ASTER DEM Research Articles

Geoinformatics for assessing the inferences of quantitative drainage morphometry of the Narmada Basin in India

Geoinformatics-based morphological studies play a significant role in planning, designing, and development of river engineering structures. Quantitative morphometric parameters affect catchment streamflow pattern through their influence on concentration time, and geomorphic characteristics of a drainage basins play a vital role in controlling the basin’s hydrology. In the present paper, an effort has been made to assess the inferences of various linear, areal, drainage, and relief aspects of quantitative morphometric characteristics of the Narmada basin and its down (13) and upper watersheds (17) using ASTER DEM data in GIS platform. Total basin area of the Narmada is about 98,796 km2, and it is identified that the study area is an eighth order drainage basin. A total 31,211 stream segments including the Narmada river are identified, and it is clear that the cumulative stream length is higher in first-order streams and decreases as the stream order increases. The bifurcation ratio (Rb) of the Narmada basin is varied from 2 to 9, and it designates that the drainage pattern of the basin has been affected by the structural disturbances. The lowest value of elongation ratio in the basin indicates high relief and steep slope, while highest value specifies relatively plain land with low relief and low slope than other down watersheds. Sinuosity index of Narmada basin is 1.58, which shows that the Narmada river is meandering in nature.

Simulasi genangan banjir menggunakan data ASTER DEM pada alur Sungai Cilemer

The Cilemer River is a river which flowing to Lada Bay in west coast of Pandeglang District, Banten Province. The influence of the tide, the high flood discharges and settlements located at the flood plain has caused flooding every year. In order to understand flood overtopping mechanism and inundation map, numerical model simulation for flood and inundation area were conducted. The numerical model of the river were conducted using cross sectional of the river, result of these simulations were further integrated with Geographical Information System (GIS). The objective of this study is to obtain inundation map area. The input for GIS is a Digital Elevation Model which is obtain from Advanced Spaceborne Thermal Emission and Reflection Radiometer Digital Elevation Model (ASTER DEM). The simulation results shows the capacity of Cilemer River upstream is 210 m3/s while on the downstream segment was only 100 m3/s. Simulation shows with overtopping of the dike of 0,96 m generate 546 Ha of inundation area for 2 year return period of flood discharge. The overtopping of 1,1 m has generated 592 Ha of inundation area for 5 year return period of flood discharge. With overtopping of 1,26 m of 10 year return period flood discharge has caused 682 Ha inundation area, while 2,56 m overtopping has generated 912 Ha inundation area for 25 year return period of flood discharge. Effect of flood control structure on the outlet of bypass has generated 19 cm increase of water level.

A study of morphometric evaluation of the Son basin, India using geospatial approach

This study deals that morphometric evaluation is feasible method of characterization of hydrological response behavior of the any river basin. In this study, Son basin a tributary of the Ganga river has been selected for the detailed morphometric evaluation. The Son basin is approximate 68,863km2 and shows sub-dendritic to dendritic drainage pattern. The measurement and analysis for Son basin and its five major sub-watershed are carried on GIS platform to describe the topography and drainage characteristics. The input parameters required to run this model are: a pour point, a minimum upstream area in sqkm and a digital elevation model. Streams were automatically extracted from ASTER DEM data. The stream order of the basin is predominantly controlled by physiographic and structural conditions. The study area is designated as sixth-order basin and lower order streams mostly dominate the basin with the drainage density value of 0.26km/km2. The slope of basin varied from 0° to 70.4° and the slope variation is mainly controlled by the local geology and erosion cycles. The bifurcation ratio (Rb) for the Son basin varies from 2.41 to 7. The higher values of Rb in basin indicate a strong structural and geological control on the drainage pattern. The elongation ratio of the basin is 0.553 indicating that the study area is extended with moderate to steep slopes. The increase in stream length ratio from lower to higher order shows that the basin is part of a mature geomorphic stage.

