ASTER DEM Research Articles

Morphometric Analysis for Sustainable Development of Watersheds Using Multisensor Satellite Data: A Case Study from Shiriya River Basin

Objectives: The goal of this research is to calculate, compare and analyze the morphometric drainage parameters of Shiriya River Basin (SRB), Kasaragod, Kerala, using DEMs acquired by different satellite sensors and topographic data (SOI toposheet) for sustainable watershed development. Methods: The Arc GIS 10.3.1 software was used to measure linear, relief, and areal aspects of morphometry. The input data used for deriving the drainage network of the SRB were SOI toposheet (1:50000 scale), SRTM DEM (90m), Cartosat, ASTER and ALOS PALSAR DEM of resolution 30 m each. The relative error percentage of basic parameters derived from DEMs concerning the toposheet is calculated. A groundwater potential map is prepared using weighted overlay analysis of thematic layers (geology, geomorphology, slope, drainage density, lineament density and depth to water level). Findings: Present study revealed that the parameters derived from SRTM DEM data are more similar to those derived from toposheet. Most of the parameters obtained from each input DEM are more or less equal, and the minor variation may be due to varied data collecting and processing methodologies used for DEM creation. SRB is characterized by 6 th order stream with a dendritic drainage pattern, which is elongated and less susceptible to soil erosion. SRB has an intermediate texture and is in a mature stage of geomorphic evolution. Inference from the ground water potential zonation map indicates that major portion of the SRB has moderate ground water potential. Application/improvement: The study would be a valuable source for identifying water recharge sites, basin modelling, and groundwater prospect mapping. Novelty:This research has attempted to compare and analyze the morphometric parameters’ results from multisensor satellite data for sustainable watershed management. An attempt has been done to understand the relation between morphometric parameters and ground water potential of SRB using Groundwater potential zonation map. Keywords: Drainage morphometry; Shiriya River basin; GIS; Karnataka; Kerala

Vulnerability Dynamics and Urban Flood Hazardscape Pattern: A Geospatial Analysis in Gombe City, Nigeria

In many Nigerian states, urban flooding has resulted into the death of numerous people and destruction of properties worth billions of Naira. This study examined the vulnerability dynamics and urban flood hazardscape pattern within Gombe city with a view to providing bases for policy formulation (where necessary), enforcement and decision making on flood risk reduction for enable sustainable urban development. ASTER DEM and Landsat images (2000, 2010 and 2019) was used to generate Digital Terrain Model (DTM) and impervious surface areas. Rainfall data for 2000-2018 was used to examine rainfall trend using regression analysis. The result revealed that flood hazardscape and vulnerability dynamics are largely influenced by physical and social factors. The results for vulnerability dynamics shows that as at 2000, about 1.4km2 lies on the relatively low vulnerable area,4.1km2falls within the moderate, and about 14.6km2 falls on critical area. By 2010, only about 1km2 lies on the relatively low area, 5.2km2 occupied the moderate and about 15km2was found within the critically vulnerable area. In 2019, the vulnerability dynamics depicts that about 33.4km2, impervious surface (builtup area) existed, out of which 2.8km2 lies on the low vulnerable area, 9.4km2 on the moderately vulnerable and 21.2km2 in critically vulnerable areas. It is concluded that flood hazardscape and vulnerability dynamics in Gombe city is influenced by both physical and anthropogenic factors. It is recommended that planning departments should put into consideration urban flood hazardscape maps for future development so as to reduce the risk and control future exposure flood impact.
 Keywords : Impervious surfaces; Feature extraction; Hazardscape; Urban flood; Vulnearbility dynamics
 
 Copyright (c) 2022 Geosfera Indonesia and Department of Geography Education, University of Jember
 This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License

Identification of Groundwater Potential Zone using Multi-Influence Factor Technique (Study Case: Brantas Groundwater Basin, East Java, Indonesia)

