O Drought Polygon it is an area of 1,108,434.82 km², corresponding to 1,348 municipalities, which is inserted in the states of Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe, Bahia and Minas Gerais. This term designates a region concentrated in the North East and in part of the Southeast that suffers from the lack of water or its low supply for long periods. Its limits are divergent between the different management, control and drought control agencies in the Northeast.
In addition to a definition, the institution of an area where the State recognizes the effects of nature on the socio-spatial organization of the territory and of its population allows specific and more effective actions to be defined that face the demands of the region, which, in this case, include actions that enable the expansion of water supply, development of research that better understand the dynamics of the climate and, above all, the financing of these actions.
What is the importance of a law that demarcates the Polígono das Droughts?
By establishing applicable legislation that recognizes the existence of the Polígono das Droughts, this region, through its municipal and state managers, is now freed from some requirements for emergency actions to care for the population that feels the lack of water, as well as receiving specific funds for combating the drought through the National Financing Fund for the North East. Thus, a natural effect also becomes a matter of State.
How is the Drought Polygon defined?
Law 1348, of 1951, established the criteria and limits to configure the delimitation of the region of “Polígono das secas”, which was recently revised and expanded by Interministerial Ordinance No. 01 of 09/03/2015. Based on a collaborative work by the Ministry of National Integration, the following criteria were adopted as the main ones to define it:
The)800 mm isohyet – that is, the minimum amount of rainfall that is measured for a given region;
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B)aridity index - it is a mathematical reference used to measure the degree of aridity of the soil based on the following conditions:
water potential (P);
amount of rainwater and the rate of evaporation and potential transpiration (ETP);
maximum amount of water loss from acidity (pollution), evaporation and transpiration.
Thus, a municipality belonging to the Polígono das Droughts presents an aridity index of up to 0.50. The definition of dryness comes from the work of climatologist Charles Warren Thornthwaite de 1941.
c) Water deficit - refers to periods when precipitation rates are lower than soil evaporation and evapotranspiration rates, in the order of 60%.
Political issue of the Polígono das Droughts
The question of dry in the Northeast it is well known. Different segments of society demonstrate awareness of the need to face this challenge and even indicate solutions to solve or minimize them. Countries like the United States or Israel show that it is possible to face this challenge by urbanizing and developing regions, even though there is low water availability.
It is observed that, in the case of the drought polygon, this is a recurrent and “apparently unresolved” theme. However, it should be considered that this same region is home to a large population, which historically was constituted as a reserve for the exercise of power by large landowners and, more recently, for the exercise of power voter. This lack of interest in solving or truly facing the drought issue in the semi-arid region became known as the Drought Industry, where demands are created for greater investments without effectively addressing the issue.
Thus, it can be said that the drought polygon, in addition to being a natural issue, is necessarily a political issue.
by Hugo Mota
Graduated in Geography
Would you like to reference this text in a school or academic work? Look:
MOTA, Hugo. "What is the Drought Polygon?"; Brazil School. Available in: https://brasilescola.uol.com.br/o-que-e/geografia/o-que-e-poligono-das-secas.htm. Accessed on June 28, 2021.
