Evaluación del riesgo de eutrofización del embalse El Quimbo, Huila (Colombia)

Abstract

The assessment of the eutrophication risk of El Quimbo water reservoir located in south of the department of Huila between the Central and Eastern Ranges on the upper basin of the Magdalena River, south of the Betania water reservoir, in the jurisdiction of the municipalities of Tesalia, Paicol , Garzon, Gigante, El Agrado and Altamira, is presented through the implementation of the simplified mathematical model for the evaluation of trophic status and management of macronutrients in tropical warm lakes / reservoirs (LACAT), developed by the Pan American Center for Sanitary Engineering and Environment Sciences (CEPIS, 2001). As sources of phosphorus that reach the El Quimbo reservoir were considered and quantified from the wastewater generated in the municipalities established in area of influence, solid waste or municipal waste and those from the dispersed population, animals manure, surface runoff and biomass in the flood area. The results show that for the filling phase of the reservoir it is advisable to remove the material in the reservoir vessel and deforest at least 22,4 % of the biomass in the flood area. During the operation phase a change in the trophic condition of the reservoir is shown from year 20 of the project horizon, from mesotrophic to eutrophic, due to the accumulation of phosphorus in the reservoir. The quantification of the magnitude of El Quimbo water reservoir eutrofication risk is considered as significant (-2) until year 10, and then as slight (-1). The conclusions highlight the need to avoid the accumulation of phosphorus in the reservoir, through the implementation of wastewater treatment systems that include removal of phosphorus and integrated systems for the management of solid waste and liquid effluents in activities agricultural areas of the nearby municipalities in the buffer zone of the reservoir. This presents values of chlorophyll between 64 and 138 ug / l, which shows its eutrophic state.