In 1996 one water level recorder and three recording rain gauges were installed in the Capetinga streamlet watershed at 'Fazenda Água Limpa' at University of Brasília, allowing to measure some hydro-meteorological parameters. Knowing the monthly average of the stream flow and the specific average, it was possible to draw the respective permanence curves of the monthly average discharge of Capetinga streamleat. From these curves it was possible to determine values of minimum monthly average at 95% probability level (Q95) and of minimum specific monthly average at 95% probability level (q95). There was not discrepancy among the q95 and the ratio betwen Q95 and the watershed area. The general extreme value type 1 or Gumbel distribution was used to calculate the return period of the maximum instantaneus annual stream as well the least annual stream with seven days period. The return periods of 5, 10, 20, 50 and 100 years it was evaluated for maximum and minimum events. It was found that Gumbel distribution adjusted very well to describe the maximum events observed as well as calculated ones, whereas for the minimum events there was no discrepancy.
management of water resources; annual maximum and minimum; discharge
