Here’s a link to a chart that shows the lake levels that the NYS Canal Authority tries to maintain during the course of the year. So as I write this on March 15th, 2019 the lake is below target levels.
The main factor that determines the optimal lake level in the winter is the snow pack in the Cayuga watershed. When the snow pack levels are high, the Canal Authority tries to keep the lake lower than normal in the winter in order to mitigate any potential flooding. Lake levels should be set to rise now.
Here’s the link: http://www.canals.ny.gov/waterlevels/netdata/cayuga-levels.pdf