Ana Luiza Coelho Netto

Mechanisms of the Recent Catastrophic Landslides in the Mountainous Range of Rio de Janeiro, Brazil

Catastrophic mass movements occurred in January 2011 in a mountainous area of Rio de Janeiro leaving more than 1,500 dead people and large destruction. Heavy thunderstorms occurred on January 11th (~100 mm/day) and 12th (~150 mm/day) and triggered thousands landslides on steep slopes with trees and block rich debris materials converged into the river channels, hence avalanches down valley. Through fieldwork, mainly translational slides and debris flow types were observed, as well as some rotational slides and rock fall. Initial studies show that translational slides occurred in saprolite soil with 1–3 m depth and on more than 30° slopes. Debris flows initiated in small catchments with very steep slopes and run out along the valley bottom where colluvial soils are present. This study focuses geological analysis and correlation between soil properties and geotechnical behavior in order to explain this catastrophic slope movement mechanisms and processes.

January 2011: The Extreme Landslide Disaster in Brazil

This work describes the extreme event of landslides occurred in January 2011 in the Rio de Janeiro mountainous region and discusses its relationship to the spatial and temporal variation of critical and prior rainfall. Interviews in the field let us establish the landslide initiation timing around the automatic pluviometer stations which supply detailed data on the rainfall intensity. The study concludes that the accumulated rainfall during the last months associated with high rainfall levels over 24h, along with local conditions like the direct impact of lightning and tremors resulting from landslides, formed the relevant conditions for thousands of landslides.

Community, University and Government Interactions for Disaster Reduction in the Mountainous Region of Rio de Janeiro, Southeast of Brazil

In January 2011, an extreme rainfall event took place in the Mountainous Region of the state of Rio de Janeiro causing a catastrophic landslide that resulted in more than 1500 deaths. This event marked a new challenge for disaster reduction in Brazil and introduced several measures for risk management. The dialogue gap between government and the local population could possibly explain the failure of the current risk management model, pointing at the urgent need to integrate actions from the government, the civil society and universities. Nonetheless, a top-down government model still prevails, and communities at risk remain distant from decision makers. This lack of interaction led to local self-organization, like the Corrego Dantas Neighborhood Residents Association (CDNRA), greatly affected by the 2011 disaster. In 2014, CDNRA and the GEOHECO research team started to develop new tools for a better dialogue with the local government. These groups recognized two fundamental needs: (1) to integrate both scientific and popular knowledge in developing a new methodology for risk evaluation and management and, (2) to integrate effective risk management actions with the actions of other disaster-related institutions, including universities, communities, NGOs and the government. Invited institutions attended the 1st Seminar on Landslide Risk Management at the Corrego Dantas Neighborhood. As a result, a multi-institutional network (called Corrego Dantas RIsk MAnagement Network) was founded to provide new tools for the identification of potential landslide disaster areas, as well as to introduce a new design for planning, according to the interests of the community. In this chapter, we describe former procedures and local studies, which have guided the development of CD-RIMAN and the establishment of its main goals.

Análise da variabilidade térmica em zonas de bordas florestais com interface urbana no maciço da Tijuca Rio de Janeiro-RJ

The goal of this research was to identify and assess the termic gradientgenerated by the spread of the brim effect on the city-forest interface in twoselected areas with different degrees of urban density ( Catrambi area – high174 Ciencia e Natura, UFSM, 29(2): 173 - 186, 2007density, and Soberbo area – low density), on the edge of Floresta da Tijuca- Rio de Janeiro (RJ). The working hypothesis was that the increase inurban pressure on the city-forest interface zone edge about a change in thedynamics of the edge effect, accelerating its propagation, especially in regardto termic changes, with a direct impact on the system’s functionality. Fielddata gathered from three transects measuring 100 meters in each area (with5 100 m2 patches in each transect). The results of this research point outthat the difference in urban density between the two researched areas bearsa significant influence on the propagation of the edge effect (with differenceuntil 3,5°C in the transect border-center) , but not directly, since it does sothrough an increase in the density of tracks and pathways internal to theedge area.

