Study assesses the impact of uncontrolled growth in the Amazon delta

Investigating how migration flows occur in the region and their socioeconomic and environmental impact is the goal of a project carried out under the scope of the FAPESP and Belmont Forum agreement

By Karina Toledo, in Washington, DC

Agência FAPESP – Nearly 90% of the cities situated along the Amazon River estuary have fewer than 20,000 inhabitants, very unstable infrastructures, few services and limited opportunities for employment. Even so, over the last decade, they have attracted large numbers of migrants from nearby riverside communities, resulting in an intense and uncontrolled process of occupation.

Investigating how migration flows occur in the region and their socioeconomic and environmental impact is the goal of a FAPESP-funded project that is bringing together researchers from Brazil and the United States under the scope of an agreement with the Belmont Forum, a group of agencies and organizations that fund global environmental change research.

Some of the initial findings were presented October 28, 2014, in Washington, DC during the FAPESP-U.S. Collaborative Research on the Amazon symposium, presented by coordinators Sandra Maria Fonseca da Costa from Vale do Paraíba University (UNIVAP) and Eduardo Brondizio from Indiana University.

“We noted that within the Amazon urban network, these cities are vitally important. They function as safeguards for the riverside populations because, despite their shortcomings, they have elementary and high schools, health clinics and are supported by government social programs,” Costa said.

According to the researcher, the migration flow is mainly regional, involving inhabitants within a 100 km radius. They include people from communities that are even smaller and more in need of basic services.

“When they get to these cities, they build houses all over and in appalling conditions. They occupy lowland areas, discharging their raw sewage into rivers and streams where the population gets its water for drinking, cooking and washing clothes. These small cities are growing at an incredible speed and all the problems associated with the phenomenon get worse every day, in the absence of any specific public policies,” Costa said.

Although the researcher recognizes that it is impossible for the government to control a city’s growth, she believes that the process could at least be monitored and guided. “The government needs to intervene in order to improve the population’s quality of life and we see that this has not happened,” Costa said.

The UNIVAP professor has been studying the subject since 2007 when she conducted her postdoctoral research at Indiana University, under the advisorship of Brondizio. In an initial FAPESP-funded regular research project, the focus of study was on the city of Ponta de Pedras, located in Ilha de Marajó, in the state of Pará.

That city’s significance, despite its small size, is related to the fact that it is a connecting point for economic flows associated mainly with the production of açaí – the municipality is the second largest producer of the fruit in Brazil. It therefore serves as a node in a network of social relationships established between the urban environment and the riverside communities.

“In the second project we are beginning under the scope of the Belmont Forum, we plan to expand the focus of our analysis to 50 municipalities in a large area known as the Amazon delta, and delve further into the reality of these cities,” Costa explained.

The studies will continue to be carried out in Ponta de Pedras, she added, in order to establish a data sequence that enables seeing the city’s evolution over time. Other important cities, such as Mazagão (AP) and Barcarena (PA), that have attracted migrants due to the presence of a large aluminum manufacturing industry, will also be included.

Data collection is being carried out through the use of questionnaires in census sectors, following a methodology of stratified random sampling. The researchers will augment this with geoprocessing and remote sensing data, in other words, satellite imaging that explains the spatial dynamics.

“The idea is to create cartographic material that allows us to understand the city’s growth dynamic and how it is changing. Based on information revealed through the questionnaires, I will be able to determine the quality of this growth, the population profile, average wages, sources of income, and network of relationships with nearby communities,” Costa explained.

Expansion of the data collection area, according to the researcher, will also enable comparative studies to be carried out based on what has already been observed in Ponte de Pedras.

Vulnerability assessment


Although intense and uncontrolled urbanization is a reality throughout the Brazilian Amazon region, the project led by Costa and Brondizio is focused on the Amazon River estuary because it is associated with the Belmont Forum’s international Delta project.

“Deltas are considered to be environmentally vulnerable regions, and therefore, the impact of the uncontrolled occupation process in these locations tends to be even bigger. It could, for example compromise the reproduction of certain species of fish or shrimp,” Costa explained.

The international project involves a large group of researchers working in three deltas: one in China, one in India and the Amazon River delta. According to Brondizio, the idea is to link all of the data and relate the information on urban growth with data regarding deforestation, changes in sea level, and fluctuations in the rainfall index, among other things, to model future scenarios and assess vulnerabilities.

“The group includes experts in hydrology, biophysics, biology, climate issues and flooding. The idea is that everyone will be able to use the huge open-access repository that is being generated to model change scenarios in various parts of the basin and assess how these changes will affect the population,” Brondizio explained.

In Costa’s opinion, discussion of the topic of global climate change is crucial when considering the issue of urbanization, which is extremely problematic. “Most studies about the Amazon focus on understanding the forest and greenhouse gas emissions. The urban issue takes a backseat, which is a fundamental flaw because it compromises the quality of life of the population and has an impact on the ecosystem,” she said.