Water Levels 101

Water Levels 101 – Seneca River and Cross Lake Ins and Outs

We live near and enjoy a collection of waterways that are incredibly complex and interconnected. When we are faced with extended flooding situations, it’s easy to point fingers and place blame. However, there are really no simple and inexpensive solutions to the problem – although there are solutions.

But the first step is to really understand as many of the variables as possible and how they impact our areas directly or indirectly. This newsletter is an attempt to provide some insight into all of the different influences affecting our water levels.

The majority of the precipitation falling across the 5,100 square miles of the Oswego River Basin eventually flows into the Seneca River and Cross Lake on its way through the Baldwinsville gates toward Lake Ontario. Here’s what some of that system looks like, and why it feels like we’re the bottleneck. Spoiler – it’s because we’re the bottleneck.

Clyde River, Canandaigua Lake, Keuka Lake, Seneca Lake, Cayuga Lake, Owasco Lake, and Skaneateles Lake all flow into Seneca River before reaching through Cross Lake. Each water source is controlled by a different organization, and with different and often conflicting goals and decision criteria.

Oswego River Basin Water Sources:

Canandaigua Lake flows into the Erie Canal via Canandaigua Outlet

Water release is controlled through gates managed by the City of Canandaigua.
Flow rates must meet certain levels required by permits associated with wastewater treatment, among other considerations.

Clyde River and the Erie Canal

Water flows unregulated into Seneca River, north of Cayuga Lake

Keuka Lake flows into Seneca Lake

Keuka Outlet is the largest tributary to Seneca Lake.
The Keuka Lake Association and local officials control the gates in Penn Yan to manage lake levels per the Keuka Lake Outlet Compact (KLOC) and using their Rule Curve as a guide.

Seneca Lake water flowing into Cayuga Lake is controlled through hydroelectric plants managed by Relevate Power.

Specific water level constraints are built into the operating license issued by FERC (Federal Energy Regulatory Commission).
Those constraints, seasonal high and low limits (Rule Curves), were developed in the 1970s and are still in use today.
Relevate manages water levels against those Rule Curves to remain compliant with their license to operate.

Cayuga Lake water flowing into Seneca River is controlled by New York State Canal Corporation (NYSCC), using those same Rule Curves as a guide.

NYSCC is responsible for protecting shorelines and infrastructure around the lake, while working to maintain safe waterways and effective navigation channels throughout the rest of the Erie Canal.
One inch of rain falling on the Cayuga Lake watershed can increase the level of Cayuga Lake by about one foot within one or two days.
Cayuga Lake can only be lowered a tenth of a foot per day when water levels in the Barge Canal system (eg Seneca River) are at normal levels.

Owasco Lake

Flows to the Seneca River via the Owasco River, through a dam owned by the City of Auburn.

Skaneateles Lake

Managed by the Syracuse Water Department with the goal of maintaining the quality of the drinking water coming from the lake.
Outflow ranges from a minimum of six million gallons per day up to 200 million gallons per da

Water leaving the Cross Lake and Seneca River areas:

Water leaving the Cross Lake and Seneca River areas is controlled through two hydroelectric plants in Baldwinsville – Brookfield Power, DBA Erie Boulevard Power on the north side of the river, and Northline Energy on the south side.

There is no Rule Curve for Cross Lake or the Seneca River, and no governing body with singular authority to manage our water level.
There is no current definition of “flood damage” that allows an equitable comparison between the Rule Curves for each of the Finger Lakes against current flood conditions on Cross Lake or Seneca River.
Capacity of the gates in Baldwinsville are significantly less than those upriver, and cannot match the water volume feeding in from Cayuga and Seneca.
There are two flood gates in Baldwinsville, compared with between six and eight in Fulton, Phoenix, Minetto and Oswego.

Rule Curves:

A LOT has changed since the Rule Curves were developed back in the mid ‘70s. Precipitation patterns have changed. Snowpack and spring thaw patterns have changed. Flood plain conditions have changed. Property development impacts have changed.

But water level decisions are still based on those original Rule Curves.

There are currently Rule Curves for eight lakes in the Oswego River Basin. The Seneca and Cayuga Rule Curves include min and max targets by month, “minor” and “major” flood damage levels identified, and a 100-year flood level indicated. They are updated with current lake levels several times per week, at the links below.