sites that confirm the reliability of the methodology used. The results of this work have produced accurate DTMs of Difference (DoD) for three terrace sites in central Europe in Italy and Belgium. Differences between actual and theoretical terraces from DTM and excavation evidence have been used to estimate the soil volumes and masses used to remould slopes. The utilization of terrace and lynchet volumetric data, enriched by geomorphometric analysis through indices such as sediment conductivity provides a unique and efficient methodology for the greater understanding of these globally important landforms, in a period of increasing land pressure.

Offshore benthic habitat mapping based on object-based image analysis and geomorphometric approach. A case study from the Slupsk Bank, Southern Baltic Sea

Benthic habitat mapping is a rapidly growing field of underwater remote sensing studies. This study provides the first insight for high-resolution hydroacoustic surveys in the Slupsk Bank Natura 2000 site, one of the most valuable sites in the Polish Exclusive Zone of the Southern Baltic. This study developed a quick and transparent, automatic classification workflow based on multibeam echosounder and side-scan sonar surveys to classify benthic habitats in eight study sites within the Slupsk Bank. Different predictor variables, four supervised classifiers, and the generalisation approach, improving the accuracy of the developed model were evaluated. The results suggested a very high significance for the classification performance of specific geomorphometric features that were not used in benthic habitat mapping before. These include, e.g., Fuzzy Landform Element Classification, Multiresolution Index of the Valley Bottom Flatness, and Multiresolution Index of the Ridge Top Flatness. Comparison of classification results with manual maps demonstrated that Random Forest had the highest performance of four tested supervised classifiers. Because the current needs include benthic habitat mapping for the whole area of the Polish Exclusive Economic Zone, the key findings of this study may be further applied to extensive areas in the Polish waters and other vast areas worldwide.

Application of Spatial Multi-Criteria Analysis (SMCA) to assess rockfall hazard and plan mitigation strategies along long infrastructures

Long infrastructures often cross areas with a high probability of landslides, causing eventually serious problems to the serviceability and compromising safety. The identification and prediction of hazardous zones are difficult, especially for what concerning rockfalls, as they can occur quickly and suddenly. In order to assess rockfall hazard, detailed data such as slope geometry, geotechnical and geomechanical properties of materials, drainage system pattern, etc. are needed. Even though thematic datasets are available and easily downloadable for the majority of the Italian territory, their scale is not adequate and ad-hoc input data must be gathered. An original multi-disciplinary procedure (GEO4) has been developed by the authors based on a mobile mapping system (ARCHITA) integrated with Airborne Lidar and ILI (In-Line Inspections), geomatics, geological models, geotechnical-geomechanical characterization and geomorphometric approach. A Spatial Multi-Criteria Analysis (SMCA) is then used to create a composed and spatially distributed index of landslide hazard based on normalized values of triggering factors. Such index is used to identify and classify the morphological unstable element along the infrastructure, supporting decision-makers in defining the most appropriate mitigation measures and planning their implementation in a clearer, more repeatable and more objective orientated-way. The presented method has been successfully applied so far to hundreds of km of railway lines in Italy.

Geomorphometric approach in geoecological assessment of groundwater in the territory of the Arkhangelsk region

It is shown that the Terrain Ruggedness Index, calculated on the digital elevation model, predetermines the chemical composition of groundwater. The high ruggedness of the relief, the small stratum of the overlying bedrocks of Quaternary deposits, the absence of water barriers contribute to the desalination of groundwater due to the penetration of ultra-fresh atmospheric precipitation. The low ruggedness of the relief also causes a low intensity of water exchange and, as a consequence, a higher mineralization of groundwater.

