Basin Relief Research Articles

Lithological controls on chemical weathering signatures in the semi-arid climatic regime: Study based on tropical small scale catchments

Lithological controls on chemical weathering can be better constrained by studying catchments having different lithologic settings in similar climatic conditions. This study compares the weathering fluxes in two small catchments having different lithology in semi-arid region (500–800 mm/year rainfall) in western India: The West Banas River (2100 km2, 372 m relief) on granitic/gneissic rocks and the Berach River (610 km2 area; 542 m basin relief) on shale. Sample collected in the year 2016 and 2017, were analysed for chemical composition to evaluate chemical weathering fluxes. Inverse model analysis and Soil and Water Assessment tool (SWAT) simulated runoff were combined to estimate the annual weathering fluxes. Total dissolved loads (TDS) in the West Banas ranged from 71 to 428 mgL−1(avg. 227 mgL−1), while the Berach River showed TDS of 190–712 mgL−1(avg. 370 mgL−1), with some higher values of due to anthropogenic sources. Silicate weathering rate (SilWR) derived as 7.7 ± 1.7 tonkm−2y−1 for the granitic West Banas catchment whereas 5.7 ± 1.2 tonkm−2y−1 for the shale lithology in Berach River. The weathering susceptibility ratio of shale to granite was derived as 2:3. The weathering intensity is highly controlled by the susceptible minerals present in these rocks. The posteriori results of elemental ratios of the silicate endmember in shale lithology basin (Berach River) shows strong indication of incongruent weathering in the basin. This weathering signatures in shale (sedimentary) lithology happened as their constituting minerals has already gone through at least one cycle of chemical weathering during their formation. Saline-alkaline soils (SAS) contribute significantly to dissolved loads, especially in the Berach (38 ± 12 %), compared to the West Banas (26 ± 7 %). The cations derived from different lithologic sources have a dependency on the drainage basin area. However, other topographical factors showed minor control on chemical weathering.

Morphometric Analysis of Kajali River Basin Using Geospatial Techniques

Soil and water are the important natural resources and important input for agricultural production. The present study has been attempted to delineate and determine morphometric characteristics of Sakharpa watershed in Ratnagiri district by using Remote Sensing and GIS. The delineation of watershed was performed in QGIS 3.18.3 software. The study area was obtained from SRTM DEM with 30meter resolution after delineation. Sakharpa watershed shows a dendritic drainage pattern. The results found for morphometric parameters were Bifurcation Ratio (Rb)2-5.5, Form factor (Ff) 0.32, Elongation ratio (Re) 0.63, Circulatory ratio (Rc) 0.32, Shape index (Sw) 3.18,Drainage density (Dd)1.18km/km2, Stream frequency (Fs)1.48 km-2, Texture ratio (Rt)1.08, Drainage texture (Dt)2.24,Constant of channel maintenance (C)0.84km2/km, Length of overland flow (Lg) 0.42, Basin relief (R) 763.92 m, Relief Ratio (Rr) 0.045,Relative Relief (Rhp) 1.27,Ruggedness Number (Rn) 0.904. The study concluded that the watershed is elongated in shape, have dense vegetation and homogeneous with less structural disturbance. This morphometric analysis of drainage basin helps to planning and development of watershed also helps to understand relation between linear, areal and relief parameters of drainage basin.

Characteristics and Comparative Assessment of Flash Flood Hazard Evaluation Techniques: Insights from Wadi Haily Basin, Eastern Red Sea Coast, Saudi Arabia

