Hypsometric analysis is considered an effective tool for understanding the stages of geomorphic evolution and geological development of river catchment, and for the delineation of erosional proneness of watershed. In ...Hypsometric analysis is considered an effective tool for understanding the stages of geomorphic evolution and geological development of river catchment, and for the delineation of erosional proneness of watershed. In the present study, twenty eight fourth order sub-basins of W. Mujib-Wala (Southern Jordan) were selected, and hypsometric analysis was carried out using 30 m ASTER DEM. Elevation-relief ratio method was employed to calculate the hypsometric integral values within GIS environment. The hypsometric integral values range from 0.71 to 0.88, whereas, the hypsometric curves exhibit remarkably upward convex shapes which indicate that all sub-basins and the W. Mujib-Wala watershed are at the youth-age stage of geomorphic development. Thus, they are of high susceptibility to erosion, incised channel erosion and mass movement activity. Marginal differences exist in mass removal from the watershed and the 28 sub-basins are attributed to variation in tectonic effect, lithology and rejuvenation processes. The relation between basin area and hypsometric integral was examined using regression analysis. Results reveal that negative and weak relationships dominate, where r<sup>2</sup> ranges from 0.05 to 0.478 which confirm with other results reported elsewhere. Indirect assessment of erosion status based on hypsometric integral values was validated using estimated sediment yield information related to wadi Mujib and wadi Wala watersheds separately. The recorded sediment yields were in affirmation with high hypsometric integrals values, where higher values of hypsometric integrals and sediment yields occurred in the western part of the W. Mujib-Wala watershed. These findings would help in the construction of appropriate soil and water conservation measures across the watershed and its sub-basins to control soil erosion, to conserve water, and to reduce sediment discharge into the W. Mujib and W. Wala reservoirs.展开更多
This research is intended to assess the regional pattern of hypsometric curves (HCs) and hypsometric integrals (HIs) for the watersheds draining into the Jordan Rift (River Jordan, the Dead Sea, and Wadi Araba watersh...This research is intended to assess the regional pattern of hypsometric curves (HCs) and hypsometric integrals (HIs) for the watersheds draining into the Jordan Rift (River Jordan, the Dead Sea, and Wadi Araba watersheds). Hypsometric analysis was performed on 22 drainage basins using ASTER DEM (30 m resolution) and GIS. The area-elevation ratio method was utilized to extract the hypsometric integral values within a GIS environment. A prominent variation exists in the HC shapes and HI values. The highest hypsometric values are found for the Dead Sea ( = 0.87) and River Jordan ( = 0.77) watersheds. Whereas the lowest values ( = 0.51) characterized Wadi Araba catchments, except Wadi Nukhaileh (lower Wadi Araba) which yields an HI value of 0.26. Seventeen HCs pertained to the River Jordan and the Dead Sea watersheds evince remarkably upward convex shapes indicating that such drainage basins are less eroded, and at the youth-stage of the geomorphic cycle of erosion. Catchments draining to Wadi Araba are of intermediate HI values (0.41 - 0.58) which are associated with a balance, or dynamic equilibrium between erosion and tectonic processes. Accordingly, they correspond to a late mature stage of geomorphic development. Additionally, Wadi Nukhaileh yields the lowest HI value (0.26) and is associated with highly eroded terrain of late mature geomorphic evolution, approaching an old stage therefore, with distorted concave upward curves. High HI values indicate that these watersheds have been subjected to tectonic uplift, down faulting of the Rift and intense rejuvenation. Differences in HI values can be attributed to disparity in tectonic uplift rate, base level heights, and mean heights of the River Jordan watersheds, the Dead Sea and Wadi Araba watersheds, and variation in lithology, which caused noticeable differences in rejuvenation processes, and channel incision. Regression analysis reveals that R<sup>2</sup> values which represent the degree of control of driving parameters on HI, are positive and generally low (ranging from 0.026 to 0.224) except for the height of base level (m) parameter which contributes 0.42 (significant at 0.1% level). Such results mean that the height of base level has a significant at 0.1% level. It is obvious that the most crucial driving morphometric factor influencing HI values of the Jordan Rift drainage basins, is the height of base level (m).展开更多
Study area is located in Southwest Iran with relatively flat topography. Outcropped lithological units in the region belong from Triassic and Jurassic till recent era. The study area of the Namdan basin is related to ...Study area is located in Southwest Iran with relatively flat topography. Outcropped lithological units in the region belong from Triassic and Jurassic till recent era. The study area of the Namdan basin is related to the tectonic zone of the high Zagros region and the compressional-extensional regime. Geomorphic indices of active tectonics are useful tools to analyze the influence of activity. One of them is hypsometric integral which has generally been used to reveal the stages of geomorphic development. It is estimated by the graphical plot of the measured contour elevation and encompassed area by using empirical formulae. In constructing the hypsometric integral curve, a Digital Elevation Model (DEM) with 30 m spatial resolution has been used. This index is calculated in the study area. Then, based on index of its values, the hypsometric properties of drainage basins are analyzed in Namdan basin. Three different approaches were used for estimation of hypsometric integrals. The hypsometric integral values (HI) range between 0.18 and 0.31 for all the basins of study basin. In the study area, one stage of erosion cycle development, namely old stage is distinguished. Our results indicate that there is anomaly in Hi value which is located on faulted area. The results indicate the Northwest of Namdan basin and a small part of its Southeast are more active than other ones.展开更多
