Cornell University has been monitoring ambient conditions in Cayuga Lake since 1998 to provide a record of water quality conditions in the lake before and after the Lake Source Cooling facility startup in 2000. The primary objective is to conduct an ambient water quality monitoring program focusing on the southern portion of Cayuga Lake to support long-term records of trophic state indicators, including concentrations of total phosphorus, soluble reactive phosphorus, chlorophyll-a, turbidity, and other measures of water quality. In addition to this water quality monitoring data set, the complete collection of annual reports is available online: http://hdl.handle.net/1813/8353