Knowing to preserve
Since 2014, ITV DS monitors the Itacaiúnas Rivers Basin in order to better understand the hydrometeorological behavior of that area. This information may help people who make decisions to develop a better planning of soil use and handling of the Basin, as well as the prevention of impacts from extreme events in the communities.
On the webinar called “Águas de Carajás” (Carajás’ Waters), on August 25th, the theme was discussed by the ITV DS researcher Paulo Pontes; by Mauro Rodrigues, from the Serviço Geológico do Brasil (Brazilian Geological Service); and by Igor Ribeiro, from the Associação dos Engenheiros Ambientais do Sul e Sudeste do Pará – AEASPA (Association of Environmental Engineers from South and Southwest of Pará), on a hearing with Vale’s employees and scientific partners.
The set of researches coordinated by ITV DS researchers is a part of the Monitoring of Hydraulic Events and Management and Planning Support project. In order to collect data, professionals who are a part of the project go to the field and work remotely, by mathematical models, producing knowledge, aiming to analyse and study the action of winds, rains, temperature, soil moisture, among other events. Weather and measurement stations were also built from the outflow level of the rivers. These are data that help to anticipate what is coming.
“Water balance is the study that estimates how much rainwater is retained on the soil, how much of it goes back to the atmosphere and how much goes through the river’s mouth. And this varies a lot, there are a lot of influences”, comments the researcher Paulo Rógenes Monteiro Pontes, who coordinates the research.
The final objective of the study is to create knowledge, observes the ITV DS researcher, Rosane Barbosa Lopes Cavalcante.
“Data generated from this project support the planning and the action on water management from this territory where we are working”.
INTERVIEW – Paulo Rógenes Monteiro Pontes:
“Every year, new scenarios”
What results can already be listed from the Project you are coordinating?
Paulo Pontes – We have new results every year. We already analyse the role of preservation areas – on the Basin, there are indigenous lands and Conservation Units – and how these areas cause an impact in hydraulic resources. We work with monitoring, remote sensing, mathematical modelling, in order to diagnose and make assumptions, try to create hypothetical assessment scenarios related to hydraulic resources. We created three scenarios, one of them is very hypothetical, in which there was not any kind of protection. And we realized that the deforestation causes, in fact, the rise of minimum outflows of the river.
What is the rise of outflows?
Paulo Pontes – It is the volume expansion of water that pass through the rivers. You may think it is a good scenario because it means more water in the Basin, but not necessarily. With the deforestation, the landscape, the soil are more exposed, which enable the erosion processes and may impact in qualitative aspects of the water.
What is water balance?
Paulo Pontes – We call water balance the study that estimates how much rainwater is retained on the soil, how much of it goes back to the atmosphere and how much goes through the river’s mouth. And it varies a lot. There is a relation between rainwater collection by the soil, the forest, and how much of this rainwater drains through the surface. And this varies a lot, the quantity and quality of the water on the soil will make an influence. This hydrological process, which gets the impact of anthropic activities, makes the Basin a living organism, which behaves with a certain dynamics, a variability. Although we are in Amazon and, because of that, we have a idea of abundance of water, it has a substantial seasonal variation. We have floods in the most humid period. At the same time, there are occasions in which the rivers practically dry, which may cause challenges regarding hydrological safety.
How do you assess extreme events?
Paulo Pontes – We check, for instance, how the water increase on the rivers impacts or floods cities at the margin of these rivers. In this way, we are able to map these flood areas. Knowing these areas, the decision makers – city halls, for instance – may be anticipated regarding these processes and make an evacuation plan. That means: it allows some kind of zoning, a handling plan in relation to the flood of the city.
INTERVIEW – Rosane Barbosa Lopes Cavalcante
“It is like the Basin had a memory”
How the water balance of the Itacaiúnas River Basin is changing?
Rosane Cavalcante – We made a study and we discovered that, since the seventies, there was not a significant precipitation change, but a modest increase of local temperature. The river outflow had a big increase in averages, maximum and minimum, a substantial variation. That happened due to deforestation. We seek to check the influence of the temperature in Atlantic and Pacific waters in the Basin. And it is clear that, when there is El Niño (temperature increase on the Pacific ocean) and La Niña (temperature decrease on the Pacific ocean), there are stronger floods and droughts in the Basin. Another interesting discovery: it is like the Basin had a memory.
Rosane Cavalcante – When it rains a lot, the soil becomes full of water and it works as a sponge, the water comes out of the soil slowly, it stays in the Basin’s memory. With that, even moderate rains may generate high outflows in the basin. The opposite happens with extreme drought events: there is a big decrease of water on soil and rocks and, due to that, even when there is regular rain again, it takes a few months to the outflows are back to normal.
In fact, with these data, ITV DS is generating knowledge…
Rosane Cavalcante – Yes, even today I was thinking about the importance of this as a whole. The information we generate now may be used in a few years, which may help to solve a problem in the future. We are generating research, baseline information that will be available for society. That is why it is important to disseminate it, even more widely.
What is the utility of this study?
Rosane Cavalcante – We already have the models that are able to predict rain in different periods of time. Gathering this with the information about water storage on the soil, we will have better conditions to predict floods and inundations.
INTERVIEW – Igor Conceição Ribeiro
“Cherish the area where we live”
As a resident of the area and environmental engineer, what does the ITV DS Water Resources Project for the Itacaiúnas Basin mean to you?
Igor Ribeiro – It is a way to support environmental entities and other specialists on the subject to make decisions, make assessments and diagnose the situation of the River’s waters quality.
How these studies may contribute?
Igor Ribeiro – Encouraging the application of preservation strategies. For instance, with the creation of the River Basins Committee and specific groups for intermediation. It also stimulated the creation of monitoring stations that can make more accurate predictions. It is also possible to predict how we want our river to be in one, two, three years, considering the population growth and the activities that cause impact on it.
Would it be important to have a strategic plan?
Igor Ribeiro – Yes. Using the ITV DS studies and with care from the population and the government, it will be possible to cherish the area where we live.
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