Navegando por Autor "Uagoda, Rogerio"

Agora exibindo 1 - 2 de 2

Texto publicado em jornal
ANALYSIS OF THE EROSION POTENTIAL AND SEDIMENT YIELD USING THE INTERO MODEL IN AN EXPERIMENTAL WATERSHED DOMINATED BY KARST IN BRAZIL
(2021) Silva Tavares, Andre; Uagoda, Rogerio; Spalevic, Velibor; Mincanto, Ronaldo
153 Tavares, A.S.; Uagoda, R.E.S.; Spalevic, V.; Mincato, R.L. (2021): Analysis of the erosion potential and sediment yield using the IntErO model in an experimental watershed dominated by karst in Brazil. Agriculture and Forestry, 67 (2): 153-162. SUMMARY Soil losses from water erosion jeopardize agricultural sustainability and food security for current and future generations. The research aimed to evaluate the application of the Erosion Potential Method by the Intensity of Erosion and Outflow-IntErO program in a karst watershed in a region with typical savanna climate in the northeast of the State of Goiás, Brazil. Input data were adapted according to the corresponding characteristics of tropical regions. The results indicated that the Extreme watershed has a value of 0.62 in the index (0 to 1) which defined the strength of the intensity of erosion. The river basin belongs to the category 3 of destruction with moderate erosion intensity, which indicates processes of surface erosion in the largest area of the hydrographic basin, and annual soil loss of 480.60 m³ km² yr-1. According to the IntErO model calculations 16% of the eroded material reaches the outflow of the hydrographic basin, and 84% of these sediments are deposited within the Basin, inside the surface and underground caves and galleries of the karst. Calculations by the IntErO model with the Erosion Potential Method in its algorithm proved to be valuable tool in evaluating the production of sediments in tropical soils, especially in evaluating different scenarios after establishing the inputs database for Brazil and will serve as a good starting point for future evaluations.
Artigo
Detection of Cover Collapse Doline and Other Epikarst Features by Multiple Geophysical Techniques, Case Study of Tarimba Cave, Brazil
(2020) Hussain, Yawar; Uagoda, Rogerio; Borges, Welitom; Prado, Renato; Hamza, Omar; Cárdenas-Soto, Martín; Havenith, Hans-Balder; Dou, Jie
Reliable characterization of the karst system is essential for risk assessment where many associated hazards (e.g. cover-collapse dolines and groundwater pollution) can affect the natural and built environments threatening public safety. The use of multiple geophysical approaches may offer an improved way to investigate such cover-collapse sinkhole and aid the geohazard risk assessment. In this paper, covered karst, which has two types of shallow caves (vadose and fluvial) located in Tarimba (Goias, Brazil), was investigated using various geophysical methods to evaluate their efficiency in the delineation of the geometry of sediments filled sinkhole. Three methods were used including Electrical Resistivity Tomography (ERT), Seismic Refraction Survey (SRS), Seismic Refraction Tomography (SRT) and Very Low Frequency Electromagnetic (VLF-EM) method. The study developed several resultant (2D) sections of the measured physical properties, including P-wave velocity and electrical resistivity, as well as the induced current (because of local bodies). For the analysis and processing of the data obtained from these methods, the following approaches were adopted: ERT inversion using a least-square scheme, Karous-Hjelt filter for VLF-EM data, and time-distance curves and Vp cross-sections for the SRS. The refraction data analysis showed three-layered stratigraphy topsoil, claystone, and carbonate bedrock, respectively. The findings obtained from ERT (three-layered stratigraphy and sediment-filled doline) as well as VLF-EM (fractured or filled caves as a positive anomaly) were found to be consistent with the actual field conditions. However, the SRS and SRT methods did not reach the depth of the cave because of shorter profile lengths. The study provides a reasonable basis for the development of an integrated geophysical approach for site characterization of the karst system, particularly the perched tank and collapse doline.