The Wadi Haily basin in southwest Saudi Arabia, which runs along the Red Sea coast, serves as an ideal natural laboratory for understanding flash flood dynamics in this region. However, limited morphometric and hydrological data are currently available in this area. This study aims to analyze key morphometric effective parameters to examine and assess flash flood risk potential within the basin. Using remote sensing, GIS, geological, and topographical datasets, this research combines advanced modeling and GIS tools to produce detailed flood hazard maps and risk assessments. This study examines 15 sub-basins of varying sizes, characterized by primary stream orders ranging from 4th to 8th. Based on morphometric analysis, the basins are categorized by flood susceptibility: four basins have a low flood risk, five exhibit moderate risk, and six are highly susceptible to flooding. Key findings indicate that the study area features a vast drainage area, high grid cell values of the drainage frequency, moderate drainage density, elongated basin shapes, low infiltration rates, and long overland flow distances, all suggesting a heightened flood hazard. Additional indicators include high values in gradient ratios, slopes, ruggedness numbers, relief ratios, and basin relief, reinforcing the basin’s flash flood vulnerability. This study provides a comprehensive morphological framework that can support strategic flood management and hazard mitigation planning for the Wadi Haily region.

Morphometric analysis and environmental planning: an educational approach in science and mathematics for understanding geomorphological processes in the Água das Araras watershed, Cornélio Procópio and Santa Mariana, Paraná, Brazil

The article develops a detailed morphometric analysis of the Água das Araras Stream Watershed, located in the regions of Cornélio Procópio and Santa Mariana, Paraná. The investigation focuses on the geomorphological characterization and the dynamics of processes shaping the basin's relief and drainage network. Using quantitative methods such as areal, linear, hypsometric, and fluvial planning analysis, the research aims to clarify the structural factors and environmental conditions shaping the basin.The study seeks not only to identify the natural potential and aspects of environmental vulnerability but also to suggest management actions that enable more effective and sustainable territorial planning. This work presents an important resource for future disciplines in favor of water resource preservation, besides strengthening interdisciplinary understanding of geomorphological processes and their relevance for sustainable development. Additionally, it highlights the application of these concepts in environmental education, especially in the teaching of Geography, Science, and Mathematics. Moreover, morphometric analysis proves to be a powerful tool for interdisciplinary teaching in Geography, Sciences, and Mathematics, promoting a practical understanding of natural processes and their impacts. The study concludes by emphasizing the relevance of the basin for environmental education and the necessity of conservation policies to ensure the sustainability of local water resources. The study also highlights the need for preservation policies and the importance of the watershed as an educational resource to foster environmental awareness.

Morphometric analysis and watershed delineation of the Karnaphuli river basin: A comparative study using different DEMs in Chittagong, Bangladesh

AbstractThe present study aimed to delineate a robust watershed boundary and extract its morphometric parameters in the Karnaphuli watershed, Bangladesh, using different digital elevation models (DEMs). Two DEMs, the shuttle radar topographic mission (SRTM) and the terra advanced spaceborne thermal emission and reflection radiometer (ASTER), were employed to delineate watershed boundaries and evaluate various morphometric characteristics. Raster data such as fill sinks, flow direction, and flow accumulation were utilized to delineate the watershed. The morphometric analysis included the estimation of linear, areal, and relief parameters. The findings revealed a noticeable difference between the datasets; ASTER delineated a larger watershed area than SRTM. Regarding stream order, there were streams ranging from 1st to 6th order, encompassing numerous small, medium, and main channels of the river. Drainage density was calculated as 0.52 km/km² for SRTM and 0.51 km/km² for ASTER, both having a spatial resolution of 30 m. The bifurcation ratio ranged from 1.94 for SRTM to 2.45 for ASTER, indicating varying degrees of structural disturbance influenced by geological factors. The form factor indicated an elongated shape of the study area. The overall dimensions of the streams and the watershed extent suggest moderate mean annual rainfall discharge. The watershed exhibited relatively high denudation rates, attributed to the basin relief. A low drainage density indicated the importance of infiltration processes. The findings of this study provide valuable insights into the spatial variability of watershed characteristics, highlighting the need for tailored management strategies for the Karnaphuli River. Implementing targeted conservation measures and watershed management practices based on these morphometric parameters can enhance water resource sustainability and ecological health in the region.