A land surface region can be decomposed into a series of watershed units with a hierarchical organizational structure. For loess landform, the watershed is a basic spatial–structural unit that can express natural lan...A land surface region can be decomposed into a series of watershed units with a hierarchical organizational structure. For loess landform, the watershed is a basic spatial–structural unit that can express natural landforms, surface morphology characteristics, spatial organization and developmental evolution. In this research we adopted the concept of node calibration in the watershed structure unit, selected six complete watersheds on China Loess Plateau as the research areas to study the quantitative characteristics of the hierarchical structure in terms of watershed geomorphology based on digital elevation model(DEM) data, and then built a watershed hierarchical structure model that relies on gully structure feature points. We calculated the quantitative indices, such as elevation, flow accumulation and hypsometric integral and found there are remarkably closer linear correlation between flow accumulation and elevation with increasing gully order, and the same variation tendency of hypsometric integral also presented. The results showed that the characteristics of spatial structure become more stable, and the intensity of spatial aggregation gradually enhances with increasing gully order. In summary, from the view of gully node calibration, the China Loess watershed structure shows more significantly complex, and the developmental situation variation of the loess landforms also exhibited a fairly stable status with gully order increasing. So, the loess watershed structure and its changes constructed the complex system of the loess landform, and it has the great significance for studying the spatial pattern and evolution law of the watershed geomorphology.展开更多
Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landfor...Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.展开更多
This study addresses the morphometric variables that determine the sediment yield in Wadi AI-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sedi...This study addresses the morphometric variables that determine the sediment yield in Wadi AI-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its mor- phometric and hydrological characteristics. The study found several results, most notably： The classification of Wadi AI-Arja basin according to the hypsometric integral value （72.1%） within an uneven topography, which in- creases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield. The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi AI-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05.展开更多
Geomorphometric analysis was carried out to illustrate the drainage characteristics and morphology of Wadi Kerak watershed, southern Jordan. The basic and derived morphometric parameters (linear, areal and relief aspe...Geomorphometric analysis was carried out to illustrate the drainage characteristics and morphology of Wadi Kerak watershed, southern Jordan. The basic and derived morphometric parameters (linear, areal and relief aspects of drainage network) for the basin were determined using ASTER DEM (30 m resolution) and Geographic Information System (GIS). These parameters describe the basin drainage network, geometry, texture, and relief characteristics. The hypsometric curve, hypsometric integral and clinographic curve were also prepared using topographic maps of 1:50,000 scale. Findings have revealed that W. Kerak is in the youth-age stage of geomorphic evolution. Fluvial erosion associated with successive phases of rejuvenation plays a significant role in drainage basin development, whereas structure and tectonics, lithology and relief dictate the drainage pattern and morphological setting of the catchment. The drainage area of the watershed is 190.9 km2 and constitutes a 5th-order drainage basin. The commonly observed drainage patterns are the trellis type, with sub-dendritic pattern recognized in the upper catchment. The drainage pattern, and the semi-linear alignment of main and branching drainage indicate the prominent influence of the Kerak-Al-fiha fault system on the drainage network. High dissection, relative relief, relief ratio, steep slopes and breaks of slopes are characteristic of W. Kerak. Morphometric analysis reveals that four rejuvenation phases caused severe erosion and down cutting activity in the past, and it is still susceptible to surface erosion at present.展开更多
Morphometric analysis and flash floods assessment were conducted for the watersheds of Ras En Naqb escarpment, south Jordan. The study area comprises of twelve small watersheds occupying the faulted-erosional slopes, ...Morphometric analysis and flash floods assessment were conducted for the watersheds of Ras En Naqb escarpment, south Jordan. The study area comprises of twelve small watersheds occupying the faulted-erosional slopes, and the dip slopes. The drainage network shows that dendritic and sub-dendritic patterns dominated the dip slopes, whereas trellis pattern characterized the faulted-erosional slopes. Stream orders range from fourth to sixth order. The mean bifurcation ratios vary between 4.2 and 5.38 for the dip slope basins, and between 3.5 and 5.0 for the faulted-erosional slope watersheds, indicating a noticeable influence of structural disturbances (i.e., faulting and uplifting), and rejuvenation of drainage networks. All watersheds have short basin lengths, ranging from 23.8 km to 42.2 km for the dip slope basins, and between 15.3 km and 45.4 km for the faulted-erosional slope catchments. This is indicative of high flooding susceptibility associated with heavy rainstorms of short duration. The circularity ratios range from 0.177 to 0.704 which denote that the catchments are moderately circular on the faulted-erosional slopes, and to some extent elongated on the dip slopes. The length of overland flow values ranges from 0.854 to 0.924 for the dip slope catchments, whereas L<sub>O</sub> values for the faulted-erosional slopes vary from 0.793 to 0.945 denoting steep slopes and shorter paths on both dip slope and faulted-erosional slope watersheds. Values of stream frequency range from 1.509 to 1.692 for the dip slope, and from 1.688 to 2.0 for the faulted-erosional slope catchments. F<sub>S</sub> values are also indicative of slope steepness, low infiltration rate, and high flooding potential. The watersheds of the dip slopes show lower values of form factor varying from 0.079 to 