Nitrate loads estimation in a rural basin and its relationship with the climate variability

Abstract

The objective of this work is to study the ability of the Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) model to estimate the load of nitrogenous fertilizer transported by surface runoff in a sub-basin of the Tapalqué River (Buenos Aires Province, Argentina). Also discussed is the impact of the climatic variability resulting from El Niño Southern Oscillation (ENSO) phases on runoff and fertilizer load. The SWRRBWQ model consists mainly of a representation of the hydrology and water quality associated with a hydrometeorological variables generator. Precipitation data from the meteorological station located in Azul was used for the period 1961-1990 as input to the SWRRB-WQ in order to analyze the variability of surface runoff and nitrate load in a control section located at the outlet of the basin under study. The results of this analysis show the effect of the variability observed in the precipitation associated with ENSO phases on surface runoff and transported nitrate loads at different time scales.