A Study on Ortho-rectification of SPOT6 Image

Orthorectification of SPOT6 image based on Rational Function and Rigorous Orbit Model was conducted using the rational polynomial coefficient file (PRC), ASTER and SRTM DEM data and the field control point data in Huludao, Liaoning Province. The accuracy difference of orthorectify model and DEM was analyzed. The results showed that both orthorectification models based on the ASTER data and SRTM data can meet the 1: 10000 digital orthophoto mapping accuracy, different DEM has no influence on the accuracy of Rigorous Orbit Model without control points, The rational function model with control point correction method using SRTM data correction precision is higher. The correction accuracy of SRTM data in using 3-4 control points reached 2.85m, the application of ASTER data correction accuracy up to 3.30m.

Evaluation of automatic drainage extraction thresholds using ASTER GDEM and Cartosat-1 DEM: A case study from basaltic terrain of Central India

In the study, the digital elevation models from ASTER GDEM and Cartosat-1 of 30m resolution were used to evaluate the thresholds in automatic extraction of stream network at six thresholds of 0.05km2, 0.125km2, 0.25km2, 0.50km2, 1.0km2 and 2.0km2 in Neri watershed in basaltic terrain of Central India. At stream thresholds of 0.05km2, Cartosat-1 DEM shows higher channel initiation points (150) than ASTER (127). As we increase the stream thresholds from 0.05km2 to 2.0km2, the channel initiation points are consistently decreased in two input DEMs. The correlation coefficient R2 between the drainage area thresholds and stream length for ASTER and Cartosat-1 DEM shows 0.94 and 0.92, respectively. The comparative evaluation of morphometric indices shows that threshold of 0.05km2 is found to be optimum to obtain the finer drainage networks particularly from Cartosat-1 DEM, when compare to the ASTER GDEM of same resolution.

Geomorphological Analysis and Hydrological Potential Zone of Baira River Watershed, Churah in Chamba District of Himachal Pradesh, India

In the present study, an attempt has been made to study the quantitative geomorphological analysis and hydrological characterization of 95 micro-watersheds (MWS) of Baira river watershed in Himachal Pradesh, India with an area of 425.25 Km2. First time in the world, total 173 morphometric parameters have been generated in a single watershed using satellite remote sensing data (i.e. IRS-P6 ResourceSAT-1 LISS-III, LandSAT-7 ETM+, and LandSAT-8 PAN & OLI merge data), digital elevation models (i.e. IRS-P5 CartoSAT-1 DEM, ASTER DEM data), and soI topographical maps of 1: 50,000 scale. The ninety-five micro-watersheds (MWS) of Baira river watershed have been prioritized through the morphometric analysis of different morphometric parameters (i.e. drainage network, basin geometry, drainage texture analysis, and relief characterizes ). The study has concurrently established the importance of geomorphometry as well as the utility of remote sensing and GIS technology for hydrological characterization of the watershed and there for better resource and environmental managements.

Vertical accuracy assessment for SRTM and ASTER Digital Elevation Models: A case study of Najran city, Saudi Arabia

Abstract Digital Elevation Model is imperative to many earth surface process analyses. In this study, the quality of DEMs acquired by SRTM ver.3 and ASTER ver.2 is evaluated. The reference levels produced from GPS elevations, and the topographic map is used to assess the vertical accuracy of SRTM and ASTAR DEMs in Najran city, Saudi Arabia. The GPS reference elevations gave us the values of ±5.94 m and ±5.07 m for used SRTM and ASTER DEMs. Also, by using elevation from the topographic map as a reference elevations the obtained accuracy was ±6.87 m and ±7.97 m for SRTM and ASTER DEMs. For our study area, the 30 m SRTM elevations data featured a much greater absolute vertical accuracy than the absolute vertical accuracy value of ±16 m, which published in the SRTM data specification.