Brantas Groundwater Basin is the biggest groundwater basin in East Java Province, Indonesia. It is covering 22 regencies/cities which have high water need. Mostly people water need is supplied from groundwater. Identification of Groundwater Potential Zone (GWPZ) is required to ensure sustain groundwater supply for fulfilling that water need. One technique for that is Multi-Influence Factor (MIF). It considers influence factors of groundwater such as rainfall, geology, geomorphology, slope, lineament density, drainage density, soil texture, and land-use/landcover. Raster data obtained from Google Earth Engine (GEE), Aster DEM, and Geological Map of East Java were included as the research data. They had score and were estimated by using MIF technique. GEE and open-sourced GIS were used in computational raster data processing of MIF technique. Identification result of GWPZ showed that Brantas Groundwater Basin consist of zones which are very poor (2% area), poor (24% area), good (47% area), and very good (17% area). The result can assist hydrogeologist and local authorities to formulate further policy of GWPZ management.

Delineating Groundwater Recharge Potential through Remote Sensing and Geographical Information Systems

Owing to the extensive global dependency on groundwater and associated increasing water demand, the global groundwater level is declining rapidly. In the case of Islamabad, Pakistan, the groundwater level has lowered five times over the past five years due to extensive pumping by various departments and residents to meet the local water requirements. To address this, water reservoirs and sources need to be delineated, and potential recharge zones are highlighted to assess the recharge potential. Therefore, the current study utilizes an integrated approach based on remote sensing (RS) and GIS using the influence factor (IF) technique to delineate potential groundwater recharge zones in Islamabad, Pakistan. Soil map of Pakistan, Landsat 8TM satellite data, digital elevation model (ASTER DEM), and local geological map were used in the study for the preparation of thematic maps of 15 key contributing factors considered in this study. To generate a combined groundwater recharge map, rate and weightage values were assigned to each factor representing their mutual influence and recharge capabilities. To analyze the final combined recharge map, five different assessment analogies were used in the study: poor, low, medium, high, and best. The final recharge potential map for Islamabad classifies 15% (136.8 km2) of the region as the “best” zone for extracting groundwater. Furthermore, high, medium, low, and poor ranks were assigned to 21%, 24%, 27%, and 13% of the region with respective areas of 191.52 km2, 218.88 km2, 246.24 km2, and 118.56 km2. Overall, this research outlines the best to least favorable zones in Islamabad regarding groundwater recharge potentials. This can help the authorities devise mitigation strategies and preserve the natural terrain in the regions with the best groundwater recharge potential. This is aligned with the aims of the interior ministry of Pakistan for constructing small reservoirs and ponds in the existing natural streams and installing recharging wells to maintain the groundwater level in cities. Other countries can expand upon and adapt this study to delineate local groundwater recharge potentials.

Uplift evolution along the Red Sea continental rift margin from stream profile inverse modeling and drainage analysis

Continental rifted margins can have complex uplift histories related to different processes including footwall uplift by mechanical unloading, dynamic uplift and interaction with transfer margins. Deciphering uplift histories along rift flanks is integral to understanding the margin evolution as a whole. Here, a combination of drainage analysis and stream profile inverse modeling is utilized to estimate the rift flank uplift along the north-eastern Red Sea onshore margin. The drainage network was extracted from an ASTER DEM (∼30 x 30 m-horizontal resolution) and the uplift history was calculated using an inverse model, which builds on the relationship between uplift, erosion and stream profile shape. Local relief, minimum erosion volumes and minimum erosion volume:catchment area ratios (Rva) were also calculated and compared to uplift estimates. Within the study area, small catchments represent footwall drainage and larger catchments are mostly associated with pre-rift structures and syn-rift accommodation zones. Uplift initiated in the southern part during early rifting (21-15 Ma) before shifting northward (12-0 Ma). This uplift distribution is reflected in Rva and relief maps. Early-rift uplift is interpreted as a record of early-rift faulting with possible additional mantle support, whereas later uplift was driven by fault linkage and mantle upwelling (12-6 Ma) as well as transform tectonics (6-0 Ma). These modeling results are largely in agreement with other independent data (low-temperature thermochronology and dated carbonate terraces). Our workflow benefits from its utilization of ubiquitous drainage data. The combination of drainage analysis and inverse modeling proves to be more discerning than either one method in isolation, and may have application to analysis of other margins.

