scholarly journals Characterization of reservoirs for water supply in Northeast Brazil using high resolution remote sensing

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Vladimir Fonseca Nascimento ◽  
Alfredo Ribeiro Neto

ABSTRACT This paper reports the application of information acquired by aerial survey to characterize water supply reservoirs in the Pajeú River Basin (Pernambuco State/Brazil). The survey was carried out with digital cameras of high spatial resolution and laser relief profiling (LiDAR technology). Two areas were selected to apply the remote sensing products. Small reservoirs in the Quixaba Creek Basin were identified based on their topographic characteristics. Given that the small reservoirs are “depressions” in the terrain, they can be “filled”, resulting in a new Digital Terrain Model (DTM). The difference between the filled DTM and the original DTM makes it possible to identify the reservoirs. A summary of the results is: 61 reservoirs were correctly detected; 18 reservoirs were not detected; 13 reservoirs were detected erroneously. In another application, the storage capacity of the reservoirs belonging to the hydrosystems of Pajeú River Basin was estimated. The storage in these reservoirs and maximum surface area were estimated using DTM and geoprocessing tools. From the total of 31 reservoirs evaluated, eight were completely empty at the time of the LiDAR data collection. The official registers reported 83.83 million m3 for the storage capacity of these eight reservoirs, whereas our applications estimated the value at 70.23 million m3. This difference is explained by the loss of volume in the reservoirs due to the process of sediment transport.

2020 ◽  
Vol 16 (02) ◽  
pp. 31-50
Author(s):  
Angélica Estigarribia São Miguel ◽  
Rafael Brugnolli Medeiros ◽  
Weslen Manari Gomes

A fragilidade ambiental diz respeito à fragilidade do ambiente em função de qualquer tipo de dano causado pela dinâmica ambiental, seja de forma natural e/ou antrópica, sendo relacionada com a erosão do solo e assoreamento dos rios. O objetivo desta pesquisa foi realizar uma análise da fragilidade ambiental da bacia hidrográfica do ribeirão São Pedro, no município de Santa Rita do Pardo/MS, analisando suas características físicas e o uso da terra e cobertura vegetal. Para tanto, a metodologia consiste em duas etapas: a primeira delas na avaliação das precipitações buscando algumas estações meteorológicas no entorno da bacia hidrográfica, trabalhando em ambiente SIG ArcGis 10. A segunda diz respeito ao manuseio das informações sobre áreas prioritárias e solos, buscou-se dados do SISLA/IMASUL, a declividade, trabalhou-se com o modelo digital de terreno SRTM e para o uso da terra e cobertura vegetal a utilização das imagens de satélite Landsat 8. Com isso, a interpolação dessas informações foi embasada na proposta metodológica de Ross (1994) para a fragilidade ambiental. As classes de fragilidade obtidas são a categoria baixa que se mostrou dominante na bacia, sendo presentes em matas nativas e pastagens, a categoria média e alta, que juntas apresentaram 39,56% da área total da bacia foram encontradas em locais com alto declive, concluindo assim que a bacia hidrográfica necessita da análise de suas características, onde qualquer mudança em um de seus elementos pode alterar a fragilidade do local, prejudicando assim, seus recursos naturais. Palavras-chave: Fragilidade ambiental. Sensoriamento Remoto. Uso da terra e cobertura vegetal.   EMPLOYMENT OF REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM IN EVALUATION OF ENVIRONMENTAL FRAGILITY OF HYDROGRAPHIC BASIN SÃO PEDRO, SANTA RITA DO PARDO/MS ABSTRACT The environmental fragility refers to the fragility of the environment due to any kind of damage caused by the environmental dynamics, either naturally or anthropically, and is related to soil erosion and silting of rivers. The objective of this research was to analyze the environmental fragility of the São Pedro river basin, in the municipality of Santa Rita do Pardo / MS, analyzing its physical characteristics and the use of land and vegetation cover. To do so, the methodology consists of two stages: the first one in the evaluation of precipitation by searching for some meteorological stations around the watershed, working in ArcGis 10 GIS environment. The second one concerns the handling of information on priority areas and soils, if data from the SISLA / IMASUL, the slope was worked with the SRTM digital terrain model and for the land use and vegetation cover the use of Landsat 8 satellite images. With this, the interpolation of this information was based on the methodological proposal of Ross (1994) for environmental fragility. The fragility classes obtained are the low category that was dominant in the basin, being present in native forests and pastures, the medium and high category, which together presented 39.56% of the total area of ​​the basin were found in places with high slope, thus concluding that the river basin needs the analysis of its characteristics, where any change in one of its elements can alter the fragility of the place, thus damaging its natural resources. Key Words: Environmental fragility. Remote Sensing. Land use and vegetation cover.   EMPLEO DEL SENSORIAMIENTO REMOTO Y SISTEMA DE INFORMACIÓN GEOGRÁFICA EN LA EVALUACIÓN DE LA FRAGILIDAD AMBIENTAL DE LA BACIA HIDROGRÁFICA DEL RIBEIRÃO SÃO PEDRO, SANTA RITA DO PARDO/MS RESUMEN La fragilidad ambiental se refiere a la fragilidad del ambiente en función de cualquier tipo de daño causado por la dinámica ambiental, sea de forma natural y / o antrópica, estando relacionada con la erosión del suelo y la sedimentación de los ríos. El objetivo de esta investigación fue realizar un análisis de la fragilidad ambiental de la cuenca hidrográfica del río San Pedro, en el municipio de Santa Rita do Pardo / MS, analizando sus características físicas y el uso de la tierra y cobertura vegetal. Para ello, la metodología consiste en dos etapas: la primera de ellas en la evaluación de las precipitaciones buscando algunas estaciones meteorológicas en el entorno de la cuenca hidrográfica, trabajando en ambiente SIG ArcGis 10. La segunda se refiere al manejo de las informaciones sobre áreas prioritarias y suelos, si los datos del SISLA / IMASUL, la declividad, se trabajó con el modelo digital de terreno SRTM y para el uso de la tierra y cobertura vegetal la utilización de las imágenes de satélite Landsat 8. Con ello, la interpolación de esas informaciones se basó en la propuesta metodológica de Ross (1994) para la fragilidad ambiental. Las clases de fragilidad obtenidas son la categoría baja que se mostró dominante en la cuenca, siendo presentes en bosques nativos y pastos, la categoría media y alta, que juntas presentaron el 39,56% del área total de la cuenca se encontraron en locales con alto declive, concluyendo así que la cuenca hidrográfica necesita el análisis de sus características, donde cualquier cambio en uno de sus elementos puede alterar la fragilidad del local, perjudicando así sus recursos naturales. Palabras clave: Fragilidad ambiental. Detección remota. Uso de la tierra y cobertura vegetal.