0.364, indicating elongated shape and suggesting a relatively flat hydrograph peak for longer duration. Similarly, values of D<sub>d</sub> are high for catchments on the dip slope basins (1.709 - 1.85) and the faulted-erosional slope watersheds (1.587 - 2.0) indicating highly dissected topography, high surface runoff, low infiltration rate, and consequently high flooding potential. Furthermore, high relief values exist, ranging from 388 m to 714 m for the dip slope basins, and from 421 m to 846 m for the faulted-erosional slope catchments indicting high relief and steep slopes. Morphometric analysis, and flash flood assessment suggest that ten watersheds (83.3%) are categorized under high and intermediate flooding susceptibility, and the faulted-erosional slope catchments are more hazardous in terms of flooding. Thus the protection of Ma’an, El Jafr rural Bedouin settlements, and Amman-Aqaba highway from recurrent flooding is essential to ensure sustainable future development in Ras En Naqb-Ma’an area.展开更多
It is of great significance for gully prevention and management to identify the potential sediment source of debris flow.Debris flow in a gully always originates from tributaries that have different gravity potential ...It is of great significance for gully prevention and management to identify the potential sediment source of debris flow.Debris flow in a gully always originates from tributaries that have different gravity potential energies and sediment condition.In this study,tributaries of the Jiangjia Gully(JJG) in Yunnan province,China,are taken as the study area to determine the possible sediment sources of debris flow.It was found that tributaries with a high evolution index(EI,the integral of the hypsometric curve) always had high gravity potential energy,which favors the occurrence of landslide activity.Furthermore,the relationship between sediment distribution,gravity potential energy,and EI is compared,respectively.The results showed that the EI had a greater influence on the occurrence of landslides,and sediments were concentrated in tributaries with EI between 0.5 and 0.6.Accordingly,tributaries with EI > 0.5 were identified as the sediment sources of debris flow.In addition,the shape of a tributary was related to EI and can reflect the condition of water and sediment storage.展开更多
Granites of the Mesozoic Era are widespread in South China,and many of them have been shaped into spectacular landscapes with high tourism development values.However,the controlling factors and evolution stages of the...Granites of the Mesozoic Era are widespread in South China,and many of them have been shaped into spectacular landscapes with high tourism development values.However,the controlling factors and evolution stages of these granite landscapes were poorly understood.In this study,the Hypsometric Integral curves(HIc),and Hypsometric Integral(HI)values of the Mount Wugong were extracted from digital elevation model data in a geographic information system environment.The relationships between the HIc,HI values,and factors including the tectonism,lithology and climate of the study area were analyzed to determine the evolution of granite landscapes evolution in the main scenic areas of the Mount Wugongshan.The HI values on the northwestern and southeastern slopes of the Mount Wugongshan range from 0.223 to 0.415 and 0.385 to 0.465,respectively;the HIc are mainly concave on the northwestern slopes and irregularly‘Sshaped’on the southeastern slopes.The main ridge of the granite geomorphic scenic area of the Mount Wugongshan,where the alpine meadow geomorphic landscape is located,is in the youthful stage of geomorphic evolution,the Mt.Jinding-Mt.Wanlong and Mt.Mingyue-Wentang scenic areas are in the old stage,and the Yangshimu scenic area is in the mature stage.Differences in watershed scale may be the main reason for the variabilities in geomorphic evolution in the area,while the regular development of tectonic phenomena is a key factor shaping the spatial variability in the watersheds on both sides of the main ridge.展开更多
The existing literature discussed only the aerial aspect and provided a brief description of tectonic-geomorphic correlation with field evidence.In present study we applied power law equations to estimate basin asymme...The existing literature discussed only the aerial aspect and provided a brief description of tectonic-geomorphic correlation with field evidence.In present study we applied power law equations to estimate basin asymmetry factor(AF),Transverse topographic asymmetric factor(T),Hypsometric Integral(HI),longitudinal profile,stream length gradient index(SL),steepness index(Ksn),Chi(χ),and knick point(Kp)analysis to examine the response of tectono-climatic fluctuations in the Mandakini River basin,central Uttarakhand Himalaya.To decouple the causative tectono-climatic factors,we employed geospatial and Stream Power Incision Modeling(SPIM)techniques.SPIM is a globally accepted tool to predict an equilibrium state between fluvial erosion rates and the escalating function of stream power.It is actively applied in modeling the transformation of river systems especially in rugged topographic regions.The present study covers SPIM-based morphometric assessment of the tectonically sensitive Mandakini River basin between Ramgarh Thrust(RT)and Vaikrita Thrust(VT)in the central region of Uttarakhand Himalaya.In the upper reaches of the basin,U-shaped glaciated valleys dominate the landscape,while a rolling topography and deeply incised narrow valleys are depicted towards the downstream.Therefore,to understand the response of active tectonic over geomorphology,the drainage basin has been divided into two separate zones from the confluence point near the Rampur area.The modeling outcomes indicate that the Mandakini drainage basin is in a disequilibrium state where channels are actively incising to bedrock.Overall,AF of 32 and 70 indicate leftward tilting in the upper reaches and rightward tilting in the lower reaches of the basin,respectively.The HI value of 0.38 indicates a stage of maturity,characterized by a concave shape profile.Based on the analysis it may be concluded that the fragile lithology and tectono-climatic fluctuations are dominantly controlling the topography and valley floor morphology of the Mandakini River.展开更多