FLOOD VULNERABILITY MAPPING OF RIVER NGADDA USING GEOSPATIAL AND REMOTE SENSING TECHNIQUES MAIDUGURI METROPOLIS, BORNO STATE

Flood disaster has been threating to animal, plants, land, human and non-human resources over the years. This have increased concerns on the need to investigate various vulnerable areas to flood for decision making. As a mitigative measures to loss of lives, properties, and livelihood which could arise from flood disaster, understanding zones at risk to flooding is vital to support all stages of disaster management including early warning and planning. River Ngadda is a major river within Maiduguri metropolis. Its plains and banks are known to have different activities and resources. When the river overflows its shores, neighboring lands could suffer destruction, there could be loss of lives and properties. This project aims to investigate flood vulnerability along River Ngadda identifying the shores, plains, and banks of the river at risk. The research adopts ground truth information, the use of Aster DEM (30m) and Sentinel 2 (10m) Satellite Imagery dataset through Geospatial and Remote Sensing techniques to assess undulating nature of the area under study, identify areas liable to flood and analyzed the flood plain. Further analysis was carried out to obtain the Land use and Landcover (LULC) within the study area using a supervised classification and areas at various flood risk were also identified. This research results presented the river plains, flood vulnerable impact on LULC, it was found that 13.17 hectares of built-up areas fall within the very high flood risk zone, over sixty six percent (66%) of the study area appears fall within the moderate to very high vulnerable flood risk zone and the production of the flood plains, LULC, risk and hazard map of the study area was presented. This result could aid early warning, planning and decision making for River Ngadda and its environs.

A combined GIS, remote sensing and geophysical methods for groundwater potential assessment of Ilora, Oyo central, Nigeria

The unavailability of water has been a major threat to agricultural and commercial activities in Ilora, Oyo central, Nigeria. This study combined GIS, remote sensing, and geophysical methods for groundwater potential zone mapping within the area in an attempt to identify prospective zones for borehole drilling activities. Landsat 8 OLI, ASTER DEM, geological, geophysical, and soil data of the research area were acquired for this study. To map the groundwater potential of the area, eight thematic layers that influence groundwater occurrences and movement controlling factors such as, geology, elevation, slope, land use land cover (LULC), fault proximity, soil, lineament density, and drainage density were mapped out from the acquired data of the area. The influence of each theme and subunit/class on groundwater recharge based on previous studies were evaluated using Analytical Hierarchical Process (AHP). The groundwater potential of the area of study was qualitatively classified into five classes, namely: very high, high, moderate, low, and very low which account for 0.3%, 7.8%, 54.8%, 35.6%, and 1.5% of the total area, respectively. The results were cross validated using well data from the area and 88.9% correlation and 0.74 kappa coefficient were achieved. The groundwater potential map generated in this research could be used as a preliminary reference in selecting suitable sites for groundwater resource exploitation in the area to ameliorate the current scarcity of water in this region.

Determination of morphological parameters of Tidi watershed using remote sensing and geographic information system approaches

Abstract In the current study, an attempt was made to determine the morphological parameters of the Tidi watershed in Udaipur district of Rajasthan, India. Remote sensing and geographic information system (GIS) technique has proved to be an efficient tool in drainage network delineation and update in morphological analysis. For detailed study, ASTER DEM was used for delineation of the watershed boundary, and GIS was used in evaluation of basic, linear, areal and relief aspects of morphometric parameters. The Tidi watershed occupies an area of 114.36 km2 with a dendritic drainage pattern. The study area is designated as fifth order basin and lower and middle order streams mostly dominate the basin with the drainage density value of 1.74 km/km2 which exhibits gentle to moderate slope terrain and medium dense vegetation. The mean bifurcation value of the watershed is 3.88 and the value varies from 2 to 4.14 which shows that the drainage network formed on homogeneous rocks when the influences of geologic structures on the stream network were negligible. An elongation ratio of 0.79 implies that the watershed is less elongated in shape. The results from the morphometric analysis of the watershed are very beneficial for developing and designing conservation structures of soil and water and watershed management measures.

