Impacto da qualidade da água nas taxas de evaporação de um lago hipereutrófico

Abstract

The estimation of the evaporation rates is indispensable for the adequate water balance of the surface water bodies. This paper aimed to evaluate the impact of water quality on the evaporation rates of a hypereutrophic lake, located in Fortaleza, Ceará, Brazil. The analysis period included the years 2013, 2018 and 2019. Two water quality models were applied: a complete mix transient model and an empirical one. Time series of total phosphorus concentrations were generated and empirical correlations were proposed between that parameter, phosphorus loads, sanitary and hydrological variables. The modeled total phosphorus concentrations and the Biochemical Oxygen Demand (BOD) were correlated to monthly Class A pan coefficients. Correlations were obtained between the inflow and the total phosphorus (R² of 0.70); and the solid waste from sweeping and cleaning the affluent channel and the total phosphorus loads contributed (R² of 0.96 and 0.64, respectively). Finally, negative and statistically significant correlations were observed between the modeled total phosphorus concentrations (R² of 0.76 and 0.52), the BOD (R² of 0.85) and the Class A pan coefficients, pointing to the influence water quality in the evaporation of the lake.