A M6.6 earthquake occurred on July 22, 2013 at Dingxi Basin in Gansu Province within the tectonially expanding northeastern margin of the Qinghai-Tibet Plateau. We analyzed the geomorphological features of the Dingxi ...A M6.6 earthquake occurred on July 22, 2013 at Dingxi Basin in Gansu Province within the tectonially expanding northeastern margin of the Qinghai-Tibet Plateau. We analyzed the geomorphological features of the Dingxi Basin by using remote sensing technology and compared them with local seismic activity. We found that most of the river basins are at the robust stage of development and that the major local rivers and the development of some basins boundaries are controlled by the seismic faults. Among four zones identified to have significant tectonic activities, the northwestly-oriented one located in the south has the highest seismic activity, and it is where the M6.6 earthquake occurrred.展开更多
Soil types, humus types and vegetation as well as their hypsometric variation were analysed in terms of sequences in the northern part of the high mountains of the Pirin National Park at altitudes between looo and 240...Soil types, humus types and vegetation as well as their hypsometric variation were analysed in terms of sequences in the northern part of the high mountains of the Pirin National Park at altitudes between looo and 2400 m a.s.1. The study area is characterised by a large variety of natural parameters like petrology （mainly marble and granite）, morphology （different slope deposits, exposition） and the orographic climate gradient. Statistical analyses using these parameters provided a basis for the soil group classification of the sites. Based on a Digital Terrain Model （DTM） and a geological map of the Pirin National Park, the results of these statistical analyses were used to generate a ＂map of potential soil groups＂ （regionalisation using GIS）. Six potential soil groups could be determined. The resulting map exhibits a confidence level of 68 % on 74.4 % of the covered area. Rendzic Leptosols, in combination with Folic Histosols and Histi-lithic Leptosols occur in the alpine and subalpine regions on calcareous substrates. With decreasing altitude they are replaced by a mosaic of Rendzic Leptosols, Phaeozems and an increasing occurrence of Cambic Umbrisols. Umbrisols found on silicatic substrates in the alpine region are replaced by Cambic Umbrisols with decreasing altitude as well. Hence, pedogenesis is characterised by increasing browning and depth of the soil profiles with decreasing altitude. The pH-level is slightly acidic to neutral in lower zones and on calcareous rocky bases. Acidification increases in the subalpine zone. Soil pH decreases down to 4 on silicate subtrates. Typical humic values in mineral topsoils are 10 to 12 %, and in organic layers of the soils above 2000 m a.s.1, they are even more. The C：N ratio closely ranges around 20 （median）.展开更多
Geomorphological study of a basin is important for understanding theoverall basin characteristics which are helpful for the management of waterresources, construction along the river bank and natural hazard mitigation...Geomorphological study of a basin is important for understanding theoverall basin characteristics which are helpful for the management of waterresources, construction along the river bank and natural hazard mitigationwithin the area. The study was carried out in the Karra Khola Basin, oneof the prominent basins in the Eastern extreme of the Hetauda Dun Valley,Central Nepal, to investigate geomorphic characteristics of the mainstream of the basin, categorize them into various stream types and studybasin development through drainage basin’s morphometric parameters.Geographical Information System (GIS) and Remote sensing techniquesusing satellite images were used as a tool to make the morphometricanalysis of the basin along with its major 13 sub-basin and delineate streamclassification following the Rosgen’s Level I hierarchical inventory. Themain stream of the Karra Khola is characterized as A-, B- and C-typeand the tributaries segments as B- and F-type. The basin is structurallyunaffected and has the permeable surface area and elongated shape. Thehypsometric analysis indicates that the basin is mostly at the old stage ofgeomorphic development while four out of 13 sub-basin being at maturestage. The Karra Khola sub-basin have higher risk to flash flooding(Lg=0.1-0.16km). Drainage density value reveals that the basin is highlysusceptible to flooding, gully erosion, etc. Similarly, dissection index valueimplies that the north eastern region of the basin is highly vulnerable toerosion as it at the younger stage of geomorphic development. Since thestudy area is highly sensitive to future natural hazards, further study andappropriate measures should be followed for safeguarding against thefuture risk along the Karra Khola basin and its tributaries.展开更多
This paper aims to unveit neotectonic imprints in topography, drainage and sediments in the 46.25 km tong course of the River Chet from its source down to its attuvial fan at the base of the Himatayan Mountain Front i...This paper aims to unveit neotectonic imprints in topography, drainage and sediments in the 46.25 km tong course of the River Chet from its source down to its attuvial fan at the base of the Himatayan Mountain Front in the Darjeeting-Jatpaiguri districts of India. A semi-circutar ridge detimits its primary catchment. Within confinement of this watershed basin the drainage pattern is composite being convergent atong the periphery and divergent on a butte inside. AtE these geomorphic neotectonic imprints are accom- panied by ramp and fiat structures and spectacutar mytonitization of rocks. High hypsometric index and convex shape of the hypsometric curve derived from the centrat near-straight course of the river between the primary catchment and the Main Frontat Thrust （MFT） atso reftects tectonic youthfutness of the river course. It is wett manifested atso in widety variabte stream index and stream gradient index ratios （SL/K） often exceeding 2. In response to neotectonism, this river course as a whore shifted westward between 1962 and 2007. Maximum reduction of the stream gradient on top of the MFT is etoquent enough about recent uptift of the thrust ridge. The high average stope gradient of canyon watt about 45.68° is wett consistent with this uptift. Very tow channet-width/vaUey-height ratio along the river further corroborates the uptift. The attuviat fan system of the River Chet is comprised of five morphogenetic fans stacked one above another with a tendency to shrink and shift progressively upstope. They differ from each other in terms of titt, axiat orientation, primary depositionat surface gradient and convexity in transverse section and thus present a writ of ongoing tectonism. Progressive upward increase in the share of distat crystattine rocks in ctast composition within attuviat fan package is a dear proxy for southerty advancement of the MFT. Concomitant increase in maximum ctast size is in good agreement with sediment source uptift. Art the five fans are, however, dormant now. Present-day River Chet deeply incises through ate of them and suggests further basement uplift in the context of frequent evidences of neotectonism att around, atthough the rote of climate remains uncertain in absence of adequate data.展开更多
