Navegando por Assunto "Soil erosion"

Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Aplicação da RUSLE a uma pequena bacia hidrográfica da Amazônia
(Universidade Federal do Pará, 2013-09-26) SANTOS, Diego Benvindo Oliveira; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The Amazon is experiencing severe changes due to anthropogenic activities, among which the transformation of forested land into areas for agricultural use stand out, intensifying erosion processes. Erosion, especially the drag of particles by runoff, causes a reduction of soil fertility impairing agricultural productivity and impacting the quality and quantity of surface water resources, a fact compounded by strong rainfall and naturally poor soils in the region. In this context, knowledge of erosion processes, such as through the use of mathematical models for predicting soil loss helps in determining management practices for sustainable use of natural resources. This study aimed to evaluate the applicability of the empirical model RUSLE (Revised Universal Soil Loss Equation) in the region, which considers the interaction between the rain energy, soil and topography characteristics, as well as the uses and management practiced. This research applied the RUSLE in the upper basin of the Igarapé da Prata stream, with an approximate area of 37 km², located in the municipality of Capitão Poço, Pará, Brazil, approximately 160 km from the capital Belém, in Pará Northeast region. This research also consisted in the construction of a geo-referenced database made from public sources; such data passed through adaptations for insertion into the environment of the ArcGIS to quantify the parameters of RUSLE, which when combined allowed the generation of a map of soil loss for the study area. The small upper basin of Igarapé da Prata presented soil loss values ranging between 0.004 and 72.48 t/ha year, with an average value of 5.12 and a standard deviation of 6.97, where approximately 12% of its total area presents environmental risks due to erosive processes.
Acesso aberto (Open Access)
Erosões urbanas para percepção de risco: o caso das voçorocas na cidade de Açailândia-MA
(Universidade Federal do Pará, 2019-02-28) MIRANDA, Antonio Carlos da Silva; LIMA, Aline Maria Meiguins de; http://lattes.cnpq.br/6572852379381594
The forms of land use and occupation without proper planning tend to generate several problems in the process of expansion of the cities, among them, mention is made of the emergence and acceleration of erosive processes, especially in places with natural vulnerability. This study aimed to characterize the urban erosions for the perception of the risks in the gullies in Açailândia-MA. The methodology used qualitative and quantitative analyzes to understand the origin of the urban erosion process (natural and / or anthropic); the evolution of these processes, by altering the natural landscape; the erosive effects resulting from natural phenomena, controlling factors and anthropic actions; the characterization of erosive features in the gully areas; and its classification as a disaster according to the Brazilian Code of Disasters - COBRADE. For the development of the methodology, two gullies were chosen, located in areas with distinct characteristics, one being located in the Barra Azul neighborhood, a transition zone from rural to urban (peri-urban) and the other in an urbanized area in the Açailândia-MA Center. According to the results found in the research it was possible to conclude that this voçoroca disaster is classified by the Brazilian Classification and Codification of Disaster - COBRADE in 1.1.4.3.3. When analyzing the origin, shape and size of the two gullies, historical data were considered for 12 years, relating the advance to each end of the rainy season. The origin of the craters is related to the interactions of the anthropic and natural factors. On the other hand, the shapes of the craters are different: the barrel of the Barra Azul neighborhood is branched and the one of the neighborhood of Centro has irregular shape, and the two gullies present their sizes classified as very large. The eroded volumes are above 40,000 m³. As a final product, a model of an Emergency or Contingency Plan for Geological Disaster Occurrences - PLANECON was prepared for the city of Açailândia (MA). The development of this allows during the crisis to develop the operationalization, the procedures and actions that should be taken, adapting them to objective planning, the hierarchy of response actions in the planning of decisions, the actual situation of the disaster during the occurrence, the use of Erosive Disaster Risk Management actions in the use of non-structural and structural measures by the responsible bodies.
Acesso aberto (Open Access)
Modelo WEPP para estimativa da produção de sedimentos em uma pequena bacia hidrográfica da Amazônia
(Universidade Federal do Pará, 2017-12-06) SAMPAIO, Liliane da Cruz; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Erosive processes produce several economic and environmental damages. The development of mathematical models has made it possible to quantify these processes, allowing estimating the magnitude of the problem, in order to minimize it. In this sense, this work uses the WEPP (Water Erosion Prediction Project) model to simulate the sediment yield in an Amazon small catchment, igarapé da Prata catchment, located in the Municipality of Capitão Poço-PA. The calibrated main parameters of the WEPP model were: initial soil saturation (Si), erosion by runoff (Ki), erosion by channel or groove flow (Kr) and saturated hydraulic conductivity (Ke). After the calibration, it was verified that most of the sediment yield is in the plans. And as is to be expected, this production is higher in areas with predominance of agriculture and livestock. The results of the estimated sediment yield calculated by the model were compared to the observed data for the year 2012. The model presented a value of 131.99 t / km², close to the observed value, which was 121.64 t / km2. This result leads to the conclusion that the values calculated by the model are consistent with the reality of the sediment yield of the small catchment in question.
Acesso aberto (Open Access)
Modelos empíricos para estimativa de produção de sedimentos
(Universidade Federal do Pará, 2015-03-20) SILVA, Danielle Sebastiana dos Santos; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
The erosive processes that occur in a watershed have been objects of concerns associated with the planning and management of land use and water resources. In this case, the empirical models of hydrosedimentological simulation are important tools, and with low cost, in the assessment of soil erosion due to the use and management of land. Thus, the study aimed to analyze the sediments yield via three empirical models applied to a small catchment of the Amazon, the catchment of Igarapé da Prata located in the municipality of Capitão Poço-PA. The analyzed and used models were the USLE (Universal Soil Loss Equation); the Poesen model; and the Langbein-Schumm model. The results showed that the USLE model had an average sediment yield equal to 146.20 (t / km²); the Langbein-Schumm model an average production equal to 114.25 (t / km²); and the Poesen model an average yield equal to 7.57 (t / km²). The results obtained by the two first-mentioned models are of the same order of magnitude, indicating that the Langbein-Schumm model, for the case analyzed, is comparable to the classical model USLE. These results were compared with observed data of suspended sediments and the Langbein-Schumm model was the one closest to the observations.