PATH ANALYSIS FOR ASSESSMENT OF WATER DEPTH AND WATER QUALITY VARIABLES ON CHLOROPHYLL-A IN A SHALLOW LAKE

Abstract

The hydro-morphological properties of lakes affect photosynthetic organism growth, leading to eutrophication and finally deteriorate water quality. In this study, the effects of some water quality variables and water depth (WD) on chlorophyll-a (Chl-a) were investigated in an important shallow lake facing eutrophication threat. For this purposes, hydro-morphological data were collected and water quality parameters were analyzed using statistical analysis methods. According to the principle component analysis (PCA) Secchi disc transparency (SDT), total nitrogen (TN), total phosphorus (TP) and Chl-a variables were found in the same component. Correlation analysis and multivariate regression analysis were used to determine the direct and indirect effects of water depth and water quality variables on Chl-a. The results of the path analysis it can be stated that total direct determination coefficients of variables explain Chl-a by 85.42%, and the most direct and indirect significant effects on Chl-a were caused by SDT, TN and TP. Considering the all multivariate analysis results, water depth fluctuations was the main reason for Chl-a variation in a shallow lake condition.