Hypsometric Integral Research Articles

AHP and TOPSIS Based Sub-Watershed Prioritization and Tectonic Analysis of Ami River Basin, Uttar Pradesh

Abstract Soil erosion is a major consequence which usually reduces soil productivity. The identification of its susceptible zones is essential in order to apply preventive measures in any basin. A detailed morphometric evaluation of Ami river basin is done using Shuttle Radar Topography Mission (SRTM) data of 30m resolution. Technique for order of preference by similarity to ideal solution (TOPSIS) and analytic hierarchy process (AHP) based prioritization and characterization of sub-watersheds is important to plan and manage the natural resources of a region. Total 18 sub-watersheds with an outlet having 4th order drainage were selected for the prioritization purpose for soil erosion susceptibility zones with the help of 10 morphometric parameters. The sub-watersheds were ordered from SW-I to SW-XVIII. In this regard, SW-XV has the highest priority (0.628) and higher soil erosion while SW-XVIII (0.317) has lowest conditions for soil erosion. Various tectonic and sinuosity related parameters are calculated and analyzed like hypsometric integral (0.49), asymmetric factor (50.1) and transverse topographic symmetric factor suggesting good symmetry of basin with no tectonic tilt. The value of standard sinuosity index (1.2) suggests that Ami river is naturally sinuous stream. Morphometric parameters suggest less structurally controlled and normal category of the basin. The basin has coarse texture of drainage with highly suspect to soil erosion and high run off.

Tectonic and Climatic Control on Quaternary Exhumation in the Eastern Pamir Domes, Western China: Insights From Geomorphic Approaches

The Kongur Shan and Muztaghata massifs, bounded by the Kongur Shan extensional system (KES), represent tectonic and topographic anomalies in the eastern Pamir region. They are ideal examples to study how normal faulting and surface erosion influence Quaternary exhumation of the dome system. We apply multiple geomorphic parameters, including hypsometric integral, stream length-gradient index, drainage basin shape, drainage basin asymmetry and ratio of valley floor width to valley height, for the catchments on both sides of the range. We first evaluated the validity of various indices and chose three active tectonic-sensitive indices to establish a newly-integrated parameter (Iat) that is used to measure relative intensities of tectonic activity in active orogens. Results suggest stronger tectonic activity west of the domes along the Kongur Shan normal fault (KSF) and Muji dextral strike-slip fault, compared to the eastern side, along the Ghez and Kalagile faults. This first-order observation reflects tectonic control on the topographic development of the domal structure, consistent with eastward crustal tilting, attested by older thermochronology ages to the east. On the western flank of the range, stronger tectonic activity occurs mostly on the Muji fault, Kingata Tagh - Kongur Shan fault segment, as well as along the western and southern Muztaghata segments of the Kongur Shan fault. This is consistent with field investigations of Quaternary offsets of landforms, which suggest continuous activity of the Muji fault and KSF since the late Miocene. Average basin-wide erosion rates derived from stream power models are highest near the Kongur Shan dome, and gradually decrease southwards and northwards, in agreement with the spatial pattern of long-term exhumation rates in the footwall of the KSF obtained by low-temperature thermochronology data. Positive correlation between exhumation/erosion rates and extensional rates along the active faults located west of the domes indicates that extensional deformation likely plays a dominant role in controlling focused dome exhumation/erosion. However, considering peaked exhumation/erosion rates, stronger rock resistivity and steeper glacial landforms, attest to the important role of glacial buzz-saw in reshaping the recent dome’s landscape.

The Hypsometric Integral Based on Digital Elevation Model for the Area West of Lvliang Mountains in Loess Plateau, Shanxi, China

