scholarly journals Analysis of the volume of silted sediments and the urbanization rate in urban river basins; a case study of the Mãe d’Água Reservoir

2020 ◽  
Vol 24 ◽  
pp. e26
Author(s):  
Felippe Fernandes ◽  
Cristiano Poleto
Keyword(s):  
Field Data ◽  
Satellite Images ◽  
River Basins ◽  
Google Earth ◽  
Aerial Photographs ◽  
Rio Grande Do Sul ◽  
Environmental Liabilities ◽  
Diffuse Sources ◽  
Urbanization Rate

The Mãe d`Água reservoir is the mouth of four streams, corresponding to an area of 352 ha and is located in the Vale Campus of the Federal University of Rio Grande do Sul. The study area is currently predominantly characterized by a residential occupation, with environmental liabilities coming from diffuse sources. The application of the methodology for computational modeling in the Mãe d'Água reservoir, inferring about the useful volume of the project in 1962, useful volume in 2014, and the silting volume was developed with the aid of the following software: AutoCAD 2018, AutoCAD Civil 3D 2018, and Google Earth which specialize in the field of geoprocessing and guidelines for the calculations that use as base the data regarding the survey and processing of field data. Two types of remote sensing products were used to evaluate the evolution of urbanization in the study area: aerial photographs and satellite images which were integrated in a geographic database. Through the results, it was possible to verify that the silting volume occupies approximately 44% of the useful volume of the reservoir, the urbanization rate has growth trends, and, 88.42% of the river basin was urbanized in 2014. Thus, it represents a spatial distribution and establishes correlations between sedimentation studies over the last five decades.

scholarly journals SISTEMATIZAÇÃO DE UMA EXPERIÊNCIA AGROECOLÓGICA NO CERRADO BRASILEIRO: SUBSÍDIOS PARA O PLANEJAMENTO DE UNIDADES PRODUTIVAS DE BASES ECOLÓGICAS

Nativa ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 573-581
Author(s):  
Isabel Corrêa Fontes Chagas de Oliveira ◽  
Renato Linhares De Assis ◽  
Adriana Maria de Aquino
Keyword(s):  
Satellite Images ◽  
Social Economic ◽  
Google Earth ◽  
Aerial Photographs ◽  
Construction Process ◽  
Brazilian Cerrado ◽  
Way Of Life ◽  
Complex Dynamic ◽  
Field Surveys ◽  
Midwest Region

Este estudo consiste na sistematização de uma experiência agroecológica a partir do ordenamento e síntese dos processos do seu uso e ocupação. A experiência iniciou em 1984, em unidade agroecológica pioneira, com características neorurais, na região Centro-oeste do Brasil. A pesquisa contou com entrevistas não estruturadas, levantamento de campo, pesquisa bibliográfica e documental (fotografias, revistas, jornais, imagens de satélite e fotografias aéreas). Utilizou-se a ferramenta Google Earth para avaliar o mosaico de agroecossistemas resultante da ação agroecológica no espaço e tempo. Os resultados apontaram uma dinâmica complexa do processo de construção de agroecossistemas e redes sociais, configurando-se num desenho agroecológico que ultrapassa as fronteiras físicas da propriedade. O processo de síntese e análise relatado, além de empoderar os protagonistas, traz a luz do conhecimento científico aprendizados de uma experiência empírica de um modo de vida integrado à natureza, com riqueza em variedade, diversidade e possibilidades nos processos biológicos, sociais, econômicos, éticos, morais e culturais, que pode inspirar e subsidiar outras iniciativas de base agroecológica. Palavras-chave: neoruralidade; gerenciamento agroecológico; redesenho da paisagem; agroecossistemas.   Systematization of an agroecological experience in the Brazilian Cerrado: subsidies for the planning of productive units of ecological bases   ABSTRACT: This study consists of the systematization of an agroecological experience from the ordering and synthesis of the processes of its use and occupation. The experience began in 1984, in a pioneering agroecological unit, with neorural characteristics, in the Midwest region of Brazil. The research included unstructured interviews, field surveys, bibliographic and documentary research (photographs, magazines, newspapers, satellite images, and aerial photographs). The Google Earth tool was used to evaluate the mosaic of agroecosystems resulting from agroecological action in space and time. The results pointed toward a complex dynamic of the construction process of agroecosystems and social networks, configuring itself in an agroecological design that goes beyond the physical boundaries of the property. The reported process of synthesis and analysis, in addition to empowering the protagonists, brings to light scientific knowledge learning from an empirical experience of a way of life integrated with nature, with a wealth of variety, diversity, and possibilities in biological, social, economic, ethical, moral and cultural processes, which can inspire and subsidize other agroecological initiatives. Keywords: neorurality; agroecological management; landscape redesign; agroecosystems.