2018 ◽  
Vol 39 (1) ◽  
pp. 17-26
Author(s):  
Faiza hassainia Bouzahar ◽  
Lahbaci Ouerdachi ◽  
Mahdi Keblouti ◽  
Akram Seddiki

AbstractThe study of flood risk involves the knowledge of the spatial variability in the characteristics of the vegetation cover, terrain, climate and changes induced by the intervention of humans in watersheds. The increased needs of the actors in land management mean that static maps no longer meet the requirements of scientists and decision-makers. Access is needed to the data, methods and tools to produce complex maps in response to the different stages of risk evaluation and response. The availability of very high spatial resolution remote sensing data (VHSR) and digital terrain model (DTM) make it possible to detect objects close to human size and, therefore, is of interest for studying anthropogenic activities. The development of new methods and knowledge using detailed spatial data, coupled with the use of GIS, naturally becomes beneficial to the risks analysis. Indeed, the extraction of information from specific processes, such as vegetation indices, can be used as variables such as water heights, flow velocities, flow rates and submersion to predict the potential consequences of a flood. The functionalities of GIS for cartographic overlay and multi-criteria spatial analysis make it possible to identify the flood zones according to the level of risk from the flood, thus making it a useful decision-making tool.This study was carried out on the territory of watersheds in the Annaba region, East of Algeria. The choice was guided by the availability of data (satellites images, maps, hydrology, etc.) and hydrological specificities (proximity to an urban area). The adopted model is divided into two parts. The first part is to establish a methodology for the preservation of wetland biodiversity and the protection of urban areas against floods. Thanks to the multi-criteria spatial analysis and the functionalities of the GIS, we established a flood risk map for the watershed defined above. The result was satisfactory compared with the field reality. The second part of the model consisted of the integration of cadastral information with the flood risk map obtained in the first part of our research.The primary objective of this mapping is to contribute to the development of flood risk management plans (in the sense of risk reduction). The mapping stage also provides quantitative elements to more accurately assess the vulnerability of a territory.


2019 ◽  
Vol 11 (9) ◽  
pp. 1111 ◽  
Author(s):  
Johannes Schmidt ◽  
Johannes Rabiger-Völlmer ◽  
Lukas Werther ◽  
Ulrike Werban ◽  
Peter Dietrich ◽  
...  