A hypsometric integral (HI) is a topographical index with important geomorphological meaning. It can both describe the development state of the watershed and reflect the strength of activity in the geological structure. Based on this index, the integral curve method was used to analyze the HI characteristics of watersheds in the region west of the Lvliang Mountains on the Loess Plateau of Shanxi Province, China, in combination with 30-m resolution Shuttle Radar Topography Mission data. In order to accurately characterize erosion development within the watershed, the HI characteristics of each topographic feature object in the watershed were comprehensively analyzed. The results of HI scale effects show that HI was not strongly dependent on the spatial resolution of Digital Elevation Model (DEM) data, but had some scale dependence on the stable area of the watershed. The spatial distribution of the HI shows that the HI values of the watersheds in the southern loess residual tableland were the largest, and the degree of erosion was the weakest; the HI values of the watersheds in the north-central part of the loess hilly-gully region were relatively small, and the degree of erosion was stronger. This result is consistent with the results of the spatial distribution of sediment yield in literatures. The reasons for the spatial distribution of the HI were analyzed in terms of geological formations and climatic environments. The results show that for the study area, tectonic activity, formation lithology, rainfall, and agrotype were not the main factors affecting the HI values. The structure of the paleotopography and erosion cutting due to the uplift of the Lvliang Mountains and later water erosion controlled the spatial distribution state of HI. Thus, for the study area, the HI value cannot reflect the strength of tectonic activity. The combination of topographic feature object method and the HI index further quantified the erosion development state of the watershed.

Active tectonics in the upper reaches of the Yellow River from Lagan Gorge to Liujia Gorge, northwestern China: Insights from geomorphic indices

The drainage basin of the upper reaches of the Yellow River from Lagan Gorge to Liujia Gorge, which spans Gonghe, Guide, Jianzha, Xunhua and Linxia basins, is located in the transition zone between the Qinghai–Tibet Plateau and the Loess Plateau, northwestern China. Its evolution is controlled by the northeastward growth and uplift of the Qinghai–Tibet Plateau. To characterize and quantify the response of surface processes to deep geological mechanisms and to investigate the types of Late Cenozoic tectonic deformation in the study area and the relationship with large geological hazards, we analysed various geomorphological indicators, combined with field observations and the estimated incision rates and established a reasonable tectonic deformation model. The results demonstrate that the variations in the geomorphic indices are highly consistent with active tectonics. Higher hypsometric integral (HI), higher normalized stream length‐gradient index (SLK), higher basin asymmetry factor (AF), higher drainage basin shape (BS) and lower ratios of valley floor width to valley height (VF) indicate higher tectonic uplift rate in the Jianzha‐Xunhua basins compared to other basins where there are many giant landslides. These giant landslides occurring there can probably be correlated with the vigorous tectonic activity, thus generating a great significance in geological hazard prevention and control along the upper Yellow River.

Relative active tectonics evaluation using geomorphic and drainage indices, in Dadra and Nagar Haveli, western India

The present study area, Dadra and Nagar Haveli, contains several lineaments and traces of active faults. The various aspect of the geomorphic analysis, i.e., stream length (SL) gradient, hypsometric integral (HI), basin shape (BS), valley floor (VF), have been applied to evaluate the relative index of active tectonics (RIAT) of the Damanganga watershed. The high and low zones of tectonic activity have been identified based on the geomorphic analysis of the watershed. After evaluation of all indices, three classes, class II- high (1.3 ≤ RIAT < 1.5), class III- moderate (1.5 ≤ RIAT < 1.8), and class IV- low (1.8 ≤ RIAT), have been obtained to outline the degree/gradation of comparative tectonic activities in the study area. The appraised outcome of the RIAT dispersal is also well reinforced by the geomorphic evidence in the field. The collective outcomes of geomorphic evidence, such as stream deflection and analysis of lineament, deflection of streams, and geomorphic indices, conceal that the Damanganga watershed is affected by tectonic activity.

An Exploration of Loess Landform Development Based on Population Ecology Method

The study of gully characteristics is one of the most effective ways to explore the loess landform development in the Loess Plateau of China. However, current studies mostly focus on gullies’ overall characteristics and ignore the different composition of the whole gully system. Therefore, a new perspective is provided in this paper for exploring loess landform development from the population characteristics of the gully system. Firstly, different types of gullies were extracted based on DEM and high-resolution images in three sample watersheds, including hillslope ephemeral gully, bank gully and different-level valley gully. Secondly, population characteristics from the amount, length, age structure and convergent relationship were calculated and analyzed by referring to the biological population in ecology. Finally, the development stages of loess landform in three watersheds were explored based on their population characteristics. The results showed that: (1) The population characteristics, including number density, length density, age structure and convergence, were obviously different in three sample watersheds. (2) The development differences of three watersheds were obtained by synthesizing all population characteristics: Linjiajian was the most developed and oldest watershed, followed by Yangjiaju and then Wangjiagou. (3) The comparison based on the existing soil erosion intensity map and predisposing factors proved that the findings of this paper were more reasonable than that of the traditional hypsometric integral. This research provides a new quantitative-based approach to explore the development degree of loess landform from the gully population, and is a beneficial attempt to combine geomorphology and ecology, further supplementing and improving the study of loess landform development.

