The Upper St. Johns watershed covers an area of 4,158 square miles in northeastern Florida. It is an important source of drinking water for the region and supports a diverse ecosystem of wetlands and wildlife. The hydrology of the area is influenced by the St. Johns River, which flows through the watershed, and by rainfall patterns. The region experiences a wet season from June to September and a dry season from October to May. In terms of surface water, the watershed includes several lakes and wetlands, including Lake George and Lake Harney. There are also several reservoirs in the area, including the Upper St. Johns River Basin Project, which helps regulate water flow and prevent flooding. Interesting climatic facts include that the region experiences an average of 50 thunderstorm days per year and has experienced increasing temperatures over the last few decades.