July 2017 Water Quality Update: Gull Lake

By Mike Gallagher, Water Quality Chair

Clarity      15 feet
Surface Temp   77.36
Temp at 100 feet  48.56
Thermocline    30-35 feet
Dissolved Oxygen at Surface    8.49 mg/l
Dissolved Oxygen at Bottom    4.36 mg/l
Max Dissolved Oxygen is 10.88 mg/l at 40 feet

The clarity for this time of the summer is normal for Gull Lake.  The lake always gets less clear at the end of July.  We could see down to 26′ two weeks ago but only 15′ today.

The thermocline is the depth where the temp of the lake changes the most.  At 30 feet the temperature is 72.14 but at 35 feet it is 62.96.

The dissolved oxygen is pretty good for this time of the summer.  Many lakes have lost all oxygen for the lower half of the lake but Gull still has 4.36 mg/l of dissolved oxygen at 100′.  Most fish need at least 4.0 mg/l to survive.  Fish are swimming at all depths of Gull Lake now but will swim to shallower depths as the dissolved oxygen gets used up at the bottom of the lake.  As dead weeds sink to the bottom and decompose oxygen is used up.  We have had summers where DO is less than 4.0 at 60 feet and below.  Last week, a small mouth bass was caught at 100′!

The boat wash is being welcomed by boaters this summer and hundreds have been washed.  Visitors are learning to come to the lake with their boats clean and their bilges and lives wells dry. Many are arriving with their bilge plugs out which saves us time and gets them into the lake the quickest. Boaters are showing their appreciation by adding to our “Contribution Post” which helps us pay for the staff.  Thank you!

Don’t forget the GLQO Annual Meeting is Tuesday, August 8 at the Kellogg Manor House. Social Hour begins at 6:30. The meeting begins at 7:30.