Investigation of the watershed hydro-morphologic characteristics through the morphometric analysis: A study on Rayeng basin in Darjeeling Himalaya

The analysis of morphometric parameters gives a precise scenario about the geomorphic characteristics and the hydrological behaviour of a drainage basin, especially in the areas where hydrological data are unavailable due to the absence of a gauging station or inaccessibility for harsh topographic conditions. So, the current study is aimed to investigate the hydro-geomorphic characteristics of the Rayeng basin in Darjeeling Himalaya. The extraction and analysis of the morphometric variables of the study area were done using remote sensing and GIS. The spatial disparity in drainage density, lineament density, stream frequency, texture ratio, and infiltration number has inferred that the Rayeng basin is carried a high runoff intensity and low infiltration rate on the upper reaches and an inverse situation in the lower reaches. The extracted ruggedness index and Melton's Ruggedness index indicate the unevenness of the topography and normal flow in the main channel in the Rayeng basin. A distinctive topographic diversity is also depicted by the basin's Topographic Positioning Index (TPI). A significant spatial variation of water availability in this basin is indicated by the Topographic Wetness Index (TWI); the depressed areas of the basin have higher TWI compared to the steep-sloped high land. The basin's hypsometric integral (HI) is inferred youthful stage. This basin has a good potentiality of water which can be sustainably used by the people of the lower reaches of the basin. This study will be helpful to assess the hydro-geomorphic characteristics of a drainage basin where hydrological data are not available.

Empirical relationships of the landslides in the Chinese Loess Plateau and affect factors analysis

The CLP (Chinese Loess Plateau) is one of the most densely distributed landslides areas. The empirical relationships of the landslides in the CLP remain unclear, and its influencing factors are controversial. According to regional landslide data, this paper studies the relationships and discusses the factors affecting landslides in the CLP. The results show that the area (A) -volume (V) of landslides follows a power law trend described by V = 1.53 A 1.19 and the frequency distribution range of H/L (height drop (H)/travel length (L)) is between 0.2 and 1.0, more specifically between 0.2 and 0.4, accounting for 26.1% of the total landslides, indicating that the landslides primarily belong to long run-out landslides. The function of V and H/L of the landslides is followed by H/L = 2.39 V −0.102. About 87% of the landslide is distributed within the equilibrium or mature stages of the watershed. The landslide’s size increases, and the slope of the landslides are steeper with an increase in HI (hypsometric integral). Meanwhile, the loess thickness, human activities, and slope effects on landslides induce landslide occurrence and have positive and negative effects on the landslides within the CLP. With climate change, the risk of landslides will increase in the CLP.

Hypsometric Analysis of Watershed using Geographical Information System

Hypsometry of drainage basins (area-elevation analysis) has generally been used to reveal the stages of geomorphic development (stabilized, mature and young). In the present study, Kanoli river watershed located in Nashik district of Maharashtra was considered as the study area. The watershed was delineated into seven sub-watersheds and hypsometric analysis was carried out for all of them using the digital contour map, which was generated using Arc/Info GIS. In analysis, a curve is derived by plotting the relative heights (h/H) and relative areas (a/A); the obtained curve is called as hypsometric curve. The area under the Hypsometric curve is the Hypsometric Integral (HI). The hypsometric integral values for all of the sub-watersheds of Kanoli river ranges between 0.45 and 0.88. It was observed from HI that the sub-watersheds WS2, WS4, WS6 are in the mature stage and moving toward the deteriorating stage. The sub-watershed WS3 yielded higher hypsometric integral value, explaining its late youthful stage which calls for suitable measures of soil and water conservation. Further, sub-watersheds WS1, WS5 and WS7 have got very high value of hypsometric integral which takes them to young stage i.e. very susceptible to erosion. Therefore, these sub-watersheds are more prone to subsequent erosion activities and needs immediately appropriate soil and water conservation measures