Geo-spatial assessment of geomorphic characteristics of Swat Valley, Pakistan

Morphometric analysis is essential for understanding drainage networks and landform evolution, particularly in complex mountainous regions like the Swat Valley. Accurate characterization of these features aids in water resource management and mitigating climate-induced challenges. The study employed GIS and remote sensing technologies, utilizing SRTM-30m DEM data to perform a comprehensive morphometric and hypsometric analysis. Key morphometric parameters such as basin size, stream order, bifurcation ratio, drainage density, circularity ratio, and elongation ratio were calculated by using Whitebox tool. Additionally, three-dimensional parameters including basin relief, roughness number, ruggedness index, and slope were analyzed. Hypsometric analysis was conducted to examine area-elevation relationships, using empirical formulas and contour data. The basin was found to be irregularly shaped, with an elongation ratio of 6.97 and a circulatory ratio of 0.3091, indicating an elongated form. Flow accumulation data highlighted areas of rapid and moderate water flow. Hypsometric analysis showed that 14 sub-basins were in an erosional stage, 8 were mature, and the remainder were older and more resistant to erosion. The overall hypsometric integral (HI) of 0.406 reflects moderate elevation variation across the basin. The study provides critical insights into the geomorphometric controls of the Swat Valley's drainage system, contributing to improved water resource management strategies. Understanding morphometric and hypsometric characteristics is vital for adapting to climate-induced risks and safeguarding water resources in mountainous landscapes.

The depositional differences of confined and unconfined turbidite sheet systems

The depositional architecture between unconfined and confined turbidite sheet systems are increasingly recognized, but the major differences are not summarized. This paper aims to summarize the major differences based on the well-studied published systems with known degree of confinement and depositional architectures. The unconfined and confined turbidite sheet systems differ greatly in four aspects: sedimentary facies, stacking patterns of individual beds, facies associations and onlap styles. The sedimentary facies in confined systems are mainly thick beds, occasionally with grain size breaks, overlain by thick mud caps; whereas beds in unconfined turbidite systems present less mud proportion. The stacking patterns in confined systems in mainly vertically stacked, whereas compensationally stacked in strike direction, and progradationally or retrogradationally stacked in dip direction. One facies association have only been identified in confined systems and four facies associations are found in unconfined systems. The vertical log of unconfined turbidite sheet systems presenting a transition of facies association, whereas no transitions in confined systems. The depositional architecture of turbidite sheet systems is controlled by both sediment supply and basin relief. The establishment between degree of confinement and various parameters in this study can be applied in the petroleum industry.

Regional power duration curve model for ungauged intermittent river basins

ABSTRACT Hydropower is a sustainable and renewable energy source that can serve as a practical and economically viable solution to the future possible energy crisis and climate change scenarios. Moreover, it possesses a higher energy density compared to other alternative renewable energy sources such as solar, wind energy, etc. In order to determine the potential of hydropower, long-term observed hydrometeorological data of streamflow, precipitation, etc. are crucial. This study investigates a new power duration curve (PDC) methodology. Basin characteristics such as drainage area and basin relief with meteorological data as precipitation are used for regional models in the application. The classification based on geographical locations is made for regional models. Six models based on equation type were utilized to determine the optimal regional model. Absolute errors of cease-to-flow point estimates ranging from 0.01 to 11.49% were observed. The model provided successful results according to Nash–Sutcliffe efficiency which is widely used in hydrological studies very close to 1 and higher than 0.87 except for one streamflow gauging station therewithal all other calculated performance metrics. It is observed that power and cease-to-flow point estimates of intermittent rivers can be obtained with a new PDC model based on basin characteristics.

Investigation of the Basin Characteristics through Morphometric Analysis of Hadejia River Sub-Basin: Implications for Groundwater Recharge

