Dam sluicing is the carrying of water away from the lower depth of the lake.
Dam Sluicing is done through use of Sluicing gates that are made of either a wood or metal barrier sliding in grooves that are set in the sides of the waterway.
The gate for dam sluicing is closed most of the time and sometimes water can spill over the gate but when needed to lower the water level in the dam the sluicing gate is opened.
When the sluicing gate is opened water flows out of the dam where the sluice gate is when it's opened and water then lowers to the level needed.
Then when the water level is also lowered down to where they want it they then close the sluice gate.