The Early Medieval Fossa Carolina is the first hydro-engineering construction that bridges the Central European Watershed. The canal was built in 792/793 AD on order of Charlemagne and should connect the drainage systems of the Rhine-Main catchment and the Danube catchment. In this study, we show for the first time, the integration of Airborne LiDAR (Light Detection and Ranging) and geoarchaeological subsurface datasets with the aim to create a 3D-model of Charlemagne’s summit canal. We used a purged Digital Terrain Model that reflects the pre-modern topography. The geometries of buried canal cross-sections are derived from three archaeological excavations and four high-resolution direct push sensing transects. By means of extensive core data, we interpolate the trench bottom and adjacent edges along the entire canal course. As a result, we are able to create a 3D-model that reflects the maximum construction depth of the Carolingian canal and calculate an excavation volume of approx. 297,000 m3. Additionally, we compute the volume of the present dam remnants by Airborne LiDAR data. Surprisingly, the volume of the dam remnants reveals only 120,000 m3 and is much smaller than the computed Carolingian excavation volume. The difference reflects the erosion and anthropogenic overprint since the 8th century AD.


2019 ◽  
Vol 11 (20) ◽  
pp. 2447 ◽  
Author(s):  
Juliana Batistoti ◽  
José Marcato Junior ◽  
Luís Ítavo ◽  
Edson Matsubara ◽  
Eva Gomes ◽  
...  

The Brazilian territory contains approximately 160 million hectares of pastures, and it is necessary to develop techniques to automate their management and increase their production. This technical note has two objectives: First, to estimate the canopy height using unmanned aerial vehicle (UAV) photogrammetry; second, to propose an equation for the estimation of biomass of Brazilian savanna (Cerrado) pastures based on UAV canopy height. Four experimental units of Panicum maximum cv. BRS Tamani were evaluated. Herbage mass sampling, height measurements, and UAV image collection were simultaneously performed. The UAVs were flown at a height of 50 m, and images were generated with a mean ground sample distance (GSD) of approximately 1.55 cm. The forage canopy height estimated by UAVs was calculated as the difference between the digital surface model (DSM) and the digital terrain model (DTM). The R2 between ruler height and UAV height was 0.80; between biomass (kg ha−1 GB—green biomass) and ruler height, 0.81; and between biomass (kg ha−1 GB) and UAV height, 0.74. UAV photogrammetry proved to be a potential technique to estimate height and biomass in Brazilian Panicum maximum cv. BRS Tamani pastures located in the endangered Brazilian savanna (Cerrado) biome.


2016 ◽  
Vol 20 (11) ◽  
pp. 4673-4688 ◽  
Author(s):  
Davi de C. D. Melo ◽  
Bridget R. Scanlon ◽  
Zizhan Zhang ◽  
Edson Wendland ◽  
Lei Yin

Abstract. Droughts are particularly critical for Brazil because of impacts on water supply and because most (70 %) of its electricity is derived from hydroelectric generation. The Paraná basin (PB), a major hydroelectric producing region with 32 % (60 million people) of Brazil's population, recently experienced the most severe drought since the 1960s, compromising the water supply for 11 million people in São Paulo. The objective of this study is to quantify linkages between meteorological and hydrological droughts based on remote sensing, modelling, and monitoring data using the Paraná River basin in south-eastern Brazil as a case study. Two major meteorological droughts were identified in the early 2000s and 2014, with precipitation 20–50 % below the long-term mean. Total water storage change estimated from the Gravity Recovery and Climate Experiment (GRACE) satellites declined by 150 km3 between April 2011 and April 2015. Simulated soil moisture storage declined during the droughts, resulting in decreased runoff into reservoirs. As a result, reservoir storage decreased by 30 % relative to the system's maximum capacity, with negative trends ranging from 17 (May 1997–April 2001) to 25 km3 yr−1 (May 2011–April 2015). Storage in upstream reservoirs is mostly controlled by natural climate forcing, whereas storage in downstream reservoirs also reflects dam operations. This study emphasizes the importance of integrating remote sensing, modelling, and monitoring data to evaluate droughts and to establish a preliminary understanding of the linkages between a meteorological and hydrological drought for future management.


2019 ◽  
Vol 95 (03) ◽  
pp. 149-156 ◽  
Author(s):  
Joanne C. White ◽  
Hao Chen ◽  
Murray E. Woods ◽  
Brian Low ◽  
Sasha Nasonova

The pace of technological change in forest inventory and monitoring over the past 50 years has been remarkable, largely asa result of the increased availability of various forms of remotely sensed data. Benchmarking sites, with the requisite refer-ence and baseline data for evaluating the capacities of new technologies, algorithms, and approaches, can be extremely valu-able for sparking innovation, as well as for enabling transparent and scientifically sound assessments of technologies, newdata streams, and associated information outcomes. Herein we describe the establishment of a remote sensing supersite atthe Petawawa Research Forest (PRF) in southern Ontario, Canada, and summarize the open access datasets that have beencompiled and made available to the public. The PRF is approximately 10 000 ha in size and represents a complex assemblageof tree species and forest structures. More than 1900 data records, including multiple airborne laser scanning datasets andassociated derivatives (i.e., digital terrain model, canopy height model), airborne imagery, satellite remote sensing timeseries, and ground plot data, among others, have been made openly available for download from Canada’s National ForestInformation System. We identify issues and present opportunities associated with the establishment of a remote sensingsupersite at the PRF, as well as share some of the lessons learned to foster the establishment and open data sharing for othernational and international remote sensing supersites. The PRF supersite can be accessed from the following link: https://opendata.nfis.org/mapserver/PRF.html .


