The aim of the study was to evaluate evapotranspiration (ET) estimation models for the municipality of Macapá, AP. The models studied were Hargreaves-Samani (HS), Turc, Camargo (CM), Jensen-Haise (JH) and Solar Radiation (RS). The ET estimated by the models were compared with those obtained by the standard Penman-Monteith method. Statistical tests of Willmot's Concordance index (d), Correlation Coefficient (r), Performance coefficient (c), Mean Absolute Error (EAM), Mean Square Error and Residual Mass Coefficient (CMR) were performed. With the results of "c" only HS, in August (c = 0.71; "good") and December (c = 0.73; "good") presented a performance considered good. JH had the worst result, between 0.05 and 0.22, considered terrible. In relation to “d”, HS also had a better result, with 0.79 and 0.83 in August and December. The worst was JH, with a minimum value of 0.09 for May. For CMR, CM, JH and RS overestimated ET. TC, on the other hand, presented both underestimation and overestimation. HS overestimated from January to July and underestimated in the other months. For EAM, the models tended to overestimate ET. For MSE, HS presented the lowest values. JH was the one with the worst results, above 4. And the coefficient of determination showed a small dispersion of data, with R2 above 0.90 for HS, TC, JH and RS. Based on what was exposed, HS was the method that presented the best responses, followed by CT and RS. And JH was the one with the highest overestimation rate.

Hydraulic energy is the main source of Brazilian electric energy, responsible for approximately 80% of national production. Therefore, this article aims to determine the evaporation of the reservoir and the water footprint (PH) of the Coaracy Nunes hydroelectric plant (UHE) in Amapá. The average daily evaporation of 2013 was the one with the lowest value, 4.87 mm/day, while 2012 indicated the highest average, 5.00 mm day. Evaporation ranged from 110 to 180 mm/month, and February has lower values, between 110 and 125 mm/month. The highest values occurred between September and December, with emphasis on October with a maximum of 180 mm/month. The monthly evaporated volume showed the highest value in October and November, above 3900000 m3. And the month of February had the lowest consumption, on average 2700000 m3. There was also a predominance of lower PH values between January and May, partly being the period of greatest energy generation. And the highest PH occurred in November, the month with the lowest energy generation. The PH showed higher values between October and December, with a maximum value in November, 53.08 m3/GJ. The average PH was 25.3 m3/GJ, above the world average, which represents an inefficiency of the HPP in terms of power generation and PH. With the results, it is concluded that the evaporation by Linacre is relevant and agrees with the behavior of the climate in Amapá. And the PH values present an important tool in the evaluation of hydroelectric projects and in the management of water resources.