STARKEY — Seneca Lake is the largest, deepest and arguably the most important of the 11 Finger Lakes.
It’s also one of the most distressed, according to Hobart and William Smith Colleges Professor and lake expert John Halfman.
Halfman gave his assessment on the health of the lake since 1990 at Wednesday’s annual meeting of the Seneca Lake Pure Waters Association at Glenora Winery in Starkey on the western shore of the lake.
SLPWA is celebrating its 25th year as an organization.
Halfman said Seneca Lake has high levels of chlorides, salt, phosphorus and blue-green algae caused by excessive nutrient flow.
“The lake is getting greener in color and will stay green if we don’t change course now. It could get like Honeoye Lake and that’s not good,” Halfman told a crowd of more than 200 people.
He said Seneca contains more than half the water in all of the Finger Lakes and contains more chloride and sodium than the other 10 Finger Lakes combined.
He said the levels are below the maximum cutoff level and the water is safe for drinking, according to the U. S. Environmental Protection Agency.
“Sodium levels, however, are above the EPA advisory level. You can drink it, except for infants, and those with hypertension because of kidney damage risk,” Halfman said.
Halfman said he’s done work to determine the source or sources of the chloride and sodium. Streams that feed the lake were examined, but showed relatively low levels, mainly from road salt runoff.
“I looked at rainfall and that showed even less of those items,” Halfman said. “So I looked at the possibility of it coming from below, the lake bottom, from salt formations,” he said.
Halfman said there are significant salt formations under and around the lake, especially at the south end.
“I thought that pressure on the salt beds from gas storage might increase the salt leaking into the lake. But I was wrong. If that was true, the bottom of the lake would show more salinity. That’s not the case,” he said.
Halfman said 100 years ago, the salinity of the lake was at 40 milligrams per liter. When salt mining was at its peak in the 1960s and 70s, it rose to 200 mg/l. Today, he said its at 120 mg/L.
“The rate is slowing down, but very slowly. It takes a lot of time to flush that out from such a large lake,” he said.
Halfman warned that if Seneca Lake is “messed up” with salt and algae, it could take two or three generations to get it back. “That’s too long. We’ve got to be pro-active now so that doesn’t happen,” Halfman said.
He said further study may indicate the source of the salt and chloride may be the old Himrod Mine, which produced salt that went into Plum Creek, which fed the lake.
He also looked at the storage of liquefied gas in underground caverns around the lake, such as what is being proposed by Crestwood Midstream for the town of Reading in Schuyler County.
“These caverns have brine water that is displaced by the gas. If it went downhill into the lake, that could be a real problem,” he said.
“I think Crestwood will likely get the OK to store gas there. If so, they should be asked to pay to keep the lake clean,” Halfman suggested.
He said the brine from the Crestwood caverns would be pumped into brine ponds and added back when the gas is removed.
“Nutrient loading is a major, long-term threat. It is creating more blue-green algae blooms and phosphorus levels are also up from agriculture, wastewater treatment plants, munitions exploded at the former Army Depot, animal feedlots and septic systems,” Halfman said.
He said the algae can be toxic and hard to eradicate.
He praised the villages of Watkins Glen and Montour Falls for planning a new, joint wastewater treatment plant that should reduce emissions into the south end of the lake.
“Rain events cause runoff into the lake that allows nutrients to get into the lake. The large Confined Animal Feeding Operations (CAFOs) are a problem source,” he said.
Halfman suggested that the 40 municipalities that surround the lake form an organization to identify problems and agree on solutions.
Otherwise, he said, a damaged Seneca Lake will not only threaten safe drinking water and recreation, but the tax base.
“If the lake is screwed up, the value of lakefront property drops and lakefront property is a major source of tax revenue,” Halfman said.
“And it would also mean fewer tourists, which would be another economic blow to the area,” he said.
Incoming SLPWA President Richard Weakland of Burdett said he will propose the organization “refocus” itself to a new mission of restoring and improving the lake for the future, with less focus on the LPG storage issue.
“I’d like us to shift to improving water quality, which was our mission when the organization was formed 25 years ago,” Weakland said.
“We also want to get more people involved in projects to clean up the lake, to grow our membership, get grants and be advocates based on solid science,” Weakland said.