Modelos de previsão de enchentes em tempo real para o município de Nova Era MG

• Autor(a) principal: Silva, João Batista Lopes da
• Data de Publicação: 2006
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/3607
• topic: Modelagem hidrológica; Chuva; Vazão; Enchentes; Hydrologic models; Rain; Runoff; Floods; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::ENGENHARIA DE AGUA E SOLO

The Rio Doce basin is frequently affected by floods that causes economical, material and human losses. Because this problem, the Companhia de Pesquisa de Recursos Minerais (CPRM) in Belo Horizonte established the Sistema de Alerta Contra Enchentes da Bacia do Rio Doce (Alert System Against Rio Doce Flooding) in order to minimizing the impacts from floods. Among the cities benefited by this system is Nova Era, where the current methodology for forecasting the floods has no satisfactory antecedence to minimize the impacts from floods. In this context, the study was carried out to increase the antecedence in forecasting the floods in Nova Era. So, two hydrologic models were constructed in IPHS1 system, as follows. The first model was based on the rainfall-runoff transformation only, by applying the model IPH II. In the second one, the basin was divided into three watersheds and the rainfall-runoff transformation model (IPH II) was used, as well as the hydraulic model so-called Muskingum-Cunge for propagation of the flood waves in the open channel. In the first model, the series from either five pluviographic stations and one fluviographic station were used as entrance data, from which two flood events were selected for calibration. In the second model, besides the entrance data of the first model, two fluviographic stations were also used for calibration of the hydraulic model. The Thiessen polygons methodology was used in both methods in order to considering the space variability of precipitation, whereas the physical characteristics of the basin were extracted from the digital elevation model (DEM) obtained at the web site United States Geological Survey (USGS) and through basin images obtained by the satellite Landsat 5. Both models were gauged by trial and error. After this calibration, the results were statistically analyzed, by using the efficiency coefficient (EC), standard error (SE) and relative mean absolute error (RMAE), as being these ones compared to those obtained by the current methodology of the alert system. The antecedence of the models for forecasting the floods was determined from the progressive simulation of precipitation. The results of the event simulations with both models were similar to the current methodology of the alert system, however the second model showed a slightly better performance. However, the antecedence in forecasting the floods were above 10 hours for both models, that is more than three times the antecedence of the current system methodology (three hours). Thus, the results showed that both constructed models have potential to substitute the current methodology of the alert system in Nova Era county.