Banca de DEFESA: JAMILLE EVANGELISTA ALVES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JAMILLE EVANGELISTA ALVES
DATE: 12/08/2022
TIME: 10:00
LOCAL: virtual
TITLE:

SUBSIDIES FOR INTEGRATED RESOURCE MANAGEMENT HYDROGRAPHIC BASIN OF THE CACHOEIRA RIVER – BAHIA

KEY WORDS:

Keywords: Hydrogeochemistry. Hydrographic basin. Hydrology. Water resources management

PAGES: 70
BIG AREA: Ciências Exatas e da Terra
AREA: Geociências
SUBÁREA: Geologia
SPECIALTY: Hidrogeologia
SUMMARY:

The present work carried out in the Cachoeira River Basin (CRB), located in the southern portion of the
State of Bahia, aimed to contribute with scientific foundations that make it possible to guide the integrated
management of water resources in that area. Two scientific articles published in the journals were
developed: Anuário do Instituto de Geociências and Boletim do Museu Paraense Emílio Goeldi. Ciências
Naturais. In the first article, entitled “Intervening factors in the groundwater salinization process,
Cachoeira River Basin, Northeastern Brazil”, hydrogeochemical diagrams and multivariate statistics were
applied in order to identify the factors that potentially influence the salinity of the waters in the crystalline
aquifer of the study region. The data used came from the hydrogeological database of the Companhia de
Engenharia Hídrica e Saneamento da Bahia (CERB). Groundwater was predominantly classified as
calcium-bicarbonate with salinity ranging from sweet to brackish. The cation that prevails in the region is
Ca2+, while carbonate and bicarbonate correspond to the dominant anions. With the factor analysis it was
possible to recognize two factors that explain approximately 93% of the total variance of the data.
Hierarchical cluster analysis resulted in 5 distinct clusters based on dissolved ion concentrations. This
study indicates that the natural mechanisms that control the chemical composition of groundwater are
mainly related to the weathering of rocks associated with evaporation contributions, and the most
significant parameters in the variability of water salinity are Ca2+, Mg2+, K+, Fe(total), Cl-. The second
article was entitled "Precipitation in the Cachoeira River Basin: Variability and Trends (1970 - 2020)",
this study aimed to identify rainfall trends and variability. The data used comprise historical series of total
monthly rainfall from six rainfall stations for the period from 1970 to 2020 (51 years) obtained from the
Hydrological Information System (HidroWeb) of the Agência Nacional de Águas e Saneamento Básico
(ANA). The Mann-Kendall, Spearman's Rho and Sen's slope tests were satisfactorily applied, allowing the
identification of significant trends and precipitation magnitude. The analysis showed that statistically nonsignificant trends prevail in the area. However, a significant negative trend was identified in the centralwest region in two rainfall stations that characterize a reduction of around 300 mm of rain in the studied
period. Periods with extreme drought/humidity were recognized and compared with ENSO phases where
it was identified that 62.5% of drought events and 42.9% of rainy events can be related to El Niño/La Niña
phenomena, respectively. With the coefficient of variation, low rainfall variability was recognized in the
eastern portion and high variability in the western portion of the area. The results obtained can be used as
a reference for the management of water resources in the river basin.

BANKING MEMBERS:
Presidente - 031.086.865-34 - SERGIO AUGUSTO DE MORAIS NASCIMENTO - UFBA
Externo ao Programa - 1005053 - HARALD RENE KLAMMLER
Externa à Instituição - DANIELA DANTAS DE MENEZES RIBEIRO
Externa à Instituição - MARIA DA CONCEICAO RABELO GOMES
Externa à Instituição - ROSA ALENCAR SANTANA DE ALMEIDA - UFRB