A Report by Dave Smail, Vice-President of the Great Sacandaga Lake Association and Chair of the GSLA Lake Level Committee.
Many of us returned to the Great Sacandaga Lake this year to find the lake level four feet below what we came to expect for this time of year and asked what happened to all of the water! The simple answer … the water never reached the lake! The first five months of 2015 left the watershed with an 8.5 inch deficit in precipitation. The dry spring impacted large sections of Upstate New York.
How is the Water Level Controlled on the Great Sacandaga Lake?
Many lake residents and recreational boaters believe that the Hudson River Black River Regulating District releases water from the Great Sacandaga Lake to control the lake level and keep the level at or near a pre-determined ‘Target Elevation’. This is only partially true because the district operates the Conklingville Dam under a Federal Energy Regulating Commission license. The license agreement requires the Regulating District to release water from the lake to maintain both a daily average and an instantaneous flow on the Sacandaga River below the Stewarts Bridge Dam and on the Hudson River below where the Sacandaga River and Hudson River meet. Therefore, the two factors: (1) lake level on the Great Sacandaga Lake and (2) the required daily average and instantaneous water flow on the two Rivers (Sacandaga River below the Stewarts Bridge Dam and on the Hudson River below the confluence) shape the Regulating District’s daily water decisions.
The requirements recognize historical precipitation and establish daily average minimums and maximum requirements based upon current water level on the lake. The Regulating District attempts to maintain the lake level near the ‘Target Elevation’ by maximizing the release when the level is above the target lake level and minimizes the release when it is below the target lake level.
Why is the Great Sacandaga Lake Lower than Usual?
Why is the Great Sacandaga Lake 3.5 feet below the 768 feet water level we expected on June 1st? Due to the lack of precipitation in March and April, the low flow on the Hudson River above the confluence of the Sacandaga and Hudson Rivers required the Regulating District to make releases that by late March resulted in a lake level which was a foot and one half below the expected 749 foot.
This year’s winter was very cold and the snow pack within the watershed was near historical average when we approached March. Most everyone, including the District, expected warm weather and rain in April. With the ground frozen most of the rain and snow melt within the watershed ends up in the lake and historically increases the lake level at rate of one foot per day during April. At the beginning of April, the Regulating District believed that they were well positioned with the lake level at 747.5 feet. If the snow melt were accompanied with four inches of rain over the month the lake level would have been over the spillway! However, April of 2015 did not bring rain, and with warm weather, the snow melted and most of the water never reached the lake because of the distance traveled within the watershed, water evaporation, absorption into ground water or absorption by vegetation prior to reaching the lake. To put things in prospective, a storm that dropped one inch of rain on the watershed when the ground is frozen or saturated would increase the lake level close to two feet over the next few days. If the storm were to arrive during a drought in the growing season the observed increase in lake level may be less than a foot.
The good news is that at the beginning of June we received rain for several days and the lake level increased by more than a foot and on June 5th, the water level is 765.5 feet. The flow into the lake is currently twice the normal historical average and if the drought has been broken and we receive historical precipitation, the lake will slowly return to the 768 feet expected for this time of the season.