Author(s):  
Oyunkhand Byamba ◽  
◽  
Elena L. Kasyanova ◽  

The development of science always depends on technological progress. Cartography is rapidly changing and developing with the introduction of new computer technologies, such as GIS and remote sensing of the Earth. Recently, there have been qualitatively new types of cartographic products, in particular 3D terrain models, which in cartography are becoming a universal, optimal and operational method for displaying terrain. The article discusses a method for creating a three-dimensional digital terrain model in the form of an irregular triangulation network based on SRTM data and GIS technology on the example of the Khenti aimag of Eastern Mongolia.


2018 ◽  
Vol 18 (2) ◽  
pp. 583-597 ◽  
Author(s):  
Ákos Török ◽  
Árpád Barsi ◽  
Gyula Bögöly ◽  
Tamás Lovas ◽  
Árpád Somogyi ◽  
...  

Abstract. Steep, hardly accessible cliffs of rhyolite tuff in NE Hungary are prone to rockfalls, endangering visitors of a castle. Remote sensing techniques were employed to obtain data on terrain morphology and to provide slope geometry for assessing the stability of these rock walls. A RPAS (Remotely Piloted Aircraft System) was used to collect images which were processed by Pix4D mapper (structure from motion technology) to generate a point cloud and mesh. The georeferencing was made by Global Navigation Satellite System (GNSS) with the use of seven ground control points. The obtained digital surface model (DSM) was processed (vegetation removal) and the derived digital terrain model (DTM) allowed cross sections to be drawn and a joint system to be detected. Joint and discontinuity system was also verified by field measurements. On-site tests as well as laboratory tests provided additional engineering geological data for slope modelling. Stability of cliffs was assessed by 2-D FEM (finite element method). Global analyses of cross sections show that weak intercalating tuff layers may serve as potential slip surfaces. However, at present the greatest hazard is related to planar failure along ENE–WSW joints and to wedge failure. The paper demonstrates that RPAS is a rapid and useful tool for generating a reliable terrain model of hardly accessible cliff faces. It also emphasizes the efficiency of RPAS in rockfall hazard assessment in comparison with other remote sensing techniques such as terrestrial laser scanning (TLS).


2015 ◽  
Vol 9 (2) ◽  
pp. 181-192
Author(s):  
Ioan Bojoagă

Abstract The paper analyses the main geomorphologic processes in the Stemnic (Buda) river basin, conditioned by the joint action of several factors, among which are the lithological peculiarities and the nature of superficial deposits, morphometric characteristics, climate, vegetation type and structure, properties of the soil cover etc. The Stemnic river basin with an area of 15662.52 ha is characterized by its elongated shape (the maximum length is of 30.5 km, maximum width of 8.5 km), its relative lithological homogeneity, but also by a variety of superficial deposits (eluvium, diluvium, colluvium and proluvium, alluvium) and by a relief energy of significant values between 136 m and 10 m (mean value of 73 m). Under these conditions, study area is characterized by a high degree of susceptibility to the occurrence of geomorphologic risk processes. For the morphometric and morphological analysis, we applied the method of the digital terrain model (DTM) with vectorisation of the contour lines on topographic maps with a scale of 1:5,000. In this paper we used indicators that highlight the particular frequency of landslides, especially in the upper and middle sectors, but the rather reduced frequency of deep erosion. Due to the satisfactory coverage of the ground with vegetation, the erosion reaction is differentiated, as it depends on the use of the land and the concentration of liquid flow on the slopes. Consequently, landslides of different ages, types and forms hold large surfaces in the basin (approx. 8%), while surface erosion affects most areas of the slopes, but with different intensities depending on their use and on agricultural technologies.


Author(s):  
M. Piragnolo ◽  
S. Grigolato ◽  
F. Pirotti

<p><strong>Abstract.</strong> The goal of this work is to assess a method for supporting decisions regarding identification of most suitable areas for two types of harvesting approaches in forestry: skyline vs. forwarder. The innovative aspect consists in simulating the choices done during the planning in forestry operations. To do so, remote sensing data from an aerial laser scanner were used to create a digital terrain model (DTM) of ground surface under vegetation cover. Features extracted from the DTM are used as input for several machine learning predictors. Features are slope, distance from nearest roadside, relative height from nearest roadside and roughness index. Training and validation is done using areas defined by experts in the study area. Results show a K value of almost 0.92 for the classifier with best results, random forest. Sensibility of each feature is assessed, showing that both distance and height difference from nearest road-side are more significant than overall DTM value.</p>


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