3D MODELING AND ASSESSMENT OF FLOOD RISK ZONES USING GIS AND REMOTE SENSING IN CATCHMENT AREA TERENGGANU, MALAYSIA

The application of 3D GIS has enabled better representation and visualization of flood events than previous 2D maps. Flooding is common in the Terengganu basin. Flash floods occur most of the year during the monsoon season, which lasts from November to January. Flooding along riverbanks is mainly affected by heavy rainfalls of 2500mm to well over 3500mm per year. This has significant impacts on environmental resources such as land use/land cover, local soil types and slopes. The study area of Kuala Terengganu was particularly affected by heavy rains and flash floods during the monsoon season. ASTER DEM resolution 5m converted to ArcScene 10.3 using ArcGIS 10.3 and 3D software. In recent years, flood monitoring methods have been developed that can predict water flow and associated risks and hazards. 3D visualization techniques include remote sensing such as satellite imagery and geographic information systems “GIS”. and LiDAR modeling

Description of the biophysical characteristic and relation with discharge of Je’ne Rakikang Catchment Area

This study aims (1) to determine the biophysical characteristics and discharge on Je’ne Rakikang Catchment Area, (2) the relationship between the biophysical characteristics and discharge on Jene Rakikang Catchment Area. This research was conducted at Jene Rakikang Catchment Area. The data were collected in the form of primary and secondary data. Primary data were determined by measuring the discharge and precipitation, during 31 days of observation and secondary data collected from government agencies or related institutions such as land cover collected the data from the Institute for Balai Pemantapan Kawasan Hutan Wil. VII Makassar, rainfall data from the Global weather (2004-2013), geological data from Ujung Pandang GRDC Sheets of 1982, the data from Aster DEM slope, soil type data from RePP Prot 1987 and the data obtained from the calculation as well as visually. The data were analyzed using the quantitative descriptive method. The results showed that the dishcarge fluctuations of Je’ne Rakikang Catchment Area very varied. Biophysical characteristics of the Je’ne Rakikang Catchment Area consist of geology, topography, soil type, orientation, area, shape, draignase density, stream gradient, flow pattern, land cover and rainfall could potentially influence the behavior of discharge. The different of biophysical characteristics of Jene Rakikang Catchment Area provide a response to discharge in the event of rain with short time. ne Rakikang Catchment Area very varied. Biophysical characteristics of the Je’ne Rakikang Catchment Area consist of geology, topography, soil type, orientation, area, shape, draignase density, stream gradient, flow pattern, land cover and rainfall could potentially influence the behavior of discharge. The different of biophysical characteristics of Jene Rakikang Catchment Area provide a response to discharge in the event of rain with short time. ne Rakikang Catchment Area very varied. Biophysical characteristics of the Je’ne Rakikang Catchment Area consist of geology, topography, soil type, orientation, area, shape, draignase density, stream gradient, flow pattern, land cover and rainfall could potentially influence the behavior of discharge. The different of biophysical characteristics of Jene Rakikang Catchment Area provide a response to discharge in the event of rain with short time.

Identification and modelling of forest fire severity and risk zones in the Cross – Niger transition forest with remotely sensed satellite data

Forest fires are a serious environmental hazard within the forest ecosystem, which can be studied with Remote Sensing and GIS. The aim of the study is to identify and model forest fires severity and risk zones within the Cross – Niger transition forest. To achieve this aim, remotely sensed data, such as Landsat – 8 OLI (2020) and ASTER DEM were used to produce land cover maps and topography parameters such as aspect, elevation and slope. The topographic maps and the Google Earth imagery were used to extract human settlements and road networks. The final forest fire risk zone (FFRZ) map was prepared by integrating the different parameters such as Land cover, aspect, elevation, slope, proximities to roads and settlements in the ArcGIS environment. The FFRZ was categorized into three categories as low, moderate and high risk zones, based on their fire susceptibility. The category of low, moderate and high FFRZ were represented as 2731.7 km2 (12.5%), 17997.69 km2 (82.59 %) and 1061.63 km2 (4.87%) respectively. The study shows that Remote Sensing and GIS are excellent tools for modelling forest fire risk zones, hence proving that fires are anthropogenic in origin.

