Water quality assessment with simultaneous Landsat-5 TM at Manzala Lagoon,Egypt

This study aims at determining relationships between water quality parameters and radiance data from Landsat-5 Thematic Mapper (TM). Fortunately, water samples and the total biomass of aquatic plants were collected at the same time of acquired satellite image (September 1995). TM bands 1, 2, 3, 4, 5 and 7 and band ratios 3/1, 2/1, 2/4, and 3/4 were compared with in situ measurements and laboratory analysis of water samples. The water quality of interest included K⁺, Na⁺, total phosphorus (TP), total nitrogen (TN), dissolved oxygen (DO), pH, Salinity, depth, Secchi disc, and biomass of the aquatic plants (submerged, floating, and emergent). Correlation and regression models were developed between each of the water quality parameter measurements and the radiance of image data. Some water quality parameters were significantly correlated with TM radiance data. Subsequently, the regression models were used to prepare digital cartographic products depicting the water quality over the entire study area. This study constitutes the first effort to use Landsat TM data for mapping water quality parameters in all over the Egyptian lagoons.