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V.D. de Campos & S M. Carvalho 2010. Risk areas to flooding in the Hidrographical Basin of Arroio dos Pereiras
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Risk areas to flooding in the Hidrographical Basin of Arroio dos
Pereiras in Irati, PR, Brazil
Vivian Dallagnol de Campos * & Sílvia Méri Carvalho
Graduate Program in Geography - Land Management of UEPG, Brazil
Abstract
This study aimed to identify and map areas the risk areas to flooding in the hidrographical basin
of Arroio dos Pereiras, located in Irati - PR (Brazil), identifying the most susceptible areas to
accidents of hydrological origin, emphasizing the floods and co-relating the natural
susceptibility derived from the natural morphodynamics of the system, where the hidrographical
basin (with its inputs and outputs of energy, allied to the relief features) and the susceptibility
created by human actions, mainly by the processes of urbanization, which modify the natural
dynamics of the system, increasing susceptibility to the occurrence of the phenomenon and
creating risks to society.
Word Keys: Mapping - risk areas - flooding - Irati - PR - Brazil.
1. Introduction
According to Tucci (2003), urbanization is one of the main constraints for the increase
of the frequency and magnitude of floods, that due to changes made in the process of human
occupation, such as soil sealing and deployment of infrastructure that alter the natural dynamics
system. Such changes reflect in a higher runoff that leads to an increase of speed and flow of the
river watercourses, potentiating the flood risk and other natural disasters linked to the dynamics
of water and land such as erosion and landslides.
Before such a reality, it is necessary to conduct studies to identify such areas at flood
risk, as well as the frequency and magnitude of the event.
1.1 Location and characterization of the study area.
The hidrographical basin of Arroio dos Pereiras is located in Irati - PR, between the
coordinates 533976/7179941 and 539906/7185815 UTM (Figure 1), comprising a total area of
354 ha. It is an hidrographical basin of 3rd order, with a total of 27 river watercourses. Its main
sources are located in rural areas and its riverbed runs to central urban area. Thus, the
occupation seated along the hidrographical basin, eventually occupy inappropriate areas as the
valleys bottoms, marginal areas and flood plains, thereby increasing the risk to flooding.
The study area is included in the geological compartment of the Paraná Hidrographical
Basin, with the main geological formation the Irati formation (pyrobituminous shale), with the
occurrence of diabase dikes. It has an amount of unevenness to its outfall of about 110 meters,
which adds up to a relief that ranges from rolling to rugged, results in areas where river flow
may have a lot of energy. However, near its outfall it was modeled a floodplain quite
expressive, where the urban area is settled. (Kazubek, 2006).
1.2 Natural and Anthropic Constraints of the flood events.
* Corresponding author. Email: vivica_pr@ibest.com.br
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.