Banca de DEFESA: ANDREIA DE ALMEIDA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ANDREIA DE ALMEIDA
DATE: 20/01/2023
TIME: 08:00
LOCAL: Sala de Informática do PTARH com Transmissão pela Plataforma MS Teams
TITLE:

SUBSURFACE HYDROLOGICAL PROCESSES AND EVAPOTRANSPIRATION MONITORING AND MODELING IN CERRADO WATERSHED

KEY WORDS:

Keywords: Soil moisture; Cerrado; Experimental basin; Applied geophysics; Soil electrical resistivity.

PAGES: 215
BIG AREA: Engenharias
AREA: Engenharia Sanitária
SUBÁREA: Saneamento Ambiental
SUMMARY:

Despite constituting a reduced portion of the global hydrological cycle, soil moisture is a key variable in the partitioning of precipitation among the other terrestrial hydrological processes. This is especially true in water limited environments, such as the Cerrado, in which the water-vegetation interaction seems to be defined especially by the availability of soil moisture compared to the energy available in the ecosystem. Therefore, understanding the impact of the land cover changes on soil moisture in these environments is one of the main challenges in the hydrology of Critical Zones - the portion of the Earth that extends from the vegetation canopy to the base of free aquifers. This challenge lies in the still limited knowledge of reference standards, derived from field data, which make it possible to analyze and predict how changes in native vegetation can affect the states and redistribution of precipitation in the Critical Zone and between it and the atmosphere. From this context, the aim of this thesis was to investigate subsurface hydrological processes and evapotranspiration, based on soil moisture patterns, and their relationship with the Cerrado predominant land cover and land use. This study included i) experimental, concentrated especially in twelve monitoring points installed at Fazenda Água Limpa (FAL/UnB); and ii) mathematical modeling stages at different spatial scales. Both were directed to the analysis of soil moisture and evapotranspiration in the Ribeirão do Gama watershed, a headwater predominantly covered by native Cerrado, located in the Distrito Federal, Brazil. Field data collection made it possible to estimate the energy and water balance in the vadose zone under native and altered vegetation, using equipments associated with turbulent fluxes towers, with an indication of increased control of soil moisture and reduction of evapotranspiration in the cerrado sensu stricto

in comparison with the eucalyptus plot (Eucalyptus urophylla x grandis). The in-situ monitoring also made it possible to evaluate the applicability of the direct current electric geophysical method as an alternative tool for monitoring moisture at different soil depths (up to 2.10 m deep). This evaluation resulted in the proposition and verification of a significant empirical model (p < 0.05) for estimating moisture from indirect measurements of soil electrical resistivity. Two-dimensional vertical sections derived from the empirical model showed the temporal behavior of moisture in the soil profile in accordance with field and water flow numerical simulation in porous media (FEFLOW) derived data. There were variations in the seasonal behavior of the moisture sections derived from the electrical resistivity in response to the characteristics of the native vegetation (“cerrado sensu stricto”: wooded cerrado; “campo limpo”: cerrado grassland; “campo sujo”: shrub cerrado; and gallery forest) and altered vegetation (eucalyptus and pasture). Finally, the incorporation of field data, obtained during the experimental stage, in the empirical (Budyko) and water balance (SWAT) hydrological modeling provided patterns of soil moisture and evapotranspiration, as well as a preliminary overview of the relationship between such patterns and the state factors of the Cerrado (land use and cover, pedology and slope). In addition, the study made it possible to structure a hydroclimatological monitoring network that will support further investigations regarding the effects of soil cover on the spatial and temporal variability of soil moisture. It is recommended to expand the spatial and temporal representativeness of field data directed to the soil moisture - evapotranspiration relation; to improve the analysis of state factors in soil moisture, especially through detailed pedological characterization, and to continue the assimilation of field and remote sensing data in the parameterization of watershed scale hydrological models.

BANKING MEMBERS:
Presidente - 404772 - SERGIO KOIDE
Interno - 2764698 - CARLOS HENRIQUE RIBEIRO LIMA
Interno - 1495411 - HENRIQUE LLACER ROIG
Externo à Instituição - EDSON CEZAR WENDLAND - USP
Externo à Instituição - LUIZ RAFAEL PALMIER - UFMG