A modelling approach to simulate Chlorophyta and Cyanobacteria biomasses based on historical data of a Brazilian urban reservoir

Abstract

A process-based model was used to simulate a hindcast based on the worst historical water quality condition of a tropical urban reservoir. Paranoá Lake is located in Brasília-DF, Brazil, and went through intense eutrophication in the 70s and 90s, with an important cyanobacterial bloom event in 1978. The parameters of phytoplankton were calibrated, focusing on the group of Chlorophyta (green algae) and Cyanobacteria (blue-green algae) at four depths (1, 10, 15 and 20m). The results indicated that the model was able to reproduce the Cyanobacteria biomass in comparison with the observations (RMSE=22-29.10-3 mgC L-1). On the other hand, the simulated Chlorophyta biomass showed good agreement with the observed data only in the bottom layer (RMSE=29. 10-3 mgC L-1 at 20m). In the hindcast simulation, the model was able to predict a significant increase in cyanobacterial biomass facing a water quality deterioration. In the meantime, the simulated Chlorophyta biomass decreased, which may indicate the phytoplankton group succession in response to the environmental conditions.

Análise de parâmetros da qualidade da água no lago Descoberto no Distrito Federal, por meio de imagens do satélite Sentinel –2B

“…De acordo com Barbosa et al, (2021) diversos fatores ambientais fazem juz para a necessidade de estudos consistentes para os corpos hídricos. Referente a quantidade e a qualidade, se torna cada vez mais urgente, tendo em conta a importância do lago Descoberto como manancial para o abastecimento público, pois este é o maior sistema de abastecimento do Distrito Federal -DF, atendendo cerca de 60 % da população local, se torna indispensável o seu estudo dado a sua importância para a região.…”