Understanding the geohydrological properties of a drainage basin in relation to the topographical feature and its flow patterns depends heavily on morphometric analysis. Estimating a watershed's frequency of infiltration and runoff as well as its other hydrological characteristics is also helpful. The study was conducted using Geographical Information System (GIS) techniques with the aim of establishing relationship between surface morphometry, underlying geology and groundwater recharge. For detailed measurement and analysis, Digital Elevation Model (DEM) and high resolution imageries were employed for basin delineation, slope characterization, channel network extraction and stream ordering in order to derive the linear, areal, and relief aspects of morphometric parameters. The findings showed that a total number of 116 streams joined the 4th order stream in which 83 streams were 1st order, 25 streams were 2nd order, 7 streams were 3rd order and the major trunk was 4th order stream, occupied an area of 1486.86km2. The stream network's drainage system exhibits dendritic design. The results further indicate that the values for stream frequency, infiltration number, drainage density, drainage texture, length of overland flow, elongation ratio and basin relief are 0.08, 0.032, 0.41km/km2, 0.023, 1.22km, 0.54 and 28.59m respectively. The observed values of both linear, areal and relief parameters were generally low. Low values for the areal and relief criteria indicates that the sub-basin is at its youthful stage of development and possesses very good permeable subsurface formation and prospect with the possibility of high potential groundwater resources. The result help us understand the connections between hydrological variables and geomorphological parameters as guidance and/or decision-making instruments for the authorities to develop decisions for the environmentally friendly growth of the basin, water supply planning, water budgeting, and disaster mitigation within the Hadejia river sub-basin.

Morpho‐Tectonic Evolution of the Southern Apennines and Calabrian Arc: Insights From Pollino Range and Surrounding Extensional Intermontane Basins

AbstractThe evolution of topography in forearc regions results from the complex interplay of crustal and mantle processes. The Southern Apennines represent a well‐studied forearc region that experienced several tectonic phases, initially marked by compressional deformation followed by extension and large‐scale uplift. We present a new structural, geomorphic and fluvial analysis of the Pollino Massif and surrounding intermontane basins (Mercure, Campotenese and Castrovillari) to unravel their evolution since the Pliocene. We constrain multiple tectonic transport directions, evolution of the drainage, and magnitude and timing of long‐term incision following base level falls. Two sets of knickpoints suggest two phases of base level lowering and allow to estimate ∼500 m of long‐term uplift (late Pleistocene), as observed in the Sila Massif. On a smaller spatial scale, the evolution and formation of topographic relief, sedimentation, and opening of intermontane basins is strongly controlled by the recent increase in rock uplift rate and fault activity. At the regional scale, an along‐strike, long‐wavelength uplift pattern from north to south can be explained by progressive lateral slab tearing and inflow of asthenospheric mantle beneath Pollino and Sila, which in turn may have promoted extensional tectonics. The lower uplift of Le Serre Massif may be explained as result of weak plate coupling due to narrowing of the Calabrian slab. The onset of uplift in the Pollino Massif, ranging from 400 to 800 ka, is consistent with that one proposed in the southern Calabrian forearc, suggesting a possible synchronism of uplift, and lateral tearing of the Calabrian slab.

Morphometric analysis of Halda River basin, Bangladesh, using GIS and remote sensing techniques

GIS and remote sensing techniques were effectively used to analyse the morphometric parameters including linear, geometric, basin texture (aerial) and relief aspects of the Halda River Basin, Bangladesh. Along with measuring the morphometric parameters using predetermined formulas, advanced geo-computing tools of spatial analysis, cartography, math, geoprocessing and geometric analysis were employed to carry out the spatial distribution of selected parameters, especially aerial parameters. The linear aspect indicates the basin is six-order and oval-shaped. The bifurcation ratio (4.03) and relevant parameters indicate the moderate effect of geology and structural control is evident. The mean stream length (1.27) and Rho value (ranges between 0.11 and 0.20) indicate high runoff in steep areas and hydrologic storage capacity in flat areas. The stream frequency (0.83), drainage density (1.22), drainage intensity (0.68), infiltration ratio (1.02), length of the overland flow (0.41), and constant of channel maintenance (0.82) indicate the presence of moderate hard rock, less structural disturbances and moderate to high surface runoff in the basin. Basin relief (489 m), relative relief (2.02), ruggedness number (400), Melton's ruggedness number (12.43), and mean slope (9.33%) indicate the potential of high erosion and material transfer. The spatial distribution of selected aerial aspects significantly correlated to elevation and slope. The hierarchical pattern and spatial distribution of the morphometric parameters indicate areas with high slopes and lower-order streams have a high potential to be affected by soil erosion, landslides and flash floods, elsewhere, the areas with low slopes are prone to short-duration riverine floods. The research findings will help policymakers for integrated river basin management, agricultural development, and water management. In addition, researchers of morphohydrological, geological and climatological research will be beneficiary.