​The Significance Impact Assessment of Morphological Parameters on Watershed: A Review

Watershed morphological analysis is momentous for controlling floods risk, forethought and management of the watershed area, as well as it is foremost useful to perceive catchment hydrology. Remote sensing and geographic information system are used in recent times as a tool for watershed delineation and its planning. Many types of input parameters generally use for watershed delineation such as Toposheet, ALOS, SRTM DEM, ASTER DEM and CARTOSAT DEM. Based on analysis SRTM DEM gives meticulous and clear results compared to other DEM files. Morphometric based prioritization of watershed was given in many research papers but an appropriate result of priority range was not given and this type of study confusing to evaluate the rank of priority based on its erosional behaviour. In many papers results of morphometric parameters were not indicate how to retaliate these results of morphometric parameters to a watershed. This paper deals with the implication of different values of morphometric parameters with adequate contextual information. This review paper can give useful information for the morphometric analysis of watersheds.

DELINEATION OF URBAN FLOOD RISK AREAS USING GEOSPATIAL TECHNIQUE

The threat posed by urban flooding in most cities of the world is becoming alarming especially within the recent decades. This makes it necessary to Identify and delineate flood risk areas within cities in order to curb it menace. This study employs geospatial technique to delineate flood risk areas within Kano metropolis with a view to mitigating its impact on lives and properties. Digital Elevation Model (ASTER DEM 30m) was used to derive excess surface run-off attributes including flow direction and accumulation. Based on these attributes, flood risk areas were determined and delineated using buffer distances of 500 meters. World View image (30 cm spatial resolution) was used to identify the landuses at risk. The result from the analysis delineated flood risk areas at varying exposure levels (i.e high, moderate and low).It was evident that flood risk level within the metropolis corresponds to the pattern of surface run-off flow accumulation areas. Settlements and farmlands found within high accumulation areas along the floodplains of River Jakara (in the North and North-eastern part) and Kano-Zaria road (southern part) are at higher risk than those found on low accumulation areas. The study concluded that excess surface run-off flow direction and accumulation are among the fundamental factors determining the risk to urban flooding. The study recommends that with the ongoing level of urban development and impervious surface expansion, urban planners and policy makers should make use of the flow direction and accumulation maps in determining safer places for future developments

SUITABLE DEM ASSESSMENT STUDY FOR DATA SCARCE CITIES TOWARDS URBAN EXTREME AND NUISANCE FLOOD MAPPING

Abstract. The high-resolution accurate topography data should be used for extreme and nuisance flood inundation modeling and mapping in cities, but not available for many cities, including most developed countries. It is necessary to study and identify an alternate open-source topographic model that satisfies high-resolution topography datasets’ conditions. We analyzed the open-source DEMs visually, elevation histogram statistics, streams and watershed identification, contour statistics, Topographic Wetness Index, and vertical accuracy of other medium-resolution DEMs compared with high-resolution LiDAR data over New York City to determine alternative open-source Digital Elevation Model in the context of urban flood modeling. In high urban sprawl areas, in the context of flood mapping, our findings have shown that the medium resolution DEMs predicted similar to high-resolution DEMs with the same linear errors around RMSE 25–35ft and LE90 30–40ft. Overall, the ALOS AW3D performed better than other open-source DEMs. Even though SRTM predicted well, it inducted smoothness in DEM where more buildings were located. It noted that ALOS PALSAR DEM is not suitable for any urban studies. ASTER DEM has also shown good agreement with LiDAR and observed elevations, but it induced by noise while processing. Finally, it can be suggested that the ALOS AW3D can be used as an alternative source for urban flood modeling which represented footprints of buildings even though it performed average in vertical accuracy.

