Extreme precipitation-streamflow event in the river araguari basin, amapá/brazil

Abstract

The objective of this investigation was to analyse the extreme river flows which have occurred between 9 and 14 April 2011 in the Rio Araguari-AP. The methodology consisted of three main steps: 1) re-analysis of precipitation estimated by the BRAMS (Brazilian Development in Regional Atmospheric Model System) model using the synoptic of the same period as support, 2) analysis of streamflow in sections of hydrological monitoring in Porto Platon, Capivari and Serra do Navio (ADCP-Accustic Profiller Doppler Current); 3) statistic analysis of the time series of maximum river flows in Porto Platon using Gumbel distribution. It was observed that the BRAMS system partially captured the standard precipitation when compared with the synoptic analysis and literature data, but the extreme hydrological responses representation still needs an optimization. In Porto Platon a flow record of 4036 m3 /s was recorded, whose behavior was analyzed from the perspective of the available monitoring mechanisms in the State. It was concluded that such extreme events are poorly detectable and offer considerable risks to users of the basin. The stream flow prediction based on available hydrological series was 100 years recurrence, but the analysis have revealed that this period would be 360 years, indicating significant deficiency of the prediction system of extreme events in the State.