scholarly journals Detection, assessment, and updating the maps of encroached forest areas: a case study from Bara district, Nepal

2017 ◽  
Vol 27 (1) ◽  
pp. 65-71 ◽  
Author(s):  
R. K. Rimal ◽  
R. Maharjan ◽  
K. Khanal ◽  
S. Koirala ◽  
B. Karki ◽  
...  
Keyword(s):  
Google Earth ◽  
Aerial Photographs ◽  
New Approach ◽  
Cadastral Maps ◽  
Cultivable Land ◽  
Desktop Tool ◽  
Forest Encroachment ◽  
Areas Of Interest ◽  
Robust Evidence

 Forest encroachment is an illegal expansion of cultivable land and settlements within the jurisdiction of forests. It has been the key threat to forest management for the last several years in Nepal. The Department of Forests (DoF) is the responsible authority for detection and assessment of forest encroachment throughout the nation and updating the forest maps accordingly. Detection and preparing the updated maps of encroached forest areas is necessary for sustainable management of forests. Traditionally, the extent of forest encroachment is assessed through estimation by the front-line forestry staff. The new approach combines the aerial photographs, the cadastral maps prepared by the Department of Survey and the Google Earth Imagery to spatially locate the encroachment. This method will work as a desktop tool for the forest manager such that appropriate strategic actions can be taken immediately. Additionally, it will bring a transparency on the forest governance to identify the location of areas of interest like point location for forest-based industries or proposed sites for development of infrastructures on the ground. The local communities may use the tool to identify the actual location of the forest boundaries, and exert social pressure to relinquish the encroached forests, if any. The result showed that 8,540 ha of the forest area in Bara district was found to be encroached during the period of last 50 years, between 1964 and 2014, of which 71% (6,038 ha) happened to be encroached in the first three decades, indicating the retarding trend of encroachment in the later years. The methodology used to assess the encroachment of forest in Bara district can be easily scaled up to other districts too, and will eventually help to assess the country’s overall forest encroachment. Since the boundary delineation will be done on the basis of the cadastral maps, the output will be used as a robust evidence to defend the forest-related cased in the court during the legal arbitrations.Banko Janakari, Vol. 27, No. 1, Page: 65-71

Mapping and monitoring of landslide-dammed lakes using Sentinel-2 time series - a case study after the 2016 Kaikōura Earthquake in New Zealand

2020 ◽  
Author(s):  
Lorena Abad ◽  
Daniel Hölbling ◽  
Raphael Spiekermann ◽  
Zahra Dabiri ◽  
Günther Prasicek ◽  
...  
Keyword(s):  
Time Series ◽  
New Zealand ◽  
Google Earth ◽  
Aerial Photographs ◽  
Optical Data ◽  
Landsat 8 ◽  
Multiple Time ◽  
Potential Hazard ◽  
Sentinel 2

<p>On November 14, 2016, a 7.8 magnitude earthquake struck the Kaikōura region on the South Island of New Zealand. The event triggered numerous landslides, which dammed rivers in the area and led to the formation of hundreds of dammed lakes. Landslide-dammed lakes constitute a natural risk, given their propensity to breach, which can lead to flooding of downstream settlements and infrastructure. Hence, detecting and monitoring dammed lakes is a key step for risk management strategies. Aerial photographs and helicopter reconnaissance are frequently used for damage assessments following natural hazard events. However, repeated acquisitions of aerial photographs and on-site examinations are time-consuming and expensive. Moreover, such assessments commonly only take place immediately after an event, and long-term monitoring is rarely performed at larger scales.</p><p>Satellite imagery can support mapping and monitoring tasks by providing an overview of the affected area in multiple time steps following the main triggering event without deploying major resources. In this study, we present an automated approach to detect landslide-dammed lakes using Sentinel-2 optical data through the Google Earth Engine (GEE). Our approach consists of a water detection algorithm adapted from Donchyts et al., 2016 [1], where a dynamic threshold is applied to the Normalized Difference Water Index (NDWI). The water bodies are detected on pre- and post-event monthly mosaics, where the cloud coverage of the composed images is below 30 %, resulting in one pre-event (December 2015) and 14 post-event monthly mosaics. Subsequently, a differencing change detection method is performed between pre- and post-event mosaics. This allows for continuous monitoring of the lake status, and for the detection of new lakes forming in the area at different points in time.</p><p>A random sample of lakes delineated from Google Earth high-resolution imagery, acquired right after the Kaikōura earthquake, was used for validation. The pixels categorized as ‘dammed lakes’ were intersected with the validation data set, resulting in a detection rate of 70 % of the delineated lakes. Ten key dams, identified by local authorities as a potential hazard, were further examined and monitored to identify lake area changes in multiple time steps, from December 2016 to March 2019. Taking advantage of the GEE cloud computing capabilities, the proposed automated approach allows fast time series analysis of large areas. It can be applied to other regions where landslide-dammed lakes need to be monitored over long time scales (months – years). Furthermore, the approach could be combined with outburst flood modeling and simulation to support initial rapid risk assessment.</p><p> [1]   Donchyts, G., Schellekens, J., Winsemius, H., Eisemann, E., & van de Giesen, N. (2016). A 30 m resolution surface water mask including estimation of positional and thematic differences using Landsat 8, SRTM and OpenStreetMap: A case study in the Murray-Darling basin, Australia. Remote Sensing, 8(5).</p><div> <div> </div> </div>