Lithologic, Hydrothermal Alteration and Structural Mapping of Okemesi Folds and Environs Using LandSat 8 OLI and ASTER DEM

Lithologic, Hydrothermal Alteration and Structural Mapping of Okemesi Folds and Environs Using LandSat 8 OLI and ASTER DEM

Mapping of coastal landforms and volumetric change analysis in the south west coast of Kanyakumari, South India using remote sensing and GIS techniques

The coastal landforms along the south west coast of Kanyakumari have undergone remarkable change in terms of shape and disposition due to both natural and anthropogenic interference. An attempt is made here to map the coastal landforms along the coast using remote sensing and GIS techniques. Spatial data sources, such as, topographical map published by Survey of India, Landsat ETM+ (30m) image, IKONOS image (0.82m), SRTM and ASTER DEM datasets have been comprehensively analyzed for extracting coastal landforms. Change detection methods, such as, (i) topographical change detection, (ii) cross-shore profile analysis, (iii) Geomorphic Change Detection (GCD) using DEM of Difference (DoD) were adopted for assessment of volumetric changes of coastal landforms for the period between 2000 and 2011. The GCD analysis uses ASTER and SRTM DEM datasets by resampling them into common scale (pixel size) using pixel-by-pixel based Wavelet Transform and Pan-Sharpening techniques in ERDAS Imagine software. Volumetric changes of coastal landforms were validated with data derived from GPS-based field survey. Coastal landform units were mapped based on process of their evolution such as beach landforms including sandy beach, cusp, berm, scarp, beach terrace, upland, rockyshore, cliffs, wave-cut notches and wave-cut platforms; and the fluvial landforms. Comprising of alluvial plain, flood plains, and other shallow marshes in estuaries. The topographical change analysis reveals that the beach landforms have reduced their elevation ranging from 1 to 3m probably due to sediment removal or flattening. Analysis of cross-shore profiles for twelve locations indicate varying degrees of loss or gain of coastal landforms. For example, the K3-K3′ profile across the Kovalam coast has shown significant erosion (−0.26 to −0.76m) of the sandy beaches resulting in the formation of beach cusps and beach scarps within a distance of 300m from the shoreline. The volumetric change of sediment load estimated based on DoD model depict a loss of 241.69m3/km2 for 62.82km2 of the area and land gain of 6.96m3/km2 for 202.80km2 of the area during 2000–2011. However, an area of 26.38km2 unchanged by maintaining equilibrium in sediment budgeting along the coastal stretch. The study apart from providing insight into the decadal change of coastal settings also supplements a database on the vulnerability of the coast, which would help the coastal managers in future.

Assessment of Flash-Flood Hazard in Arid Watersheds of Jordan

Flash flood hazard initiated by heavy rainstorms is common in arid Jordan, and often has induced immense damage to life and infrastructures. The current study presents a flash flood assessment for Wadi Rajil (northern Jordan) and Wadi Wuheida (southern Jordan) watersheds using ASTER DEM, GIS, and geomorphic field observation. A total of 23 morphometric parameters of paramount relation to flash flood risk estimation were extracted and calculated using ASTER DEM, GIS, and mathematical formulae developed for this purpose. Two methods were employed to assess flash floods and to generate flooding risk susceptibility maps. The first method is El-Shamy’s approach, and the second is the morphometric hazard degree assessment method. Consequently, sub-basins with high and extreme flooding susceptibility were demarcated and displayed spatially using GIS. The maps so produced are meant to help planners and decision makers to devise appropriate plans to mitigate harmful flooding impacts, and to deal with flooding hazards.

