Have you seen this article in the Conservationist magazine: "Revealing Seneca Lake's Hidden Secrets", page23, https://cloud.3dissue.com/129417/129610/151833/NYSConsMagAprMay24/index.html The two leaders of the Seneca Lake Bathymetry Project (see article, Art Cohn and Tom Manley) might be able to provide some info/answers.