Mapas de inundação em área urbana na cidade de Araguaína/TO: estudo de caso da interferência da CGH Corujão

Abstract

The habitation occupation in the area of influence of CGH (hydroelectric power station) - Corujão is quite significant, however, there is an imminent risk of flooding in the area, a factor that motivated the development of the study, to understand the real risks incident on the area. Therefore, this work aimed to analyse the impacts of the CGH Corujão dam reservoir in the urban area of the city of Araguaína/TO. A data collection and characterization of the Neblina stream, which flows into the CGH reservoir, were carried out to understand how the occurrence of high levels of rain causes the stream to overflow and increase the risks of flooding in an urban area, being calculated the maximum rainfall. With these data, a simulation was performed using the HEC-RAS program, which led to the generation of flood maps. Regarding the impacts of the dam reservoir in the urban area of the city, it was possible to observe that it has little influence in the flood areas, according to the maps obtained from the aplicativo HEC-RAS. From the results it was possible to verify that most of the maps presented risks to human life and structural damage. These data show that it is an area of vulnerability to floods and, consequently, to life, health, infrastructure, economy and socioeconomic development. The estimated contributions of the study involve the population and the government. The identification of areas of greater vulnerability in terms of failures and collapses of masonry structures, essential information for the development of a master plan in which these areas of greater risk are excluded from use for housing, commerce, services and other activities. With access to the full risk map, the city has the possibility to develop future housing programs so that the existing structures are deactivated and companies, residences, services and others are directed to other areas, with safety and guarantee of rights. Urban planning, in activities such as drainage studies, needs this information so that they can be developed in an assertive and effective way, benefiting the public administration, by avoiding damages that need to be corrected and require resources, in addition to improving the infrastructure of services and making the daily life of citizens safer. The civil defence, in possession of the data obtained, can develop support programs for the residents of the region, issue risk alerts more broadly in the face of the forecast of intense rains and floods, allowing individuals who are in these areas to seek more safe for these moments of risk. With this study, it is possible to define risk reduction approaches that guarantee more health for the population, reduce the demand for resources for health care after the floods, as well as reduce the occupancy of beds for the sick and injured due to the floods. In view of the above, it appears that the benefits are numerous, both for the population and for the public administration, with a reduction in expenses and costs to the public coffers, in addition to a greater guarantee of preservation of the life and patrimony of individuals who, in the present, live in areas of high vulnerability.