An integrated statistical-geospatial approach for the delineation of flood-vulnerable sub-basins and identification of suitable areas for flood shelters in a tropical river basin, Kerala

Flood vulnerability assessment is crucial for developing effective flood management and mitigation strategies. The present study aims to understand the flood vulnerability of the Kallada River Basin (KRB) and identify suitable locations for safe flood sheltering facilities in the basin. As part of this, morphometric analysis of KRB was carried out by dividing the basin into fifty-eight 4th-order sub-basins to understand the sub-basin-wise terrain characteristics and the degree of vulnerability to flooding. GIS tools were used to assess various morphometrical parameters, such as drainage frequency, texture ratio, ruggedness number, basin relief, bifurcation ratio, length of overland flow, drainage density, circularity ratio and area, and geo-environmental factors such as sand percent, rainfall, and mean slope of these basins. The morphometric parameters exhibited distinct spatial trends, with higher values primarily concentrated in the east and northeast parts for certain parameters and in the western parts for others. Using hierarchical cluster analysis, the sub-basins were categorized into six clusters, revealing that 51% were vulnerable to floods, 26% moderately vulnerable, and 22% not vulnerable. Sub-basins in the central and western KRB were found to be highly vulnerable to flooding, while those in the eastern parts showed moderate vulnerability or were not vulnerable. Flood vulnerability mapping was validated using flood data of 2018 and 2019. Additionally, the weighted overlay method identified suitable areas for flood shelters in moderately vulnerable and vulnerable sub-basins and the areas were categorized into highly suitable, suitable, moderately suitable, and not suitable areas. Most areas of SB53 and SB55 were found highly suitable, emphasizing their potential for flood shelter locations. The findings of this study can be used by competent authorities to initiate flood mitigation and to develop targeted flood preparedness measures in similar river basins, particularly in the context of increasing flood events.

Green Heat and Wind Factors in Sustainable Urban Development of Mountain-Basin Relief

The article studies mountain basin relief’s influence on the heat and wind regime organization when developing it for sustainable urban planning purposes. Each time a unique relief is identified, it requires an individual design approach taking into account the identification of the aesthetic expressiveness of green settlement development. Depending on the slope, there may be different options for using the site. The article presents the features of the geometry of the mountain-basin space associated with the relative depth of the mountain basin. The thermal field of the mountain-basin space, which is formed due to the energy of incoming solar radiation and the internal heat of insolated urban development, is analyzed. The city’s mountain-basin terrain requires an individual design approach, taking into account the identification of the aesthetic expressiveness of green settlement development. Based on the generalization and analysis of studies of air flows’ structure, their direction, velocity, and temperature fields, as well as the characteristics of the microclimate in the development of the mountain-basin space, an aerodynamic picture of air movement arising under the influence of natural thermal forces was obtained. The thermal field of the mountain-basin space has been established, which is formed due to the energy of incoming solar radiation and the internal heat of insolated urban development. The proposed methodology for calculating the heat and wind conditions of development is the basis for preliminary forecasting, assessment, and regulation of heat and wind parameters, as well as optimization of the sustainable development planning of mountain-basin relief.

Assessment of Morphometric and Hypsometric Analysis of the Ruste Basin Using Remote Sensing and Geographical Information System Techniques

