Water quality monitoring of Lake Burullus (Egypt) using Landsat satellite imageries.

Abstract

Lake Burullus is one of the most important coastal lakes in Egypt, as it participates with a considerable amount of fish yield in Egypt. Despite its importance, it is considered as a vulnerable lake, since it is subjected to significant environmental changes caused by various anthropogenic activities. Severe deterioration of its water quality status, as well as a decrease in its water area, has been noticed throughout the last four decades. The main objective of this study is to evaluate the ability of remote sensing for assessing the water quality status of the lake for the period from August 2010 to August 2013. Remote sensing technique was used to retrieve and predict the lake water quality parameter records through the assessment period (August 2010 to August 2013). Stepwise multi-linear regression technique was used to correlate between the field measurements of water quality parameters and the reflectance of remote sensing imageries, and then the derived models were validated. The results revealed the critical status of water quality conditions of the lake, particularly of its southern and southeastern parts. The results showed also that some water quality parameters (Chl-a, TSS, pH, Fe, Zn, Cr, and NH4) can be retrieved from remote sensing imageries with reasonable accuracy (R2 = 0.86, 0.67, 0.65, 0.63, 0.62, 0.61, and 0.6, respectively), while the water quality parameters, which can be predicted, based on calibrated and validated regression models are TSS and Chl-a, with acceptable accuracy (R2 = 0.6 and 0.43, respectively). Lake Burullus needs urgent plans and strategies to protect its water quality from the potential hazards of human activities. The study proved the ability of remote sensing as an effective technique to monitor the changes in water quality conditions of shallow coastal lagoons and to predict with some water quality parameters without field measurements; therefore, it is highly recommended to be used by decision makers.