Lake stabilized a couple feet above target elevation

The snowmelt is gone and the Great Sacandaga Lake has stabilized at an elevation of about 768 feet after overflowing the spillway for more than 10 days this spring.

It’s still 2 feet above the target elevation for this date, but Chief Engineer Robert Foltan of the Hudson River Black River Regulating District said officials are well-positioned for the coming summer season.

The district, a public benefit corporation, operates the man-made lake as a flood control reservoir, capturing runoff in the spring, and drawing it down to augment the flow of the Hudson over the drier summer months.

Twice during April and May, the district was forced to deviate from the settlement agreement that stipulates how the lake is regulated.

Foltan said regulators deviated from the agreement April 9 and again from April 25 to May 4.

Inflow has decreased and so have reservoir releases, he said.

The high water has receded and boaters reported no debris in the lake last weekend. Mayfield Supervisor Herb McLain said that Proper Road is no longer underwater but sustained some damage and is still soggy and soft.

Foltan took issue this week with reports in The Gazette that the lake is considered full at 768 feet above mean sea level with the 3 remaining feet to the Conklingville Dam spillway used as emergency reserve capacity.

That was the case as late as 1997 as stated in the access-permit holder’s handbook. In the most recent edition, published in 2001, the paragraph was edited and the word “full” is gone.

In its place is the following:

“The filling of the reservoir each spring is controlled with three objectives in mind: 1) keeping enough Sacandaga water out of the Hudson to prevent flooding, 2) bringing the surface elevation of the reservoir up to 768 feet above mean sea level, 3) maintaining enough reservoir storage capacity all the while to handle any sudden increase in runoff that might occur.”

Foltan said the regulating district made a mistake when they said it was full at 768.

“In terms of operation, in terms of mechanics, it was probably incorrect,” he said.

Siphons on the dam are designed to begin operating at about 773 feet and be fully operational at 774.5, he said, as the offer of settlement “clearly contemplates and plans for reservoir operation above an elevation of 773 feet.”

“Historic operation from 1930-2000 has produced a mathematical average reservoir elevation of approximately 768 feet. However, the reservoir was not, and is not, considered full at this elevation,” he said.

Foltan said the district has resumed normal operations and will try to keep the lake at 768 feet through June 1, and then draw it down to target levels over the course of the summer.