Quantitative Regionalization of W. Mujib-Wala Sub-Watersheds (Southern Jordan) Using GIS and Multivariate Statistical Techniques

In arid and semi-arid watersheds, sustainable management of natural resources (i.e. land, water and ecological resources), and watershed management are crucial issues in applied morphometric studies. Geomorphometric parameters and their interrelationships are of paramount importance in characterizing the morphology, topography, geology and structure, hydrological potential, and geomorphic evolution of such catchments. An analysis of spatial characteristics and morphological development of the demarcated 76 sub-watersheds related to W. Mujib-Wala catchment, was carried out using ASTER DEM and GIS. Multivariate statistical techniques such as Principal Component Analysis (PCA), Cluster Analysis (CA), and Discriminant Analysis (DA), were also employed to assess different aspects of drainage networks, and their morphometric properties. Principal Component Analysis (PCA) reduces the 22 morphometric parameters to five components, which explain 90.4% of total variance. The relationship of these components to the morphometric variables and to the individual sub-watersheds was evaluated, and then the degree of inter-correlation among the morphometric descriptors was explored. The 76 sub-watersheds were classified according to their individual relation to the components, and similarities in their morphometric characteristics. Regionalization of sub-watertsheds was achieved using hierarchical Cluster Analysis (CA). The validity of the resultant cluster groups was tested statistically by means of Discriminant Analysis. The present investigation provides information which highlights the benefit of geomorphometric analysis and multivariate statistics in modeling hydrological responses: i.e., surface runoff and sediment yield, hydrological assessment, water resources planning, and watershed management. Furthermore, the results can be useful for soil and water conservation planning, and assessment of flash floods potential.

Morphometric and Morphotectonic Analysis of Ferozpur Drainage Basin Left Bank Tributary of River Jhelum of Kashmir Valley, NW Himalayas, India

The Morphotectonic and morphometric analysis by the use of geomorphic indices and landforms helped us in deciphering the tectonic nature of the Ferozpur watershed. The present study has been carried out to study the tectonic geomorphology of the Ferozpur drainage basin, a left bank tributary of the River Jhelum, located in the Kashmir Himalayas. Various morphometric parameters like stream ordering, stream number, stream length, bifurcation ratio and Morphotectonic parameters like hypsometric integral, basin elongation ratio, drainage basin asymmetry, stream gradient index and river profiling (longitudinal) were calculated using Aster DEM, Toposheets, software’s like Glober Mapper and Arc Gis 10.2. Overall assessment of the morphometric and morphotectonic analysis revealed that the tectonic uplift, lithology and climate forcing determine a significant position in the landscape evolution of the Ferozpur drainage basin plus the basin has experienced differential uplift and erosion rates from time to time. Thus, it is hoped that the result from this investigation will aid inference about the tectonic activity and provoke some thoughts about the futuristic ramifications of the geomorphic processes operating in the Ferozpur drainage basin.

Morphometric Assessment of Wadi Wala Watershed, Southern Jordan Using ASTER (DEM) and GIS

Morphometric analysis is of vital concern to understand hydromophological processes in a given watershed, and thus, it is a priority for assessing water resources in drainage basins. A morphometric analysis was conducted to identify the drainage properties of Wadi Wala and the 23 fourth-order sub-basins. ASTER DEM data was employed to compile slope, elevation, and aspect maps. Arc GIS software was used to measure and calculate basic, derived and shape morphometric parameters. W. Wala is found to be a sixth-order drainage basin, and the drainage pattern is trellis to sub-trellis in the central and lower part of the catchment, whereas it is dendritic to sub-dendritic pattern in the southern and northern parts. The slopes of the catchment vary from 0° - 5° to >35° in slope categories. Tectonic uplifting and tilting, lithology, structure and rejuvenation are the major factors controlling morphological variation over the watershed. The recognized fault systems are chiefly controlling the drainage pattern, and the elongated shape of the sub-basins is attributed to dense lineaments in the central and eastern parts of the watershed. The Rb values for the entire catchment and the sub-catchments range from 2 to 7, with a mean of 4.55, which indicates the distortion of drainage pattern by geological structure. Hypsometric integral values are high for the W. Wala watershed and the sub-basins, where it ranges from 70% to 89%. High HI values indicate that drainage basins are at the youth-age stage of geomorphic development, and they are affected by tectonic uplifting, tilting, and the dominance of hillslope process. Variation in HI values is apparent between sub-basins located at the western part, or, the rejuvenated belt where HI values range from 85% to 89%. Whereas the HI values of the sub-basins located at the eastern part of the watershed, vary from 70% to 84%. Regression analysis reveals that R2 values, which represent the degree of control of driving parameters on HI are reasonably high for the height of local base level (m) and the mean height of sub-basins (m). Both parameters contribute 0.42 and 0.39 respectively (where the F-value is significant at 0.1% and 0.5% levels). Such results imply that the height of local base level (m), and the mean height (m) are the only morphometric driving parameters which have significant control on HI values in the W. Wala watershed. High annual soil loss and sediment load estimated recently, denote that the catchment is highly susceptible to surface erosion at present. Hence, the present study, and the resultant information would help to plan for efficient soil and water conservation measures to reduce soil erosion rates, conserve water, and to control sediment into W. Wala dam.

