Avaliação do comportamento dos níveis dos aquíferos Beberibe-PB e Açú-RN utilizando modelos de séries temporais como ferramentas de gestão.

Abstract

The knowledge about the occurrence of groundwater assumes a very important and strategic role, mainly in the Northeast Region, which is characterized by being a territorial extension, for the most part, dominated by the scarcity of surface water resources and with limited use of water both in quantitative and qualitative terms. Seeking to generate the technical knowledge necessary for the sustainable management of this important resource, the use of models and methods becomes necessary to allow an analysis of monitoring data that makes it possible to detect changes in the hydrological cycle and generate scenarios of future trends through an approach quantitative analysis of the system, establishing a dynamic relationship between the behavior of the phreatic level, whether due to local hydrogeological conditions or conditioned by more comprehensive climatic events. Therefore, the objective of this work is to explain, based on the HARTT autoregressive model (Hydrograph Analysis: Rainfall and Time Trend), the oscillations of the water tables of the Açu­RN Aquifer and the Beberibe­PB Aquifer. With that, understand how they respond to different stimuli of precipitation events being in different climatic contexts, under different rainfall regimes, so that a comparison can be made between these two formations. In addition, perform the annual recharge calculation and estimate the annual volume withdrawn by wells with grants in both aquifers, to deepen the hydrogeological knowledge of these areas. In order to carry out this research, in addition to a strong theoretical basis comprised of a vast bibliographic review, data collections and analyzes were carried out. The investigation of the grant data and construction of the HARTT model explains the evolution of the water table over time in each of the 10 wells that are inserted in the 9 municipalities and represent these aquifers, using the raw climatological and monitoring data of the well as input, obtained on the online platforms of institutions such as ANA and EMPARN. For the series of monitored groundwater levels, the information was obtained on the CPRM website through RIMAS, and the volume data of the wells with grants were obtained on the AESA and IGARN website. The results at HARTT revealed the tendency to lower or raise the static level in the wells and the high significance values (p­values <0.05) with an average R² of 78.88% in Beberibe and 88.91% in Açu aquifer , satisfactorily characterizing the strong dependence relationship between fluctuations in groundwater levels and accumulated precipitation, with the response time of the sheet to rainfall ranging from 1 to 2 months in the potiguar aquifer and up to 1 month or less in the paraiba aquifer plus a continuous lower of the static level after the rainy season. The average annual recharge estimated by VNA based on average precipitation values was 39.38 mm/year for Açu and 298.69 mm/year for Beberibe. The flow rates in the grants showed a worrying trend of increasing exploration. Based on the results found, it was concluded that the tools adopted in this research demonstrated a good efficacy with respect to the methods of supporting the sustainable management of water resources and in the comparison or analysis of the characteristics of the Beberibe­PB and Açu­RN aquifers.