Behavior of precipitation and quantification of the water balance of the river Atrato high basin in the department of Chocó

Abstract

This paper presents the behavior of average rainfall, through two methods, the normal mean arithmetic and the one based on an analysis of isoyetas. There is also a quantification of water balance in the upper basin located in the Atrato River (5° 21' to 6o 00' N and 76o 06' to 76o 44' W) of the Department of Choco, using the monthly records (monthly averages) recorded during a period of 20 years (1983 to 2003). We find that the behavior of high precipitation in the watershed of the Atrato River is a bimodal, presenting two maxima and two thresholds. The first maximum towards the months of April and May, and the second highest among the months of July and August. These are the seasons in which the basin receives the largest amount of rainfall. The station was Tutunendo which presented the highest values of rainfall followed by Station AP Quibdo, and the lowest in El Carmen de Atrato. The study concludes with an estimate of water balance for the Atrato River high basin, in which the great contribution of rainfall to the formation of a runoff great consideration in the region can be seen.