A basin’s characteristics and features need to be comprehended completely by conducting morphometric analysis, such as evaluating the basin’s size, form, and surface features, to estimate floods and erosion rates properly. The main objective of this investigation is to evaluate morphometric measures and hypsometric analysis of Erbil’s Ruste Basin employing remote sensing and geographical information system methods. To investigate the significant tributaries of the selected area, the hydrology tool within the Spatial Analysis Tools of ArcGIS, version 10.7, was utilized to define the basin boundaries, map the drainage networks, and obtain topographic data. The findings of the linear morphometric parameters revealed that the logarithmic relationship between stream orders and stream numbers was negative. The difference in stream order and number seen in the watershed is due to topography and bedrock influence. The results also showed a negative correlation between stream length and stream order, and a coefficient of determination of 0.972, which indicates that the basin is made of low-permeability formation and subsoil materials. Considering the areal morphometric parameters, the circularity ratio, elongation ratio, and form factor are 0.594, 0.853 and 0.572, respectively, suggested a semi-circular shape. A drainage density value of 2.259 km-1 showed that the Ruste Basin is a basin with steeply to very steeply sloping hilly terrain with varying plant covering. Furthermore, the Ruste Basin has high relief and slope with a relief ratio of 0.151 and basin relief of 2.576 km, both of which imply that it has a steep slope with high erosive force, limited infiltration, and a high runoff rate. Ruste Basin’s ruggedness number was 5.819, indicating that it has badlands topography. The average hypsometric integral was 0.467, denoting a mature basin featuring S-shaped hypsometric curves. In conclusion, the results showed that analysis of morphometric parameters and hypsometric integral and curve provides us with a notion to basin characterization and guidance to making appropriate decisions to establish effective actions to sustainable water and soil conservation and natural resources management through applying water harvesting methods, check dams, and bench terraces.

Sub-Watershed Prioritization for Erosion Susceptibility based On Drainage Morphometric Characters

Watershed located in a Hilly-plain environment is more susceptible for soil erosion. Loss of fertile soil in agricultural land hampers the life of the farmers of the region. Identification of the vulnerable areas and devising strategies to minimize the damage caused due to soil erosion are important to address the problems faced by the agrarian society. In our current work, drainage morphometric parameters were evaluated to assess the soil erosion susceptibility of the four sub-watersheds (SW01, SW02, SW03 and SW04) of the Yagachi watershed located in the Hemavathi river basin in Karnataka State using Remote Sensing (RS) and Geographical Information System (GIS). Seventeen morphometric parameters namely Area, Stream Order, Mean Bifurcation Ratio, Drainage Density, Stream Frequency, Texture Ratio, Infiltration Number, Compactness Co-Efficient, Length of Overland Flow, Elongation Ratio, Circulatory Ratio, Form Factor, Relief Ratio, Shape Factor, Basin Relief, Dissection Index and Ruggedness Number were considered. The priority rank and category for each sub-watershed were assigned based on Compound Factor (CF) value. The sub-watersheds with the lowest CF value are most susceptible to erosion and need highest priority for the soil conservation measures. Based on CF values, the sub-watersheds were categorized into 4 priority groups: ‘Very High’ priority (<2.00), ‘High’ priority (2.01–2.50), ‘Moderate’ priority (2.51–3.00) and ‘Low’ priority (≥3). Out of 4 sub-watersheds, SW03 falls in ‘Very High’ priority category in terms of erosion susceptibility and needs appropriate soil conservation measures in order to arrest fertile soil erosion and increase agricultural produce output.

Geomorphic interpretation on the formation of strike-slip basins along the Northern Sumatran fault

This study describes geomorphic expressions and constructs the schematic evolution of the Northern Sumatran Fault based on the development of transverse drainage basins and streams. This fault is a 400-km NW-SE right-lateral strike-slip fault with three segments, namely the Aceh and Seulimeum Faults in the northern section and the Tripa Fault in the southern section. The two faults at the northern section are sub-parallel and they link at the southeast termination of the latter fault. The examination on the geomorphic expressions comprised the fault configuration, stream deflections, and the delineation of landforms based on their genesis and geometry. This study applied drainage basin relief ratio (Rh), drainage basin volume-to-area ratio (Rva), and transverse stream profile analysis (normalized stream profile, qualitative interpretation of the profile shapes, stream concavity index (SCI), stream gradient, and knickpoint distribution) for investigating the development of transverse drainage basins and streams. For constructing the schematic evolution, this study evaluates drainage maturity level from the applied methods to interpret relative timing of basin formation. This study suggests that the Aceh and Tripa Faults constituted the initial configuration and they propagated to the southeast and northwest, respectively, before merging. The Seulimeum Fault, which formed subsequently, propagated to the northwest after merging with the Aceh Fault at its southeast termination. This study also infers that fault section with lower drainage maturity coincides with greater numbers of earthquakes.