文摘Hypsometric analysis is considered an effective tool for understanding the stages of geomorphic evolution and geological development of river catchment, and for the delineation of erosional proneness of watershed. In the present study, twenty eight fourth order sub-basins of W. Mujib-Wala (Southern Jordan) were selected, and hypsometric analysis was carried out using 30 m ASTER DEM. Elevation-relief ratio method was employed to calculate the hypsometric integral values within GIS environment. The hypsometric integral values range from 0.71 to 0.88, whereas, the hypsometric curves exhibit remarkably upward convex shapes which indicate that all sub-basins and the W. Mujib-Wala watershed are at the youth-age stage of geomorphic development. Thus, they are of high susceptibility to erosion, incised channel erosion and mass movement activity. Marginal differences exist in mass removal from the watershed and the 28 sub-basins are attributed to variation in tectonic effect, lithology and rejuvenation processes. The relation between basin area and hypsometric integral was examined using regression analysis. Results reveal that negative and weak relationships dominate, where r<sup>2</sup> ranges from 0.05 to 0.478 which confirm with other results reported elsewhere. Indirect assessment of erosion status based on hypsometric integral values was validated using estimated sediment yield information related to wadi Mujib and wadi Wala watersheds separately. The recorded sediment yields were in affirmation with high hypsometric integrals values, where higher values of hypsometric integrals and sediment yields occurred in the western part of the W. Mujib-Wala watershed. These findings would help in the construction of appropriate soil and water conservation measures across the watershed and its sub-basins to control soil erosion, to conserve water, and to reduce sediment discharge into the W. Mujib and W. Wala reservoirs.
文摘This research is intended to assess the regional pattern of hypsometric curves (HCs) and hypsometric integrals (HIs) for the watersheds draining into the Jordan Rift (River Jordan, the Dead Sea, and Wadi Araba watersheds). Hypsometric analysis was performed on 22 drainage basins using ASTER DEM (30 m resolution) and GIS. The area-elevation ratio method was utilized to extract the hypsometric integral values within a GIS environment. A prominent variation exists in the HC shapes and HI values. The highest hypsometric values are found for the Dead Sea ( = 0.87) and River Jordan ( = 0.77) watersheds. Whereas the lowest values ( = 0.51) characterized Wadi Araba catchments, except Wadi Nukhaileh (lower Wadi Araba) which yields an HI value of 0.26. Seventeen HCs pertained to the River Jordan and the Dead Sea watersheds evince remarkably upward convex shapes indicating that such drainage basins are less eroded, and at the youth-stage of the geomorphic cycle of erosion. Catchments draining to Wadi Araba are of intermediate HI values (0.41 - 0.58) which are associated with a balance, or dynamic equilibrium between erosion and tectonic processes. Accordingly, they correspond to a late mature stage of geomorphic development. Additionally, Wadi Nukhaileh yields the lowest HI value (0.26) and is associated with highly eroded terrain of late mature geomorphic evolution, approaching an old stage therefore, with distorted concave upward curves. High HI values indicate that these watersheds have been subjected to tectonic uplift, down faulting of the Rift and intense rejuvenation. Differences in HI values can be attributed to disparity in tectonic uplift rate, base level heights, and mean heights of the River Jordan watersheds, the Dead Sea and Wadi Araba watersheds, and variation in lithology, which caused noticeable differences in rejuvenation processes, and channel incision. Regression analysis reveals that R<sup>2</sup> values which represent the degree of control of driving parameters on HI, are positive and generally low (ranging from 0.026 to 0.224) except for the height of base level (m) parameter which contributes 0.42 (significant at 0.1% level). Such results mean that the height of base level has a significant at 0.1% level. It is obvious that the most crucial driving morphometric factor influencing HI values of the Jordan Rift drainage basins, is the height of base level (m).
文摘Study area is located in Southwest Iran with relatively flat topography. Outcropped lithological units in the region belong from Triassic and Jurassic till recent era. The study area of the Namdan basin is related to the tectonic zone of the high Zagros region and the compressional-extensional regime. Geomorphic indices of active tectonics are useful tools to analyze the influence of activity. One of them is hypsometric integral which has generally been used to reveal the stages of geomorphic development. It is estimated by the graphical plot of the measured contour elevation and encompassed area by using empirical formulae. In constructing the hypsometric integral curve, a Digital Elevation Model (DEM) with 30 m spatial resolution has been used. This index is calculated in the study area. Then, based on index of its values, the hypsometric properties of drainage basins are analyzed in Namdan basin. Three different approaches were used for estimation of hypsometric integrals. The hypsometric integral values (HI) range between 0.18 and 0.31 for all the basins of study basin. In the study area, one stage of erosion cycle development, namely old stage is distinguished. Our results indicate that there is anomaly in Hi value which is located on faulted area. The results indicate the Northwest of Namdan basin and a small part of its Southeast are more active than other ones.