Drainage Basin Characteristics of Dhund River Basin, Eastern Rajasthan India, Using Remote Sensing and GIS Techniques

Morphometric analysis is mathematical evaluation and measurement of the earth’s shape, surface and its landform’s dimension. Morphometric analysis of Dhund river basin in Jaipur district of Rajasthan India has been carried out to evaluate various morphometric parameters following the linear, areal and relief aspects. The drainage basin, which covers a total area of about 1828 km2 lies in eastern part of the district with maximum and minimum elevation of 603 m and 214 m respectively. Morphotectonic parameters like Hypsometric Integral, Sinuosity index and Asymmetry Factor have also been computed to identify the tectonic characteristics of the drainage basin. Primary and secondary data such as SOI topographic map, Cartosat-1 DEM and other relevant data were utilized. ArcGIS software (Arc Map 10.2) was used for geo-referencing of topographic maps, delineation of watershed and preparation of DEM, slope and drainage network. The basin is 6th order drainage basin having dendritic pattern of drainage network. A relatively lower mean value of Bifurcation ratio suggests that the drainage basin is formed by uniformed materials. Drainage basin area has little elongated shape and is less prone to floods. Basin has different erosional stages and levels of tectonic activity, Moderate Meandering and unstable setting.

Morpho-tectonic Assessment of the Abu-Dabbab Area, Eastern Desert, Egypt: Insights from Remote Sensing and Geospatial Analysis

The Abu-Dabbab area, located in the central part of the Egyptian Eastern Desert, is an active seismic region where micro-earthquakes (≈ML &lt; 2.0) are recorded regularly. Earthquake epicenters are concentrated along an ENE–WSW trending pattern. In this study, we used morphological indexes, including the valley floor width-to-valley floor height ratio (Vf), mountain front sinuosity (Smf), the asymmetry factor index (Af), the drainage basin shape index (Bs), the stream length–gradient index (SL), hypsometric integral (Hi) water drainage systems, and a digital elevation model analysis, to identify the role of tectonics. These indexes were used to define the relative tectonic activity index (RTAI), which can be utilized to distinguish low (RTAI &lt; 1.26), moderate (RTAI = 1.26–1.73), and high (RTAI &gt; 1.73) tectonic activity signals all over the study area. Firstly, our results indicate low to medium tectonic activity and general anomaly patterns detected along the major tectonic zones of the study area. Secondly, based on most of the low to medium tectonic activity distributed in the study area and the detected anomalies, we discuss two potential drivers of the seismicity in the Abu-Dabbab area, which are fault-controlled and deep-rooted activities.

Modelling spatial variation in erosional status and geomorphic evolution of the Limbang river basin in Northern Borneo through hypsometric analysis

Erosional status and geomorphic evolutional stages of the Limbang River Basin (LRB) and its fifteen subwatersheds were investigated in the present research through analysis of hypsometric curve characteristics. Spatial analysis of topographic parameters (elevation, slope and relative relief), shows differential and varying proneness of the subwatersheds to erosion. Hypsometric curve parameters like hypsometric integral (Ea), maximum concavity (Eh), coordinates (a*, h*) of the curve-slope inflection point (I), and normalized heights of the hypsometric curve at 20%, 50%, 80% and 90% of the area revealed similar characteristics of the subwatersheds with more detailed information about its spatial variation. Hypsometric curves showed dominance of concave, convex and mixed concavo–convex shapes in spatial-proximity with integral values indicating an almost equal number of subwatersheds (seven) with old (Ea <0.30) and (eight) mature (Ea >0.30) stages of geomorphic evolution. Parameters such as concavity, slope inflection point, normalized hypsometric curve height at various points revealed varying level of influence of fluvial and diffusive processes in terrain erosion and subwatershed characteristics. Further, subwatersheds with varying Ea and Eh signifies the role of varying lithology to the tectonic processes operated in the region. Spatial variation of lithology in proximity and its differential response to the tectonic processes has induced the variation in erosional characteristics and thus controlled the geomorphic evolutional stages of the subwatersheds in LRB.