Glacial Geomorphology of Mt. Munkh Saridag in the Khuvsgul Mountain Range, Northern Mongolia

This study reconstructs palaeoglacial extent in the Khuvsgul Mountain Range in northern Mongolia based on the mapping of glacial landforms of Mt. Munkh Saridag. For the accurate reconstruction of palaeoglaciations in the Khuvsgul Mountain Range, glacial landforms including glacial valleys, glacial cirques, end moraines, medial moraines, marginal moraines and glacial lineations were mapped at a scale of 1:100.000 for Mt. Munkh Saridag. Mapping was conducted using Google Earth, 30 m resolution ASTER DEM data and 30 m resolution Landsat 5TM satellite imagery. This mapping revealed abundant glacial erosional and depositional landforms in the Khuvsgul Mountain Range, in particular, large end moraine complexes mark palaeoglacial advances in the mountain valleys of Mt. Munkh Saridag. Results indicate that Mt. Munkh Saridag, the center of Khuvsgul Mountain Range, had lost 42.6% of its total glacier area between 1970 (900 m²) and 2007 (384 m²) when the equilibrium-line altitudes (ELAs) of the glaciers were retreated by 47 m and 80 m on north and south aspects, respectively. The outer limits of these glacial landforms show development of small ice caps on peaks and ice fields in valleys of Mt. Munkh Saridag where their maximum glaciation was reconstructed to have covered 186 km². The spatial analyses show the dynamic change of the modern glaciers in Mt. Munkh Saridag, and how this depends on topographical elements of elevation and aspects, durations of solar radiation and vulnerability to the solar insolation. This study demonstrates that spatial analysis of the glacial landforms is crucial for reviewing the extent of palaeoglaciers that could be detailed with dates in further work.

Prioritization of Semi-Arid Agricultural Watershed Using Morphometric and Principal Component Analysis, Remote Sensing, and GIS Techniques, the Zerqa River Watershed, Northern Jordan

Remote sensing and GIS techniques were employed for prioritization of the Zerqa River watershed. Forty-three 4th order sub-watersheds were prioritized based on morphometric and Principal Component Analysis (PCA), in order to examine the effectiveness of morphometric parameters in watershed prioritization. A comparison has been carried out between the results achieved through applying the two methods of analysis (morphometric and PCA). Afterwards, suitable measures are proposed for soil and water conservation. Topo sheets and ASTER DEM have been employed to demarcate the 43 sub-watersheds, to extract the drainage networks, and to compile the required thematic maps such as slope categories and elevation. LANDSAT 8 image (April-2015) is employed to generate land use/cover maps using ENVI (v 5.1) software. The soil map of the watershed has been digitized using Arc GIS software. Prioritization of the 43 sub-watersheds was performed using ten linear and shape parameters, and three parameters which are highly correlated with components 1 and 2. Subsequently, different sub-watersheds were prioritized by ascribing ranks based on the calculated compound parameters (Cp) using the two approaches. Comparison of the results revealed that prioritization of watersheds based on morphometric analysis is more consistent and serves for better decision making in conservation planning as compared with the PCA approach. The recommended soil conservation measures are prescribed in accordance with the specified priority, in order to avoid undesirable effects on land and environment. Sub-watersheds classified under high priority class are subjected to high erosion risk, thus, creating an urgent need for applying soil and water conservation measures. It is expected that decision makers will pay sufficient attention to the present results/information, activate programs encouraging soil conservation, integrated watershed management, and will continue working on the afforestation of the government-owned sloping lands. Such a viable approach can be applied at different parts of the rainfed highland areas to minimize soil erosion loss, and to increase infiltration and soil moisture in the soil profile, thus, reducing the impact of recurrent droughts and the possibility of flooding hazards.