基金supported by the auspices of the National Natural Science Foundation of China (Grant Nos. 41471331, 41601408, 41506111)
文摘A land surface region can be decomposed into a series of watershed units with a hierarchical organizational structure. For loess landform, the watershed is a basic spatial–structural unit that can express natural landforms, surface morphology characteristics, spatial organization and developmental evolution. In this research we adopted the concept of node calibration in the watershed structure unit, selected six complete watersheds on China Loess Plateau as the research areas to study the quantitative characteristics of the hierarchical structure in terms of watershed geomorphology based on digital elevation model(DEM) data, and then built a watershed hierarchical structure model that relies on gully structure feature points. We calculated the quantitative indices, such as elevation, flow accumulation and hypsometric integral and found there are remarkably closer linear correlation between flow accumulation and elevation with increasing gully order, and the same variation tendency of hypsometric integral also presented. The results showed that the characteristics of spatial structure become more stable, and the intensity of spatial aggregation gradually enhances with increasing gully order. In summary, from the view of gully node calibration, the China Loess watershed structure shows more significantly complex, and the developmental situation variation of the loess landforms also exhibited a fairly stable status with gully order increasing. So, the loess watershed structure and its changes constructed the complex system of the loess landform, and it has the great significance for studying the spatial pattern and evolution law of the watershed geomorphology.
文摘Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.
文摘This study addresses the morphometric variables that determine the sediment yield in Wadi AI-Arja through the analysis of the impact of different morphometric characteristics along the course of the valley on its sediment yield, as well as the analysis of spatial and formal dimensions and morphologies of the basin and its relationship to the sediment yield. The study also addresses the size of variation in the volume of sediment yield of the river tributaries that make up the water network of the valley under the differences of its mor- phometric and hydrological characteristics. The study found several results, most notably： The classification of Wadi AI-Arja basin according to the hypsometric integral value （72.1%） within an uneven topography, which in- creases the force of the erosive activity and the size of the sediment yield if the basin was exposed to moist climatic periods. The study also showed the presence of convergence in the intra-spaces between the river tributaries in the water network. This increases the volume of water flows when these tributaries meet with each other and thus increasing their erosive ability and sediment yield. The study also showed the presence of marked variation in the sediment yield of the river tributaries depending on the differences in its morphometric characteristics. The results of the step-wise regression analysis confirmed the importance of the morphometric and hydrological variables, and plant coverage in interpreting the variation in the size of the sediment yield of the river tributaries of different stream order in Wadi AI-Arja basin, where these variables interpreted 43% of the total variation, with statistical significance less than 0.05.
文摘Geomorphometric analysis was carried out to illustrate the drainage characteristics and morphology of Wadi Kerak watershed, southern Jordan. The basic and derived morphometric parameters (linear, areal and relief aspects of drainage network) for the basin were determined using ASTER DEM (30 m resolution) and Geographic Information System (GIS). These parameters describe the basin drainage network, geometry, texture, and relief characteristics. The hypsometric curve, hypsometric integral and clinographic curve were also prepared using topographic maps of 1:50,000 scale. Findings have revealed that W. Kerak is in the youth-age stage of geomorphic evolution. Fluvial erosion associated with successive phases of rejuvenation plays a significant role in drainage basin development, whereas structure and tectonics, lithology and relief dictate the drainage pattern and morphological setting of the catchment. The drainage area of the watershed is 190.9 km2 and constitutes a 5th-order drainage basin. The commonly observed drainage patterns are the trellis type, with sub-dendritic pattern recognized in the upper catchment. The drainage pattern, and the semi-linear alignment of main and branching drainage indicate the prominent influence of the Kerak-Al-fiha fault system on the drainage network. High dissection, relative relief, relief ratio, steep slopes and breaks of slopes are characteristic of W. Kerak. Morphometric analysis reveals that four rejuvenation phases caused severe erosion and down cutting activity in the past, and it is still susceptible to surface erosion at present.
文摘Morphometric analysis and flash floods assessment were conducted for the watersheds of Ras En Naqb escarpment, south Jordan. The study area comprises of twelve small watersheds occupying the faulted-erosional slopes, and the dip slopes. The drainage network shows that dendritic and sub-dendritic patterns dominated the dip slopes, whereas trellis pattern characterized the faulted-erosional slopes. Stream orders range from fourth to sixth order. The mean bifurcation ratios vary between 4.2 and 5.38 for the dip slope basins, and between 3.5 and 5.0 for the faulted-erosional slope watersheds, indicating a noticeable influence of structural disturbances (i.e., faulting and uplifting), and rejuvenation of drainage networks. All watersheds have short basin lengths, ranging from 23.8 km to 42.2 km for the dip slope basins, and between 15.3 km and 45.4 km for the faulted-erosional slope catchments. This is indicative of high flooding susceptibility associated with heavy rainstorms of short duration. The circularity ratios range from 0.177 to 0.704 which denote that the catchments are moderately circular on the faulted-erosional slopes, and to some extent elongated on the dip slopes. The length of overland flow values ranges from 0.854 to 0.924 for the dip slope catchments, whereas L<sub>O</sub> values for the faulted-erosional slopes vary from 0.793 to 0.945 denoting steep slopes and shorter paths on both dip slope and faulted-erosional