Remote sensing-based water resource diagnosis in regions with intensive expansion of irrigation in Brazil

• Ano de defesa: 2024
• Autor(a) principal: Santos, Ana Beatriz dos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Meteorologia Aplicada
• Palavras-chave em Português: Irrigação por pivô central; Irrigação agrícola; Sensoriamento remoto; Desenvolvimento de recursos hídricos; Climatologia
• Link de acesso: https://locus.ufv.br//handle/123456789/32290; https://doi.org/10.47328/ufvbbt.2024.090

Center pivot irrigation has been leading irrigation growth in Brazil in recent years. However, the intensification of climate change effects may lead to issues in regions highly occupied by center pivots. The reduction in precipitation volume or the duration of the dry season often generates conflicts over water usage between irrigators and other water users. Therefore, formulating a diagnosis of the hydrological situation in these regions is crucial. This study selected three Brazilian regions with intensive irrigation expansion: the Corrente and Grande rivers' basins in Bahia and the Alto Rio das Mortes in Mato Grosso. Although these are considered areas with a high technological level in the field, there is no systematic measurement network for water usage yet. Remote sensing products enable the estimation of center pivot water demand through evapotranspiration (ET). For the Corrente and Grande River basins, the MODIS ET product (MOD16A2 Version 6 Evapotranspiration/Latent Heat Flux product) was applied to identify sub-basins with a higher risk of water conflicts. After comparing the estimated irrigation water demand with river flow data, three sub-basins demonstrated a potentially critical situation regarding water resource usage. An in-depth analysis of these sub- basins also revealed that water use by center pivots has steadily increased over the years, pushing water consumption to its limits. In addition to the MODIS product, another database was applied to estimate the irrigation by center pivots, the daily evapotranspiration dataset provided by the GLODET (Global Daily evapotranspiration) platform for the Alto Rio das Mortes. Moreover, ET data measured via eddy covariance were used to assess the accuracy of the two products. The results showed that the new ET dataset exhibited improvements compared to the previous version used, which underestimates evapotranspiration in the region. Additionally, the results represent a first step in understanding irrigation in Mato Grosso, showing immense potential for application in future studies. Keywords: Center pivots; Remote sensing in agriculture; Water security.