Effects of Urban Occupation in Rivers Morphology: The Case Study of Upper Pedras River, in Jacarepaguá District, at the Tijuca Massif

This paper discusses the effects of urban occupation on rivers morphology and how they contribute to increase landslide risks from extreme precipitation events. It presents results of the research “Applying Innovative Urban Infrastructure Technologies in River Revitalization Processes”, which aims to expand the understanding of urban river processes and non conventional urban infrastructure technologies, in order to propose on-site innovative sewage treatment and sediment control solutions for Rio de Janeiro urban favelas with local water supply. The methodology involves the formation of a collaborative network and the characterization of the urban settlement through field surveys and thematic mapping using ArcGIS 10.1. Water quality availability and improvement in urban watersheds demand a transdisciplinary approach, the articulation of complementary methods of analysis and collective planning, grounded on community involvement.

Conflicts After the Tragedy in the Mountains of the State of Rio de Janeiro in 2011: The Relationship Between Residents of Córrego d’Antas and the Zoning of Evacuation Areas for an Adaptation to Climate Change

The Zoning of Evacuation Areas, carried out by Rio de Janeiro’s State Environment Institute (INEA) after the 2011 tragedy in the state mountains, has been causing conflict. This paper evaluates such zoning and whether the constructions that mandatorily had to be unoccupied were, in fact, unoccupied. The constructions that had to be unoccupied were listed based on images from 2011. Using images from 2014, the unoccupied constructions were quantified and located. Field work was carried out to check whether the owners of the remaining constructions had remained there. The zoning did not consider the dwellers’ knowledge and demands. The methods used by INEA were not made public, making it impossible to evaluate whether it was adequate to the process of removing the dwellers. Therefore, there were many conflicts. Even today, part of the constructions in high-risk areas have not yet been unoccupied. The continuation of this project will evaluate whether these constructions are really in risk areas in order to instrumentalize the community in discussing it.

“Córrego d’Antas—The Power of Union”: A Film to Strength the Culture of Risk Management for Climate Change Adaptation at Córrego d’Antas, Nova Friburgo, RJ, Brazil

Climate change has increased the frequency of extreme precipitation events, such as the one in January 2011 in the Rio de Janeiro state mountains, causing thousands of landslides in the Corrego d’Antas drainage basin, in the municipality of Nova Friburgo. The development of the Corrego d’Antas Risk Management Network (RIMAN-CD)—which includes communities, education and research institutions, as well as the government—was a response to this process, aiming at a greater level of adaptation of the local population to climate change. A film on disasters was produced within the network. This paper analyzes the production of the film as a form of support to the development of a culture of disaster risk management and adaptation to climate change. The film is being produced collectively, based on an articulation of institutions, but it is a product made by the young people ahead of its technical development. It was observed that these youths are absorbing the issues of disaster risk management and climate change and are disseminating them to their families.

IMPACTO AMBIENTAL AO LONGO DE TRILHAS EM ÁREAS DE FLORESTA TROPICAL DE ENCOSTA: Maciço da Tijuca Rio de Janeiro - RJ

The goal of this research was to identify and assess the environmental gradient generated by the spread of the edge effect on the forest trail in two selected areas with different degrees of urban density ( Catrambi area – high density, and Soberbo area – low density), on the edge of Floresta da Tijuca - Rio de Janeiro (RJ). The working hypothesis was that the increase in urban pressure on the city-forest interface zone edge about a change in the dynamics of the edge effect, accelerating its propagation, especially in regard to structural and microclimatic changes, with a direct impact on the system’s functionality. Field data were restricted to four main variables: analysis of vegetation structure on trail border, Soil Apparent Density on trail, microclimatic variability between the trails and, finally, litter analysis on the patches of the border forest.