Water productivity using SAFER - Simple Algorithm for Evapotranspiration Retrieving in watershed

Produtividade da água estimada pelo SAFER - Simple Algorithm for Evapotranspiration Retrieving em bacia hidrográfica

ABSTRACT

The Cabeceira Comprida stream’s watershed, located in Santa Fé do Sul, São Paulo state, has great environmental importance. It is essential for supplying water to the population and generating surpluses for sewage dilution. This study aimed to evaluate the annual performance of the components of water productivity from Landsat-8 images of 2015, using the Simple Algorithm for Evapotranspiration Retrieving (SAFER), calculating the actual evapotranspiration (ET_a), biomass (BIO) and water productivity (WP). The annual averages of ET_a, BIO and WP were 1.03 mm day^-1, 36.04 kg ha^-1 day^-1 and 3.19 kg m-3, respectively. The average annual values of ET_a for land use and occupation were 1.40, 1.23, 1.05, 0.97 and 1.08 mm day^-1 for the remaining forest (RF), invasive species (IS), pasture (Pa), annual crop (AC) and perennial crop (PC), respectively, with BIO of 57.64, 46.10, 36.78, 32.69, 40.03 kg ha^-1 day^-1 for RF, IS, Pa, AC and PC, respectively, resulting in WP of 3.94, 3.59, 3.25, 3.09, 3.35 kg m^-3 for RF, IS, Pa, AC and PC, respectively. The ET_a, BIO and WP adjust to the seasonality of the region, and RF and IS stood out with the highest values.

Key words:
biomass; evapotranspiration; remote sensing; Typha