slope watersheds. Values of stream frequency range from 1.509 to 1.692 for the dip slope, and from 1.688 to 2.0 for the faulted-erosional slope catchments. F<sub>S</sub> values are also indicative of slope steepness, low infiltration rate, and high flooding potential. The watersheds of the dip slopes show lower values of form factor varying from 0.079 to 0.364, indicating elongated shape and suggesting a relatively flat hydrograph peak for longer duration. Similarly, values of D<sub>d</sub> are high for catchments on the dip slope basins (1.709 - 1.85) and the faulted-erosional slope watersheds (1.587 - 2.0) indicating highly dissected topography, high surface runoff, low infiltration rate, and consequently high flooding potential. Furthermore, high relief values exist, ranging from 388 m to 714 m for the dip slope basins, and from 421 m to 846 m for the faulted-erosional slope catchments indicting high relief and steep slopes. Morphometric analysis, and flash flood assessment suggest that ten watersheds (83.3%) are categorized under high and intermediate flooding susceptibility, and the faulted-erosional slope catchments are more hazardous in terms of flooding. Thus the protection of Ma’an, El Jafr rural Bedouin settlements, and Amman-Aqaba highway from recurrent flooding is essential to ensure sustainable future development in Ras En Naqb-Ma’an area.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA23090202)the National Natural Science Foundation of China (Grant Nos.41790432,41877261)the Key International S&T Cooperation Projects (Grant No.2016YFE0122400)。
文摘It is of great significance for gully prevention and management to identify the potential sediment source of debris flow.Debris flow in a gully always originates from tributaries that have different gravity potential energies and sediment condition.In this study,tributaries of the Jiangjia Gully(JJG) in Yunnan province,China,are taken as the study area to determine the possible sediment sources of debris flow.It was found that tributaries with a high evolution index(EI,the integral of the hypsometric curve) always had high gravity potential energy,which favors the occurrence of landslide activity.Furthermore,the relationship between sediment distribution,gravity potential energy,and EI is compared,respectively.The results showed that the EI had a greater influence on the occurrence of landslides,and sediments were concentrated in tributaries with EI between 0.5 and 0.6.Accordingly,tributaries with EI > 0.5 were identified as the sediment sources of debris flow.In addition,the shape of a tributary was related to EI and can reflect the condition of water and sediment storage.
基金supported by the Doctoral Scientific Research Foundation of East China University of Technology(Grant No.DHBK2019005)the Postdoctoral Research Foundation of the Geological Survey of Jiangxi Province(Grant No.202020)。
文摘Granites of the Mesozoic Era are widespread in South China,and many of them have been shaped into spectacular landscapes with high tourism development values.However,the controlling factors and evolution stages of these granite landscapes were poorly understood.In this study,the Hypsometric Integral curves(HIc),and Hypsometric Integral(HI)values of the Mount Wugong were extracted from digital elevation model data in a geographic information system environment.The relationships between the HIc,HI values,and factors including the tectonism,lithology and climate of the study area were analyzed to determine the evolution of granite landscapes evolution in the main scenic areas of the Mount Wugongshan.The HI values on the northwestern and southeastern slopes of the Mount Wugongshan range from 0.223 to 0.415 and 0.385 to 0.465,respectively;the HIc are mainly concave on the northwestern slopes and irregularly‘Sshaped’on the southeastern slopes.The main ridge of the granite geomorphic scenic area of the Mount Wugongshan,where the alpine meadow geomorphic landscape is located,is in the youthful stage of geomorphic evolution,the Mt.Jinding-Mt.Wanlong and Mt.Mingyue-Wentang scenic areas are in the old stage,and the Yangshimu scenic area is in the mature stage.Differences in watershed scale may be the main reason for the variabilities in geomorphic evolution in the area,while the regular development of tectonic phenomena is a key factor shaping the spatial variability in the watersheds on both sides of the main ridge.
基金The authors are thankful to the UPES,Dehradun and the Department of Science and Technology,Govt of India(Project:CRG/2023/000555)for supporting this study.
文摘The existing literature discussed only the aerial aspect and provided a brief description of tectonic-geomorphic correlation with field evidence.In present study we applied power law equations to estimate basin asymmetry factor(AF),Transverse topographic asymmetric factor(T),Hypsometric Integral(HI),longitudinal profile,stream length gradient index(SL),steepness index(Ksn),Chi(χ),and knick point(Kp)analysis to examine the response of tectono-climatic fluctuations in the Mandakini River basin,central Uttarakhand Himalaya.To decouple the causative tectono-climatic factors,we employed geospatial and Stream Power Incision Modeling(SPIM)techniques.SPIM is a globally accepted tool to predict an equilibrium state between fluvial erosion rates and the escalating function of stream power.It is actively applied in modeling the transformation of river systems especially in rugged topographic regions.The present study covers SPIM-based morphometric assessment of the tectonically sensitive Mandakini River basin between Ramgarh Thrust(RT)and Vaikrita Thrust(VT)in the central region of Uttarakhand Himalaya.In the upper reaches of the basin,U-shaped glaciated valleys dominate the landscape,while a rolling topography and deeply incised narrow valleys are depicted towards the downstream.Therefore,to understand the response of active tectonic over geomorphology,the drainage basin has been divided into two separate zones from the confluence point near the Rampur area.The modeling outcomes indicate that the Mandakini drainage basin is in a disequilibrium state where channels are actively incising to bedrock.Overall,AF of 32 and 70 indicate leftward tilting in the upper reaches and rightward tilting in the lower reaches of the basin,respectively.The HI value of 0.38 indicates a stage of maturity,characterized by a concave shape profile.Based on the analysis it may be concluded that the fragile lithology and tectono-climatic fluctuations are dominantly controlling the topography and valley floor morphology of the Mandakini River.