Assessing site suitability potential for soil and water conservation structures by using modified micro-watershed prioritization method: geomorphometric and geomatic approach

Assessing site suitability potential for soil and water conservation structures by using modified micro-watershed prioritization method: geomorphometric and geomatic approach

Application of Geomorphometric Approach for the Estimation of Hydro-sedimentological Flows and Cation Weathering Rate: Towards Understanding the Sustainable Land Use Policy for the Sindh Basin, Kashmir Himalaya

Application of Geomorphometric Approach for the Estimation of Hydro-sedimentological Flows and Cation Weathering Rate: Towards Understanding the Sustainable Land Use Policy for the Sindh Basin, Kashmir Himalaya

Increasing the Efficiency of Detailed Soil Resource Mapping on Transitional Volcanic Landforms Using a Geomorphometric Approach

For developing countries, detailed soil resource data and maps are essential in land-use planning. Unfortunately, obtaining detailed soil data for mapping is expensive. Detailed soil studies and mapping in developing countries often use the grid method. In addition to being time-consuming, the grid method needs a lot of sample points and surveyors. Geomorphometry can be a less expensive alternative for detailed soil mapping. Geomorphometry uses computationally measured terrain characteristics to describe other hard-to-measure terrain and soil properties. In our study, landform arrangements and slopes were analyzed together to create a map of soil pH. Bompon watershed, Indonesia, was used as a case study. Soil mapping units with potentially similar soil pH were created based on a classification system of the two geomorphometric parameters. Soil samples were taken from each of the units. The samples' soil pH was measured and compared to the geomorphometric predicted result. Regression tests were performed to see the significance of geomorphometric parameters on soil pH conditions. Regression tests show that the results of p value of the four soil layers are 0.046, 0.019, 0.037, and 0.047, respectively, on a 5% confidence level. According to the test result, landform arrangements and slopes can indicate soil pH conditions in Bompon. Our estimate suggests that our geomorphometric method is cheaper than the grid method by a factor of seven. The ability to use geomorphometric parameters to describe other soil properties could enable a cheap and fast production of detailed soil maps for developing countries.

Flood susceptibility mapping using a geomorphometric approach in South Australian basins

Watershed characteristics and their hydrological responses can have severe effects on the occurrence and extent of floods. Therefore, this study focuses on the integration of geospatial techniques and remote sensing data to identify watershed terrain characteristics and evaluate the influence of these characteristics on flood susceptibility in South Australia. Data from the Shuttle Radar Topography Mission (SRTM) and geologic and topographic maps and a geographic information system (GIS) were used to delineate drainage basins, measure morphometric parameters and link different parameters to evaluate the degree of flood vulnerability. Depending on their relations to the flood hazards, the morphometric parameters were categorized into two groups; then, a rank score was assigned to each group. Finally, the flood susceptibility of the basins was visualized, and the basins were classified into low, intermediate and high flood hazard areas. The results show that approximately 45.7, 44.7 and 9.7% of the study area is at risk of high, medium and low degrees of flooding, respectively. The results were validated through secondary data relating to historic floods. The causes of flooding were analysed using rainfall and road density data, while the consequences of flooding were verified by the population distribution across the study area. The findings of this study can be used to support decision-makers in planning and investing in mitigation measures, especially in highly susceptible areas of South Australian basins.

A Multivariate Geomorphometric Approach to Prioritize Erosion-Prone Watersheds

Soil erosion is considered one of the main degradation processes in ecosystems located in developing countries. In northern Mexico, one of the most important hydrological regions is the Conchos River Basin (CRB) due to its utilization as a runoff source. However, the CRB is subjected to significant erosion processes due to natural and anthropogenic causes. Thus, classifying the CRB’s watersheds based on their erosion susceptibility is of great importance. This study classified and then prioritized the 31 watersheds composing the CRB. For that, multivariate techniques such as principal component analysis (PCA), group analysis (GA), and the ranking methodology known as compound parameter (Cp) were used. After a correlation analysis, the values of 26 from 33 geomorphometric parameters estimated from each watershed served for the evaluation. The PCA defined linear-type parameters as the main source of variability among the watersheds. The GA and the Cp were effective for grouping the watersheds in five groups, and provided the information for the spatial analysis. The GA methodology best classified the watersheds based on the variance of their parameters. The group with the highest prioritization and erosion susceptibility included watersheds RH24Lf, RH24Lb, RH24Nc, and RH24Jb. These watersheds are potential candidates for the implementation of soil conservation practices.

