Evapotranspiration represents a significant part on the water balance and, thus, the correct evaluation of this hydrological parcel is relevant when modeling a watershed. The objective of this work is to evaluate the Soil and Water Assessment Tool (SWAT) model’s capability in adequately simulating evapotranspiration in a watershed with predominance of the Brazilian Cerrado biome. Hydrological modeling of the Gama watershed located in the Federal District, which has 57.5% of its total area covered by pristine Cerrado, was conducted. Hydrometeorological and turbulent flow variables have been monitored in weather station and Eddy Covariance (EC) tower, respectively. SWAT simulations were performed for potential evapotranspiration methods: Hargreaves (H), Priestley–Taylor (PT) and Penman–Monteith (PM). Modified versions of SWAT for estimating actual (ET) by Strauch and Volk (2013) (SV) and Arroio Junior (2016) (AR) were also tested. The calibration and verification of the SWAT model, in terms of daily flow, were carried out using a Particle Swarm Optimization algorithm, and fair results were obtained with all the methods evaluated. The actual evapotranspiration (ET) simulated with SWAT (ETsim) using the PM, PT, H, SV and AR methods for a Cerrado hydrological response unit (HRU) were evaluated and compared with the ET obtained using the turbulent flow (Eddy Covariance) method (ETobs). Comparing ETobs and ETsim results, the PM method showed the best fitness and the H and PT methods showed better fit for the dry and the rainy periods, respectively. Although representing an advance on ET modeling, the SV and AR modifications did not improve the response in terms of simulation of the studied area.

Este artigo discute resultados parciais da análise de trancamentos de matrículas em um Câmpus da Rede Federal durante o primeiro ano da Pandemia Covid-19. Trata-se de uma pesquisa quanti-qualitativa, que fez uso dos dados de solicitações feitas por meio do sistema Secretaria Online. Foram analisadas 154 solicitações de trancamento que evidenciaram o aumento de 71,11% em comparação com o ano anterior. Em uma segunda etapa, foram separadas e analisadas 62 requisições que descreviam os motivos entre duas macro-categorias sugeridas pelos autores: Ensino Remoto Emergencial e Pandemia. Esta etapa permitiu identificar os impactos causados pela pandemia na vida pessoal que se relacionam com a evasão escolar. A análise também permitiu observar a relação direta entre o aumento do número de solicitações e a implantação do Ensino Remoto Emergencial. O abandono escolar já era uma problemática presente no campo da educação, porém o fenômeno Covid-19 repercutiu nas relações escolares, derivando novas formas de interação educacional, e sobretudo, acarretando o aumento de casos de evasão. Assim, este estudo tem como objetivo analisar as possíveis causas da evasão escolar em tempos de pandemia, no intuito subsidiar e ampliar o debate sobre os desafios impostos e possíveis intervenções que visem minimizar estes impactos.

Similarities in both water and electric current flows allow the relation of hydraulic and geoelectric parameters of porous aquifers. Based on this assumption and the importance of the hydraulic parameters for groundwater analyses, this study aimed to estimate hydraulic conductivity (K) and transmissivity (T) with vertical electrical sounding (VES) in the porous aquifer at the experimental farm of the University of Brasilia, Brazil. VES is a geophysical technique that provides electrical resistivity (ρ, Ω m) and thickness (h) of the subsurface layers. The ρ and h aquifer data, associated with lithology, water table level (WTL), and groundwater electrical resistivity (ρw, Ω m), allowed the calculation of complementary geoelectric parameters (formation factor, F, and Dar Zarrouk parameters) and the relation with K and T, determined via slug test. VES data allowed the elaboration of geoelectric models, with mean absolute percentage error (MAPE) below 6% compared to field data, and the identification of the aquifer in each VES station. Significant exponential regression models (R2 > 0.5 and p-value < 0.05) showed the possibility of using geoelectric parameters to estimate hydraulic parameters. This study allowed the verification of the applicability of consolidated models and the identification of appropriate empirical relationships for hydrogeological characterization in the Brazilian tropical porous aquifers. The results of this work, besides the rapid sampling and low cost of performing vertical electrical sounding (VES), may justify the use of this geophysical technique for preliminary porous aquifer characterization, especially in regions absent of or with insufficient monitoring wells.

ABSTRACT. The aim of this study was to analyze the soil geoelectric behavior, through geophysical surveys, in the surrounding region to Bonita Lake, a natural reservoir located in the Ecological Station águas Emendadas (ESECAE), 50 kilometers from Brasília (Brazil). Sixteen vertical electrical sounding (VES) were performed with Schlumberger array. The geoelectrical model, obtained by inversion of the field data and statistical analysis of the inverted data, indicated structure with superficial dry soil above partially saturated layer, and finally a soil or rock with low permeability, related to the aquifer formation with varying thickness, about ten meters below the lake and up to twenty meters deep in the surrounding area. The VES showed that the aquifer has great lateral extension to the north, east and west of the lake; providing water to the same, while in the south, the aquifer is possibly limited by quartzites of the Canastra Group. This restriction can result in the absence of aquifer recharge in the southern portion, and coincides with the region where the lake drains into the source of Mestre D’Armas stream. This information is important because it can be used in the delineation of the hydrogeological basin and the Bonita Lake protection perimeter. Keywords: Ecological Station of águas Emendadas, aquifer, geophysics, vertical electrical soundings. RESUMO. O objetivo deste estudo foi analisar o comportamento geoelétrico do solo, por meio de levantamentos geofísicos, na região circundante à Lagoa Bonita, um reservatório natural localizado na Estação Ecológica de águas Emendadas (ESECAE), a 50 quilômetros de Brasília (Brasil). Dezesseis sondagens elétricas verticais (SEV) foram realizadas com arranjo de Schlumberger. Os modelos geoelétricos, obtidos pela inversão dos dados de campo e análise estatística dos dados invertidos, indicaram uma estrutura com solo superficial seco sobreposto a uma camada parcialmente saturada e, por fim, um solo ou rocha com baixa permeabilidade, referente a formação aquífera, com espessura variável, cerca de dez metros abaixo da lagoa e até vinte metros de profundidade na área circundante. As SEV demonstraram que o aquífero possui grande extensão lateral para norte, leste e oeste da lagoa; fornecendo água para a mesma, enquanto que, na direção sul, o aquífero é possivelmente limitado por quartzitos do Grupo Canastra. Esta restrição pode resultar na ausência de recarga do aquífero na porção sul, e coincide com a região onde a lagoa drena para a nascente do ribeirão Mestre D’Armas. Esta informação é importante, pois pode ser utilizada no processo de delimitação da bacia hidrogeológica e delimitação do perímetro de proteção da lagoa Bonita.  Palavras-chave: Estação Ecológica de águas Emendadas, aquífero, geofísica, sondagem elétrica vertical.

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