drawdown
n.— «Fisheries officials from Sioux Falls will be siphoning Lake Alvin during the week of Oct. 3 to test a method of improving fish populations.… The objective of the operation is to test the equipment, labor and logistics needed to lower the lake three feet next spring. The technique is called “drawdown” and can be an effective method for improving fish populations.» —“Game, Fish & Parks News” Marshall County Journal (S.D.) Oct. 5, 2005. (source: Double-Tongued Dictionary)