DELINEATION OF URBAN FLOOD RISK AREAS USING GEOSPATIAL TECHNIQUE

The threat posed by urban flooding in most cities of the world is becoming alarming especially within the recent decades. This makes it necessary to Identify and delineate flood risk areas within cities in order to curb it menace. This study employs geospatial technique to delineate flood risk areas within Kano metropolis with a view to mitigating its impact on lives and properties. Digital Elevation Model (ASTER DEM 30m) was used to derive excess surface run-off attributes including flow direction and accumulation. Based on these attributes, flood risk areas were determined and delineated using buffer distances of 500 meters. World View image (30 cm spatial resolution) was used to identify the landuses at risk. The result from the analysis delineated flood risk areas at varying exposure levels (i.e high, moderate and low).It was evident that flood risk level within the metropolis corresponds to the pattern of surface run-off flow accumulation areas. Settlements and farmlands found within high accumulation areas along the floodplains of River Jakara (in the North and North-eastern part) and Kano-Zaria road (southern part) are at higher risk than those found on low accumulation areas. The study concluded that excess surface run-off flow direction and accumulation are among the fundamental factors determining the risk to urban flooding. The study recommends that with the ongoing level of urban development and impervious surface expansion, urban planners and policy makers should make use of the flow direction and accumulation maps in determining safer places for future developments.

Using multispectral and radar remote sensing data for geological investigation, Qena-Safaga Shear Zone, Eastern Desert, Egypt

In the present study, Qena-Safaga Shear Zone (QSSZ) has been the subject matter of detailed remote sensing investigation using Landsat-8, ASTER, and SRTM DEM data. Gathering information from these sensors allowed revealing the different lithological, geological, and structural features. Field observations were carried out to verify the remotely sensed data analysis and interpretation. A fused Landsat-8 OLI and ALOS/PALSAR data clearly improved the view of structural elements that are difficult to be revealed by optical images. The results showed that the area is controlled by the dextral ENE-WSW shearing trend which extends across the Nile at Qena Bend. Lineament analysis and lineament density map demonstrated that the area was subjected to different phases of stress; accordingly, conjugate faults were formed; most of these trends were rejuvenated. The ENE- WSW, NE-SW, and NW-SE are the major tectonic trends affecting the area but the N-S direction is less dominant. WNW, NW, NE, E, and N directions are indicated by sinistral strike-slip movements. The ENE, NE, and WNW are governed by right-lateral strike-slip movements and most of these trends controlled the emplacement of granitoids. The image transformation technique also allowed revealing hydrothermal alteration effects related to the NW-SE and NE-SW fault systems. Overall, combining of multispectral and radar data and field observations is significant for characterizing the geological features in arid regions.

Investigation of Groundwater Potential Using Remote Sensing and Geographical Information System (GIS) Techniques in Fakai Local Government of Kebbi State, Nigeria

Groundwater is one of the most precious natural resource which supports human health, economic development and ecological diversity. Remote sensing and Geographical Information System (GIS) Techniques have been effectively used for the investigation of the potentiality of groundwater resource in Fakai local government area. The dataset for this research work are Landsat 8 Operational land imager (OLI), ASTER DEM, Topographical map and Geological map from which the essential criteria were obtained. The study used Weighted Linear Combination approach which involves mathematical weighing and ranking of the criteria. Multi-criteria evaluation was carried out on all the criteria using the Weighted Linear Combination approach in ArcGIS 10.4. Spatial analysis was carried out on the derived result using the Suitability Index (SI) value created from pairwise comparison analysis. The suitability map for groundwater recharge in the study area was hence produced using the suitability index. The result shows four classes for the study area. The classes include highly suitable, moderately suitable, less suitable and least suitable. Thus, the area most suitable for groundwater are found most towards the northern part, around the center and some regions in the northern part of the study area this serves as an indicator that most of the study area has good potential for groundwater recharge.