Өгий нуурын хотгорын морфологийн гарал үүсэл: Флювиаль процесс ба тектоник хагарлын холбоо

The study of the origin of lake depressions is very important. Data on the origin and morphology of the lakes in Mongolia is relatively rare. The origin of the Lake Ugii depression is contested. The lake is one of the fresh water lakes on the Orkhon valley, Arkhangai province. The main purpose of the present research is to explore the origin of the Lake Ugii depression. The study applied the Hypsometric Integral analysis, spatial improvement method, morphostructural and morphgeographic methods. Integrated the results in the topographic map, geological map, satellite images, and other materials. The Lake Ugii is supplied with the tectonic fault and river discharge. Depression in the middle of the Lake Ugii may relate to the tectonic fault from west to east and seem to originated from fluvial and tectonic actions. The study applied the geomorphometric approach combined with detailed geomorphology analysis that allows to refine the structural geometry of this key area of the Lake Ugii.

Flash flood susceptibility modelling using geomorphometric approach in the Ushairy Basin, eastern Hindu Kush

This study focuses on flash flood susceptibility modelling using geomorphometric ranking approach in the Ushairy Basin. In the study area, flash floods are highly unpredictable and the worst hydrometeorological disaster. An advanced spaceborne thermal emission and reflection radiometer global digital elevation model was used as input data in a geographic information system environment to delineate the target basin. A total of 17 sub-basins were delimited using a threshold of $$4 \hbox {km}^{2}$$ . The attribute information of each sub-basin was analysed to compute the geomorphometric parameters by applying Hortonian and Strahler geomorphological models. The results were analysed and categorised into five classes using statistical techniques, and the rank score was assigned to each class of all parameters depending on their relation with flash flood risk. In this study, 16 parameters were analysed to quantify the geomorphometric number of each sub-basin depicting the degree of flash flood susceptibility. The geomorphometric number of each sub-basin was linked to the geo-database for spatial visualisation. The analysis reveals that extremely high, very high, high and moderate sub-basins susceptible to flash floods were spread over an area of 55%, 8.5%, 23.7%, and 11.5%, respectively. It was found that out of total settlements, 53% are located in the extremely highly and very highly susceptible sub-basins. In the study area, the upper reaches are characterised by snow-covered peaks, steep slopes and high drainage densities ( $${>}1.7 \hbox { km/km}^{2})$$ . The analysis further indicated that the flash flood susceptibility increases with the increase in area, relief and relief ratio of the sub-basins. Model accuracy was assessed using primary data regarding past flood damages and human fatalities. Similarly, socio-demographic conditions of each sub-basin were also compared and linked to the extent of flash flood susceptibility. This study may assist the district government and district disaster management authority of Dir upper to initiate flood risk reduction strategies in highly susceptible zones of the Ushairy Basin.

