Banca de DEFESA: LEANIZE TEIXEIRA OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : LEANIZE TEIXEIRA OLIVEIRA
DATA : 05/10/2020
HORA: 09:00
LOCAL: Sala de videoconferência do Colegiado da Pós-graduação em Geologia - UFBA
TÍTULO:

TRANSITIONAL WATER BALANCE AND ANALYSIS OF WATER LEVEL VARIATIONS IN SOUTHERN PORTION OF THE URUCUIA AQUIFER - BAHIA

PALAVRAS-CHAVES:

Flow simulation; Urucuia aquifer; Water budget; Isotopic analysis.

PÁGINAS: 99
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
SUBÁREA: Geologia
ESPECIALIDADE: Hidrogeologia
RESUMO:

The west of the state of Bahia-Brazil, the largest agribusiness area in the state, is experiencing a progressive occupation since the 1980s, causing pressure on water resources, mainly after the introduction of irrigation, and already presenting conflicts between water users. The water resource has been the driving force behind agricultural activities, and given its strategic importance and the hydraulic coupling between rivers and aquifers, hydrological studies need analyzes that integrate the dynamics of surface and groundwater. This research presents a spatial and temporal analysis of the components of the water balance in order to understand the dynamics of the main water flows in the Arrojado, Formoso and Éguas watershed, tributaries of the Corrente river basin in Bahia, and their reflections in the groundwater levels of the Urucuia aquifer. The effects of the extraction of groundwater by wells in a portion of the Urucuia Aquifer System and the quantification of the components of the water balance were made using the simulation of groundwater flow in a stationary regime for three scenarios: i) without pumping; ii) with current pumping and; iii) with 60% more extraction by wells. After defining the production flows of the current wells (4.6 m3 s-1) and modeling the geometry of the aquifer base (maximum thickness of 535 m), the stationary models without pumping and with pumping show that, in long term, groundwater storage decreases by 2 km3 (average drop in the 0.8 m aquifer) without interference in the direction of regional flow. The mass balance shows that the base flow of the main rivers is reduced by approximately 6% after the current groundwater extraction and a further 2.5% after the increased extraction. Isotopic analysis was also used in conjunction with the numerical simulation of transient flow to describe the dynamics of the components of the water balance between 2005 and 2018. The isotopic analysis highlights the river-aquifer interaction, the effect of evapotranspiration on the recharge and the amount effect. The results show a progressive decrease in recharge between 2012 and 2017, the importance of EVPT in recharge calculations, and a decrease in rainfall, causing a decline in groundwater levels and the base flow of rivers (average river flows also come declining, reflecting joint actions to decrease base flow and direct withdrawal of water for irrigation), and suggests that effective recharges occur in high volume rains. The simulation also predicts that in the event of a 10% decrease in recharge, hydraulic loads and base flows take approximately a decade to rebalance. Considering that the exploitation of aquifers must be guided by the environmental sustainability of the water system in order to balance the pumping conditions and the mitigation of their consequences, the importance of continuous hydroclimatological monitoring and measurement of withdrawals becomes evident, aiming to follow the dynamics between demands and water availability. The results point to a greater impact of the exploitation of aquifers on rivers, caused by a reduction in storage and base flow.

MEMBROS DA BANCA:
Interno - 2298240 - LUIZ ROGERIO BASTOS LEAL
Externo ao Programa - 2349838 - MARIA DO ROSARIO ZUCCHI
Externo à Instituição - JOANA ANGELICA GUIMARAES DA LUZ - UFSB
Externo à Instituição - José Geilson Alves Demétrio - UFPE
Externo à Instituição - MARIO JORGE DE SOUZA GONÇALVES