UTILIZING ARCMAP’S MAP ALGEBRA TO UNDERSTAND SPATIOTEMPORAL CHANGES OF WATER QUALITY PARAMETERS IN A LAKE SYSTEM

The relationship between nutrients and chlorophyll-α (an indicator of algae activity) is well established for a number of aquatic systems. However, this relationship is not well understood in Lake Sinclair, located on the Oconee River in middle GA. This study investigates the spatial distribution and dynamics in phosphorous and chlorophyll-a levels in Lake Sinclair over the past decade. The study also looks and the correlation between Phosphorus and chlorophyll-a levels. To accomplish this task, historical data was obtained from Georgia Power, which for the last few decades (since 1979) has been consistently monitoring water quality in the lake. Additional data were also collected in the spring of 2014. The results show phosphorous and chlorophyll-α levels falling within the water quality guidelines set by the Georgia Environmental Protection Division (EPD) for lakes in the region. However, there were some years when the levels exceeded the set guidelines, as well as times when algal blooms were observed and reported. Distribution maps of the time periods in question for phosphorus and chlorophyll-α were prepared using ArcGIS spatial analysis tools, and Map Algebra was used specifically to analyze temporal dynamics. The distribution maps also highlighted the spatial correlations among phosphorus, changes in chlorophyll-α, and algal blooms. Furthermore, the study also uses historical remote sensing data and other available data to understand what might have caused these relatively higher levels. This study provides maps that are easy to read and understand but very useful for anyone interested in understanding water quality distribution in Lake Sinclair and other similar lake systems.