scholarly journals A comparison of mono-seasonal and multiseasonal Landsat images for vegetation cover classification in the Mediterranean region: a case study in Latakia, Syria

2021 ◽  
Vol 310 ◽  
pp. 05001
Author(s):  
Vasiliy Malinnikov ◽  
Assem Khatib
Keyword(s):  
Vegetation Cover ◽  
Mediterranean Region ◽  
Satellite Images ◽  
Landsat Imagery ◽  
Google Earth ◽  
Landsat Images ◽  
Significance Level ◽  
The Mediterranean ◽  
Spectral Channels

Providing constantly updated information on vegetation serves as a basis for studies of natural resources and ecological issues. This paper discusses the question related to an appropriate season(s) for classification vegetation cover in the Mediterranean region and detecting its changes using Landsat imagery. Autumn, spring, and multi-seasonal satellite images, captured in 2017, were used to classify vegetation cover in a part of the Lattakia province, Syria. The satellite images were classified using the random forest algorithm, and high spatial resolution satellite images Google Earth Pro were used as reference data. The results indicate better effectiveness of the autumn images over spring ones for vegetation cover classification with 73.6% and 62.4% overall accuracy, respectively. In addition, a comparison of autumn and multi-seasonal Landsat images indicates no significant statistical difference in the accuracy of vegetation cover classification at the significance level of 0.05, which illustrates the effectiveness of using autumn images to classify the vegetation cover of the Mediterranean region. Furthermore, the obtained results show the necessity of using additional features as the spectral channels may not be sufficient for mapping vegetation cover in the Mediterranean region with high accuracy.

Classification of vegetation in Cucphuong National Park with the aim of large-scale mapping, Vietnam

1996 ◽  
pp. 64-67 ◽  
Author(s):  
Nguen Nghia Thin ◽  
Nguen Ba Thu ◽  
Tran Van Thuy
Keyword(s):  
National Park ◽  
Large Scale ◽  
Satellite Images ◽  
Field Work ◽  
Aerial Photographs ◽  
Vegetation Map ◽  
Dense Forest ◽  
Broad Leaved Forest ◽  
Leaved Forest

The tropical seasonal rainy evergreen broad-leaved forest vegetation of the Cucphoung National Park has been classified and the distribution of plant communities has been shown on the map using the relations of vegetation to geology, geomorphology and pedology. The method of vegetation mapping includes: 1) the identifying of vegetation types in the remote-sensed materials (aerial photographs and satellite images); 2) field work to compile the interpretation keys and to characterize all the communities of a study area; 3) compilation of the final vegetation map using the combined information. In the classification presented a number of different level vegetation units have been identified: formation classes (3), formation sub-classes (3), formation groups (3), formations (4), subformations (10) and communities (19). Communities have been taken as mapping units. So in the vegetation map of the National Park 19 vegetation categories has been shown altogether, among them 13 are natural primary communities, and 6 are the secondary, anthropogenic ones. The secondary succession goes through 3 main stages: grassland herbaceous xerophytic vegetation, xerophytic scrub, dense forest.

Sediment transport under dry weather conditions in a small sewer system

1998 ◽  
Vol 37 (1) ◽  
pp. 155-162
Author(s):  
Flemming Schlütter ◽  
Kjeld Schaarup-Jensen
Keyword(s):  
Sediment Transport ◽  
Field Data ◽  
Field Measurements ◽  
Weather Conditions ◽  
Sewer System ◽  
Transport Models ◽  
Sewer Systems ◽  
Combined Sewer ◽  
Initial Results

Increased knowledge of the processes which govern the transport of solids in sewers is necessary in order to develop more reliable and applicable sediment transport models for sewer systems. Proper validation of these are essential. For that purpose thorough field measurements are imperative. This paper renders initial results obtained in an ongoing case study of a Danish combined sewer system in Frejlev, a small town southwest of Aalborg, Denmark. Field data are presented concerning estimation of the sediment transport during dry weather. Finally, considerations on how to approach numerical modelling is made based on numerical simulations using MOUSE TRAP (DHI 1993).

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