GIS applications in morphometric analysis of Koshalya-Jhajhara watershed in northwestern India

The present paper deals with morphometric analysis of Koshalya-Jhajhara (K-J) watershed, tributaries of Ghaggar in northwestern India. The area forms a rugged topography having elevation range from 399 m to 1810 m MSL. Aster DEM and SOI toposheets have been used to calculate various parameters using Geographic Information System (GIS). Linear, areal and relief aspects for morphometric analysis were calculated using GIS. Total number of streams in the watershed are 991 out of which 543 are of 1st order, 259 are of 2nd order, 124 are of 3rd order, 58 are of 4th order and only 7 are of 5th order. The order of stream determines the chances of flood in the stream. Higher the stream order more the probabilities of flood. The present paper indicates that K-J watershed is of 5th order and less elongated in shape having lower peak flows of longer duration with dendritic pattern and having fine drainage texture. Bifurcation ratio varies from 3 to 5 which indicate that geological structures don’t have dominant influence on drainage pattern. High slope is witnessed in NE part and low slope in SW part with very low gradient ratio. Variables like stream frequency and drainage density determines the volume of the water discharge and its speed of flow in the river channels. Higher the stream frequency and drainage density more will be the probability of floods. These variables also effects temporal variations in the speed at which the water flows in the stream when flood reaches its peak.

An integrated approach for identification of potential aquifer zones in structurally controlled terrain: Wadi Qena basin, Egypt

Wadi Qena basin represents one of the most promising regions for future development in Egypt. Fresh water supplies are crucial for such plans. We provide an integrated remote sensing (Landsat, ASTER DEM, Geoeye-1), geophysical (aeromagnetic), isotopic (δ18O, δ2H), field (stratigraphic and structural interpretation) and geochemical (major dissolved ions) approach to delineate zones of potential groundwater resources in Wadi Qena basin. Four water-bearing horizons were sampled: fractured crystalline aquifer, Nubian Aquifer System (NAS), Post Nubian Aquifer System (PNAS) and the Quaternary aquifer. Findings include: (1) spatial analysis of remote sensing data in a GIS environment indicates extensive structural deformation by dextral faults trending NE-SW (i.e. Qena-Safaga shear zone [QS]) and sinistral faults trending NW-SE (i.e. Najd shear zone) and sufficient surface water supply from the east through Wadi Fattera sub-basin; (2) analysis of geophysical data indicates that these faults control the water-bearing horizons in the subsurface; (3) isotopic analysis reveals four isotopic groups including two end members, one mixed group and one mixed and evaporated group: group (I) highly depleted fossil Nubian waters (range: δ18O from −6.39 to −6.74‰ and δ2H from −48.21 to −52.46‰); group (II) modern waters in fractured basement (range: δ18O from −1.41 to −1.51‰ and δ2H from 5.46 to −6.04‰); group (III) a mixed cluster between NAS and modern waters (range: δ18O from −4.82 to −5.05‰ and δ2H from −33.28 to −38.54‰); and group (IV) samples which have both mixing between the Nubian and meteoric waters and also have a considerable deviation from the Global Meteoric Water Line (GMWL) (range: δ18O from −0.58 to −4.69‰ and δ2H from −19.59 to −38.68‰), (4) samples with a mixed isotopic signature (in group III), which tap the NAS and are located along the main channel of Wadi Fattera (area 3600km2) provide evidence for modern recharge along surface exposures of the NAS and enhanced infiltration along deep-seated faults; (5) samples with a mixed isotopic signature (in group IV), which tap the Quaternary and PNAS aquifers and are located along deep-seated faults provide evidence of artesian upward leakage from the deep NAS into the shallower Quaternary and PNAS aquifers. The present study improves our understanding of the role of structural control and modern recharge in exploration for aquifer potential in arid environments.