Delineation of the Causative Fault of Recent Earthquakes (April-May 2020) in Delhi from Seismological and Morphometric Analysis

Recently, amid the pandemic of COVID-2019, the north-east Delhi region experienced two small earthquakes in a short span of 1 month; the first occurred on 12th April 2020 (Mw 3.5) and the other on 10th May 2020 (Mw 3.4). These events were followed by 4 aftershocks of magnitude Mw ≤ 3.0. We carried out morphotectonic (high stream length-gradient index) and static Coulomb stress failure analyses to delineate the hidden causative fault(s) in the region. In the study, ASTER DEM data of 30 m resolution and Survey of India (SoI) toposheets on 1:50,000 scales were used for morphotectonic analysis. The analysis depicted a very high stream length-gradient (SL) and fall in elevation in the epicentral area, suggesting the area to be tectonically active with a NE-SW trending fault line. In addition, the nature of static Coulomb failure stress contours for both the main events, Mw 3.5 and Mw 3.4, suggests an NNE-SSW trending high Coulomb stress regime. Such a high coulomb stress regime is obvious at the location where a high SL index and fall in elevation were marked, which clearly indicates the presence of NNE-SSW trending a causative fault, named ‘Khanpur-Japti fault’.

Geospatial tourist information system for promoting tourism in trans-himalayas: A study of leh ladakh India

Ladakh is a famous tourist destination in India. The number of tourists visited in 1974 was 527 which increased to 327,366 in 2018. However, tourism potential has largely remained untapped due to the lack of proper dissemination of information. Nowadays, the GIS-based Tourist Information System has gained great importance among tourists, as it allows familiarizing with places and at the same time exerting profound appeal for trip planning. The purpose of the present study was to develop an interactive GIS-based Tourist Information System for Leh Ladakh. To compile database, topo-sheets and satellite imageries including CARTO-SAT, LISS-IV, and ASTER DEM was used. Besides, GPS and field surveys were conducted to generate vector data layers, viz., hotels, guesthouses, road networks, airports, parks, golf courses, water bodies, fuel stations, health amenities, banks, and ATMs. Moreover, multimedia data like video clips, audio narrations, and photographs were integrated with each feature as attribute data, to make it particularly informative for tourists and other stakeholders. The proposed GIS-based Tourist Information System is a one-time investment and can be uploaded on the internet as well as updated when needed via database updating. It is expected to bring tourists from across the world via virtual travel experience.

Use of ASTER DEM data for Morphometric Analysis of Megech Dirma-Watersheds, Blue Nile Basin, Ethiopia: Implications for Soil and Water Conservation

Quantitative morphometric analysis was carried out for Megech-Dirma, sub-basin of the Blue Nile, by estimating (1) linear, (2) aerial, and (3) relief aspects. An endeavor has been made to measure the Megech-Dirma watershed’s morphometric characteristics to implement conservation methods for soil and water properly. ASTER DEM has been used as input data for extracting morphometric parameters. Strahler’s classification scheme was used to classify the extracted drainage network in ArcGIS extension ArcMap 10.4. The watershed covers a total surface area of 1309.56 km2. The shape of the watersheds as calculated from elongation, circularity, and form factors reveals the elongated shape and the watersheds parade dendritic pattern. The sub-watersheds include third-order for Megech and sixth-order streams. Lower stream orders, in particular first-order streams, dominate the sub-watersheds. The length of overland flow has a higher value (1.06) for Megech indicates low relief, whereas the values of length of overland flow, which are relatively low (0.20) for Dirma, indicate high relief. The drainage density of the study watershed was morphometrically analyzed and obtained 0.47 km/km2 for the Megech sub-basin, which indicates the basin is highly permeable and result in better underground water storage capacity and 2.46 for the Dirma sub-basin indicating very coarse and coarse channel, respectively. The ruggedness number for Megech and Dirma sub-basins was 0.56 and 0.07, respectively, indicating moderate and long, rugged topography, which could be susceptible to flash flood and soil erosion. The dissection index values for Megech 0.40 and 0.36 for Dirma show river sub-basins are moderately dissected. The ruggedness number is 0.56 for Megech implies moderate soil erosion probability, whereas the high infiltration number (14.29) for Dirma river shows the high runoff potential in the sub-basin. The findings of this study include drainage morphometry data that can be used to better understand watershed characteristics and serve as a framework for better planning, management, and decision-making to ensure the long-term use of watershed resources of water and soil.