The Living Earth Institute (LEI) in a cooperative project with the Chilean government conducted with a technical analysis of pollution in Lake Villarrica, Chile. These results have been provided to CONAMA (Comision Nacional del Medio Ambiente).
The goal of this study was to develop a recommendation for a pollution control strategy to help protect the beneficial uses of Lake Villarrica. The natural lake is an increasingly important body of water in Southern Chile. The lake serves to supply domestic water and is increasingly being used for recreational purposes. As tourism continues to increase in the area, maintaining acceptable water quality in the lake will become increasingly important.
The main objective of the study was to create a water quality model to help assess alternative pollution control solutions for the protection of Lake Villarrica. A second objective was to recommend the application a different management approach to pollution control than has been used previously Chile. Various pollution control alternatives can be assessed using the water quality model. These alternatives can then be posed in community forums for discussion. When local acceptance of an alternative begins to form, implementation of the pollution controls should be easier to achieve than if the controls were mandated from the central government.
As a tool to assess alternative pollution control strategies, a dynamic mass balance model of total phosphorus was constructed for Lake Villarrica. The calibrated and verified lake response model was used to determine the relative phosphorus loads entering Lake Villarrica. Loads were determined for various pollution source categories. It was found that most of the phosphorus load to the reservoir comes from nonpoint sources within the watershed. The calibrated lake response model was also used to estimate the effect of various pollution controls on phosphorus concentrations entering Lake Villarrica. Treatment efficiencies for point sources and nonpoint sources were taken form literature sources. The lake response model was also used to predict the effect of a combination of various pollution controls applied individually and in combination. The lake response model was used to predict the total phosphorus concentration of the lake using each of the all of the most efficient pollution controls for domestic wastewater, agricultural best management practices, and urban storm water treatment. It was found that if each of these approaches is applied throughout the watershed, the total phosphorus concentration of the lake is reduced by 10% in the summer. It was also found that providing wastewater treatment to the shoreline homes would be the one activity which would provide the most protection of the beneficial uses from eutrophication.
Details can be found in the technical report (Acrobat PDF)
The information has also been published (in Spanish) in the Proceedings of the Third International Water Conference held October 2001 in Santiago, Chile, titled Modelación de la Respuesta del Lago Villarica ante Aportes de Fósforo (Acrobat PDF) presented by Sibel Villalobos Volpi of CONAMA.
LEI has also prepared a proposal for an education program with Lake Villarrica as a curriculum focus (Acrobat PDF)
Steve Butkus
LEI Project Manager
info@living-earth.org
Víctor Durán
LEI Regional Manager
info@living-earth.org