| ELSEVIER The Science of the Total Environment 158 (1994) 127-133 the Science of the Total Environment Ai Immaem~ J*~nd tw sd*~m¢ ItnoJ6 A correlation between optical properties from satellite data and some indicators of eutrophication in Lake Garda (Italy) E. Zilioli*, P.A. Brivio, M.A. Gomarasca Telerilevamento, IRRS - - CNI~ 56, I/ia Aml~re, 20131 Milano, Italy Received 12 August 1993; accepted 9 May 1994 Abstract Here we present the first results of a research project in the field of optical remote sensing from a satellite platform to monitor the lacustrine environment. Landsat Thematic Mapper imagery was considered, on the basis of good performances in the visible bands, which is particularly useful for studies of water quality. The study involves Lake Garda (Italy) and concerns the correlation between remote sensing observations of the surface characteristics of water bodies and the eutrophication trend, as derived from bottom sediment cores. Image processing provided radiance-derived quantities, by means of transects, from the shoreline to the pelagic environment, in two separate sub-basins marked by different eutrophication. A correlation between the recent and present eutrophication trends and the optical properties of the water, as seen by remote sensing, was observed. This approach can be seen as a new remote sensing application to the study of lacustrine environments, since it permitted a comparison of instantaneous information, taken from a space platform, with a long-term data set obtained from sediments deposited at the bottom of the lake. Keywords: Satellite data; Remote sensing; Lacustrine water; Eutrophication 1. Introduction Applications of satellite remote sensing to wa- ter mass studies are mainly based on the use of optical bands, from blue to red, to explore rela- tionships among upwelling spectro-radiances and water quality parameters [1]. For lakes, studies were aimed at the determination of various com- * Corresponding author. ponents such as suspended material or turbidity, dissolved organic carbon and chlorophyll-a con- centrations [2-4]. A prediction of the trophic state of inland waters can be also accomplished by means of chromaticity analysis of subsurface irradiance reflectance, according to studies on the lower Great Lakes [3], the French and Swiss alpine lakes [5] and the Italian sub-alpine lakes [6]. This paper concerns the application of remote sensing optical analysis to the study of the water 0048-9697/94/$07.00 © 1994 Elsevier Science BV. All rights reserved. SSD! 0048-9697(94)04249-M