Impact of the ENSO phenomenon on dissolved oxygen at two stations on the Cauca River-Colombia: 1985 to 2015

Climate variability is one of the main challenges faced by mankind, andunderstanding its relationship with water quality will generate knowledge that willenable the development of early adaptation strategies and the integral managementof water resources. This study assessed the impact of the different intensities of the“El Niño-Southern Oscillation” (ENSO) climate phenomenon on Dissolved Oxygen(DO) from 1985 to 2015, at two monitoring stations on Cauca River. Spatialtemporal variation analysis of DO was performed using descriptive and inferentialstatistical techniques under different ENSO phases. The correlation betweenDO and the intensities of the ENSO phases was assessed using the Spearmancorrelation coefficient. No statistical differences were found in DO concentrationat the two studied stations (p = 0.1164). Statical differences of DO were founddepending on the ENSO phases at the Mediacanoa station (p = 0.002556); it wasalso found that the highest median concentrations of DO took place when LaNiña was present. No correlation was found at the studied stations between theintensities of the ENSO phases and DO. The water quality of the Cauca River, at theYotoco and Mediacanoa stations, showed very poor conditions, which has producednegative social, economic and environmental effects.