基金supported by the Director Foundation of the Institute of Seismology,China Earthquake Administration(201116002,201056076)
文摘A M6.6 earthquake occurred on July 22, 2013 at Dingxi Basin in Gansu Province within the tectonially expanding northeastern margin of the Qinghai-Tibet Plateau. We analyzed the geomorphological features of the Dingxi Basin by using remote sensing technology and compared them with local seismic activity. We found that most of the river basins are at the robust stage of development and that the major local rivers and the development of some basins boundaries are controlled by the seismic faults. Among four zones identified to have significant tectonic activities, the northwestly-oriented one located in the south has the highest seismic activity, and it is where the M6.6 earthquake occurrred.
文摘Soil types, humus types and vegetation as well as their hypsometric variation were analysed in terms of sequences in the northern part of the high mountains of the Pirin National Park at altitudes between looo and 2400 m a.s.1. The study area is characterised by a large variety of natural parameters like petrology （mainly marble and granite）, morphology （different slope deposits, exposition） and the orographic climate gradient. Statistical analyses using these parameters provided a basis for the soil group classification of the sites. Based on a Digital Terrain Model （DTM） and a geological map of the Pirin National Park, the results of these statistical analyses were used to generate a ＂map of potential soil groups＂ （regionalisation using GIS）. Six potential soil groups could be determined. The resulting map exhibits a confidence level of 68 % on 74.4 % of the covered area. Rendzic Leptosols, in combination with Folic Histosols and Histi-lithic Leptosols occur in the alpine and subalpine regions on calcareous substrates. With decreasing altitude they are replaced by a mosaic of Rendzic Leptosols, Phaeozems and an increasing occurrence of Cambic Umbrisols. Umbrisols found on silicatic substrates in the alpine region are replaced by Cambic Umbrisols with decreasing altitude as well. Hence, pedogenesis is characterised by increasing browning and depth of the soil profiles with decreasing altitude. The pH-level is slightly acidic to neutral in lower zones and on calcareous rocky bases. Acidification increases in the subalpine zone. Soil pH decreases down to 4 on silicate subtrates. Typical humic values in mineral topsoils are 10 to 12 %, and in organic layers of the soils above 2000 m a.s.1, they are even more. The C：N ratio closely ranges around 20 （median）.
文摘Geomorphological study of a basin is important for understanding theoverall basin characteristics which are helpful for the management of waterresources, construction along the river bank and natural hazard mitigationwithin the area. The study was carried out in the Karra Khola Basin, oneof the prominent basins in the Eastern extreme of the Hetauda Dun Valley,Central Nepal, to investigate geomorphic characteristics of the mainstream of the basin, categorize them into various stream types and studybasin development through drainage basin’s morphometric parameters.Geographical Information System (GIS) and Remote sensing techniquesusing satellite images were used as a tool to make the morphometricanalysis of the basin along with its major 13 sub-basin and delineate streamclassification following the Rosgen’s Level I hierarchical inventory. Themain stream of the Karra Khola is characterized as A-, B- and C-typeand the tributaries segments as B- and F-type. The basin is structurallyunaffected and has the permeable surface area and elongated shape. Thehypsometric analysis indicates that the basin is mostly at the old stage ofgeomorphic development while four out of 13 sub-basin being at maturestage. The Karra Khola sub-basin have higher risk to flash flooding(Lg=0.1-0.16km). Drainage density value reveals that the basin is highlysusceptible to flooding, gully erosion, etc. Similarly, dissection index valueimplies that the north eastern region of the basin is highly vulnerable toerosion as it at the younger stage of geomorphic development. Since thestudy area is highly sensitive to future natural hazards, further study andappropriate measures should be followed for safeguarding against thefuture risk along the Karra Khola basin and its tributaries.
基金UGC,Minor Research Project,Govt. Of India(F.PSW-032/08-09_ERO) for financial supportfinancial help from DST(ESS/16/243/2006-EMR-ll)
文摘This paper aims to unveit neotectonic imprints in topography, drainage and sediments in the 46.25 km tong course of the River Chet from its source down to its attuvial fan at the base of the Himatayan Mountain Front in the Darjeeting-Jatpaiguri districts of India. A semi-circutar ridge detimits its primary catchment. Within confinement of this watershed basin the drainage pattern is composite being convergent atong the periphery and divergent on a butte inside. AtE these geomorphic neotectonic imprints are accom- panied by ramp and fiat structures and spectacutar mytonitization of rocks. High hypsometric index and convex shape of the hypsometric curve derived from the centrat near-straight course of the river between the primary catchment and the Main Frontat Thrust （MFT） atso reftects tectonic youthfutness of the river course. It is wett manifested atso in widety variabte stream index and stream gradient index ratios （SL/K） often exceeding 2. In response to neotectonism, this river course as a whore shifted westward between 1962 and 2007. Maximum reduction of the stream gradient on top of the MFT is etoquent enough about recent uptift of the thrust ridge. The high average stope gradient of canyon watt about 45.68° is wett consistent with this uptift. Very tow channet-width/vaUey-height ratio along the river further corroborates the uptift. The attuviat fan system of the River Chet is comprised of five morphogenetic fans stacked one above another with a tendency to shrink and shift progressively upstope. They differ from each other in terms of titt, axiat orientation, primary depositionat surface gradient and convexity in transverse section and thus present a writ of ongoing tectonism. Progressive upward increase in the share of distat crystattine rocks in ctast composition within attuviat fan package is a dear proxy for southerty advancement of the MFT. Concomitant increase in maximum ctast size is in good agreement with sediment source uptift. Art the five fans are, however, dormant now. Present-day River Chet deeply incises through ate of them and suggests further basement uplift in the context of frequent evidences of neotectonism att around, atthough the rote of climate remains uncertain in absence of adequate data.