Slip Distribution and Footwall Topography of the Yanggao‐Tianzhen Fault (Northern Shanxi Graben): Implications for the Along‐Strike Variations in Fault Activity and Regional Deformation

AbstractSpatial patterns in fault activity were examined along the Yanggao‐Tianzhen Fault (YTF) in the northern Shanxi Graben, North China. First, we reconstructed the distribution of fault slips and quantified slip rates at seven sites along the fault, based on satellite image interpretation, field investigation, topographic surveying, and optically stimulated luminescence dating. The T3terraces and their contemporaneous alluvial fans with a best‐estimate age of 31.7 ± 1.4 kyr were used as strain markers to estimate slip magnitudes. We determined vertical slip and dip‐slip rates of ∼0.10–0.31 mm/yr and ∼0.11–0.37 mm/yr, respectively, at the surface. Assuming fault dips of 40 ± 10° at seismogenic depths, we predicted extension rates of ∼0.17–0.55 mm/yr. This suggests that at least 10% and up to 28%–54% (95% confidence interval) of the total extension of the northern Shanxi Graben is inhomogeneously partitioned by different sections of the YTF. We also evaluated the along‐fault relative tectonic activity by analyzing of five widely used geomorphic indices: hypsometric integral, basin elongation ratio, asymmetric factor, valley‐floor‐width‐to‐height ratio, and mountain front sinuosity. The determined fault slip rates and geomorphic indices demonstrate that the most prominent fault activity center occurred in the middle of the fault, and that fault activity wanes toward the fault tips. Moreover, the fault activity is highly heterogeneous and fluctuates along the fault strike, which may be attributed to either fault segmentation and linkage or the possible strike‐slip component of motion along the fault. Further exploration of fault kinematics and paleoseismic history is warranted.

Active Tectonics of Gülbahçe Fault Zone (GBFZ) by Using Geomorphic Indices, İzmir Province, Western Anatolia, Turkey

The Gülbahçe Fault Zone is a dextral strike-slip fault that extends for ~24 km on land and ~46 km under the sea, which consists of the significant southernmost active segments of İzmir Balıkesir Transfer Zone. In this study, the active tectonic behaviour of the Gulbahçe Fault Zone was evaluated by using of morphometric analysis of geomorphic indices. 30 sub-basins identified using ArcGIS ®10.5 (ESRI). All sub-basins were calculated by using mountain-front sinuosity (Smf), valley-floor width to valley height ratio (Vf), basin asymmetry factor (Af), basin shape indice (Bs), drainage density (Dd), and hypsometric integral (Hi) values. The obtained mean results of values are to define each sub-basin's relative tectonic activity (Iat). The Smf, Vf, Af, Bs, Dd, and Hi values range from 1.05 to 1.33; from 0.21 to 4.09; from 25 to 77; from 1.03 and 3.06; from 0.28 to 0.67, respectively. All the results were gathered under three classes, which sign high tectonics activity (Class 1), moderately active tectonic (Class 2), and low tectonics activity (Class 3). The results show that relative active tectonics indice value (Iat) was obtained between 1.33 and 2.33, indicating very high to moderately tectonic activity.

Analysis of Basin Morphologic Characteristics and Their Influence on the Water Yield of Mountain Watersheds Upstream of the Xiongan New Area, North China

