Análise da influência da evaporação na disponibilidade hídrica de um reservatório tropical

Abstract

The water balance in lakes and reservoirs can be affected by evaporation losses. In this sense, the present study aimed to analyze the impact of evaporation on water availability in the Santo Anastácio reservoir, located in Fortaleza, Ceará. Direct evaporation of the reservoir was estimated using the mass transfer method. Eleven-year evaporation time series were generated and compared to the evaporation measured by the Class A pan, through the relationship between modeled and measured data, as well as by linear regression. Subsequently, a 20-year time series of hydrological data (2000 to 2019) was analyzed to estimate water availability. The Vyelas water balance model was used and different correction coefficient obtained were used to analyze scenarios of the impact of evaporation on water availability. Class A pan coefficient were obtained for annual, monthly and seasonal averages between 0.5-0.6, lower than suggested by the literature. Simulations with Vyelas showed that reductions in evaporation greater than 30% imply an increase in water availability in the same proportion. It is concluded that water balance is very sensitive to the evaporation estimate, suggesting the need for accuracy in the evaporation calculation methods for the effective operational management of water resources.