Quantifying soil erosion and influential factors in Guwahati's urban watershed using statistical analysis, machine and deep learning

Soil erosion is a complex environmental issue influenced by rapid climate change, resource exploitation, and soil degradation etc. These factors have triggered global acceleration of soil erosion, primarily due to rapid transformation of topographical features and landscape composition. Guwahati, a thriving financial hub in northeast India, witnessing significant landscape change on both the banks of the Brahmaputra river therefore becomes disaster-prone zones. Hence, the objective of the present study is to identify soil erosion factors and assess its impact using statistical, machine learning, and deep learning techniques. It employs Revised Universal Soil Loss Equation (RUSLE) model for soil erosion estimation, furthermore analyzing physical attributes such as morphometrics, topography, drainage networks, and land use fragmentation indicators. Partial Least Squares Regression (PLSR), Random Forest (RF) sensitivity analysis, and Deep Neural Network (DNN) techniques are used in the study. The RUSLE model showed a significant range of soil erosion rates in the study area, spanning from 168.16 to 188.60 tonnes/hectare/year. Particularly, Silsako, Bharalu, North Guwahati, and Foreshore experiences the most severe soil loss. Amongst all influential factors contributing to soil erosion, the most important key parameters are rainfall, drainage density, landscape fragmentation components (such as cohesion index, edge density, and Shannon diversity index), along with stream frequency and basin relief, as indicated by the RF and DNN models. Furthermore, the PLSR analysis assigned linear weights to variables, highlighting the effectiveness of 14 out of 15 independent predictors derived from basin characteristics in accurately estimating soil erosion. This study provides important quantitative insights through rigorous scientific analysis, enabling well-informed decisions in urban watershed management within the Brahmaputra region. Furthermore, it enhances understanding of the area's urgent needs, societal implications, and environmental conditions related to soil erosion.

Striking a Balance between Conservation and Development: A Geospatial Approach to Watershed Prioritisation in the Himalayan Basin

This study was undertaken in the Himalayan basin, in the river Lohawati, Uttarakhand, to study its hydro-morphological characteristics and prioritise the watersheds using geospatial tools. Advanced Spaceborne Thermal Emission and Reflection (ASTER-30 m) data and the Survey of India’s topographic sheets were used to analyse the study area comprehensively. Nine watersheds were identified within the basin in order to calculate the hydro-morphological characteristics in terms of basic, shape, texture, and relief aspects. The basin was identified as being elongated, with a total drainage area of 337.48 km2. The interaction between the terrain, rock formations, and precipitation levels produced a branching structure in the areas drainage system that ranged from dendritic to sub-dendritic. The basin had been classified as a fifth-order basin, comprising a network of 500 stream segments spanning a total length of 492.41 km. In each of the watersheds, the primary streams are of the first order, followed by those of the second order, and so forth. The physiography and lithology of the basin have a significant influence on this pattern. The calculated elongation ratio, circulatory ratio, form factor, shape index, and shape factor ranged from 0.57 to 0.80, 0.35 to 0.64, 0.26 to 0.50, 1.98 to 3.89, and 0.57 to 1.77, respectively. These values indicate that watersheds are elongated, suggesting moderate lag times. The parameters, including drainage density (0.98 to 1.62), stream frequency (1.07 to 1.59), infiltration number (1.04 to 2.59), drainage texture (0.67 to 2.82), and drainage intensity (0.93 to 1.12), pointed towards the coarser drainage texture, higher infiltration, and minimal runoff characteristics of the basin. In light of the relief characteristics of the basin, a higher basin relief, relief ratio, and relative relief were observed for the watersheds, indicating the possibility of higher erosion and deforestation rates. Using the Weighted Sum Analysis (WSA) method, the computed factors were utilised to rank the watersheds based on their potential for erosion. Based on the WSA approach, watersheds were classified into high-, moderate-, and low-prioritisation zones. This further indicates that 36.14% (121.95 km2) of watersheds are in the high-priority zone, and that 48.84% (164.91 km2) and 15.00% (50.62 km2) of watersheds are in the moderate- and low-priority zones, respectively. The WSA is a practical strategy to prioritise watersheds when making appropriate decisions.