Influence of digital elevation model resolution on rockfall modelling

Spatial models are an effective tool for determining potential rockfall source, transit and deposit areas. The reliability of the final rockfall modelling results depends on the quality of the input data, which is mostly based on the digital elevation model (DEM). The spatial resolution of the DEM holds key information about the main morphological properties of the surface, which is crucially important when modelling this kind of geomorphological phenomenon. Therefore, this article studies the influence of DEM spatial resolution on the modelling of rockfall source, transit and deposit areas. Modelling was carried out at five different DEM spatial resolutions available for Slovenia (1 m, 5 m, 12.5 m, 25 m and 100 m). Rockfall source areas were identified using a geomorphometric approach based on a high resolution DEM and a geographical information system. Rockfall transit and deposit areas were modelled using the Conefall computer program, which is designed to estimate potential rockfall risk areas. The area of study was the municipality of Vipava (107.4 km2) in Slovenia, EU. A spatial resolution of 1 m was chosen as a reference layer to which all modelling results of the other spatial resolutions were compared. Validation of modelling included rockfall source area comparison with orthorectified aerial images and location collection of silent witnesses (rock deposits) in the field for estimating maximum runout zones. The modelling results indicate that a spatial resolution of 1 m is the most suitable for modelling on a local scale; resolutions of 5, 12.5 and 25 m can be used for modelling on a regional scale (depending on the purpose of the modelling results); and a resolution of 100 m should not be used for rockfall modelling. Major differences between spatial resolutions can be observed when modelling rockfall source areas, i.e. in areas with the most diverse topography, while in deposit areas the observed differences are smaller due to the less rugged surface.

Connectivity patterns in contrasting types of tableland sandstone relief revealed by Topographic Wetness Index

Recognition of structural connectivity is particularly challenging in terrains lacking a hierarchical fluvial system, but typified by strong bedrock control, extreme ruggedness of relief, the presence of sinks (closed depressions) as in karst, or considerably modified by anthropogenic interventions. In this paper, the issue of connectivity mapping in such a very rugged terrain – a sedimentary tableland underlain by sandstones, mudstones and marls – is addressed. Three specific geomorphic contexts were selected for detailed study. These are steep escarpments, canyon-riddled cuesta backslopes, and residual tabular hills (mesas), with relative relief of 100–300 m. This work is primarily based on geomorphometric approach, with the Topographic Wetness Index used as a tool to recognize pathways of water and possible sediment transfer across the sandstone tableland. In addition, maps of distribution of closed depressions were generated. High resolution (1 m) digital terrain models provided input topographical data. The results of desk research were verified by the results of field work aimed at recognition of visible signatures of geomorphological connectivity in the physical landscape. Specific connectivity patterns were identified for each setting, with two common features being strong structural control due to regular joint pattern and the presence of numerous sinks, resulting in widespread surface disconnectivity. Furthermore, differences between structural and functional connectivity emerge. The latter occurs very rarely, during rather infrequent extreme precipitation events, and there are only a few evident, permanent sediment transfer pathways in the areas subject to analysis. The presence of well-jointed and porous sandstones accounts for drainage diversion underground and restricted surface runoff from the tableland and hence, for an underdeveloped network of perennial streams and clearly identifiable valley morphology.

A Hydrological and Geomorphometric Approach to Understanding the Generation of Wadi Flash Floods

Abstract: The generation and processes of wadi flash floods are very complex and are not well understood. In this paper, we investigate the relationship between variations in geomorphometric and rainfall characteristics and the responses of wadi flash floods. An integrated approach was developed based on geomorphometric analysis and hydrological modeling. The Wadi Qena, which is located in the Eastern Desert of Egypt, was selected to validate the developed approach and was divided into 14 sub-basins with areas ranging from 315 to 1488 km2. The distributed Hydrological River Basin Environment Assessment Model (Hydro-BEAM) was used to obtain a good representation of the spatial variability of the rainfall and geomorphology in the basin. Thirty-eight geomorphometric parameters representing the topographic, scale, shape and drainage characteristics of the basins were considered and extracted using geographic information system (GIS) techniques. A series of flash flood events from 1994, 2010, 2013, and 2014, in addition to synthetic virtual storms with different durations and intensities, were selected for the application of this study. The results exhibit strong correlations between scale and topographic parameters and the hydrological indices of the wadi flash floods, while the shape and drainage network metrics have smaller impacts. The total rainfall amount and duration significantly impact the relationship between the hydrologic response of the wadi and its geomorphometry. For most of the parameters, we found that the impact of the wadi geomorphometry on the hydrologic response increases with increasing rainfall intensity.