The Cayuga Lake Locks – how water levels rise and fall

Have you ever wondered what controls the water level of Cayuga Lake? Water enters the lake from the south and flows out to the north. Streams between Taughannock Falls and Ithaca make up 40% of incoming water, with Fall Creek being the largest single input. When you take a dip at Buttermilk Falls on a hot summer day, you are swimming in water that will soon find its way to the lake. The water flowing into Cayuga Lake comes from rainfall and snow melt funneled into the lake throughout the surrounding land.

Precipitation in the Cayuga Lake watershed has the strongest influence on water levels. At the north end of the lake, Mud Lock controls the amount of water that drains into the Seneca River (aka the Cayuga-Seneca Canal). The lock connects Cayuga Lake to the Erie Canalway via the Cayuga-Seneca Canal. While an inch of rain across the watershed can raise water levels by a foot in just days, only a tenth of an inch of water can be drained from the lock each day. This means that rain fills the lake much more quickly than we can respond. The New York State Canal Corporation, which controls the lock, must rely on weather predictions and act before heavy rainfall occurs.

Cayuga Lake is maintained at an optimal water level that minimizes the risk of flooding while allowing boats to pass into the Canal, the Cayuga Inlet and marinas. At the end of the fall, the Canal Corporation begins to drain the lake to prepare for spring snow melt and runoff. The water level is at its lowest in the winter, after which water is slowly let into the lake to prepare for summer navigation and recreation. When water levels are high enough, boats like ours, the MV Teal, can navigate the lake. This year the water took longer than usual to rise and we were a bit nervous but now all is well and we’re happily back to cruising in and out of the Allen H. Treman Marina. By now, we’re busy hosting kids and adults on the boat for all of our various cruises. We hope you can join us!