Morphometric analysis of the North Liuleng Shan Fault in the northern Shanxi Graben System, China: Insights into active deformation pattern and fault evolution

The North Liuleng Shan Fault (NLSF) is one of the major active faults in the northern Shanxi Graben System (SGS) in North China. Although the fault has been investigated extensively in terms of late Quaternary activity, its active deformation pattern is still poorly characterized. In this study, we conducted a morphometric analysis of the fault using various geomorphic indices to assess the along-strike relative uplift rates, which include basin relief, slope, mountain front sinuosity (Smf), hypsometric integral (HI) and curves, valley floor width-to-height ratio (Vf), asymmetry factor (Af), basin elongation ratio (Re), and normalized channel steepness indices (ksn). Our findings indicate that the central portion of the fault has experienced higher relative uplift rates than the southwestern and northeastern portions, as demonstrated by higher basin-averaged slopes and ksn values, and lower Vf, Re, and Smf values. This spatial distribution pattern of relative uplift rates appears to correlate well with along-strike changes in the fault geometry and kinematics of the NLSF. We interpret the EW-striking, central portion of the NLSF as a releasing bend formed by the NE-striking, right-stepping, en-echelon southwestern and northeastern portions of the fault system, which are characterized by right-lateral oblique slip. Furthermore, the northeastward increase in HI values along with the regional basin evolution history suggest that the NLSF likely propagated from southwest to northeast. We propose that the southwestern portion of the fault most probably initiated earlier and that the central and northeastern portions formed later as extensional structures at the termini of the fault zone. Our findings contribute to a better understanding of the tectonics and genesis of the basin-and-range geomorphology in the northern SGS.

Watershed prioritization and hydro-morphometric analysis for the potential development of Tabuk Basin, Saudi Arabia using multivariate statistical analysis and coupled RS-GIS approach

The Tabuk province of Saudi Arabia (SA) has an arid zone, few aquifers, high groundwater salinity (seawater intrusion), and accelerated population, industrial, and agricultural development. The development of Tabuk Basin is essential for the addition of new freshwater resources and the enhancement of aquifer recharge potential. The hydrological characteristics of the drainage basin aid in the identification of watersheds, enabling the protection and management of land erosion and ground/surface water resources. This study analyzed hydro-morphometric data from the eighteen sub-basins of the Tabuk Basin using multivariate statistical approaches and coupled remote sensing (RS) and geographic information systems (GIS) for water priority determination. The results show that the four principal components(PC1-4) have a variance of90.4% concerningbifurcation ratio (Rb), ruggedness number (Rn), elongation ratio (Re), drainage density (Dd), basin relief (Bh), circularity ratio (Rc), and relief ratio (Rh). The Al Ula, Thaibah, Hamd, Dama, Al Wajh, Al Ghamra, and Azlam sub-basins showed the highest priority, indicating soil erosion and the necessity for mitigating measures to reduce infrastructure damage. Mostexposed geology (67%) exhibited strong permeability and good infiltration (sedimentary cover and Quaternary sediments). The rest(23%) showed low to medium permeability(igneous, metamorphic, and carbonate rocks). The bestpromisingsitesfor building new wells can reduce surface runoff and soil erosion through aquifer infiltration and abstraction. The aquifer potentiality map was accomplished for Al Ula, Thaibah, Hamd, and Dama drainage basins. The most prospective groundwater investigation regions were identified, coincidingwith the drilled wells that confirmed and validated the results. The estimated zones of high to very high aquifer potentiality were used to add additional wells for investment reduce soil erosion, mitigate alternatives, agriculture,urbanization, etc. The other sub-basins have a medium to low priority, with less soil erosion and aquifer recharge.