In this study, based on the DEM, we extracted the drainage networks and watersheds of the Daqing River with ArcGIS, investigated the basin characteristics and the differences in their spatial distributions and analyzed the relations of the drainage density with some surface conditions and how the drainage density influenced the water yield. The results suggested a power function between the mainstream length and drainage area, showing that with the increase in basin area, the basins became longer. The result of the power function between the relief and drainage area with negative exponent values means the relief changed more slowly with increasing basin area. The values of the circularity ratio and elongation ratio indicate that the basin shape of the mountain watersheds in the Daqing River was narrow and predisposed to flooding during periods of heavy rainfall. The orders of the streams in the mountain watersheds ranged from five to seven. The average bifurcation ratio of those nine mountainous watersheds reveals the order of the u + 1 rivers in each basin of the Daqing River was on average 4 times larger than that of order u rivers. The drainage density (Dd) was high in the north and low in the south of the Daqing River. Rainfall was negatively correlated with drainage density, but the correlation between them was not significant at the 0.05 level. Drainages developed in places with poor vegetation cover. The drainages in the southwest, north and west developed considerably, while drainages in the east and southeast did not develop much. Yet, the available data showed the impact of the watershed area, elongation ratio and drainage density on the water yield was not significant. In contrast, there was a significant positive correlation between channel slope and the water yield modulus. The hypsometric integrals and the relation between drainage density and hypsometric integral suggest that the landform evolution of the mountain basins along the Daqing River were in the old stage with no further increase trend of drainage density in the future.

Using morphometric and geomorphic indices to assess Western São Francisco Craton neotectonic traces

Recently, geomorphometric properties of river networks and catchments have been described and applied as an efficient tool in the investigation of the landforms' response to neotectonics. Geometric parameters of the Cotovelo River catchment extracted from an Alos-Palsar digital elevation model were used to compute morphometric and geomorphic indices to investigate whether the bedrock structure and recent active tectonics influence the local drainage network. The Cotovelo catchment is situated in the Middle to Upper Proterozoic western foreland basin of the São Francisco craton, in northwestern Minas Gerais, Southeastern Brazil; it is presumed to be a stable piece of earth’s crust. The automatically generated streams were processed at the sub-catchment scale to calculate the hypsometric integral, relief ratio, stream frequency, and drainage density morphometric indices as well as supported a geomorphic study based on the basin shape, asymmetry factor, valley floor width-to-height ratio, mountain front sinuosity, transverse topographic symmetry factor, and stream-length gradient index. Achieved results revealed recent and low-rate tectonic activity and structural control on the fluvial morphology. Prominent knickpoints, aligned with mapped fault scarps, disclose straight erosive fronts away from stratigraphic borders, indicating these features are unrelated to lithological changes. Despite the catchment location, the area exhibits impressive fluvial anomalies, and dissection occurs preferentially along ancient faults and fractures densely occurring in the rocky strata. Channel parallelism in context of medium to high relief and steep slopes, remarkably structurally drive fluvial dissection, asymmetric and elongated drainage catchments, and aligned landforms suggest neotectonic influence on the drainage network.

Tectonic geomorphology assessment of neotectonics in the north of Damghan Region, Alborz Mountain Belt, Northern Iran

In mountain ranges, recent and active tectonics can be viewed as the main factor contributing to rock uplift, their present-day topography being the result of the competition between tectonic and erosional processes. The region coincides with three faults which show signs of activity during the late Quaternary period: The Astaneh, North Damghan, and Damghan faults, which collectively make up the SW section of the left‐lateral Shahrud fault system. In this study we have analyzed morphotectonic and neotectonic indices to evaluate tectonic activity of the study area.Tectonic geomorphological indices that are used in this study are drainage basin based (drainage basin asymmetry factor (Af), Hypsometric integral (Hi)) and mountain front based (mountain-front sinuosity (Smf), valley floor width – valley height ratio (Vf)) which can be useful tools for studying active tectonics. The study area includes pop-up structures that are formed during inverse tectonic activities of Alborz mountain belt. Strike-slip faults and flower structures suggest transpressional tectonic regime at eastern part of Alborz.

Quantitative Geomorphological Parameters Analysis for the Aynalem- Illala Streams, Tigray, Northern Ethiopia

