Cuantificación de concentraciones de determinantes de calidad del agua a partir de información teledetectada, en el río Magdalena

Abstract

Remote sensing systems have become increasingly important today by providing reliable and readily available information, filling the data gaps that prevent the monitoring and evaluation of water quality dynamics along a river. The vast majority of rivers in Colombia have limited information to characterize the quality of their waters in time and space. Therefore, the objective of this study is to use remote-detected information to quantify concentrations of the water quality determinants Nitrates, Total Phosphorus and Total Suspended Solids, at monitoring points of the Magdalena River, Colombia. For its development the product MOD13Q1 was used that comes from the information recorded by the satellite MODIS Terra and means the use of reflectance of the bands 645 nm and 858 nm to calculate the indices Turbidity, Chlorophyll-a and Phycocyanin by teledetection algorithms. The concentrations of the aforementioned water quality determinants that were provided by the environmental authorities CORMAGDALENA and IDEAM were also used. Based on this information, regression models were constructed to quantify the determinants according to the calculated indices and their performance was evaluated with the coefficient of determination. For the determinants Total Suspended Solids and Total Phosphorus did not present good results, unlike the Nitrates that, by the logarithmic transformation linear regression model used for its quantification as a function of the minimum values of the Chlorophyll-a index, an R2 = 0.5625 was obtained, This leads to the conclusion that there is a favorable adjustment between the data and the potential use of remote sensing information to characterize some determinants of water quality in places with scarce information or difficult access to execute monitoring activity.