Forest type mapping using object-based classification method in Kapilvastu district, Nepal

In the recent years, object-based image analysis (OBIA) approach has emerged with an attempt to overcome limitations inherited in conventional pixel-based approaches. OBIA was performed using Landsat 8 image to map the forest types in Kapilvastu district of Nepal. Systematic sampling design was adopted to establish sample points in the field, and 70% samples were used for classification and 30% samples for accuracy assessment. Landsat image was pre-processed, and the slope and aspect derived from the ASTER DEM were used as additional predictors for classification. Segmentation was done using eCognition v8.0 with the scale parameter of 20, ratios of 0.1 and 0.9 for shape and color, respectively. Classification and Regression Tree (CART) and nearest neighbor classifier (k-NN) methods were used for object-based classification. The major forest types observed in the district were KS (Acacia catechu/ Dalbergia sissoo), Sal (Shorea robusta) and Tropical Mixed Hardwood. The k-NN classification technique showed higher overall accuracy than the CART method. The classification approach used in this study can also be applied to classify forest types in other districts. Improvement in classification accuracy can be potentially obtained through inclusion of sufficient samples from all classes.Banko JanakariA Journal of Forestry Information for NepalVol. 26, No. 1, Page: 38-44, 2016

Multi-sensor Space-Borne Earth Observation Data for Characterizing Fluvial-Geomorphic Provinces: A Case Study from Kosi River, India

The dynamism of geomorphic provinces in fluvial systems present considerable ambiguities in mapping by remote sensing. This necessitates use of multiple satellite data to characterize such depositional provinces. We use, an integrated dataset to characterize the geomorphic provinces (e.g. active flood plain, older food plain, fan etc.) of the Kosi River (Bihar), India. This is done using contrast in spectral signatures derived from multispectral bands (of IRS-P6 LISS III), radiant temperature (from ETM+) and radar-roughness (from radar brightness image RISAT-1). ASTER DEM has been used in deriving topographic profiles. The optical imagery, enables regional characterization through direct tonal changes (e.g. active flood plain is brighter than older flood plain). The radiant temperatures show variations across provinces. Geomorphic transitions are represented by topographic breaks. Radar backscatter imagery, show differences in radar-return from different sub-provinces. Observations made using specific sensor characterize each provinces and is supplementary/complimentary to the parameter(s) from other sensors.

Subsurface profile interpretation of landslides, examples from Bashilo River watershed, Ethiopia

This research utilized the cost-effective methods for regional landslide characterization to serve as “roadmap” for more detailed landslide subsurface characterization. ASTER DEM’s data with 30 m resolution and topographic maps with 40 m resolution were used for this regional scale landslide study to explore the foundation for the concepts embedded in the “expert-driven” practice of estimating the likely subsurface structure of bedrock landslides based on their surface expression. The projected subsurface structure of mapped landslides in the Bashilo River watershed, Ethiopia, reflects the active role of past ongoing mass-wasting processes in shaping the Bashilo River watershed’s current setting. This regional study could help planners and engineers as guide map in contingency planning of geohazards in Tekeze and Blue Nile River watersheds.