Remote sensing GIS to predict on the risk of eutrophication in Aquatic systems

RODRÍGUEZ, CLAUDIA; BONANSEA, MATIAS; BONATTO, FLORENCIA; REYNOSO, VIVIANA; PROSPERI, CARLOS; MANCINI, MIGUEL; LEDESMA, CLAUDIA

Med-e-Tel

Luxexpo

Lugar: G. D. of Luxembourg; Año: 2006 p. 343 - 345

1819-186X

Lakes and dams are exposed to environmental degradation, and the low renovation time of some of them, makes them vulnerable to pollution as a result of anthropic impacts. Main objectives of this work were the prediction of water quality for different uses, and the evaluation of eutrophication in dams of central Argentina, by means of physico-chemical, biological and phycological analysis, integrating remote sensing and GIS in order to asses potential risks for animal and public health. The first (Río Tercero, 64º 23?W y 32º 10?S; 4600 ha) and the last (Piedras Moras 32º 12?S, 64º 19?W; 832 ha) dams in the basin of Ctalamochita or Tercero River were studied. Both are used as reservoirs for drinking water, hydraulic engeneering, irrigation, recreational and sports activities. Seasonal samplings were performed during three consecutive years in both sites. Parameters were evaluated in situ and in the laboratory, according to standard methodology. For Rio Tercero dam, water characteristics were those corresponding to freshwater, calcium bicarbonated. Trophyc status was mesotrophyc. Phycological counting showed that, during summer, Bacillariophyceae were dominating over Cyanophyceae. The studies integrating sensors, GIS and Landsat 5TM images to determine spatial variability of chlorophyll-a showed a higher concentration at the affluents during spring time. For Piedras Moras dam, the aplications of Surfer for Windows, Idrisi and Variowin were used, integrating in a GIS the experimental information together with the one obtained by means of digital processing of Landsat 5TM images. The aplication of spatial interpolation techniques -kriging- determined that dispersion of total nitrogen was different according to the season. Total phosphorous at spring showed its higher levels at Soconcho River and Balneario stations. Maximal levels of chlorophyll-a were observed in spring at those stations corresponding to affluents and recreational areas. The studied dams are situated between the guidelines proposed by actual legislation. Risks of bloomings could happen all over the year, diminishing during fall season. According to the importance of these systems, it is necesary not only the performing of monitorings to evaluate and protect these reservoirs, but also to establish an integral program of strategies for the prospective management of dams in order to determine risky areas and early warning systems to protect health.