Author(s): M. Granero; A. Bustamante; F. López; M. Ruiz

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Keywords: Eutrophication; internal load; P cycle

Abstract: San Roque Reservoir (Córdoba, Argentina) is the main resource for drinking water to the city of Córdoba and its surroundings with a total population of nearly 1.5 million inhabitants. Water-quality related problems have increased in the reservoir due to deforestation, urban run-off and particularly the discharge of untreated sewage. The reservoir is currently receiving large inflows of nutrients and the process of eutrophication started decades ago. As a consequence, regular and continuous algae blooms occurred since 1988. The reservoir presents summertime stratification regime, when thermocline is formed, and consequently the bottom layer becomes anoxic. Redox potential gets reductive and numerous compounds release from sediment sucn as phosphorus. This work presents the results of a comprehensive field study consisting of 12 campaigns during a chronological year (2000). Water at the hipolimnion and sediment samples were taken at three monitoring stations: the center of the reservoir, old wall and the water intake surroundings. In situ dissolved oxygen and temperature were measured in the water column. Phosphorus fractions and related phosphorus ions were analyzed in water samples while total phosphorus was determined in sediment samples. The gathered information reveals the clear influence of anoxic conditions in the dynamics of phosphorus processes related to ion sediment release.

DOI: https://doi.org/10.1080/00221686.2004.9728396

Year: 2004