Morphometric analysis is the measurement and mathematical analysis of the configuration of the surface, shape, and dimension of landforms. The objective of this study is to characterize the Aynalem and Illala streams using the morphometric parameter. The topographic map at a scale of 1:50,000 taken from the Ethiopian National Mapping Agency was used to characterize the linear and areal aspects. ASTER Digital Elevation Model with 10m resolution was used to characterize the relief aspect. The Arc GIS 10.4.1 was used during the morphometric analysis. The analysis result of the streams is summarized based on the linear, areal, and relief aspects. The area is characterized by a dendritic drainage pattern which is characteristics of massive hard rock terrain. The Aynalem and Illala streams are 4th and 5th order streams. Considering the number of streams in the Aynalem (75.81%) and Illala (74.66%) is composed of first-order streams that indicate a flashy flood and the mean bifurcation value of Aynalem (6.8) and Illala (4.7) shows that the Aynalem area is more structurally affected than Illala but both show less stream integration. The analysis of areal aspects such as elongation ratio, circularity ratio, and form factor has indicated that both streams are characterized as elongated streams, this implies that both streams are flowing in heterogeneous rock material, presences of structural effect, and slow runoff discharge. The other areal aspect such as drainage density, stream frequency, infiltration number, and length of overland flow all show smaller values in both streams. This implies that the streams are characterized by a relatively permeable rock material with a higher infiltration capacity. The relief aspect of the Aynalem and Illala was also analyzed using basin relief, relief ratio, ruggedness number, hypsometric curves, and Hypsometric integral. The streams are characterized by a lower relief ratio and ruggedness number which implies a relatively flat slope and lower relief. The hypsometric curves and the Hypsometric Integral of the streams indicate that the Aynalem and Illala are at the maturity stage. This shows the area is characterized by higher erosion but less affected by recent structures. Based on the morphometric parameter analysis result it is possible to conclude that the stream development is dependent on the topography and geology of the study area and both streams show similar morphometric character.

Novel Technique to Investigate Glacio-fluvial Hypsometry in Hunza Using Local Indicator of Spatial Autocorrelation (LISA)

Hypsometric Integral (HI) displays the effect of active tectonics and sensitivity on geomorphic structures. In this study we calculated HI values for Hunza valley to investigate neotectonics, development of topographic structures and process of erosion using SRTM DEM 90m. ArcGIS and MATLAB is used to generate HI and hypsometric curve (HC). We generated HI and HC values by using D8 algorithm in MATLAB to extract drainage basins for 5 and 6 Strahler orders. HI and HC values show the stages of erosion for instance high values of HI and convex HC displays young and tectonically active stage. We used different grid sizes in ArcGIS to calculate maximum, mean and minimum elevation utilizing different statistical techniques. We used Local Indicator of Spatial Autocorrelation (LISA) instead of Global Moran Index to determine the extent of distribution of clustered, dispersed and randomized HI values. This technique indicates high positive z score for auto correlated data. Regions with high HI value indicate relative uplift, undissected and young structures while low HI values indicate sediment accumulation and shallow earthquakes.

Vegetation and cloud cover shape semi‐arid carbonate landform development

AbstractWe study the relationships among precipitation, vegetation, and morphological characteristics of watersheds draining either side of the Dhofar Mountains in southeastern Oman to understand the geomorphic signature of water availability in a semi‐arid carbonate landscape. Water availability is expressed in terms of vegetation and cloud cover. The integral and the statistical moments of the hypsometric curve were used to determine whether hyper‐arid, inland‐draining watersheds are significantly different from seasonally wet watersheds on the coast side of the mountain range. We demonstrate that the vegetation and cloud cover are correlated, with locations with longer cloud periods also having a longer period with a vegetation canopy. The analysis shows that the hypsometric curve and its statistical moments capture the morphological difference between wet watersheds shaped by groundwater sapping and dry watersheds with fluvial morphology. Specifically, the curves exhibit two shapes: watersheds with more vegetation and cloud cover are characterized by higher convexity, and those with less vegetation and cloud cover are characterized by higher concavity. A variance analysis of cloud cover, vegetation, and hypsometric integral shows that they are significantly different between the wet and dry watersheds. The link between hydrology and morphology is not strong at the scale of a single watershed, but it is significant when the watersheds are aggregated in zones. The statistical moments of the hypsometric curve in the range of values of the integral and skewness show good separation between watersheds dominated by sapping and fluvial erosion processes. We can separate the watersheds draining the mountain range in two distinct groups on the basis of their bimodal hydrological and morphological characteristics. Our findings support other studies that hypothesize a trade‐off from chemical‐ to mechanical‐dominated denudation in carbonate terranes as precipitation decreases.