8. WINTER KILL

9. Oxygen Demand in Ice Covered Lakes as It Pertains to Winter Aeration Christopher R. Ellis and Heinz G. Stefan

13. Oxygen consumption and thus depletion is a function of oxygen concentration and velocity of near sediment water

14. Winterkill Lake Facts • Stratify quickly after ice cover. • Oxygen consumption is greater than production. • Oxygen production slows or ceases as light penetration decreases. • Oxygen consumption is greatest at the water sediment interface. • Oxygen consumption decreases as oxygen concentrations fall below 3.8 ppm.

15. How to cause a winterkill • We need to destratify the lake/wetland. • We need to create currents that cause the oxygenated water on the top to go to and move along the bottom. • Need to make sure our actions are not increasing the amount of oxygen in the system.

16. Reverse Aeration

17. REVERSE AERATION Reverse aeration is the use of lake aeration techniques that increase the oxygen concentration and velocity of near sediment water which increases oxygen consumption and depletion

19. Water currents (convection) Diagram of water flow during aeration operation

21. Questions?

22. Equipment Needs • Two complete systems ($5,000)

26. Equipment Needs • Two complete systems ($5,000) • Generator ($1,300)

28. Additional Equipment • Do meter • Hand held depth finder • 8-inch ice auger • Ice chisel • Snow shovel • Repair tools for the poly tubing • Mud motors

31. Questions?

32. How to approach a project.

48. Questions?

49. SAFETY FIRST!!!!!!

50. Safety Equipment • Floatcoat or life jacket • A throwable flotation device • Life guard spikes • Ice creepers • Rope • Ice chisel or board for probing the ice